CA2082521C - Thermo-plastic heat exchanger - Google Patents

Thermo-plastic heat exchanger Download PDF

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Publication number
CA2082521C
CA2082521C CA002082521A CA2082521A CA2082521C CA 2082521 C CA2082521 C CA 2082521C CA 002082521 A CA002082521 A CA 002082521A CA 2082521 A CA2082521 A CA 2082521A CA 2082521 C CA2082521 C CA 2082521C
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compartment
temperature
fluid
heating
set point
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CA002082521A
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French (fr)
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CA2082521A1 (en
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David E. Seitz
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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24HFLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/10Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium
    • F24H1/101Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium using electric energy supply
    • F24H1/102Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium using electric energy supply with resistance
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24HFLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00Control of fluid heaters
    • F24H15/10Control of fluid heaters characterised by the purpose of the control
    • F24H15/128Preventing overheating
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24HFLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00Control of fluid heaters
    • F24H15/10Control of fluid heaters characterised by the purpose of the control
    • F24H15/174Supplying heated water with desired temperature or desired range of temperature
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24HFLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00Control of fluid heaters
    • F24H15/20Control of fluid heaters characterised by control inputs
    • F24H15/212Temperature of the water
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24HFLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00Control of fluid heaters
    • F24H15/20Control of fluid heaters characterised by control inputs
    • F24H15/281Input from user
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24HFLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00Control of fluid heaters
    • F24H15/30Control of fluid heaters characterised by control outputs; characterised by the components to be controlled
    • F24H15/355Control of heat-generating means in heaters
    • F24H15/37Control of heat-generating means in heaters of electric heaters
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24HFLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00Control of fluid heaters
    • F24H15/40Control of fluid heaters characterised by the type of controllers
    • F24H15/407Control of fluid heaters characterised by the type of controllers using electrical switching, e.g. TRIAC
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05DSYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00Control of temperature
    • G05D23/19Control of temperature characterised by the use of electric means
    • G05D23/1927Control of temperature characterised by the use of electric means using a plurality of sensors
    • G05D23/193Control of temperature characterised by the use of electric means using a plurality of sensors sensing the temperaure in different places in thermal relationship with one or more spaces
    • G05D23/1932Control of temperature characterised by the use of electric means using a plurality of sensors sensing the temperaure in different places in thermal relationship with one or more spaces to control the temperature of a plurality of spaces
    • G05D23/1934Control of temperature characterised by the use of electric means using a plurality of sensors sensing the temperaure in different places in thermal relationship with one or more spaces to control the temperature of a plurality of spaces each space being provided with one sensor acting on one or more control means
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05DSYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00Control of temperature
    • G05D23/19Control of temperature characterised by the use of electric means
    • G05D23/20Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature
    • G05D23/24Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature the sensing element having a resistance varying with temperature, e.g. a thermistor
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00Ohmic-resistance heating
    • H05B3/78Heating arrangements specially adapted for immersion heating
    • H05B3/82Fixedly-mounted immersion heaters
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28HEAT EXCHANGE IN GENERAL
    • F28FDETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/26Arrangements for connecting different sections of heat-exchange elements, e.g. of radiators

Abstract

A flow-through instantaneous fluid heater system (10) designed to satis fy the need for a heater not limited by being connected to a storage tank and which can be made using a plastic casing (42, 62) incorporates cool-down when out of service and features of venting and simplified flushing and draining. The system incorporates the use of one or more compartments (40, 60) usually assembled in two compartment modules connected in series. Each compartment includes a casing (42, 62) having a hollow cylindrical interior region. An inlet aperture (44) is located at one end of the casing and an outlet aperture (46) is located at t he other end of the casing. The lower end of each casing is closed by a removable base (8 0) and the upper end of the casing is closed by a top plate (85) and a heating element (140, 160). The heating element (140, 160) is positioned axially in the interior region of the compartment. A control system (200) uses temperature comparisons to dete ct flow through the system to determine whether the heating elements (140, 160) should be activated to maintain the fluid at a stand-by temperature or at an operational temperature.

Description

WO 91/17640 PCf/US91/03213 THERMO-PLASTIC HEAT EXCHANGER
2~'~ :~~1, Field of the Inv_en ion The present invention generally relates to a flow-through heating apparatus for the instantaneous heating of fluids, i.e., water, and, more particularly, is concerned with a self-insulating, easy to install thermo-plastic heat exchanger of expandable modular construction for heating water without the use of a storage tank.
The typical hot water heater which has been in use for several decades now i s a storage tank heater whi ch i s made of metal, These heaters have several disadvantages including a limitation upon the amount of hot water which can be stored and therefore used at a given time, energy being wasted in that the supply of water must continually be reheated, the possibility of harmful gas leaks, the potential for fires and explosions since a majority of these heaters in residential applications are gas heaters, and the heaters take up a large amount of space since a storage tank is needed. These heaters are generally located far from the point of delivery of the hot water resulting in heat loss between the storage tank and the point of delivery as well as significant loss and waste of potable water that is senselessly discharged down the drain while waiting for hot water to reach the fixture.
At the time when conventional storage tank hot water heaters became widely accepted, we did not have the benefit of the improved plastic materials now available. Engineering plastics now provide a lightweight, inexpensive alternative to metals for use in structures for handling hot water.
The need for domestic hot water is typically intermittent and of relatively short duration. State of the art design now allows for continuous flow-through type hot water heaters which only require that water be heated once and at the time of use.
The advantages of an instantaneous flow-through hot water neater include savings an water heating bi 1 ls, savings on potabl~ water because of the ability to install near major points of use, increased safety through the use of electric heat~rs eliminating the need for gas and open flames, less space requirements since 2~'8.~ ~1.
., no storage tank is required, ease of maintenance, lower cost of repairs and the lifestyle benefits associated with a continuous supply of hot water. Problems resulting from corrosion of the tank can also be eliminated through the use of plastics as the material used for many of the components in the hot water heater system.
Other continuous flow water heaters have been described.
U,S, Patent No. 3,898,428 to Dye describe:; an inline water heating apparatus which has a cylindrical heater element surrounded by a length of helically corrugated tubing. U.S.
Patent No, 4,567,350 to Todd describes an~instantaneous electric water heater which includes five water heating chambers which are connected by lengths of metal mixing pipes, The heating chambers include electrical heating elements, and a pressure relief valve is located at the bottom of the last heating chamber. U.S.
Patent No. 4,604,515 to Davidson discloses a tankless electric water heater and includes four heating chambers which are arranged as pie-like portions of a cylinder. Each chamber has a heating element and a separate temperature sensor, and one of the chambers includes a pressure relief valve, U.S. Patent No.
4,645,907 to Salton describes an electric y!ater heater which includes a casing with three separate heating elements.
The patents described above have several shortcomings. The patents fail to comprehend the design of a flow-through instantaneous water heater as described herein as my invention which can be constructed in series from any desirable number of flow-through instantaneous water heating compartments, usually assembled as a series of two-compartment modules, to meet the hot water output requirements of the user's application. These patents also fail to recognize the advantages of the invention that the hot water heater compartments can be constructed from plastic, that the compartments should and can.be constructed for ease of draining and cleaning for maintenance purposes and removal of particulate matter which can clog the system, to construct with off the shelf type components easily obtainable for installation and replacement, the importance of the WO 91/17640 PCf/US91/03213 Capability to determine the temperature at the outlet .of each compartment, the importance of venting entrapped air or gas from the upper end of each and every separate compartment used in the hot water heating system during normal operations as opposed to using pressure relief valves and in only some of the compartments, solving problems associated with overtemperature conditions due to inaccuracies from reading the temperature of the fluid at the very top of the compartment where steam can collect if uses are not vented and the importance of incorporating, optionally, an electronic control system into the operation of the heating system for detecting water level and for electronically detecting flow (without moving parts) in order to determine if the system is in an operational or a stand-by state, and for sequentially modulating the heating elements in consecutive compartments in order to achieve a desirable output temperature from the system which will shut off the heating elements when temperatures within the compartments reach excessive levels.
Consequently, a need exists for significant improvements in complete flow-through instantaneous water heating systems with the objective of solving all of the above-mentioned disadvantages.
Su_mma_r_y of the Inv,ent,ion The present invention provides a flow-through instantaneous fluid heater system designed to satisfy the aforementioned needs.
The system incorporates the use of one or more compartments, usually assembled in two compartment modules connected in series.
Each compartment includes a casing having a hollow cylindrical interior region. An inlet aperture is located at one end of the casing and an outlet aperture is located at the other end of the casing. The lower end of each casing is closed by a removable base and the upper end of the casing is closed by a top plate and a heating element. The heating element is positioned axially in the interior region of the compartment. The heating element is activated by a control system which senses and compares temperatures of the water at the compartment outlets. The control system uses temperature comparisons to detect flow through~the system to determine whether the heating elements should be activated to maintain the fluid at a stand-by temperature or at an operational temperature, ~.CL~f~g~~~~?_~.!1_Qf Ghe_..~.rRwi,n,gs Fig. 1 is an elevational view of a two compartment flow-through heating~apparatus representing a single module of the water heater.
Fig. 2 is a side view of a two compartment flow-through heating apparatus.
Fig. 3 is a top view of a two compartment flow-through heating apparatus.
Fig. 4 is a cross-sectional view of a two compartment flow-through heating apparatus shown in Fig. 1..
Fig. 5 is a crass-sectional view of a two compartment flow-through heating apparatus taken along the line 5-5 of Fig. 4.
Fig. 6 is.an end view of the vent plug.
Fig. 7 is an exploded perspective view of the invention described herein incorporating two compartments.
Fi9. 8 is a functional block diagram of the control system of the invention described herein.
Fi9. 9 is a schematic of the flow detection device incorporated alternately in the herein described invention.
Fig. 10 is a functional block diagram of the control logic in accordance with this invention.
Det~i led Description of_ the Invention Referring now to the drawings, and more particularly, to F i g. 1 , there i s shown one embodi ment of the f 1 ow-through heati ng apparatus and system, generally designated 10, for the .
instantaneous heating of a fluid, preferably a liquid, such as, for example, water. For purposes of discussion of the embodiments of this invention, the heater will be discussed as if it is a water heater, the most common use for it. The ~~~ u,~.l.
J
instantaneous water heater 10 generally incorporates a few basic conduit elements joined in series, namely an inlet pipe 20 at the upstream end of the system 10, a first compartment 40, a second compartment 60 and a discharge pipe 90 at the downstream end of the system 10. The first compartment 40 and second compartment 60 contain~heating elements 140 and 160, respectively, for the instantaneous heating of water as it passes through. For purposes of this invention two compartments will be considered to be a module for simple expansion purposes where needed.
As shown\in Figs. 1, 2 and 3, inlet,pipe 20 is supported by an inlet pipe support 24. The inlet pipe support 24 includes 0-ri ng groove 27 , ( Fi g. 4 ) , f i is around the outer ci rcumference of inlet pipe 20, and is attached to first compartment 40 by bolts 26. The lower end of inlet pipe 20 is threaded for connection to inlet fitting 28. Inlet fitting 28 is attached to the lower side proximate the lower end of first compartment 40 by bolts 29.
Sectioned drawings, Figs. 4 and 5, show a first compartment 40, surrounded by a casing 42, as being a hollow, cylindrical interior region. Casing 42 is shown as being tubular, though not necessarily so, having a first aperture 44 located proximate the lower end and a second aperture 46 located proximate the upper end of casing 42. A third aperture 48 as optional to simplify the plastic molding process for modularity of compartments and if included is located proximate the upper end of casing.42 opposite second, aperture 46. A connector 100, which is tubular in construction is used to connect inlet fitting 28 to first compartment 40 through the first aperture 44 to allow fluid communication from the inlet pipe 20 with first compartment 40.
An 0-ring 110 is seated in groove 25 in inlet~fitting 28 in order to provide an effective seal between inlet fitting 28, connector 100 and first compartment casing 42.
As shown, third aperture 48 in first compartment 40 is Closed by plug 102 and sealed using an O-ring 112 seated in groove 27, Plug 102 is cylindrical and solid.
Second aperture 46 is used for connecting the flow path of the water through the first compartment 40 to the second a v.i ~~.

compartment 60. Connector 104 is used for making this connection between first compartment 40 and second compartment 60 and is positioned adjacent the top of first compartment 90. Connector 104 is the same as connector 100 and is mounted in second aperture 46 of first compartment 40 and in first aperture 64 of second compartment 60 and is sealed by O-ring 114 seated in groove 47 in first compartment 40.
Second compartment 60 is the same as or similar to first , compartment 40~ Second compartment 60 is a cylindrical longitudinal cavity in casing 62 having first aperture 64 and second aperture 66 proximate the upper end and third aperture 68 Located proximate the lower end.
Both the first compartment 40 and second compartment 60 are closed at the lower end by a base 80 which is attached by bolts or other suitable means of attachment, Preferably, 0-rings 81 and 82 will be placed in grooves 83 and 84 in base 80, respectively, in order to seal the lower end of the compartments 40 and 60. The base 80 is readily detachable and reattachable to allow for cleaning of corrosion and other particulate matter from the compartments 40 and 60 and heating elements 140 and 160 without removing electrical wiring, The casings 42 and G2 or base 80 could also be tapered and constructed with a valve for each compartment 40 and 60 to allow pneumatic or some other type of blow down without removal of base 80, It is to be understood that the base 80, while shown as a single piece closing both compartments 40 and 60, it could be manufactured as two separate pieces, one each to be connected to the bottom end of first compartment 40 and second compartment 60. As shown in Fig. 2, the lower end 88 of base 80 is preferably webbed to provide structural strength while saving on material costs.
Top plate 85 preferably provides an electrical ground means for the heating elements and is held against heating elements 140 and 160 when heating elements 140 and 160 are threaded or attached by other suitable means of attachment to casing 42 and 62 . Though p 1 ate 85 i s shown as a s i ng 1 a p 1 ate , i t i s to be understood that top plate 85 could also be manufactured as two WO 91!17640 PCT/US91/03213 2~~ ~~1.

separate plates, one each to be attached to the tops of casing 42 and 62. Top plate 85 is preferably a grounding plate to be connected to any suitable grounding surface for grounding heaters 140 and 160.
As shown in Fig. 4, heating element 140 extends down through the opening in top plate 85 and extends axially through the interior region of first compartment 40, Heating element 140 extends downward in an axial direction into the hollow interior region of firsi; compartment 40. The axial location of the heating element 140 within the hollow interior region is such that the heating element t4.0 is substantially equidistant from casing 42 at any point around the circumference of casing 42.
The heating element 140 is seated on top plate 85 and preferably is attached to compartment 40 through a mating threaded connection. O-ring 86 is placed in groove 88 between heating element 140 and top plate 85 for sealing off the top end of first compartment 40. A preferable heating element for water is sized between 3500 and 7000 watts output based on the design rating of the specific heater. The uniformity of the heat transfer from the heating element 140 to the water flowing through first compartment 40 is enhanced due to the substantially symmetrical location of the element 140 with respect. to the hollow cavity through which the fluid, water, will flow.
Heating element 160 extends.down through the opening in top plate 85 and axially into the second compartment 60. Heating element 160 is the same as or similar to heating element 140.
Heating element 160 is seated on top plate 85 and preferably is attached to compartment 60 through a mating threaded connection,.
0-ring 87 is placed in groove 89 between heating element 160 and top plate 85 for sealing off the top end of second compartment 60.
A temperature sensor or thermistor 120 (Fig. 7) protrudes into the interior region of first compartment casing 42 proximate the second aperture 46 for sensing the temperature T1 of the water flowing out of first compartment 40. Sensor 120 may protrude within the compartment casing 42 from other positions WO 91/1?640 PCT/US91/03213 2~'~ d~~~.

so long as it is in the flow path of the water and proximate the second aperture. For purpose> of this invention any water downstream from the first heating element 140 and upstream from second aperture 46 can be considered to be proximate the second aperture 46.
A temperature sensor or thermistor 125 protrudes into the interior region of second compartment casing 62 proximate the third aperture 68 for sensing the temperature T2 of the water flowing out of~'sacond compartment 60, Sensor 125 may protrude within the compartment casing 62 from other positions so long as it is in the flow path of the water and proximate the third aperture 68. For purposes of this invention, any water downstream from the second heating element 160 and upstream from third aperture 68 can be said to be proximate the third aperture 68.
Discharge pipe 90 is connected to second compartment 60 through discharge fitting 92 and bleeder fitting 96. Connector 106 is used for connecting second compartment 60 to discharge fitting 92 and is sealed by O-ring 116 which seats in groove 69 in casing 62. Discharge fitting 92 is attached to second compartment 60 by bolts 94, Discharge fitting 92 and bleeder fitting 96 may be threaded or attached b.y other suitable means to pipe 90, or may be prefabricated as part of pipe 90.
Fitting 96 is attached to second compartment 60 by bolts 94.
Vent plug 108 is mounted in second aperture 66 of second compartment 60 and vents air, steam and other gases into fitting 96 and from there into outlet pipe 90 , Vent plug 108 is partially sealed within second aperture 66 by 0-ring 118 which is seated in groove 67 in casing 62, As seen in Fig, 6, vent plug 108 has a channel 109 preferably positioned adjacent to the top of second compartment 60. Channel 109 in vent plug 10a allows gases during normal operating conditions in first compartment 40 and second compartment 60 to be separated from the liquid and released into discharge pipe 90 and out of the system without requiring pressure to be built up before such gases are released. Channel 109 is large enough to allow the vapors to escape but small enough to prevent any appreciable liquid bypass.
Of course as an alternative to aperture 66, plug 108 and vent 109, the casing could be cast without such aperture and a small vent hole could be drilled to allow passage of gases into fitting 96 and outlet pipe 90.
Water flowing through inlet pipe 20 will enter the lower end of first compartment 40 and be heated by heater element 140 as the water rises within first compartment 40. The water will then flow-through connector 104 and down through second compartment 60 as it is heated by heater element 1G0. The water then reaches the lower end of second compartment GO and is discharged through discharge fitting 92 and out discharge pipe 90, which may be fabricated as a single piece if desired. Any gases which may build up in the system through the interaction of heaters 140 and 160 with the water will automatically rise to the top of first compartment 40 and second compartment 60 because of the lower density of the gases.
As shown in Figs. 4 and 6, connector 104 and vent channel 109 located in vent plug 108 creates an outlet for these gases through discharge pipe 90 so that heating elements 140 and 160 will remain submerged at all times and so that temperature sensor 120 will sense a fluid temperature and not. vapors. Water flowing through vent channel 109 in vent plug 108 will be limited because of the decreased area of vent channel 109, It is to be understood that all attachments made by bolts may be made by other suitable attachment means such as adhesive or sonic welding, for example, and that inlet pipe 20, inlet fitting 28, discharge fitting 92 and bleeder fitting 108 may each or all be made as pieces threldable or otherwise attachable to pipes 20 and 90 or as features mRnufactured into the pipes 20 and 90. It is also to be understood that compartments 40 and GO
could be prefabricated as one piece which eliminates the need for connectors and O-rings between the two compartments although connection could still be made to additional compartments added on to the two compartments.
Referring now to Fig. 7, a more detailed view of the flow-through heating apparatus 10 shown in Figs. 1-6 is shown. Triac heat sink 170 is to be mounted on inlet pipe 20. Screw mounted triacs 171, 172, 173 and 174 are mounted an heat sink 170. High limit thermostatic cut-off switch 177 and grounding plate 178 are to be connected over aperture 65 located in the upper end of second compartment 60. High limit switch 177 senses excess temperature within the heatin g apparatus 10 and cuts-off heaters 140 and 160 when such overtemperature conditions are sensed. An optional contro l board mounting plate 175 is shown connected to f i rst compartment 40 and second compartment, 60 and el ectri c i nput terminal 176 is shown connected to second compartment 60. These terminals may be placed at any suitable location and are shown as described above merely for illustration.
Fi9. 8 illustrates a two compartment fluid heating apparatus 10 for fluids, such as water, and includes first compartment 40 and second compartment 60. Fluid enters compartment 40 where it is heated. The fluid leaves compartment 40 and then enters compartment 60 where i t may a 1 so be heated , The f 1 a i d then ex i is from compartment 60. The temperature of the fluid leaving compartment 40 is identified as temperature T1 and the temperature of the fluid exiting compartment 60 is identified as temperature T2.
The design of control system 200 - as described below illustrates a preferred control system design. Once given the control system concepts such design would be known to one of ordinary skill in the art for carrying out a preferred mode of the invention. Other control system designs known to one of ordinary skill in the art could also be used.
The control system 1 og i c ~00 i s shown and may i nc 1 ude an optional water level permissive which enables the control function whenever sufficient water level is detected in the heating compartments using conductivity measurement means. Also it is shown to have an operat~nd set point OSP, a transitional -set point TSP and a stand-by set point SSP which controls when the heater is at rest. The stand-by set point SSP serves to prevent stand-by heating losses and to prevent the heating 2~~ i~~~.

apparatus 10 from freezing when in a stand-by mode in a freezing location. The transitional set point TSP is the actual target temperature prov i ded to the heat i ng apparatus 10 by the 1 og i c 200. It is a set point derived from operating set point OSP.
The operating set point OSP is the selected temperature for hot fluid leaving the instantaneous flow-through heating apparatus when the heating apparatus 10 is functioning, The transitional set point TSP is also derived from stand-by set point SSP, Starid-by set point SSP represents a lower set point than the operating set point OrP while transitional set point TSP
is a value between SSP and O~P and preferably floats above the incoming temperature of the fluid and the freeze point of the fluid. The stand-by set point SSP functions to allow the fluid heating apparatus 10 to cool down, use less power and have lower heat losses when in a non-flow or stand-by mode. The operating set point OSP, stand-by set point SSP, temperature T1 and temperature T2 are all inputs to control system logic 200. The transitional set point TSP is internally generated within the control system logic 200. The output of control system logic 200 is first heater drive 240 and second heater drive 260. Heater drive 240 provides energy to heater 140 which is located in compartment 40 and heater drive 260 provides energy to heater 160 which is located in compartment 60.
As previously discussed, the logic 200 as shown permits a time delayed transition between the operating set point OSP and stand by set point SSP which is known as transitional set point TSP. If the designer chooses, the transition time can be established as instantaneous, in which case the transition set point TSP becomes equal to either operating set point OSP or slightly higher than the stand by set point SSP based upon whether there is flow through the heating apparatus 10 as determined by the , relationship between temperature T1 and temperature T2. With slight modification one skilled in the art can eliminate the sophistication of TSP and design the units logic to operate at either OSP and 5SP based on the ex,istance of flow which is determined by the relationship between T1 and T2.

WO 91/17640 ~~~'?~?~ PCT/US91/03213 A designer can likewise choose transition set point TSP to be a floating value determined by a fixed number added to temperature T1 or subtracted from temperature T2. Thus (depending upon whether flow is detected by the relationship between temperatures T1 and T2) the transitional set point TSP
(regardless of whether it is instantaneous or floating) is modified to a design chosen dead band range around operating or stand-by condition. Typical values for a domestic home water heater might be an operating set point OSP of 1450 Fahrenheit (630 Celsius) and a stand-by set paint SSP of 400 Fahrenheit (4° Celsius) or some other value above the fraezing point of the fluid being conducted through the heater 10.
Now referring to Fig. 9, an example of logic switch implementation for Fig. 10, there is shown a schematic diagram for the flow switch circuit, generally designated 214, which is an analog switch which differentiates between two analog inputs and yields an output representing a logic 1 or a logic 0 based upon which of the two inputs is higher These circuits are well known to those skilled in the art and function as switches throughout the control system of this embodiment.
The circuit 214 entails two input voltages V1 and V2 which respectively represent the compartment outlet temperatures of the first compartment 40 and the second compartment 60 through current limiting.resistors R3 into an operational amplifier A which has a tie back capacitor C to the inverting input. Typical components and/or values for such J
components shown in Fig. 9 would be as follows: Thermistors T1 and T2, General Automotive Specialties number 25502; resistors Rl, approximately 800 to 1200 ohms; resistors R2, 0 ohms when using General Automotive number 25502 (the case of the -thermistor is grounded and R2 is automatically 0). Resistors R3 serve only a current limiting function and may be any value between 1,000 ohms and 100,000 ohms; the tie back capacitor C
is typically between .1 to .4 microfarads; the operational amplifier A would typically be 1/4 of a Motorola integrated circuit number MC3403P. Others may be used, of course, but the foregoing components may be used with satisfactory results.
SUBSTITUTE SHEET

t3 . The internal logic 200 for controlling the flow-through heating apparatus 10 is unique because it incorporates flow detection without requiring ~ conventional flow switch. The electronic flow detection 'is bF~sed on the following principle:
First heater 140 will mttintFrin temperature T1 higher than " temperature T2 during a stand-by mode when thQre is no flow through the heating apparatus 10; when flow begins the warmer water from compartment 40 is fc~rcarJ in to compartment GO causing T2 to become equal or nearly equal to T7 thereby indicating flow;
and when the heaters 140 anti 1G0 for the fluid are activated or heated sequentially in suctn a manner that hector t40 is activated sequentially ahead of hQater 1G0 whoa flow starts and are deactivated sequentially in such c~ manner that heater 1G0 shuts dawn sequentially ahead of the shutdown of heatQr 140 when flow stops, then flow detection can be based on the relationship between two separate locations,or chamber such as temperature T1 in Compartment 40 and temperature T2 in compartment 60. Given the flow detection concept, one skilled in the art could design the flow detection method to operate based on the temperature relationship between any two locations within the heater, such as the temperature. re 1 at i onsh i p between the i ncomi ng f 1 a i d supp 1 y 20 to the fluid in compartment 40. For flow detection one temperature sensor must be located downstream from another and a heating means rnust be positioned such that a temperature differential is maintained between the sensors when there is no fluid flow, This 'invention controls the activation of the heatef"s 140 and 160 based on the flow detection principle and, because such flow detection is done without mechanical moving parts, such detection is quite reliable and effective, For operation, the flow switch ~t 4 only requi res that heat be appl i.ed in the first compartment 40 and then only enough to maintain the temperature at or above the standby set point SSP.
The control system uses the temperature sensor 120 located in the first compartment 40 to measure a value for T1 and the temperature sensor 125 located in the second compartment 60 to measure a value for T2 the difference between the temperatures -a r_ ~~
~~~u:~ . ...

of the two compartments is used to detect flow, When there is no f 1 a i d f 1 ow , heat i s f i rst added to the f 1 a i d i n the f i rst Compartment 40 through the first heating element 140 in order to maintain the fluid in the first compartment 40 at or above the stand-by set point temperature SSP. In this state, the temperature T1 in the first cornpartmQnt 40 will be higher than the temperature T2 in the second compartment 60, In a situation where there is no flow and where temperature T1 drifts in such a manner that~it approaches T2 and flow is indicated by output signal 312 such a condition lasts only momentarily because the following sequensce of events occurs, As seen in Fig. 10, TSP
is incremented by output signals 302 and 312; heater No. 1 is incremented by signals 314 and 326, temperature T1 increases qu i ck 1 y because there i s no f 1 ow ; T 1 becomes h i ghe r than T2 wh i ch restores the "no flow" signal 3t0; TSP is decremented by output signals 306, 310, and 314; heater No, t demand is decremented by output signals 3t6 and 322; and the "no flow" stand-by state is restored.
When the fluid begins to flow, even though heat will be added, the temperature T1 in the first compartment 40 will fall below the temperature T2 in the second compartment 60 and by comparing these two temperatures T1 and.T2, or the temperature differential, the control system determines that there is flow through the system. When the control system detects flow the set point normally changes from an idle or transitional set point TSP
to an operating set point OSP as described below and shown in Fig, 10, The operating set point OSP is generally equal to the desired output temperature of the system.
When fluid stops flowing or flows at very low rates through the system the temperature sensed in the first and second ' compartments 40 and 60 wi 1 1 beg i n to ectua 1 i ze and when f 1 ow stops the temperature T1 in the first compartment 40 will exceed the temperature T2 in the second compartment 60. The control logic !
200, by comparing the temperature difi~ferential or by registering a low first heater demand HtD, wi 11 determine that there is a "no flow" state and the furthest downstrearn heating element which is activated will be decremented until it is deactivated at which time, if required, the adjacent heating element will be decremented so that the fluid temperature will be changed from operating set point OSP to a transtional set point TSP, approaching stand-by set point SSP, between operational set point OSP and stand-by set point to reduce stand-by losses in energy.
The stand-by point temperature SSP may be a floating set point temperature or a fixed point temperature as well. A
preferable floating stand-by set point temperature SSP will float to remain at a margin of 80 or loo Fahrenheit (-130 or -12o Celsius) above the inlet temperature to the water heater system 10 but it should always be maintained at the margin selected above the freezing temperature of the fluid.
Logic element 214, as described, is comparable to each of the other logic elements shown in Fig. 10, these being logic elements 210, 212, 216, 218, 220 and 222.
Where appropriate, the control system will include electrical conductivity to detect an acceptable water level in the compartments as a permissive for the application of power to the control system logic. An electrical contact pair (not shown) is located proximate to thermistors 120 and 125 for detecting the presence of a full compartment of water through conductivity means as an optional permissive to operation o~
the heating apparatus 10.
Fig, 10 outlines the design logic for a two chamber heating apparatus 10 using temperature derived electronic flow detection, it being understood that such control logic system 200 is applicable for any pair of a series of chambers greater than twa, which may be assembled together. On the left side of Fig. 10 are the four inputs to the control system logic 200, namely, operating set point OSP, stand-by set point SSP, outlet temperature Tl of first compartment 40, and outlet temperature T2 of compartment 60.
The logic required to operate the two compartment 40 and 60,,two heater element 140 and 160, heating apparatus 10 consists of SUBSTITUTE SHEET

seven analog logic switches 210, 212, 214, 216, 218, 220 and 222, two maximum demand limit set points Hlh1 and H2M one each for f i rst heater 140 and second heater 1 60 ; s i x 1 og i c "AND" gates are required to complete the logic; three additional inputs to the logic are generated from the outputs: These are transitional set point TSP, first heater demand H1D and second heater demand H2D.
There are six outputs from heater control logic 200. The first output 230 functions to increment the transitional set point TSP and th'e second output 232 functions to decrement the transitional set point TSP.
The third output 234 of the heater logic ~00 is to increment the demand of the first heater 140 and tyre fourth output 236 is to decrement the demand of th a first heater t40. These two outputs 234 and 236 go to first heater demand H10 which is also provided as a signal back into logic ~00.
The f i fth output 238 of the heater 1 ogi c 200 i s to i ncrement the demand of the second heater 160 and the sixth output 239 is to decrement the demand of the second heater 160. These two outputs 238 and 239 go to second heater demand H2D which is also provided as a signal back into logic 200.
The functioning of internal logic 200 shown in Fig. 10 is described as follows. As shown, the conditions required to increment the transitional set point TSP are a yes output 302 from logic 210 and a no output 312 from logic 214. This output, 230, is used to increment the transitional set point TSP above the stand-by set point SSP but no higher than the operating set point OSP. The conditions required for output signal 232 to decrement the transitional set point TSP are a yes output 306 from logic 212, a yes output 310 from logic gate 214 and preferably also includes a yes output 314 from logic gate 216.
Yes output 306 results when the transitional set point TSP is greater than the stand-by set point SSP. Yes output 310 results when temperature T1 is greater than temperature T2. Yes output 314 results when the transitional set point TSP is greater than temperature T2 which limits the transitional set point TSP to tracking temperature T. during cool down when the heating 2~~ ~~~1 apparatus 10 is in a stand-by state.
First heater demand HID is controlled by increment output signal 234 and decrement output signal ~36 provided through logic "AND" gates. The conditions required to increment signal 234 the first heater demand H1D are a yes outputs 314 and 326, respectively from logic gates 21~ and 222, These conditions are met in logic gate 216 when trapsition set point TSP is greater than temperature T2 and are met in logic gate 222 when first heater maximum~demand limit Hlht is greater than first heater demand H1D. Thus, the transitional set point TSP is calling for more heat and the f i rst heate r max i mum H 1 M 1 i mi t has not been reached, The conditions required to decrement signal 23G the first heater demand H1D are a no output 316 from analog logic switch gate 216 and a yes output 322 f rom l og i c gate 220 . No output 31 6 results when transitional set point TSP is not greater than temperature T2. Yes output 322 results in analog logic switch 220 when the second heater demand H2D is substantially equal to zero ZV which preferably results when 0.05 volts are registered although other voltage reading limits can be used. In brief, if the outlet temperature T2 exceeds the transitional set point TSP
and the second heater demand H2D is substantially zero, then decrement the first heater demand H1D, The second heater demand H2D i:~ controlled by increment signal 238 and decrement signal 239 provided through logic "AND"
gates. The conditions required to increment signal 2313 the second heater demand H2D are a yes output 314 from logic gate 216, a no output 328 from logic gate 222 and a no output 320 from logic gate 218. A yes output 31.~ results in logic gate 216 when the transitional set point TSP is greater than temperature T2.
A no output 328 resu 1 is f rom 1 og i c gate 222 when the max i mum capability of the first heater H1M is not greater than the first heater demand HiD, A no output 320 results from logic gate 218 when the second heater demand H~D is not greater than or equal to the maximum capability of the second heater H2M. In brief if the outlet temperature T2 is less than the target temperature w ~ (~~ r_,I,/~'~'/
~~i~i~IU~~.
TSP, the demand of the first heater H1D is at maximum capability H1M and the demand of the second heater H2D is not at maximum capability H2M, then the demand on the second heater H2D should be incremented.
The conditions required 1;o decrement signal 23J the second heater demand F12D area a no output. ~ 1 G f rom 1 og i c gate 21 G and a no output 324 from logic gHte ~v0, r~ no output 31G resulis in logic gate 216 when the tran;;itional set point TSf~ is not greater than temperature T2, A nca outr~ut 3?4 results from logic gate 22p when the second heater demand hl?U i~,: not substantially equal to zero ZV, In brief, if' the outlet tvrnperwture T'.' is greater than or equal to the target t~miiF~r,itur~e TSi~ and i:here i s a demand on the second heater H2D, suoh demand on the second heater H2D
should be decremented.
For simplicity, all of the above has been drawn and discussed based on a two compartment, two heater element fluid heating apparatus 10 for such fluids as domestic water. The same logic can be applied to control of a multi-element, multi-compartment heating apparatus with more than two heating elements and more than two compartments simply by incorporating all additional heating elements within the additional compartments sequentially after heating element 160 and compartment 60. The designer can adapt the invention to the output needs of the end user by incorporating the necessary control system, and number of compartments and heating elernents. Thus, one skilled in the art would simply sequence each successive heater to the limit required.
Likewise, in a heating apparatus 10 having more than two compartments one would separate temperature T2 into two separate measurements. Temperature T? represented in logic element 214 ' used to~determine if Flow exists would be sensed by temperature sensor 125 located in the second sequential compartment ~
However, temperature T2 used as the main heater control input in logic element 216 would preferably be sensed from the last sequential compartment (e.g, if' there are six compartments, in the sixth compartment), 2~'~ ~2'~..
1~
Likewise, one skilled in the art can use the inputs to analog logic switches ~14 and __~1G also as inputs to differential amplifiers to establish rate or occeleration/daceleration limits for a moving transitional set point TSP, first heater demand H1D
and second heater demand H~U fm- even more precise control.
In the preferred embodiment:, tran:,itional set point TSP, f i rst heater demand H 1 D and srrcr~nd hreater demnnd HAD represent analog memory units operating between 0 and 5 volts d/c. Their output is converted to asynchronous pulses using a pulse width modulator such as Motorola MC3:~060 whose output is used to drive NOR logic drivers such as Motorol<~ SN74LS2nN which in turn drive optical isolation units such as Motorola MOC3040. The optical , isolation units are directly connected to triac switches which control power to the heating elements 140 and iGO, Of course equivalent components are known which can accomplish the results set forth above.
The control system uses the pulse width modulator to modulate each of the heating elements in each compartment in response to the comparison rnade between the set point SSP or TSP
and the temperature as sensed at the outlet of each compartment.
One object of the control system is to achieve a constant outlet temperature from the instantaneous water heater as determined by the user of the heater, This object is achieved by sequentially modulating the activation or "on" time of the heating element adjacent to the last sequential heating element which is fully on until the desired outlet temperature from the entire system is achieved. If the user of thQ system then desires to lower the outlet temperature of the system the control system will then reverse itself to sequentially modulate the deactivation of the heating elements and shut off heatin g elements as required to allow the outlet temperature of the fluid to lower. The acceleration of the duty cycle of modulation can be adjusted to either be an increasing, decreasing or constant rate of acceleration or deceleration depending upon the needs of the system.
When hot water is desired from the heating apparatus 10 at La ~~". w ~,s'w ~.
rest, the control syst~:m will initi,~lly begin to modulate the first heating element 1~0 located in the first compartment 40.
The percentage "on" time of the first hefting element 140 will continue to increase until either a first switching point temperature is reached (at which time the first heating Qlement 140 goes from a high duty cycle to a fully on position) or until the desired outlet temperature from the system is reached, If the first switching point temperature is reached prior to reaching the o~rtlet temperature, the first heating clement 140 will go from a high duty cycle, tc~ a fully on position and the second heating element 160 wall begin to modulate, The duty cycle of the second beating element t60 will increase once again until the desired outlet temperature is reached or until it is turned fully an. If it is turned fully on and a third sequential Compartment is included, then the process will continue as described above, If only two compartments are included, the system will then be operating at maximum output capability.
An embodiment used for electronic control of electric heating elements has been described. However, the output increment and decrement signals could be provided to a stepping motor which sets a pi lot valve for a gas operated heater as wel 1 .
It is not the intention to limit this, invention to either electric or gas heating, since either mode of heating can be applied and incorporated into the invention.
The control system utilizing the control logic 200 and flow detection device 214 of the present invention as shown in Figs.
8, 9 and 10 preferably operates with two or more compartments although one compartment may be used as well. If only one compartment is used, the ternperature must be sensed both at or proximate the inlet end and at or proximate the outlet end of such compartment.
As previously described for the two compartment embodiment the temperature sensors 120 and 126 are located proximate the outlet aperture of the first and second compartments 40 and 60.
If there are more than two compartments, the preferred embodiment of this invention need only include temperature sensors in the first and second compartment; and in the last sequential compartment. However, temperature sensors may be loo ted in each and every compartment or in the inlet andlor outlet pipes as well. The control system u::es thesN temper,~ture sensors to detect the flow of a fluid through the system, to detect overtemperature conditions within the system, and in order to determine whether heating eloment;> within the system should be activated in order to achieve ,~ desired output temperature of the fluid flowing out of the system, When there are more than two compartmen t , the control system can either establish an operating set point OSP for each compartment separately or can maintain an operating set point OSP
for only the outlet from the entire system, The operating and stand-by set points are both adjustable or variable. The operating set point OSf~ may be set before the instantaneous water heater is installed or may be adjusted by the user. If temperature sensors are included in each compartment, the control system can compare the temperature reading at the outlet of each compartment as sensed by the temperature sensors to the respective set point temperatures. However, in the preferred embodiment, the control system will compare the set point temperature with the temperature reading ~t the outlet from the anti re system as sensed by the temperature sensor i n the 1 ast sequential compartment.
The control system logic 200 also includes an overtemperature shut down feature. When the sensor 125 senses that the outlet temperature T2 of the second compartment 60 (or the final compartment in a multiple compartment system) exceeds the transitional Set point TSP, the control system logic 200 wi 11 determine that the first compartment 40 has reached an overtemperature and will decrement the heating elements 140 and t60. The heating elements 140 and 160 will be modulated back on agai n as soon as temperature T2 roe 1 s down be 1 ow the t runs i t i on a 1 set Point temperature TAP. The control system logic 200 incorporates an additional overtemperature shut down feature through input from high limit thermostatic cut-off switch 177 WO 91/17640 ~~~~r"~~.

which will switch off the heating elements 140 and 160 in the event that overtemperature conditions exist due to a failure in the control logic 200, sensors 120 or 125, etc.
All of the parts used to make the flow-through heating ' apparatus can be made from plastic except for the electronic control and wiring; heating elements 140 and 160, the temperature sensors 120 and 125; 0-rings and miscellaneous hardware. Through the use of plastics, the compartments can be made at a low cost while being non-corrodible, self-insulating, lightweight, sturdy, durable and capable of operating at temperatures above 150° Fahrenheit (65° Celsius). High temperature thermoplastic resins can be used to satisfy the engineering design requirements. Preferable high temperature thermoplastic is a group of resins sold under the registered trademarks "NORYL" and "ULTEM" by the General Electric Company. "NORYL" and "ULTEM" can be used for operational temperatures up to and exceeding 1800 Fahrenheit (82°
Celsius). "NORYL" resins retain tensile and flexural strength and modulus at temperatures above 200° Fahrenheit (93°
Celsius), have relatively low coefficients of thermal expansion (between 1.4 and 4.1 in/in/°F a 10-5 or 2.5 and 7.4 cm/cm/°C a 10 5), allow for a wide choice of heat deflection temperatures while under load, have low water absorption rates at elevated temperatures which contributes to dimensional stability under high water temperature conditions and has low heat loss rates. "ULTEM" is useful in applications where a high resistance to chemical degradation from petroleum products ~is needed and is more stable than "NORYL" at high temperatures. Other materials such as ceramic may also be used for construction of the compartments. Various operating temperatures can be implemented by the designer or installer through the stand-by set point SSP and the operating set point OSP which may be set manually. The placement of 0-rings and grooves can be varied between connecting parts. However, it is intended that the 0-rings and grooves be placed for modularity and compatibility of the compartments, The compartments could also be sealed by other means such as chemically or by sonic welding.
The preferred embodiment of this invention has been shown WO 91/I7b40 PCT/US91/03213 ivlw and described above. It is to be understood that minor changes in the details, construction and arrangement of the parts may be made without departing from the spirit or scope of the invention as claimed,

Claims (17)

Claims:
1. A water heater for the substantially instantaneous heating of water, said water heater comprising:
a first compartment having a first inlet aperture located proximate one end thereof and a second outlet aperture located proximate the opposing end thereof, said first compartment including first heating means and first temperature sensing means, and a second compartment downstream from said first compartment and having a third inlet aperture located proximate one end thereof and in fluid communication with said second outlet aperture, and a fourth outlet aperture located proximate the opposing end thereof, said second compartment including second heating means and second temperature sensing means, a downstream flowline in fluid communication with said fourth outlet aperture for transmitting heated water downstream from said second compartment, wherein said second and third apertures function as a means for automatically and continuously venting gas from said first compartment to said second compartment during operation of said water heater, and further including a vent aperture having a restriction greater than said fourth outlet aperture for automatically and continuously venting gas from a portion of said second compartment spaced from said fourth aperture to said downstream flowline during operation of the water heater, such that the majority of water flows from said second compartment to said downstream flowline through said fourth outlet aperture while a majority of gas within said first compartment and second compartment flow through said vent aperture to said downstream flowline.
2. A water heater as defined in claim 1, wherein said first inlet aperture is located at a lower end of said first compartment, said second outlet aperture is located at an upper end of said first compartment, said third inlet aperture is located at an upper end of said second compartment, and said fourth outlet aperture is located at a lower end of said second compartment.
3. The apparatus as defined in claim 2, wherein the vent aperture is located at an upper end of said second compartment.
4. The water heater as defined in claim 1, wherein said first and second compartments include a readily detachable and reattachable draining and cleaning means located at one end of said compartments, whereby the entire interior region of said first and second compartments is directly assessed by the removal of said draining and cleaning means such that fluid and solids may be readily drained and flushed from said compartments and the interior region of said compartments may be cleaned.
5. The apparatus as defined in claim 1, wherein each of said first and second compartments are defined by respective first and second housings, and each of said first and second housings include flange means for modular connection of said second outlet aperture and said third inlet aperture.
6. The apparatus as defined in claim 5, wherein each of said first and second housings is fabricated from a self insulating, high temperature resistant, chemically resistant thermoplastic.
7. A flow-through heating apparatus for the substantially instantaneous heating of fluids, the apparatus comprising:
a first compartment having a first inlet aperture located proximate one end thereof and a second outlet aperture located proximate the opposing end thereof, said first compartment including first heating means and first temperature sensing means, and a second compartment downstream from said first compartment and having a third inlet aperture located proximate one end thereof and in fluid communication with said second outlet aperture, and a fourth outlet aperture located proximate the opposing end thereof, said second compartment including second heating means and second temperature sensing means, each of the first and second compartments defined by respective first and second housings substantially similarly configured, said second aperture outlet from said first housing having a modular connector for selective connection or removal from said third inlet aperture of said second housing, such that a selected number of compartments for said water heater may be readily altered by adding or deleting additional second housings.
8. The flow-through heating apparatus as defined in claim 6, wherein said connector on said first and second housings comprises:
a planar flange for bolted interconnection of said first and second housings; and sealing means for sealing between said flanges on said first and second housings for fluid tight communication between said first and second compartments.
9. A flow-through heating apparatus for the substantially instantaneous heating of fluids, the apparatus comprising:
a first compartment having a first inlet aperture located proximate one end thereof and a second outlet aperture located proximate the opposing end thereof, said first compartment including first heating means and first temperature sensing means, and a second compartment downstream from said first compartment and having a third inlet aperture located proximate one end thereof and in fluid communication with said second outlet aperture, and a fourth outlet aperture located proximate the opposing end thereof, said second compartment including second heating means and second temperature sensing means, control means responsive to said first and second temperature sensing means for controlling actuation of said first and second heating means, and flow detecting means responsive to said first and second temperature sensing means for detecting flow through said heating apparatus and for altering said control means in response thereto.
10. The heating apparatus as defined in claim 9, wherein said control means includes a set point temperature selecting means which represents a desirable temperature of the fluid output from said heating apparatus, whereby when said flow detecting means detects flow, said set point temperature selecting means will select an operational set point temperature, and when said flow detecting means fails to detect flow and said set point temperature, said selecting means will select a standby set point temperature less than said operational set point temperature.
11. The flow-through heating apparatus as defined in claim 10, wherein said control means includes sequential, continuous and random modulating means for varying the percentage of activation time of said heating means within each of said first and second compartments sequentially in a continuous and random manner such that the sensed temperature will approach the set point temperature.
12. The flow-through heating apparatus as defined in claim 11, wherein said flow detecting means comprises temperature comparison means for comparing the temperature sensed by the first and second temperature sensing means.
13. The flow-through heating apparatus as defined in claim 11, wherein said first and second compartments each include a readily detachable and reattachable draining and cleaning means located at one end of said compartments, whereby the entire interior region of said first and second compartments is directly assessed by the removal of said draining and cleaning means such that fluid and solids may be readily drained and flushed from said compartments and the interior region of said compartments may be cleaned, and each of said first and second compartments is formed from respective first and second housing fabricated for a self-insulating, high temperature resistant, chemically resistant thermoplastic.
14. A flow-through heating apparatus which senses temperature in a fluid conducting means through which the fluid flows, said apparatus comprising:
a first heating means located within said fluid conducting means; a first temperature sensing means associated with said first heating means for sensing the temperature of the fluid within said fluid conducting means; a second temperature sensing means, located within said fluid conducting means downstream from said first heating means and said first temperature sensing means, a control means including a set point temperature means for varying the temperature sensed by said first temperature sensing means when there is no fluid flow while the temperature sensed by said second temperature sensing means remains relatively constant after drifting toward an ambient temperature, and said control means further including a temperature comparison means for detecting fluid flow when the temperature sensed by said first temperature sensing means converges with the temperature sensed by said second temperature sensing means, a second heating means located within said fluid conducting means downstream from said first temperature sensing means and associated with said second temperature sensing means, said control means further including means for selecting an operating set point temperature to which the fluid is to be heated when there is flow through said fluid conducting means; said control means further including means for transitioning the temperature of the fluid by targeting a transitional set point temperature between a stand by set point and said operating set point, said control means further including means for incrementing said transitioning means which is activated when said operating set point is greater than said transitional set point and the temperature of the fluid sensed by said first temperature sensing means is not greater than the temperature of the fluid sensed by said second temperature sensing means; said control means further including means for decrementing said transitioning means which is activated when said transitional set point is greater than said stand by set point and the temperature of the fluid sensed by said first temperature sensing means is greater than the temperature of the fluid sensed by said second temperature sensing means, said control means further including means for incrementing the demand on said first heating means activated when said transitional set point is greater than the temperature of the fluid sensed by said second temperature sensing means and the demand on said first heating means is not at a maximum demand, said control means further including means for decrementing the demand on said first heating means activated when said transitional set point is not greater than the temperature of the fluid sensed by said second temperature sensing means and the demand on said second heating means is substantially equal to zero, said control means further including means for incrementing the demand on said second heating means activated when said transitional set point is greater than the temperature of the fluid sensed by said second temperature sensing means, said first heating means is at the maximum demand and the demand on said second heating means is not at the maximum demand, and said control means further including means for decrementing the demand on said second heating means activated when said transitional set point is not greater than the temperature of the fluid sensed by said second temperature sensing means and the demand on said second heating means is not substantially equal to zero.
15. The apparatus of claim 14 wherein said fluid conducting means comprises: at least one compartment including a casing having a hollow interior region, a fluid inlet located proximate one end and a fluid outlet located proximate the other end whereby the fluid passes from said inlet through the hollow interior region and out said outlet, and said compartment including a base having a means for isolated attaching and detaching of said base to an end of said casing, said isolated attaching and detaching means being isolated from the fluid passing through said compartment for readily and directly accessing the entire interior region after detachment of said base such that fluid and solids may be readily drained and flushed from said compartment and the interior region of said compartment may be cleaned.
16. The apparatus of claim 14, including: a plurality of compartments, each of said compartments including a casing having a hollow interior region, a fluid inlet located proximate one end and a fluid outlet located proximate the other end whereby the fluid passes from said inlet through the hollow interior region and out said outlet, said heating means including a heating element oriented in each compartment, and each of said compartments including interconnected automatic continuous venting means located at an upper end of said compartments whereby gases may be vented from said compartments and a last sequential compartment including an automatic continuous venting means located at an upper end for venting the flow-through heating apparatus during operating conditions.
17. The apparatus of claim 14, wherein said casing of said compartment is made from a self-insulating, high temperature resistant, chemical resistant thermoplastic.
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Families Citing this family (77)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5216743A (en) 1990-05-10 1993-06-01 Seitz David E Thermo-plastic heat exchanger
WO1993019332A1 (en) * 1992-03-18 1993-09-30 KKW Kulmbacher Klimageräte-Werk GmbH Electric instantaneous water heater
US5438642A (en) * 1993-07-13 1995-08-01 Instantaneous Thermal Systems, Inc. Instantaneous water heater
US5479558A (en) * 1993-08-30 1995-12-26 White, Jr.; James A. Flow-through tankless water heater with flow switch and heater control system
JP3265895B2 (en) * 1995-02-20 2002-03-18 トヨタ自動車株式会社 Air-fuel ratio sensor heater control device
JPH08248805A (en) * 1995-03-07 1996-09-27 Mita Ind Co Ltd Fixing part temperature controller for image forming device
US5590240A (en) * 1995-05-30 1996-12-31 Process Technology Inc Ultra pure water heater with coaxial helical flow paths
US5729653A (en) * 1995-06-07 1998-03-17 Urosurge, Inc. Fluid warming system
AU7016396A (en) * 1995-10-10 1997-04-30 Donald Kuhnel Fluid heater with improved heating elements controller
WO1997024562A1 (en) * 1995-12-28 1997-07-10 H-Tech, Inc. Heater for fluids
US6080971A (en) * 1997-05-22 2000-06-27 David Seitz Fluid heater with improved heating elements controller
US5892887A (en) * 1997-07-17 1999-04-06 Venturi Technologies, Inc. Electric water heater with a pair of interconnected heating chambers having concentric copper tube structures
US6246831B1 (en) 1999-06-16 2001-06-12 David Seitz Fluid heating control system
DE10003042B4 (en) * 2000-01-25 2012-03-08 Stiebel Eltron Gmbh & Co. Kg Electric water heater
KR100711687B1 (en) 2001-10-01 2007-05-02 엔테그리스, 아이엔씨. Apparatus for conditioning the temperature of a fluid
ITPN20020082A1 (en) * 2002-10-10 2004-04-11 Irca Spa PERFECTED FLUID HEATER TUBE.
US7190894B2 (en) * 2003-01-03 2007-03-13 Mc3 Technology, Inc. Energy efficient electric water heater system that provides immediate hot water at a point of use and a method therefor
US20040131346A1 (en) * 2003-01-03 2004-07-08 Chamberlain Roland J. Energy efficient electric water heater system that provides immediate hot water at a point of use and a method therefor
US6701069B1 (en) * 2003-02-12 2004-03-02 Cem Cezayirli Pre-heating contiguous in-line water heater
WO2004072562A2 (en) * 2003-02-12 2004-08-26 Cem Cezayirli Pre-heating contiguous in-line water heater
CN1299093C (en) * 2003-06-24 2007-02-07 上海电力学院 Multi-stage liquid-bahting heat exchanger
US7112768B2 (en) * 2004-02-02 2006-09-26 9090-3493 Quebec Inc. Temperature control system for a bathing unit
US6909843B1 (en) * 2004-02-24 2005-06-21 Eemax Incorporated Electric tankless water heater
US20070289732A1 (en) * 2004-03-11 2007-12-20 Pillion John E Apparatus for conditioning the temperature of a fluid
TWM265577U (en) * 2004-05-27 2005-05-21 Min-Jie Chen Heat pipe type electric water heater
US7779790B2 (en) * 2004-08-06 2010-08-24 Eemax, Inc. Electric tankless water heater
JP5186216B2 (en) * 2004-12-20 2013-04-17 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ Operation method of flow-through type heating device
DE102005007935A1 (en) * 2005-02-15 2006-08-24 E.G.O. Elektro-Gerätebau GmbH Heating device for an electrical appliance
US7164851B2 (en) * 2005-03-15 2007-01-16 Sturm William R Modular tankless water heater control circuitry and method of operation
US7046922B1 (en) * 2005-03-15 2006-05-16 Ion Tankless, Inc. Modular tankless water heater
US7020387B1 (en) * 2005-03-28 2006-03-28 Andrakin James W Hybrid water heater
US8861943B2 (en) 2005-05-04 2014-10-14 Isi Technology, Llc Liquid heater with temperature control
US7817906B2 (en) * 2005-05-04 2010-10-19 Isi Technology, Llc Direct electric resistance liquid heater
WO2006130929A1 (en) * 2005-06-09 2006-12-14 Ollin Sustainable Technologies Pty. Ltd. Compact water heating apparatus
WO2007111602A1 (en) * 2006-03-29 2007-10-04 Andrakin James W Hybrid water heater
US7460769B2 (en) * 2006-10-31 2008-12-02 Ryks William R Modular water heating systems
US20080264617A1 (en) * 2007-04-26 2008-10-30 David Martin Heat exchanger
US7971603B2 (en) 2007-01-26 2011-07-05 Hayward Industries, Inc. Header for a heat exchanger
US20080223561A1 (en) * 2007-01-26 2008-09-18 Hayward Industries, Inc. Heat Exchangers and Headers Therefor
US8103156B2 (en) * 2007-02-12 2012-01-24 Gaumer Company, Inc. Fuel gas conditioning system
US8869880B2 (en) 2007-02-12 2014-10-28 Gaumer Company, Inc. System for subsea extraction of gaseous materials from, and prevention, of hydrates
US8728219B2 (en) 2007-02-12 2014-05-20 Gaumer Company Inc. Heater for vaporizing liquids
US8061263B1 (en) * 2007-04-16 2011-11-22 Richard W. Hein Sensor head and brew cup for a beverage brewing device
US8165461B2 (en) * 2007-05-07 2012-04-24 Sullivan Joseph M Modular heating system for tankless water heater
JP2009002424A (en) * 2007-06-21 2009-01-08 Nitta Moore Co Piping structure of heating and heat-retention pipe
JP4823980B2 (en) * 2007-07-30 2011-11-24 ニッタ株式会社 Equipment with heating and heat insulation tubes
US8744252B1 (en) 2008-03-12 2014-06-03 John Snyder Tankless hot water generator
US8150246B1 (en) * 2008-07-22 2012-04-03 Niagara Industries, Inc. Tankless water heater assembly
CA2639413A1 (en) * 2008-09-11 2010-03-11 Ray King Closed loop heating system
IES20090347A2 (en) * 2009-05-01 2009-10-14 Tekelek Patents Ltd A method and apparatus for detecting flow of a fluid through a heat exchanger
KR100982702B1 (en) * 2009-06-30 2010-09-17 웅진코웨이주식회사 Heating apparatus
EP2375854B1 (en) * 2010-04-06 2015-12-02 Plastic Omnium Advanced Innovation and Research Heater for a vehicular fluid tank, motor vehicle comprising same, and method for heating a vehicular fluid tank
ITTO20100351A1 (en) * 2010-04-27 2011-10-28 N&W Global Vending Spa BOILER FOR THE HEATING OF A LIQUID
US8577211B2 (en) 2010-09-14 2013-11-05 Eemax Incorporated Heating element assembly for electric tankless liquid heater
DE202011002357U1 (en) * 2011-02-03 2012-05-08 Stiebel Eltron Gmbh & Co. Kg Instantaneous water heater for heating water
US20120224836A1 (en) * 2011-03-04 2012-09-06 Ray King Electro-thermal heating system
US9091457B2 (en) * 2011-03-04 2015-07-28 Dynacurrent Technologies, Inc. Electro-thermal heating system
US9167630B2 (en) * 2011-10-17 2015-10-20 David E. Seitz Tankless water heater
US8975329B2 (en) 2011-12-02 2015-03-10 Sabic Global Technologies B.V. Poly(phenylene ether) articles and compositions
US9074819B2 (en) * 2012-04-04 2015-07-07 Gaumer Company, Inc. High velocity fluid flow electric heater
TWI471510B (en) * 2012-05-16 2015-02-01 Yu Chen Lin Electric heating device
US10222091B2 (en) 2012-07-17 2019-03-05 Eemax, Inc. Next generation modular heating system
US9140466B2 (en) 2012-07-17 2015-09-22 Eemax, Inc. Fluid heating system and instant fluid heating device
US9822985B2 (en) * 2012-11-01 2017-11-21 Dynacurrent Technologies, Inc. Radiant heating system
WO2014098943A1 (en) 2012-12-21 2014-06-26 Eemax, Inc. Next generation bare wire water heater
WO2014116943A2 (en) * 2013-01-25 2014-07-31 Spx Corporation Companion water heater
CN104296363A (en) * 2014-10-09 2015-01-21 合肥天鹅制冷科技有限公司 Automatic air exhaust mechanism for heat exchanger in fan coil
CN111238024A (en) 2014-12-17 2020-06-05 伊麦克斯公司 Water tank-free electric water heater
CN104964452B (en) * 2015-07-28 2017-12-19 芜湖美的厨卫电器制造有限公司 For water heater liquid case and there is its water heater
US11014105B2 (en) * 2016-10-15 2021-05-25 Akurate Dynamics, Llc Multi-segment heated hose having segment-specific heating means
US10670300B2 (en) * 2016-12-13 2020-06-02 Choronomite Laboratories, Inc. Dual element electric tankless water heater
US10583928B2 (en) 2017-04-10 2020-03-10 B/E Aerospace, Inc. Inline heater controller
US10830492B2 (en) 2017-04-14 2020-11-10 Chronomite Laboratories, Inc. Ultra-low flow electric tankless water heater
EP3511376A1 (en) 2018-01-10 2019-07-17 SABIC Global Technologies B.V. Polyphenylene ether composition, method for the manufacture thereof, and articles comprising the composition
CA3107466A1 (en) 2018-07-25 2020-01-30 Hayward Industries, Inc. Compact universal gas pool heater and associated methods
US11060764B2 (en) * 2018-11-13 2021-07-13 White Knight Fluid Handling Inc. On-demand heater and temperature control system and related process
US11662122B2 (en) * 2019-07-18 2023-05-30 Stiebel Eltron Gmbh & Co. Kg Tankless water heater system

Family Cites Families (50)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1322897A (en) * 1919-11-25 Chill-plate
US1318237A (en) 1919-10-07 Innocente sordi
US3280299A (en) * 1966-10-18 Water heater
US1196487A (en) 1915-12-07 1916-08-29 Maurice Simon Electric water-heater.
US1224117A (en) 1916-11-08 1917-04-24 Samuel D Nesmith Electric water-heater.
US1731058A (en) 1925-06-27 1929-10-08 Standard Electric Stove Co Water heater
US1766068A (en) 1928-09-14 1930-06-24 Holland Furnace Co Instantaneous electric water heater
US2140389A (en) 1935-02-16 1938-12-13 Gen Electric Zone heating
GB462931A (en) 1936-03-07 1937-03-18 William Charles Gee Improvements in or relating to geysers
US2237808A (en) 1939-09-07 1941-04-08 Edison General Elec Appliance Water heater and control therefor
US2444508A (en) 1945-10-29 1948-07-06 Paul P Horni Electric heater for flowing fluid
US2465208A (en) 1947-04-30 1949-03-22 Peter De Gelleke Tubular electrical heating unit
US2553212A (en) 1949-10-26 1951-05-15 Earnest T Rippetoe Electric house-heating apparatus
US2710908A (en) 1954-02-23 1955-06-14 Doniak Michael Portable electrically heated preheater
US2825791A (en) 1956-06-28 1958-03-04 Combustion Eng House heating unit using electrical heating elements novelly organized and controlled
US2911511A (en) 1957-09-11 1959-11-03 Edward P Megarry Hot water heater
US2958755A (en) 1958-05-01 1960-11-01 Lennox Ind Inc Electronic sequencer control circuits
DE1232720B (en) * 1960-08-22 1967-01-19 Licentia Gmbh Electrically heated instantaneous water heater
US3196679A (en) * 1962-05-22 1965-07-27 Lockheed Aircraft Corp Fluid no-flow detection apparatus
US3175075A (en) 1963-01-28 1965-03-23 Nordson Corp Paint heater
GB1098077A (en) * 1963-10-12 1968-01-03 Nat Inst For Res In Nuclear Sc Improvements in or relating to apparatus for the measurement of rate of flow of a fluid
US3261963A (en) 1963-12-06 1966-07-19 Commercial Factors Ltd Automatic electric fluid heating apparatus
US3660987A (en) * 1970-06-22 1972-05-09 Poirier & Mclane Corp Freeze hole air bleeder system
US3680377A (en) * 1970-08-17 1972-08-01 Hewlett Packard Co Fluid flow meter
US3952182A (en) 1974-01-25 1976-04-20 Flanders Robert D Instantaneous electric fluid heater
US3898428A (en) 1974-03-07 1975-08-05 Universal Oil Prod Co Electric in line water heating apparatus
US3942378A (en) * 1974-06-28 1976-03-09 Rca Corporation Fluid flow measuring system
FR2300292A1 (en) 1975-02-05 1976-09-03 Eaton Williams Raymond ELECTRODE BOILER
US4167663A (en) * 1977-01-24 1979-09-11 Baxter Travenol Laboratories, Inc. Blood warming apparatus
US4185187A (en) * 1977-08-17 1980-01-22 Rogers David H Electric water heating apparatus
DE2804818C2 (en) 1978-02-04 1986-12-11 Fritz Eichenauer GmbH & Co KG, 6744 Kandel Electric heater
DE2948591A1 (en) 1979-12-03 1981-06-11 Fa. Fritz Eichenauer, 6744 Kandel CONTINUOUS HEATER
US4395618A (en) 1980-03-03 1983-07-26 Emerson Electric Co. Electric circulation heater for heating fluids such as oil
US4337388A (en) 1980-05-29 1982-06-29 July Mark E Rapid-response water heating and delivery system
US4502164A (en) * 1980-12-01 1985-03-05 Gemmell Leslie W Device for destroying bacterial flora
US4436983A (en) * 1981-03-12 1984-03-13 Solobay Leo A Electric water heater with upwardly inclined zig-zag flow path
IT1142816B (en) * 1981-09-14 1986-10-15 Aldo Giorgetti AUTOMATIC DEVICE FOR RAPID HEATING OF LIQUIDS IN PARTICULAR WATER
US4459465A (en) 1982-09-09 1984-07-10 Demand Hot Water Inc. Thermostatically controlled electric instantaneous fluid heater
US4480467A (en) * 1982-11-29 1984-11-06 Hyperion, Inc. Flow monitoring device
US4567350A (en) * 1983-01-06 1986-01-28 Todd Jr Alvin E Compact high flow rate electric instantaneous water heater
DE3401935C3 (en) * 1983-01-31 1994-05-11 Vaillant Joh Gmbh & Co Electrically heated water heater
DE3325892A1 (en) * 1983-07-19 1985-01-31 Basf Ag, 6700 Ludwigshafen METHOD FOR PRODUCING FINE-PART ELECTRICALLY CONDUCTIVE PYRROL POLYMERISATS
US4538673A (en) * 1984-05-02 1985-09-03 Geo-Systems, Inc. Drilled well series and paralleled heat exchange systems
US4604515A (en) 1984-10-16 1986-08-05 Cmr Enterprises, Inc. Tankless electric water heater with staged heating element energization
US4645907A (en) 1985-07-12 1987-02-24 Salton Lewis L Electric hot water heater
DE3680161D1 (en) * 1985-07-22 1991-08-14 Matsushita Electric Ind Co Ltd ELECTRIC WATER HEATER.
DE3526186A1 (en) * 1985-07-23 1987-02-05 Ego Elektro Blanc & Fischer ELECTRIC HEATING FOR LIQUID TANKS
US4900896A (en) * 1986-02-28 1990-02-13 Maus Daryl D Continuous flow water heater with magnetically-actuated flow switch
US5129034A (en) 1989-12-08 1992-07-07 Leonard Sydenstricker On-demand hot water system
US5216743A (en) 1990-05-10 1993-06-01 Seitz David E Thermo-plastic heat exchanger

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US7616873B1 (en) 2009-11-10
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AU7740794A (en) 1995-01-05
AU7987791A (en) 1991-11-27

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