WO2002069066A2

WO2002069066A2 - Method and apparatus for adding an additive to a fluid

Info

Publication number: WO2002069066A2
Application number: PCT/IE2002/000025
Authority: WO
Inventors: Brian Francis Mooney; Kevin Dowling
Original assignee: Brian Francis Mooney; Kevin Dowling
Priority date: 2001-02-27
Filing date: 2002-02-27
Publication date: 2002-09-06
Also published as: AU2002234842A1; WO2002069066A3

Abstract

The method and apparatus relate to adding an additive into a delivery of a fluid in a duct. Additive is stored in an additive tank (1). Injection pump (4) delivers additive to an additive pipe (11) into the delivery duct (20). The delivery of fluid is measured by meter-register (17). A controller (22) obtains signals from the meter-register (17) and regulates the rate at which additive is added to the fluid. The delivery duct (20) may contain fluid of a significant volume compared to the delivery. The rate of regulation by the controller (22) may vary depending on circumstances and requirements.

Description

METHOD AND APPARATUS FOR ADDING AN ADDITIVE TO A FLUID.

The present invention relates to a method and apparatus for adding an additive to a fluid. The invention relates particularly, but not exclusively, to a method and apparatus for adding a fluid additive to fluid dispensed from a delivery means which is required to deliver fluid with and without an additive. The invention also relates particularly, but not exclusively, to a delivery means which is a heating oil tanker truck and to a method for adding a fluid additive to heating oil.

The invention is more particularly defined in appended Claims 1 to 85 which are included in the description by reference.

The description of the invention relates particularly but not exclusively to adding a fluid additive to a fluid, such as fuel, delivered from a tanker truck delivery vehicle which is required to deliver fuel with and without the additive. The following paragraphs relate the terms used in the description with the more general terms used in the claims.

The truck is fitted with a duct, a fluid delivery means and fluid flow measurement means comprising a fuel delivery pipe, a fuel delivery hose and a fuel meter-register, or an apparatus such as a truck computer which delivers an output related to the output from a meter-register, for example an output compensated for temperature variations.

The apparatus includes an additive storage means, an additive adding means and an additive connection means comprising an additive storage tank, an additive injection pump and a line connecting the pump to the fuel delivery pipe. The apparatus also includes a controller means which comprises a programmable electronic controller and may also include some other logic components on the truck.

The apparatus also includes a pre-set means, a selection means and optionally by timing means comprising an electronic pre-set device, an electrical selector switch and an electronic timer device within the controller. The apparatus additionally includes a detection means and a communication means comprising a visual check by the operator into the customer's fuel tank and a radio controlled link from the operator to the controller on the truck.

The apparatus further includes a recording means and an operating element of the addition of additive to the fuel comprising the controller and a screen which visually displays the records and a link to some element of the additive injection process, such as a count of the strokes of the injection pump. It also includes a resetting means, comprising an operator reset button which allows the operator to reset the record where required.

The apparatus also includes a securing means comprising a wire seal and enclosure containing the controller, where the wire seal secures the door of the enclosure. The apparatus also includes a setting or adjusting means which comprises alterations to the software in the controller which can only be made where there is direct physical access to the controller.

The apparatus additionally includes a sensing means comprising an electronic flow sensor on the additive line and the pumping means is of the type which pumps in discrete amounts comprising an injection type pump.

The apparatus further includes a sampling means comprising a two way valve which permits a sample to be taken of the output from the additive pump.

The description also relates to a method of obtaining a signal from a fluid flow measurement means, where the signal is an electronic pulse signal and the fluid flow measurement means is a meter-register on a fuel tanker truck.

The meter-register comprises a metering means, a display means and a casing on the display means, which comprise a fuel meter and a register and its protective casing. The meter-register also includes a rotating driving means, an engagement means on the metering means and an engagement means on the display means which comprise the driving shaft from the meter to the register and the engagement pieces on the meter side and register side which allows the register to be readily separated from and repositioned on the meter.

The apparatus includes a target means connected by a connection means comprising a target disk and split bush which allows it to be connected to the rotating components within the register. It further includes a detection means and a controller means which comprise an electronic sensor and an electronic controller, where the sensor detects the movement of projections or holes on the target means and sends corresponding signals to the electronic controller. The signals may be interpreted as changes of state where the controller registers the signal being switched on or off. The controller may also be provided with a calibration means which allows the signals from the apparatus to be converted to whole units of measurement where the register is of the post-calibration type.

The invention will now be described more particularly with reference to the accompanying drawings which show, by way of example only, an embodiment of the invention which is suitable as an apparatus for adding a fluid additive to heating oil, henceforth referred to as fuel, delivered from a tanker truck delivery vehicle which is required to deliver fuel with and without the additive. In the drawings:

Figure 1 shows, in diagrammatic form, an apparatus for adding additive to fuel on a tanker truck;

Figure 2 shows in diagrammatic form, an underneath view of an electronic pulser suitable for use with a mechanical fuel meter-register; and

Figure 3 shows in diagrammatic form, a side view of the pulser 18 shown in Figure 2.

The following is an index of the reference numerals used in the drawings:

1. Additive tank.

2. Stop valve. 3. Inlet check valve.

4. Injection pump.

5. Pump housing.

6. Pump air cylinder.

7. Pump air piston.

8. Pump plunger.

9. Pump plunger seal.

10. Outlet check valve.

11. Additive pipe.

12. Bypass pipe.

13. Additive pipe stop valve.

14. Bypass pipe stop valve.

15. Check valve.

16. Fuel flow from truck tank compartments.

17. Fuel meter-register.

18. Pulser.

19. Signal wires from pulser.

20. Fuel delivery pipe.

21. Fuel delivery hose.

22. Electronic controller and operator interface

23. Solenoid air valve.

24. Air lines.

25. Pulser target wheel.

26. Pulser target wheel retaining screws.

27. Pulser sensor.

28. Pulser sensor retaining nuts.

29. Pulser split bush.

30. Pulser split bush retaining screws.

31. Pulser split bush locating rim.

32. Pulser base plate.

33. Register drive shaft.

34. Register drive shaft engagement piece. Referring now to Figure 1, there is shown an embodiment of the present invention. Fuel is stored in tank compartments on a tanker truck and is delivered through a fuel delivery pipe 20 to a reel mounted delivery hose 21. A fuel meter-register 17 is located on the fuel line 20 and records the quantity of fuel delivered when a delivery is made.

Additive is stored in an additive tank 1 mounted in a location on the truck which is convenient for refilling. An outlet pipe from the additive tank 1 ducts additive through a suction pipe to an injection pump 4 via an inlet check valve 3. The injection pump 4 delivers additive through an outlet check valve 10 to an additive pipe 11 through which it is ducted to a further check valve 15. The outlet from this check valve 15 is connected into the fuel delivery pipe 20 on the truck.

The injection pump 4 comprises an air actuator which is connected to a pump housing 5. The air actuator comprises an air cylinder 6 and air piston 7 with air connections on either side of the air piston 7 and a guide bush at one end. A plunger 8 is connected to the piston 7 and extends into a cavity in the pump housing 5. The cavity in the pump housing 5 communicates with an inlet and outlet port. These ports are provided with screw threads and the inlet and outlet check valves 10 are screwed into them. The cavity in the pump housing 5 is provided with a stationary seal in the region adjacent the air actuator. The plunger 8 passes through the seal and a sealing contact is made between it and the seal. The plunger 8 has a smooth surface suitable for making sealing contact with the seal. The seal may comprise a U seal made from an elastomeric material, such as VITON. When compressed air is alternately ducted to and exhausted between the two ports of the air actuator, the piston 7 and plunger 8 reciprocate back and forth within the actuator and pump housing 5 cavity. The available space within the cavity changes as the plunger 8 reciprocates and accordingly additive is drawn into the cavity through the inlet check valve 3 when the plunger 8 withdraws and additive is expelled through the outlet check valve 10 when the plunger 8 extends.

An injection pump 4 of this type has many advantages over conventional injection pumps. It has only one moving part and is simple, reliable and accurate. The small diameter plunger facilitates the development of high additive pressures. It is inexpensive to manufacture.

The following preferred embodiment is suitable where the additive is added to fuel at nominal ratios ranging from around 1:500 to 1:5000. The injection pump 4 has a nominal stroke capacity of 5ml. It has a plunger of 10mm diameter and stroke length of 63.7 mm. This embodiment will deliver one pump stroke of additive for every 10 litres of fuel where the proportion of fuel to additive is 1 part to 2000.

There are several advantages to using an injection pump 4 with a relatively small stroke capacity. The additive and fuel are more evenly mixed. The proportion of additive added to fuel can be more accurately carried out. The injection pump 4 and additive pipes 11 are smaller and easier to install.

It is important that the injection pump 4 pressure is significantly higher than the pressure of the fuel in the fuel delivery pipe 20, which can typically be up to about 10 bar. The additive pressure is principally determined by the air line pressure and the ratio of the areas of the air piston to the plunger. Compressed air is obtained from the truck air system. In the preferred embodiment, an air piston diameter of 25mm and plunger diameter of 10mm are used which causes the additive pressure to be intensified to more than six times the air supply pressure. The use of an injection pump 4 with a relatively high delivery pressure has the advantage that its output is less likely to be affected by pressure variations in the fuel delivery pipe 20.

The additive pipe 11 is provided with a bypass outlet to allow the injection pump 4 operation to be checked and calibrated. The bypass outlet is normally closed. However, by means of stop valves 2 on the bypass outlet and on the additive pipe 11 downstream of the bypass outlet, the output from the injection pump 4 can be selectively diverted to the bypass outlet. Alternatively, a three way valve can be used to selectively direct the additive flow to the additive pipe 11 or to the bypass outlet. The injection pump 4 is controlled by a controller 22. The controller 22 may be an electronic or electrical controller which sends a control signal to a solenoid operated air valve, where the signal is converted to a compressed air signal which operates the injection pump 4. Alternatively, the controller may be a pneumatic controller which directly operates the injection pump 4.

The controller 22 may comprise a relay-type electronic programmable controller, with electronic or electrical inputs and outputs. This type of controller is commercially available from many different manufacturers. A controller of this type, henceforth referred to as a relay-type controller, is capable of accepting electrical or electronic inputs, executing simple logic according to how it has been programmed and giving appropriate electrical or electronic outputs.

It is capable of simple counting and timing functions but is not capable of carrying out mathematical functions such as can be performed by programmable logic controllers

(PLCs) or computers. Similarly, it cannot transmit data externally other than in the form of simple and relatively slow on or off output signals. Furthermore, it is also very limited in its ability to transfer data internally from one part of the controller to another. However, largely due to its relative simplicity, a relay-type controller has the relative advantages of being easy to program and less prone to software problems. Furthermore, it usually has the advantages of being of lower cost and smaller size than PLCs or computers. The relay-type controller also usually differs from PLCs and computers in that it has a small integral display screen, which is principally provided to facilitate programming and to allow visual monitoring of the status of its inputs and outputs.

The present invention overcomes the relay-type controller's limitations in performing mathematical functions and transmitting or transferring data while retaining its advantages over PLCs and computers.

An embodiment of the invention, which is particularly suited to operator control, is described below. When a fuel delivery is made which requires additive, the controller operates the injection pump 4 by one of two operating modes. When a fuel delivery is made which does not require additive, the operator does not switch the controller to the operating position and no additive is added to the delivery of fuel.

In one operating mode, henceforth referred to as pulser mode, use is made of a pulse signal from a pulser 18 on the fuel meter-register 17 to regulate and pace the addition of additive. Where an electronic or electrical pulse is used, the pulser 18 is electrically connected to an input terminal on the controller. The controller 22 monitors and counts pulse signals from the pulser 18. These pulse signals can be arranged to issue at different rates, and the controller is programmed to signal the pump to stroke each time a counter in the controller, counting the pulse signals, reaches the number which corresponds to the amount of fuel to be mixed with the amount of additive in one injection stroke. The controller then resets the counter to zero and repeats the process through the duration of the delivery.

In the other operating mode, henceforth referred to as pre-set mode, the controller 22 operates in the following manner. The operator switches on the controller 22 and enters a number or selection on an operator interface, henceforth referred to as the pre-set number and pre-set interface, where the number or selection corresponds to the volume of fuel in the delivery or to the amount of additive to be added in the delivery.

The program in the controller 22 converts the entry to the appropriate number of pump strokes. The controller 22 can be arranged to delivery additive into the fuel at a rate which is different to the nominal rate, yet still add the correct proportion to the pre-set amount of fuel. This can advantageously be used to avoid the final portion of additive from one delivery being retained in the hose and carried to the next delivery. The unavoidable retention of the final portion would otherwise cause problems where all successive deliveries did not require additive.

Where pre-set mode is used, the controller 22 causes the injection pump 4 to operate in three stages over the course of the delivery. Initially, additive is injected at a rate significantly higher than the nominal rate. In the second stage, additive is injected at the nominal rate. This stage continues until sufficient pump strokes have occurred to deliver the correct amount of additive into the pre-set quantity of fuel. In the final stage, additive injection stops and the final portion of the delivery is made without additive. The stages are arranged such that the deliberate higher rate of injection in the first stage causes the volume of the final stage to be greater or equal than the volume of the hose and fuel delivery pipe 20 system downstream of the point where additive is injected into the fuel, henceforth referred to as the hose volume.

The arrangement of the stages may be achieved by various methods. In one method, the controller 22 causes the pump 4 to stroke at twice the nominal rate during the first stage, when an amount of fuel equal to the hose volume is registered by the fuel meter 17. For example where pulses are delivered one per litre of fuel, where the nominal pump rate is one stroke every 10 litres of fuel and where the hose volume is 70 litres, a 600 litre delivery may be staged as follows. Injection occurs at a rate of one stroke for every 5 litres of fuel during the first stage, and this stage terminates when 70 litres is recorded by the fuel meter 17, to give an amount equal to the hose volume. The system will therefore have given 14 pump strokes and added sufficient additive for 140 litres of fuel during this first stage of 70 litres. The second stage will run for the next 460 litres of fuel, giving a further 46 pump strokes. The controller will recognise that 60 strokes have been completed, sufficient for 600 litres of fuel and additive injection will stop. The final 70 litre stage of the fuel delivery will be made without additive.

The arrangement of the stages may also be achieved on a timed basis with the additive rates being determined by electronic timing devices instead of pulses from the meter- register 17. The timing devices can be set in the knowledge that truck delivery systems have a recognised maximum flow rate. Where a timed basis is used, the pulser 18 is only used to provide an indication that flow is in progress. The controller 22 monitors the pulser 18 signals when the apparatus is switched to pre-set mode and initiates the addition of additive when pulses are detected. The controller 22 may continue to monitor pulses from the fuel meter-register 17 and terminate the addition of additive if fuel flow is detected to have stopped or fallen below a threshold level.

Pre-set mode, which is achieved on a timed basis, can also be used on trucks without meter-register pulsers. In this instance, alternative means can be used to detect fuel flow. These means may include the use of a differential pressure switch connected to two positions on the fuel delivery pipe 20, across which a pressure difference arises when fuel flow takes place.

In one embodiment of the invention, the apparatus is arranged such that it is capable of adding additive either using pulser mode or pre-set mode. A selector switch is provided which allows the operator to select the required operating mode on a delivery-by-delivery basis.

When pulser mode additive addition is selected, the apparatus automatically doses the correct amount using the fuel meter-register 17 pulses. This method is advantageously selected when there is advance knowledge that successive deliveries require additive. It has the advantage that it saves the operator the trouble of entering the pre-set selection corresponding to the volume of the fuel delivery. It also provides a slightly more even spread of additive into the fuel during delivery.

When pre-set mode additive addition is selected, the operator makes the appropriate volume entry and the apparatus automatically doses the correct amount, using the staged injection described earlier. Dosing only takes place during fuel flow and the controller 22 paces the dosing such that it ends prior to the final hose volume of the delivery. Pre-set mode additive addition is advantageously selected when there is any uncertainty or knowledge that successive deliveries might not require additive. It has several advantages. It eliminates the need to pre-plan deliveries or flush hoses. It allows the decision to add or not add additive to be made at the point-of-sale. It allows the operator to ensure that the customer receives the correctly dosed amount.

The ability to select either the pulser mode or the pre-set mode allows the apparatus to be used with advantage over a range of delivery conditions.

In an optional embodiment of the invention, the pre-set interface limits the selection of the pre-set amounts to relatively large multiples of the unit volume measurement, for example in multiples of 100 litres instead of multiples of single litres. This is based on the required amount not usually being known with an accuracy greater than this large multiple in advance of filling the customer's fuel tank, and the pre-set amount must be decided before the tank is filled. A pre-set interface of this type can be advantageously established with a simple relay-type controller of the type described earlier.

The cabinet housing the controller is provided with an external two digit visual display and external push button, henceforth referred to as the pre-set button. When the system is set at pre-set mode and the pre-set button is depressed, a regularly repeating electrical pulse is sent to the controller, for example at a steady rate of one every 300 milliseconds. Each time this pulse is received, it causes the visual display to increase by one unit, and also causes a counter in the controller to increase by one unit, such that the visual display and the counter will be set at the same number. The number may represent multiples of 100 litres of fuel and the final number shown on the display will correspond to the pre-set value. The operator can therefore quickly enter numbers corresponding to many hundreds of litres of fuel on the display by depressing the pre-set button for a few seconds. The system is arranged such that when it is switched off or switched out of pre-set mode, the display and the counter are reset to zero, accordingly, both always commence at zero. Also, if the operator makes an error and causes the display value to go beyond the intended value, the system can be switched out and back to pre-set mode, to reset the values to zero, and the setting process can be started again.

When the pre-set delivery takes place, the controller 22 generates a signal corresponding to each multiple of fuel delivered, and this signal simultaneously causes the display and counter to decrease by one unit. When the display and counter reach zero, the controller terminates the operation of the injection pump 4 and addition of additive.

The apparatus may be located in various positions on the truck. For example, the cabinet housing the controller 22 may be mounted on the internal rear wall of the truck cab, in a central position above the level of the cab seats. The controller 22 and solenoid valve 23 are located within the cabinet, but with the controller screen visible through an opening or window in the front wall of the cabinet. The visual display, pre-set button and selector switch are panel mounted on the cabinet in positions which are visible and accessible to the operator, who will typically be the truck driver. These components may be positioned on a side wall or portion of a side wall which lies at an angle of about 45° to the front face of the cabinet, facing towards the operator's normal position in the cab.

Optionally, a four digit display may be used, with the final two digits remaining at zero when the display and controller counter are being increased. The final two digits may also remain inactive when the display and controller are being decreased or optionally may become active when the number is being decreased to allow the decrease to occur in smaller multiples or in single units.

The pre-set interface mentioned above has several advantages, including the following. It is easy for the operator to understand and operate as it requires just one button pressing action when the system is switched to pre-set mode. It requires only one additional operator button, which accordingly can be provided in a relatively large and robust form. It is suitable for use with a relay-type controller and therefore provides an overall inexpensive solution. It also reduces manufacturing and installation costs by grouping all of the electrical and electronic components, other than the pulser 18, in a single cabinet.

Alternatively, the pre-set apparatus and interface may be provided in the following arrangement. The pre-set interface comprises the digital keypad of an electronic countdown relay device, which is used in conjunction with the controller. The count-down device is operable to receive input pulses which incrementally reduce the entered pre-set number. When the number is reduced to zero, the count-down device is operable to produce an output signal. In the case of the present invention, the pre-set number is entered corresponding to the number of units of fuel in the delivery. When the delivery is in progress, the controller 22 provides a train of signals to the count-down device, corresponding to units of fuel delivered. When the number is reduced to zero, the countdown device signals the controller 22 to terminate the operation of the additive pump. The count-down device and its interface may be located at the controller cabinet or may be located remote from it, for example at the dashboard of the truck or externally on the truck near the meter-register. Where required, the controller 22 can also be programmed to selectively allow more than one dosing rate, that is the proportion of additive to fuel, to be provided by the apparatus. In this instance, the apparatus is provided with a switch which is selectively moved to different positions by the operator to activate different electrical inputs on the controller. These inputs cause different counters to be used by the controller. The value in each counter can be programmed in the controller.

The ability to readily provide more than one dosing rate can provide several advantages to a fuel distributor. For example, where the distributor is delivering two types of fuel, such as kerosene and a middle distillate oil such as gas oil, the distributor may use an additive formulation which is suitable for both fuels but which must be used with different proportions of additive to fuel. In another example, the distributor may sell a fuel in several different grades, a lowest cost grade with no additive, a higher cost grade with a full proportion of additive and one or more middle grades with proportions of additive less than the full proportion.

Where required, the apparatus can also be made operable to dose different additives, In one embodiment, the additives are stored in separate additive tanks 1 and any one of the tank outlets can be selectively connected to the inlet of a common injection pump 4 by means of valves. The valves may be operated manually or may be operated by the controller 22. In an alternative embodiment, each additive tank 1 is connected to a separate injection pump 4. The operator selects the appropriate additive on a selector switch and this causes the controller to operate the injection pump 4 associated with the selected additive.

The controller 22 also maintains and provides a record of additive delivered. In a preferred embodiment, the potential difficulty of the relay-type controller's limitations in communicating data is overcome by using the integral display screen to display the record of additive delivered. The screen can typically display about four lines of characters. Several of the internal electronic counters of the controller 22 are used to count the volume of fuel to which additive has been added. These values are stored in different formats and simultaneously displayed on the screen. One record format is a count of the total amount of fuel-with-additive. Maximum counter values are typically limited to four or five digits and to overcome this limitation, two counters are used in cascade to provide a very high count value. The value may be reset to zero when required by activation of an appropriate input to the controller 22.

Another record format is a count of the last quantity of fuel delivered with additive. This can advantageously provide a confirmation of whether additive was or was not added during a delivery which had just taken place.

A further record format is a count of the delivered quantity of fuel-with-additive between signals given by an operator, henceforth referred to as the record reset. The signal may comprise the operator pressing a reset button on the apparatus at the occurrence of agreed events. For example, the agreed event may be each beginning or end of a work shift, or may be a regular calendar event such as each beginning or end of a week, or may be an operational event such as each additive tank refill. The relay-type controller's limitations in transmitting data internally or externally presents a potential problem in preserving the record between one record reset and another when a new record reset period commences. The limitation is overcome in the following manner. The controller screen displays two values. One of these values is the current record of fuel-with-additive delivered since the last record reset. The other value is the previous record of fuel-with-additive delivered between the last record reset and the record reset previous to it. When a record reset is carried out, the controller program is arranged such that the previous record display is zeroed and the current record becomes the previous record. An indication appears on the screen, such as an asterisk symbol, to identify which record is the current record, since the value shown on one line of the screen typically cannot be transferred to another line. The purpose of this double record system is to preserve the recorded value for a full reset-to- reset period when the current record is reset to zero. The system does not rely on an operator writing down the record before resetting it since the previous record remains available for inspection.

The button used as the record reset button is also used as the button on the pre-set interface. When the selector switch is in pre-set mode, the controller is programmed to accept its signal as the pre-set button. When the selector switch is in pulser mode, the controller is programmed to accept its signal as the record reset button.

The additive system may be advantageously arranged such that deliveries of fuel-with- additive always contain a full complement of additive. This is achieved by arranging the system such that the controller monitors the status of the hose contents between successive deliveries. The controller 22 causes a compensating volume of additive to be added to a delivery of fuel-with-additive if the contents of the hose at the beginning of the delivery- did not fully comprise fuel-with-additive. The system, henceforth referred to as the compensating system, is arranged such that this occurs automatically, thereby ensuring that the customer always receives a full complement of additive when a delivery of fuel-with- additive is made. To operate with full effect, the compensating system requires delivery sizes to be sufficiently greater than the hose volume to allow time for the addition of the compensating amount of additive.

Hose compensation is of importance where the volume of the hose is significant in comparison to the size of the delivery, in particular the size of the smallest normal delivery. Typically, the hose volume is about 60 to 70 litres and the minimum size of a fuel delivery is about 300 litres, in which case the volume is about 20% of the delivery size and is very significant. With fluid types where deliveries are much larger, compared to the hose volume, and where the additive is not of high cost or is not deemed to be a contaminant, the volume might not be significant. As an approximate guide, the volume would always be deemed significant if it exceeded 5% of the volume of the smallest normal delivery or where the additive was a potential contaminant in the fluid without additive, the relevant percentage will be the allowable level of contamination.

A preferred embodiment of the compensating system, the method includes the following elements and steps.

The system is provided with pulser and pre-set modes and the pre-set mode is available as an optional means by which the operator can ensure that the hose will not contain additive at the end of a delivery, where such is required. Pre-set mode is of the type which is paced by the pulser 18 on the meter-register 17, and is arranged such that additive injection ceases when the delivery is one hose volume away from the end of the delivery. The controller also causes the fuel delivery to terminate when the amount of fuel entered on the pre-set has been delivered.

The controller 22 determines and memorises the quantity of fuel-with-additive in the hose 21 at the end of every delivery. For convenience, this quantity will henceforth be referred to as the residual quantity. It will vary from a minimum of zero to a maximum equal to the hose volume, which is memorised in the program on the controller as a fixed value. The determination of the residual quantity by the controller is done in the following way.

After a delivery without additive, the residual quantity is always determined as zero, because the hose will not contain fuel-with-additive. After a pulser mode delivery of fuel- with-additive, the residual quantity is always determined as the hose volume, because the hose will end full of fuel-with-additive. After a pre-set mode delivery of fuel-with- additive, the residual quantity is determined as zero, unless the actual delivery size differs from the pre-set delivery size. If the delivery is a pre-set mode and the actual quantity of fuel delivered is less than the quantity of fuel entered on the pre-set by a quantity Q, then the residual quantity is set to Q, up to a maximum value equal to the hose volume.

When a new delivery starts, whether in pre-set or pulser mode, the controller 22 checks the status of the hose 21 and if it determines that it is not filled with a full complement of fuel- with-additive, it will automatically strive to make up the full hose amount, by dosing at a greater rate than that which gives the normal concentration of additive in the fuel, until an amount has been dosed which will give the normal concentration when averaged over the full amount of fuel delivered. The additional amount will equal the hose volume less the determined residual quantity. For example, if the increased rate of dosing is twice the normal rate, then when the hose starts empty, this double dosing rate should be carried out while one hose volume of fuel is delivered at the beginning of the delivery. The controller then changes to single dosing as the delivery progresses

If the delivery is in pulser mode, single dosing is continued up to the end of the delivery. If the delivery is in pre-set mode and a count-down device is being used, single dosing is continued until the pre-set count-down is complete. The pre-set count-down is arranged such that only a portion of it causes injection strokes to occur, this portion being the pre-set volume of fuel-with-additive less the residual quantity at the start of the delivery. This is done by signalling an additional number of pulses, corresponding to the residual quantity in the starting hose, to the count-down counter which does not result in operation of the injection pump 4. The balance of signals sent to the count-down counter result in operation of the injection pump 4 and accordingly the amount of additive injected will be proportional to the pre-set volume less the residual quantity in the starting hose. This method overcomes a potential problem where a separate count-down device is used in conjunction with the controller, and the controller does not have access to the pre-set number until the count-down is completed.

Advantageously, the system should dose the compensating amount at the maximum rate at which it can be accurately and safely carried out. This will minimise the potential problem of there being insufficient time available to dose the compensating amount.

The method described for the compensating system has many advantages, including the following ones. It ensures that the customer always obtains a full complement of additive in a delivery of fuel-with-additive. Furthermore, it achieves this in an automatic manner without additional cost in operator time. It also provides a means where the distributor can minimise the proportion of additive to fuel because no allowance needs to be made for possible dilution of a deliver- ith-additive by a starting hose with fuel without additive. It additionally provides a pre-set mode means by which the fuel distributor can minimise the amount of additive lost where the delivery is changed from fuel-with-additive to fuel without additive, due to additive being retained in the hose between deliveries. Similarly, it provides a means where the distributor can ensure that additive does not remain in the hose in circumstances where it would constitute an unwanted contaminant in the next delivery. Where the compensating system is used, two separate records are kept of fuel-with- additive. One of these records shows the quantity of fuel-with-additive produced by the system and will normally be directly proportional to the number of injection pump 4 strokes carried out in the period corresponding to the record. The other record shows the quantity of fuel-with-additive delivered to customers as fuel-with-additive. The second record is constructed by subtracting from the first record any residual quantity remaining in the hose when a delivery of fuel-without-additive is made. The controller is programmed to reduce the record by the residual quantity when a delivery of fuel-without-additive is commenced.

Each of these records is useful to the fuel distributor. The first record relates to the cost of additive and allows a reconciliation to be made to the records of additive consumed. The second record relates to sales of additive sold in fuel and allows a reconciliation to be made to the records of deliveries of fuel-with-additive. The comparison of one record to the other, either as a ratio or as a difference, also provides a measure of additive waste and a measure of operator efficiency in using the pre-set mode to prevent additive waste, waste referring to additive being inadvertently left in the hose and carried into deliveries of fuel sold as fuel-without-additive.

The invention also provides an additive system with additional security precautions against accidental or deliberate error by the operator. The provision of such security can sometimes be a requirement of regulatory bodies with responsibility for protecting customer interests.

In- an advantageous embodiment where such requirements exist, the controller is located in an enclosure which is secured with a wire seal or security lock. The enclosure is also provided with a viewing window which allows the secured record to be viewed without the need to open the enclosure. The wire seal may be of the well known type where a wire is affixed to the parts to be sealed in such a way that the wire must be broken to gain access. The ends of the wire are sealed by passing them through a hole or holes in a lead piece which is squeezed in a sealing tool which imprints a seal on the lead piece and at the same time closes the holes and prevent the wires being removed. The sealing tool is only made available to authorised personnel.

In an alternative embodiment, the means to alter the program or settings on the record are located within the sealed enclosure but the visual record display is external to it. In an example of this alternative embodiment, the controller is located within the enclosure and the visual record screen is be panel mounted on outward facing wall of the enclosure, or the enclosure door or cover, but in such a way that its connections or fastenings can only be accessed from inside the enclosure or inside the door or cover.

The provision of the secured record has several advantages. Although the fuel distributor will normally maintain routine records of deliveries of fuel, including fuel-with-additive, these records essentially show what was intended to be delivered rather than what was actually delivered. These fuel distributor records may take different forms, including, for example, office records of deliveries or electronic records generated by a computer mounted on the truck. The secured record provided by the invention has the advantage that it provides an independent record which is related to the actual process of additive addition.

The invention also provides a flow sensor on systems where security is of importance, its purpose being to verify that the flow of additive into the fuel has actually occurred. Where additive is injected in discrete amounts, the flow sensor may be of the known type which comprises a magnetic piston and a housing with a tapered or stepped bore. The housing with the tapered or stepped bore is located on the additive line. The bore is vertical, with the narrower end at the bottom. Flow in the additive line enters the bottom of the bore and exits from the top. The piston is located in the bore and has a diameter similar to the smallest diameter of the bore. When additive flow occurs, it momentarily drives the piston upwards. When additive flow stops, the piston falls back under the force of gravity. The movement of the magnetic piston is detected by an electronic sensor which is mounted on the outside of the housing. The sensor returns a signal to the controller. The controller checks that the signal occurs each time an injection stroke is signaled to the pump. The controller initiates appropriate responses if the signal is absent. Such responses typically include the activation of a visual or audible alarm to alert the operator. The responses also include shut-down of the additive injection system and prevention of any additions being made to the record of fuel-with-additive deliveries. The activation of the alarm primarily provides security against accidental malfunction of the equipment, including running out of additive. Shut-down of the system and prevention of additions to the record primarily provide security against careless or deliberate misuse by the operator.

The controller monitors the signal from the flow sensor and registers an error if the signal does not switch ON and OFF corresponding to the ON and OFF signal operating the injector pump. A very brief time difference is allowed between the two sets of ON and OFF signals such that the controller only recognises a genuine corresponding signal.

Where a test sampler outlet is provided on a system fitted with a flow sensor, the sampler valve is located upstream of the flow sensor to ensure that flow through the sampler outlet does not operate the flow sensor. This provides security against possible diversion of additive through the sampler outlet when a fuel-with-additive delivery is being made. It also prevents the possibility of the sampler valve being accidentally left open during a delivery.

When trucks are fitted with computers, these are commonly referred to as on-truck computers, or OTCs. They are usually linked to the truck meter register and have various capabilities. One typical capability is the automatic maintenance of records of deliveries. Another is provision of a facility which enables the operator to enter details of the customer's delivery on a keypad which results in the appropriate type of delivery being permitted or made by the truck delivery system. In addition, the OTC usually has the capability to communicate signals with other electronic devices.

When trucks are fitted with OTCs, they may advantageously be used with the present invention. Where the operator selects a delivery of fuel-with-additive on the OTC, the

OTC automatically sends an electronic signal to the controller which in turn activates the additive system. In the preferred embodiment, the additive system will then operate in pulser mode, unless the operator overrides this by selecting pre-set mode.

The operator interface of the OTC, which usually includes a keypad and display screen, may be advantageously used to provide the operator interface for the pre-set mode function, including selection of pre-set mode and entering of the pre-set quantity. The OTC may also be programmed to carry out the pre-set count-down functions.

Where the additive system is provided with a flow sensor, the controller monitors signals from the sensor and shuts down the delivery if the appropriate signals are absent either by sending or terminating an appropriate electronic signal to the OTC or by interrupting a fail safe circuit which causes the delivery to stop. The OTC display screen is also used to transmit a warning or alarm to the operator where a problem has been detected by the controller. Alternatively, the additive system is provided with an audible or visual alarm which alerts the driver to the detected error.

An increased level of security is achieved when the additive system is directly interfaced with the OTC and is intentionally placed beyond the control of the driver. When a delivery of fuel-with-additive is entered on the OTC, the additive system is automatically activated and cannot be switched off by the operator. The additive system cannot be activated by the operator by any other means.

Where trucks deliver various types of fuel, such as diesel fuel and heating fuel, they are frequently equipped with more than one hose, for example one long and one short hose, additive injection takes place downstream of the meter but upstream of any flow directional valve which could cause a fuel-with-additive delivery to bypass the injection point. Procedures are adopted to make all heating fuel deliveries through the long hose and the hose volume compensator will be programmed with the volume of the long hose. Where trucks are fitted with more than one hose and with electrical control of the hose directional valve (or valves), the hose system will be arranged such that all heating fuel deliveries are directed to the long hose. The electrical control signal to the directional valve, or valves, will also be signalled to the additive system controller and will be appropriately used in determining the residual quantity in the hose at the end of a delivery. Hose volume management is simplified by this restriction to just one hose as additive waste cannot occur in the short hose. Where trucks are fitted with more than one hose, but without electrical control, the compensator makes the conservative assumption that all deliveries may pass through the long hose and all fuel-with-additive deliveries are compensated in the normal way. Accordingly, hose volume management is very similar to a single hose system and the pre-set device can still be used to prevent additive wastage on all deliveries.

The operator may control the size of a delivery into a customer's tank in various ways, typically including one of the following methods. He may set a pre-set on the fuel meter- register 17 which automatically stops the fuel delivery when the required amount is delivered. He may monitor the filling of the tank and stop the delivery by closing the valve on the nozzle at the end of the hose when the level in the tank is detected as being close to the top. Where pre-set mode is used, a difficulty sometimes arises in that the delivery must be stopped before the ordered and pre-set quantity is delivered because the starting contents of the tank was greater than had been predicted.

The invention provides a means to overcome this difficulty. The operator is provided with a communication means which allows a signal to be relayed to the additive system giving advance warning when the level in the tank approaches one hose volume away from the desired filling level. The signal causes the additive system to terminate the addition of additive and causes the fuel delivery system to terminate the delivery of fuel one hose volume later. Accordingly, when the delivery ends, the hose is filled with fuel-without- additive. The communication means may comprise a radio signalling device controlled by the operator at the customer's tank and a corresponding radio receiving device connected to the controller or OTC on the truck. The controller or OTC is programmed to cause the appropriate termination of the addition of additive and delivery of fuel. Detection of the level in the tank reaching the level where the signal should be sent can be achieved by various means. For example, the operator may directly observe the level in the tank, stopping and restarting the delivery with the nozzle valve if necessary. Alternatively, the operator may use a probe or level indicator in the tank which detects when its contents reaches the relevant level.

The invention also provides a method whereby no additive is carried into deliveries without additive. This is of particular advantage where wasting of additive, or where cross contamination between deliveries with and without additive, must be minimised or prevented. The method is similar to that described earlier where the controller monitors the residual quantity in the hose and automatically adds a compensating amount of additive where the hose does not commence with a full complement, and where the delivery is normally terminated with the hose full of fuel-with-additive unless operator takes steps to arrange the delivery to terminate with the hose containing fuel without additive, for example by using a pre-set device. However, in this instance the controller is arranged such that it prevents the commencement of a new delivery of fuel without additive unless it determines that the hose does not contain additive. The method for preventing the delivery is the same or similar to any of the methods described earlier where an error is detected in a system requiring security.

This method for preventing additive waste or cross contamination requires the operator to plan ahead where the delivery type is changed from fuel-with-additive to fuel without additive. Where an unplanned change to fuel without additive arises and the hose contains fuel-with-additive from the previous delivery, the operator may make a small delivery, equal to one hose volume, back into a compartment on the tanker truck set aside for that purpose.

Many of the security advantages provided by the invention can also be used where the additive system is not provided with either pre-set means or hose compensation. In some circumstances, pre-set means or hose compensation is not required, for example where a truck is provided with separate hoses for fuel with and without additive, or where there is a policy to flush the contents of the hose back into one of the tank compartments when a change is made from one type of fuel to the other. In an advantageous embodiment, the injection pump 4 is provided without any possibility of mechanical adjustment. The pump operating program is arranged such that the number of fuel pulser signals, which cause the injection pump 4 stroke signal, can be varied from the nominal value, if required. This number is reset to compensate for any differences found between the actual measured stroke capacity of the pump and the nominal value, if a sampling test indicates that the pump capacity differs from its nominal value. This method of calibration has several advantages. It simplifies the construction of the pump, increasing its reliability and reducing its cost. It provides a single stage calibration method, because the pump does not need to be retested when the adjustment is made since no mechanical adjustment is made to the pump. It provides a more secure system by eliminating the possibility of a mechanical pump adjustment device changing or being changed where change is not required.

Where a sampling test shows that the pumped volume varies from the nominal setting, the nominal number is arithmetically adjusted to directly compensate for the variation from the nominal value. For example, where the pulse rate is 10 pulses per litre, the nominal pump stroke capacity is 5.0ml and the proportion of additive to fuel is 1 : 2,000, the count required for each operation of the pump will have a nominal value of 100, corresponding to 10 litres of fuel. If tests show that the actual pump stroke capacity is 4.9ml, then the number is reset in the controller at 98, corresponding to 9.8 litres of fuel.

The system uses two alternative methods for recalibrating the pump, depending on whether the pump can be adequately calibrated in complete increments of the units recorded by the pulser 18 or whether smaller divisions of these increments is required.

Where a truck is fitted with a pulser 18 which records flow at a relatively high resolution, such as the example shown above where pulses are delivered at 10 per litre of fuel, the calibration can be done directly as indicated in the example.

Where a truck is fitted with a pulser 18 which records flow at a relatively low resolution, such as 1 pulse per litre, the resolution may not be sufficiently accurate to allow calibration by the method described above. This presents a potential problem for control by a relay- type controller which is unable to process ordinary arithmetic calculations. This problem is overcome by using several counters within the controller in the following manner. Where the pump is calibrated downwards from the nominal value, the controller is programmed with a main counter set at the nominal value, a second counter set at a value below the nominal value and a third counter which causes the second counter to replace the main counter each time the set number of the third counter is reached. For example, where the nominal number is 10 for a nominal pump capacity of 5.0 ml, and tests show that the actual pump capacity is 4.97 ml, the main counter is set at 10, the second counter is set at 9 and the third counter is set at 17. This will cause the pump to operate on every tenth pulse for sixteen cycles and then operate on the ninth pulse on the following seventeenth cycle. This sequence is repeated throughout the delivery. The net effect is to reduce the average number of pulses per pump stroke from 10.00 to 9.94, as can be seen from the calculation {[(16 x l0) + (l χ 9)] / 17}. Where the pump is calibrated upwards from the nominal value, the main counter is again set at the nominal value, but this time the second counter is set at a value above the nominal value. For example, where the nominal number is 10 for a nominal pump capacity of 5.0 ml, and tests show that the actual pump capacity is 5.04 ml, the main counter is set at 10, the second counter is set at 11 and the third counter is set at 13. This will cause the pump to operate on every tenth pulse for 12 cycles and then operate on the eleventh pulse on the following thirteenth cycle.

Although the specific descriptions given above relate to additive systems using discrete injection methods, many aspects of the invention can be used with other types of additive system. Such other systems include metered additive systems where control of the additive flow is achieved by regulating the flow of additive into the flow of fuel by opening or closing a valve and measuring the flow of additive with a flow meter. Such systems can be used in pulser and pre-set modes in a manner similar to the injection system.

The invention also provides a pulser 18 for mechanical fuel meters and registers on trucks. Such meters and registers, sometimes referred to as meter-registers, typically have the following characteristics. The meter comprises- a vane or lobe type positive displacement device, which causes its mechanism to rotate in proportion to the volume of fuel passing through it. The register is fitted above the meter and connects to it through a mechanical drive, which drives various several outputs including a display of digit wheels, which are externally visible, and a printer drive and a printer, which has the capability to print a customer ticket showing the amount of fuel dispensed during a delivery.

The register comprises an external casing, which is sealed in accordance with weights and measures regulations. The casing comprises a main box like section with a removable top cover. The register and its casing are flange mounted above the meter casing. The register mechanism occupies the lower region of the register casing and is designed to fill this region with very little space wasted. It is withdrawn through the top opening when maintenance or setting is required. The printer occupies the upper region of the casing and the design is significantly more spacious in this region due to the shape requirements and reciprocating movement requirements of the printer.

The relationship between the amount of fuel delivered and the rotation of the drive shaft into the register, the shaft driving the display and the shaft driving the printer, is usually a round number associated with the fuel flow measurement. Typically, one revolution of these shafts will correspond to 10 litres or 1 gallon of fuel, depending on the units of measurement used. On certain types of meter-registers, which will be referred to as pre- calibration type, the number of revolutions of the shafts, will correspond exactly with the round number because mechanical calibration of the meter and register takes place on the meter side of the meter to register interface. On other types of meters, which will be referred to as post-calibration types, mechanical calibration of the meter and register takes place within the register between the first register drive shaft 33, henceforth referred to as the register drive shaft 33, and the display and printer shafts. Accordingly, the number of revolutions of the display and printer shaft will correspond exactly with the round number but the number of revolutions of the register drive shaft 33 can be a little smaller or greater than it. The drive between the meter and the register is effected by two vertical coaxial shafts, one being the register drive shaft 33 and other being its counterpart in the meter. The shafts are connected by engagement pieces. The engagement pieces allow separation and re- engagement of the register and meter for maintenance or calibration purposes. The engagement pieces frequently take the form of a fork with two or more radial arms with short downward prongs, mounted on the end of the register drive shaft 33, and a star wheel with multiple radial prongs, mounted on the end of the meter drive shaft. When the two pieces are engaged, the two coaxial shafts are aligned and the downward prongs of the fork enter the spaces between the radial prongs. The engagement piece is frequently spaced a small distance away from the underside of the register mechanism and its drive shaft is often fitted with a tubular shaped spacer bush. This spacing is typically provided to accommodate various other small components, such as gears and spindle ends, which are located below the underside of the register mechanism and which otherwise might come into contact with either of the engagement pieces. The register engagement pieces and drive shaft is usually provided with a small amount of axial play to facilitate its connection to the meter engagement piece.

Referring now to Figures 2 and 3, there is shown a pulser 18 which can be fitted to a mechanical meter-register 17. The figures show the pulser 18, the register drive shaft engagement piece 34 and the lower end of the register drive shaft 33. For the sake of clarity, other parts of the register are omitted in the figures.

In the preferred embodiment, the pulser 18 comprises a target wheel 25, which is attached to and rotates with the register drive shaft 33. It also comprises a sensor 27, which is attached to a stationary part of the register and can detect movement of the target wheel 25.

The sensor comprises an inductive proximity sensor 27 which can reliably detect the presence of a steel target up to 3mm distant. Such sensors 27 can be obtained in very small sizes, typically with a diameter of 8mm and a length of 25mm. The sensor 27 has a threaded cylindrical body, which allows easy adjustment of its position relative to the target. The sensor 27 is also available in an intrinsically safe format, which is suitable for installation within an explosive environment. The sensor 27 is mounted on a base plate 32 which is fastened to the underside of the register mechanism. The base plate 32 is made from flat sheet metal with a small flat portion bent at 90° to the base. The sensor 27 is mounted through a hole in the bent portion and secured in position using lock nuts on its threaded surface. The portion of the base plate which fastens to the register is provided with appropriate holes and cut-outs to allow the base plate fit over the various small register components which are located on the underside of the register mechanism. For clarity, these are not shown in the figures.

The target wheel 25 comprises a mild steel cogged wheel with five cogs. The sensor 27 detects the external edge of the cogs each of which forms part of a cylindrical surface.

The wheel is made from 5mm thick material in order to present a relatively large target surface to the sensor. Mild steel is used because it is amongst the most readily detected material for sensors of this type. The wheel is manufactured by laser cutting and is zinc plated to prevent corrosion. The wheel is provided with five cogs to give the minimum wheel dimensions which can provide ten changes of state in the sensor, corresponding to the ten litres delivered for each revolution of the wheel. The cogs and the spaces between them are made equal around the diameter of the wheel and the sensor detects ten alternating on and off signal changes as the wheel rotates through one revolution, each signalling one litre of fuel. Accordingly, the pulser 18 has the advantage of providing a finely resolved indication of units of fuel flow, typically giving an accurate indication per litre or per one tenth of a gallon.

An alternative target wheel comprises a thinner cogged disk where the sensor detects the sides of the cogs rather than the edges. Where this is used, it may be necessary to overcome the potential problem of axial play in the drive shaft where this would otherwise be translated to the target wheel, as this axial play may exceed the available sensing range of a proximity sensor. The potential problem may be overcome by eliminating or reducing the axial play in the target wheel or in the shaft itself. Alternatively, a sensor may be used which is capable of tolerating the axial play, such as an optical sensor.

In the preferred embodiment, the target wheel 25 is arranged such that it can be fitted to the register drive shaft 33 without the need to disassemble any of the register components, including the drive shaft 33 or the engagement piece 34. This is achieved by fitting a split bush 29 on the exposed portion of the drive shaft 33 between the engagement piece 34 and the register mechanism, which can be fitted without disassembling the drive shaft 33. The split bush 29 comprises two halves, each with a half cylindrical centre, which clamp around the drive shaft 33 or its spacer bush, and which are held together with two retaining screws. The split bush 29 is also provided with a face with a locating rim and threaded holes on its surface which will face towards the meter. The target wheel 25 is located on this face and a hole in its centre locates on the locating rim. The target wheel 25 is fastened to the split bush with two further retaining screws, which are fitted subsequent to the split bush being fastened to the drive shaft 33. The hole in the target wheel 25 is also appropriately shaped to allow it to pass over the register engagement piece 34. This also ensures that the wheel 25 rotates as one with the drive shaft 33 and engagement piece 34. The holes in the target wheel 25, for the retaining screws, are counterbored to prevent the heads of the retaining screws standing fully proud of the surface of the target wheel.

The arrangement of the pulser 18 is very much limited by the confined space available within the lower region of the register casing. The target wheel 25 occupies a region which is originally provided merely as clearance for the rotating engagement pieces 34. The target wheel 25 does not interfere with this clearance because it is fastened to one of the rotating pieces and because its shape is confined within a relatively small disk shaped envelope. The base plate lies flat against the existing register mechanism base and can be readily accommodated. The sensor 27 can also be readily accommodated, it is small and can be mounted on any radial position relative to the target wheel, provided that its sensing end is within the 3 mm sensing range.

When fitted to a post-calibration type meter-register, the changes of state signalled by the sensor can be used as a direct indication of units of fuel flow. When fitted to a pre- calibration type meter-register, the changes of state will not provide an exact indication of units of fuel flow, but may differ by up to about 1%. However, any such variations will be corrected automatically when the injection pump 4 is calibrated in accordance with the method of the invention. A significant advantage is gained from fitting the pulser 18 in the region of the engagement pieces rather than in the more spacious upper region of the register. It permits the pulser 18 to be fitted without any disassembly of the components of the meter-register 17 other than separation of the register head from the meter. This results in substantial savings in installation time. Meter-registers 17 are frequently difficult to take apart and reassemble due to corrosion and damage caused by exposure to weather and difficult working conditions. It can also result in substantial savings in installation cost because it is not necessary to employ installation personnel skilled in meter-register maintenance. It additionally avoids the costs associated with the possibility of the meter-register being damaged or having its settings inadvertently altered during disassembly or reassembly.

It will of course be understood that the invention is not limited to the specific details described herein, which are given by way of example only, and that various modifications and alterations are possible within the scope of the invention as defined in the appended claims.

Claims

CLAIMS:

1. A method of adding an additive into a delivery of a fluid in a duct, using an additive storage means, an additive adding means, an additive connection means into the duct and a fluid delivery means connected to the duct, downstream of the additive connection means characterised by;

obtaining signals from a fluid flow measurement means; and

regulating the rate at which additive is added by a controller means;

2. A method as claimed in Claim 1, wherein

addition of additive is carried out at a rate which causes it to be added to the fluid in proportions which differ from its nominal proportions; and

a volume of fluid of significant size compared to the delivery, is contained in the fluid delivery means; and/or

wherein the volume of fluid is at least 5% of the size of the delivery or wherein the volume of fluid is sufficient to cause contamination in a delivery without fluid additive.

3. A method as claimed in Claim 1 or Claim 2, including a selection means, wherein addition of additive is selectively carried out at different rates which cause it to be added to the fluid in corresponding different nominal proportions.

4. A method as claimed in Claim 1 or Claim 2 wherein addition of additive is carried out at a rate which causes it to be added to the fluid in proportions which are greater than its nominal proportions.

5. A method as claimed in Claim 4, which includes a pre-set means and where a preset value is entered in the pre-set means corresponding to the size of delivery of fluid and additive is added in an amount corresponding to the pre-set value and at a rate whereby the addition is completed sufficiently in advance of the completion of the delivery of fluid such that additive is not present in the fluid delivery means at the end of the delivery.

6. A method as claimed in the rate of addition of additive is paced by one or more set proportions of the pace of signals received from the fluid flow measurement means or by timing means or by a combination of both.

7. A method as claimed in Claim 5, wherein the rate of addition of additive is paced by timing means and fluid flow is detected by the receipt of signals received from the fluid flow measurement means or by a change in pressure between different points in the duct or delivery means caused by fluid flow in the duct or delivery means.

8. A method as claimed in Claim 1 or Claim 2, wherein addition of additive is paced in proportion to signals received from the fluid flow measurement means.

9. A method as claimed in Claim 5 and Claim 8, which includes a selection means where addition of additive can be selectively regulated either by being paced in proportion to signals received from the fluid flow measurement means or controlled by a pre-set means whereby the addition is completed sufficiently in advance of the completion of the delivery of fluid such that additive is not present in the fluid delivery means at the end of the delivery.

10. A method as claimed in Claim 5 and Claim 8, wherein the addition of additive is terminated prior to the end of the delivery and when the remaining volume of the delivery is equal to the volume contained in the fluid delivery means.

11. A method as claimed in Claim 8, which includes a detection means adjacent the distal end of the fluid delivery means operable to detect when the remaining volume of the delivery is substantially equal to the volume contained in the fluid delivery means;

a communication means between the controller means and the detection means, and

where the addition of additive is terminated by the controller means when the detection means detects and communicates that the remaining volume of the delivery is substantially equal to the volume contained in the fluid delivery means.

12. A method as claimed in Claim 4, wherein the controller means is operable to monitor or determine the complement or shortfall of additive in the fluid delivery means at the end or at the commencement of a delivery of fluid with additive.

13. A method as claimed in Claim 12, wherein the controller means monitors or determines the complement or shortfall of additive in the fluid delivery means at the commencement of a delivery of fluid with additive and causes additive to be added to the fluid in proportions which are greater than its nominal proportions until sufficient has been added to compensate for any shortfall.

14. A method as claimed in Claim 13 and Claim 5, Claim 10 or Claim 11, wherein the controller means monitors or determines the complement or shortfall of additive in the fluid delivery means at the commencement of a delivery of fluid with additive and causes additive to be added to the fluid in proportions which are greater than its nominal proportions until sufficient has been added to compensate for any shortfall and which includes a pre-set means and/or where a pre-set value is entered in the pre-set means corresponding to the size of delivery of fluid and additive is added in an amount corresponding to the pre-set value and at a rate whereby the addition is completed sufficiently in advance of the completion of the delivery of fluid, where the addition of additive is terminated prior to the end of the delivery, and when the remaining volume of the delivery is equal to the volume contained in the fluid delivery means, such that additive is not present in the fluid delivery means at the end of the delivery.

15. A method as claimed in Claim 12, wherein the controller means prevents the commencement of a delivery of fluid without additive where it has determined that additive is present in the fluid delivery means prior to commencing the delivery.

16. A method according to any one of the preceding claims, which includes a recording means and where records are maintained of the usage of additive or the usage of fluid with additive and where such records are determined by measurement of an operating element of the addition of additive to the fluid.

17. A method as claimed in Claim 13 and Claim 16, wherein two records are maintained of the usage of additive or the usage of fluid with additive, one being a record of the amount of additive added to the fluid during all deliveries and the other being a record of the amount of additive added to the fluid which was added to the fluid and which was intentionally delivered as fluid with additive, and where the monitoring or determination of the complement or shortfall of additive in the fluid delivery means is used in the determination of these records.

18. A method as claimed in Claim 16, which includes a resetting means, and where two records are maintained, one of additive usage since the last reset and the other of additive usage between the last reset and the reset previous to it.

19. A method according to any one of the preceding claims, which includes a securing means and setting or adjusting means, and where the securing means is operable to deny access to the setting or adjusting means.

20. A method as claimed in Claim 16 and Claim 19, wherein the secured record can be freely viewed and where unauthorised access to set or adjust the record is denied by the securing means.

21. A method as claimed in Claim 19, wherein the additive adding means is adjusted or set by the controller means, and where unauthorised access to set or adjust the additive adding means is denied by the securing means.

22. A method according to any one of the preceding claims, which includes a sensing means which is operable to sense flow of additive in the additive adding means or the additive connection means into the duct, and where the sensing means communicates with the controller means to verify that additive is being added to the fluid.

23. A method as claimed in Claim 20, wherein the controller means initiates alarm responses if it fails to verify that additive is being added to the fluid, such alarm responses including the activation of visual or audible alarms, the termination of the fluid delivery, the termination of the addition of additive to the fluid and the deactivation of the records.

24. A method as claimed in Claim 22, wherein the adding means is of the type which adds in discrete amounts and where each discrete amount is initiated by a signal from the controller means, and where the controller means compares the timing of the signal to the adding means with the timing of the responding communication from the sensing means.

25. A method as claimed in Claim 22, which includes taking a sample from a sampling means, where the sampling means is located on the additive connection means between the adding means and the sensing means; and the sampling means is operable such that it either ducts the flow of fluid to an outlet on the sampling means or ducts it to the additive connection means, but not to both.

26. A method as claimed in any one of the preceding claims, wherein additive is added to fluid on a truck and where the fluid delivery means comprises a delivery hose.

27. An apparatus for adding an additive into a delivery of a fluid in a duct, the apparatus comprising;

an additive storage means; an additive adding means;

an additive connection means into the duct; and

a fluid delivery means connected to the duct, downstream of the additive connection means, the apparatus including a controller means which is operable to obtain signals from a fluid flow measurement means and to regulate the rate at which additive is added.

28. An apparatus as claimed in Claim 27, in which

the controller means which is operable to regulate the rate at which additive is added, at different rates including a rate which is greater than its nominal proportions; and

the additive connection means is operable to contain a volume of fluid, of significant size compared to the delivery; and/or

wherein the volume of fluid is at least 5% of the size of the delivery or where the volume of fluid is sufficient to cause contamination in a delivery without of fluid additive.

29. Apparatus as claimed in Claim 27 or 28, wherein the additive adding means comprises;

an injection pump which includes an inlet check valve;

an outlet check valve ;

a pump housing with a cavity which communicates with the check valves; a plunger which reciprocates in the cavity;

an air actuator which drives the plunger and is connected to it;

a stationary seal which seals the clearance between the plunger and the cavity; the stroke length of the pump is at least four times greater than the plunger diameter; and or

the diameter of the air actuator piston is at least two times greater than the diameter of the plunger.

30. Apparatus as claimed in Claim 27 or 28, wherein the controller means is an electronic or pneumatic programmable controller or computer, operating alone or in conjunction with other logic components, including other elecfronic or electrical relays and/or other computers, such as truck computers, and where the controller means is operable to receive an elecfronic or pneumatic signal from a fluid flow measurement means, such as a fluid meter with an electronic or pneumatic pulse output.

31. Apparatus as claimed in Claim 27 or 28, wherein the controller means is an electronic relay-type controller with on and off inputs and outputs.

32. Apparatus as claimed in Claim 27 or 28, which includes a selection means, which is operable to select addition of additive at different rates which cause it to be added to the fluid in corresponding different nominal proportions.

33. Apparatus as claimed in Claim 32, wherein the selection means comprises an electrical switch which is operable to be set at different positions which open and close different sets of electrical contacts.

34. Apparatus as claimed in Claim 27 or 28, which includes a pre-set means which is operable to have a pre-set value corresponding to the size of delivery entered into it, and is operable to add additive in an amount corresponding to the pre-set value and at a rate whereby the addition is completed sufficiently in advance of the completion of the delivery of fluid.

35. Apparatus as claimed in Claim 34, wherein the pre-set means comprises an electronic pre-set device which includes a display screen; operator buttons to set a pre-set number on the display screen; input contacts which are operable to receive an input signal which causes the pre-set device to count down from the pre-set number; and output contacts which are operable to allow the pre-set device to send a signal when the pre-set number has counted down to a target value, such as zero.

36. Apparatus as claimed in Claim 34, which is operable to pace the rate of addition of additive by one or more set proportions of the pace of signals received from the fluid flow measurement means or by timing means or by a combination of both.

37. Apparatus as claimed in Claim 36, wherein the timing means comprises an electronic timing device or relay within the controller means.

38. Apparatus as claimed in Claim 34, which is operable to pace the rate of addition of additive by timing means and to detect fluid flow by the receipt of signals received from the fluid flow measurement means or by a pressure sensing means which is operable to sense a change in pressure between different points in the duct or delivery means caused by fluid flow in the duct or delivery means.

39. Apparatus as claimed in Claim 28, wherein the pressure sensing means is an electrical or elecfronic differential pressure sensor and comprises a moving component with two sides, such as a diaphragm or piston, and each side of the moving component is connected to different points in the duct or delivery means.

40. Apparatus as claimed in Claim 27, which is operable to pace the rate of addition of additive in proportion to the pace of signals received from the fluid flow measurement means.

41. Apparatus as claimed in Claim 34 and Claim 40, which includes a selection means, which is operable to select addition of additive which is regulated either by being paced in proportion to signals received from the fluid flow measurement means or by the pre-set means.

42. Apparatus as claimed in Claim 41, wherein the selection means comprises an electrical switch which is operable to be set at different positions which open and close different sets of electrical contacts.

43. Apparatus as claimed in Claim 34 and Claim 40, which is operable to terminate the addition of additive prior to the end of the delivery when the remaining volume of the delivery is equal to the volume contained in the fluid delivery means.

44. Apparatus as claimed in Claim 40, which includes;

a detection means adjacent the distal end of the fluid delivery means operable to detect when the remaining volume of the delivery is substantially equal to the volume contained in the fluid delivery means;

a communication means between the controller means and the detection means; and

wherein the controller means is operable to terminate the addition of additive when the detection means detects and communicates that the remaining volume of the delivery is substantially equal to the volume contained in the fluid delivery means.

45. Apparatus as claimed in Claim 44, wherein the communication means is a radio signalling device with a transmitter adjacent the distal end of the fluid delivery means and a receiver which is operable to send a signal to the controller means.

46. Apparatus as claimed in Claim 27, wherein the controller means is operable to monitor or determine the complement or shortfall of additive in the fluid delivery means at the end or at the commencement of a delivery of fluid with additive.

47. Apparatus as claimed in Claim 46, wherein the controller means is operable to memorise the maximum volume of fluid in the fluid delivery means as a fixed value.

48. Apparatus as claimed in Claim 46, wherein the controller means is operable to monitor or determine the complement or shortfall of additive in the fluid delivery means at the commencement of a delivery of fluid with additive and to cause additive to be added to the fluid in proportions which are greater than its nominal proportions until sufficient has been added to compensate for any shortfall.

49. Apparatus as claimed in Claim 48 and Claim 34, Claim 43 or Claim 44, wherein the confroUer means is operable to monitor or determine the complement or shortfall of additive in the fluid delivery means at the commencement of a delivery of fluid with additive and to cause additive to be added to the fluid in proportions which are greater than its nominal proportions until sufficient has been added to compensate for any shortfall and which includes a pre-set means and/or where the pre-set means is operable to have a preset value entered, corresponding to the size of delivery of fluid, and where the apparatus is operable to have additive added in an amount corresponding to the pre-set value and at a rate whereby the addition is completed before the point in advance of the completion of the delivery of fluid when the remaining volume of the delivery is equal to the volume contained in the fluid delivery means.

50. Apparatus as claimed in Claim 46, wherein the controller means is operable to prevent the commencement of a delivery of fluid without additive where it has determined that additive is present in the fluid delivery means prior to commencing the delivery.

51. Apparatus according to any one of the preceding claims, which includes a recording means which is operable to maintain records of the usage of additive or the usage of fluid with additive and to determine such records by measurement of an operating element of the addition of additive to the fluid.

52. Apparatus as claimed in Claim 51, wherein the apparatus includes a controller means with an integral visual display screen which is operable to display the record and, advantageously, where the controller means is a relay-type controller with an integral visual display screen.

53. Apparatus as claimed in Claim 48 and Claim 51, wherein the recording means is operable to maintain two records of the usage of additive or the usage of fluid with additive, one being a record of the amount of additive added to the fluid during all deliveries and the other being a record of the amount of additive added to the fluid and which was intentionally delivered as fluid with additive, and where the recording means is operable to use the monitoring or determination of the complement or shortfall of additive in the fluid delivery means in the determination of these records.

54. Apparatus as claimed in Claim 51, wherein two records are maintained, one of additive usage since the last reset and the other of additive usage between the last reset and the reset previous to it, and which includes a resetting means which is operable to reset the previous record to zero and to cause the last record to become the previous record.

55. Apparatus as claimed in Claim 54, wherein the resetting means comprises an electrical push button or switch.

56. Apparatus according to any one of the preceding claims, which includes a securing means and setting or adjusting means and where the securing means is operable to deny access to the setting or adjusting means.

57. Apparatus as claimed in Claim 56, wherein the setting or adjusting means is located within an enclosure with a door or cover; and where a securing means prevents the door or cover being opened or removed; and where the securing means comprises a wire seal connected to the enclosure and/or the door or cover such that the door or cover cannot be opened or removed unless the wire seal is broken or alternatively, where the securing means comprises a lock.

58. Apparatus as claimed in Claim 51 and Claim 56, which includes a securing means and setting or adjusting means, and where the securing means is operable to deny access to the setting or adjusting means.

59. Apparatus as claimed in Claim 51 and Claim 57, which includes a securing means and setting or adjusting means, and where the securing means is operable to deny access to the setting or adjusting means, and which includes a viewing means through which the secured record can be freely viewed.

60. Apparatus as claimed in Claim 58, wherein the setting or adjusting means comprises the means to program a controller or to alter the program or the program settings on a controller.

61. Apparatus as claimed in Claim 58, wherein the controller has a visual display screen and the controller is located within an enclosure and the enclosure comprises an opening or window through which the record is visible.

62. Apparatus as claimed in Claim 56, wherein the additive adding means is adjusted or set by the controller means, and where the securing means is operable to deny unauthorised access to set or adjust the additive adding means.

63. Apparatus as claimed in Claim 62, wherein the adding means is an injection pump, where its adjustment is by means of a setting within a controller; and where the setting or adjusting means is located within the enclosure.

64. Apparatus according to any one of the preceding claims, which includes a sensing means which is operable to sense flow of additive in the additive adding means or the additive connection means into the duct, and where the sensing means is operable to communicate with the controller means to verify that additive is being added to the fluid.

65. Apparatus as claimed in Claim 64, wherein the sensing means comprises a piston, such as a magnetic piston, in a bore; where the rest position of the piston is at the upstream end of the bore; and where the flow of fluid through the bore moves the piston away from the rest position; and the movement of the piston activates an electronic sensor, such as an external sensor which can detect the proximity of a magnetic piston.

66. Apparatus as claimed in Claim 64, wherein the controller means is operable to initiate alarm responses if it fails to verify that additive is being added to the fluid, such alarm responses including the activation of visual or audible alarms, the termination of the fluid delivery, the termination of the addition of additive to the fluid and the deactivation of the records.

67. Apparatus as claimed in Claim 64, wherein the adding means is operable to add in discrete amounts and where the controller means is operable to initiate each discrete amount by a signal, and to compare the timing of the signal to the adding means with the timing of the responding communication from the sensing means.

68. Apparatus as claimed in Claim 64, wherein the adding means is an injection pump, the sensing means is an electronic flow sensor and where the controller means is an electronic controller which sends a signal to the injection pump and receives a corresponding signal from the flow sensor, and the controller measures the time period between the signals and compares it to a reference value.

69. Apparatus as claimed in Claim 64, which includes a sampling means, where the sampling means is located on the additive connection means between the adding means and the sensing means; and the sampling means is operable such that it either ducts the flow of fluid to an outlet on the sampling means or ducts it to the additive connection means, but not to both.

70. Apparatus as claimed in Claim 69, wherein the sampling means comprises a two way valve, such as a two way ball valve, located on the additive connection means.

71. Apparatus as claimed in any one of the preceding claims, wherein additive is added to fluid on a truck and where the fluid delivery means comprises a delivery hose.

72. A method for obtaining a signal from a fluid flow measurement means, which includes;

a metering means;

a display means;

a casing on the display means;

a rotating driving means;

an engagement means on the metering means;

an engagement means on the display means;

the display means is operable to be disengaged and separated from the metering means;

the method including connecting a target means to the engagement means on the display means, and/or to driving means connected to the engagement means on the display means;

connecting a detecting means to the display means; and

detecting the rotation of the target means with the detecting means.

73. A method as claimed in Claim 72, wherein the target means comprises irregularities, such as teeth or holes, at regularly spaced intervals, and wherein the detecting means detects the rotation of the target by detecting the presence or absence of the target material as the irregularities pass the detection means.

74. A method as claimed in any one of Claims 72 to 74, which includes a controller means, and where signals are sent from the detection means to the controller means, and the controller means registers each change of state of the signal.

75. A method as claimed in any one of Claims 72 to 74, which includes a controller means, and where signals are sent from the detecting means to the controller means; and the controller means includes a calibration means where it counts the number of signals from the detection means and registers an event when a set number of signals, or a set combination of set numbers of signals, is counted.

76. Apparatus for obtaining a signal from a fluid flow measurement means, which includes;

a metering means,

a display means;

a casing on the display means;

a rotating driving means;

an engagement means on the metering means;

an engagement means on the display means; and

the apparatus including a target means, which is operable to rotate with engagement means on the display means, and/or with driving means connected to the engagement means on the display means; and

which is operable to be detected by a detecting means;

a target detecting means which is operable to detect the rotation of the target means;

a target connecting means which is operable to connect the target means to the engagement means on the display means, and/or to driving means connected to the engagement means on the display means.

77. Apparatus as claimed in Claim 76, wherein the target means comprises irregularities, such as teeth or holes, at regularly spaced intervals, and where the detecting means is operable to detect the rotation of the target by detecting the presence or absence of the target material as the irregularities pass the detection means.

78. Apparatus as claimed in Claim 77, where the target means and irregularities comprise a flat component or disk with cog projections; the target means comprises a central hole which surrounds all or part of the engagement means on the display means; the detection means is fastened to the display means; the detection means is directed radially towards the edges of the cog projections; and the detection means is operable to detect the cog projections.

79. Apparatus as claimed in Claim 77, where the detection means is directed towards one of the sides of the target means or from one side to the other of the target means.

80. Apparatus as claimed in any one of Claims 76 to 79, wherein the target connecting means comprises two parts which are operable to be clamped or fastened around the engagement means on the display means, or the driving means connected to the engagement means on the display means, and is operable to be connected to the target means, such that the target means can be connected without the removal of components on the display means.

81. Apparatus as claimed in any one of Claims 76 to 80, wherein the detection means is an elecfronic proximity sensor, optionally with a threaded cylindrical body which is operable to adjust the distance between the sensor and the target means.

82. A method of adding an additive into a delivery of a fluid in a duct substantially as herein described with reference to the accompanying drawings.

83. An apparatus for adding an additive into a delivery of a fluid in a duct substantially as herein described with reference to, and as shown in, the accompanying drawings.

84. A method for obtaining a signal from a fluid flow measurement means substantially as herein described with reference to the accompanying drawings.

85. Apparatus for obtaining a signal from a fluid flow measurement means substantially as herein described with reference to, and as shown in, the accompanying drawings.