WO1987005697A1

WO1987005697A1 - Device and method for dosing a liquid fluid

Info

Publication number: WO1987005697A1
Application number: PCT/DK1987/000026
Authority: WO
Inventors: Ole Koustrup Hansen; Rene Johnny Bernhard Wass
Original assignee: On Computer Electronics A/S
Priority date: 1986-03-11
Filing date: 1987-03-09
Publication date: 1987-09-24
Also published as: DK112386D0; EP0260309A1

Abstract

A device for dosing, i.e. metering and dispensing a liquid medium by means of which it is possible to dispense an accurately metered quantity and the dispensing can be performed quickly by means of a simple construction comprising a valve housing (4), in which a valve body (5) is rotatably mounted, said valve body having a flow passage (18) having a mouth opening (19) in the side and a mouth opening (20) in the bottom. In the valve housing (4) a port (7) is provided in the bottom, said port being intended for communication with the mouth opening (20) in the bottom of the valve body, and in the side of the valve housing at least two ports (8) are provided. These at least two ports (8) are intended for connection to a storage container (27) for the medium to be dispensed and at least one container (28) into which the medium is to be dispensed. By means (3) for shifting the valve body (5) and holding it in position the ports (8) can be brought into communication with the mouth opening (19) in the side of the valve body (5), and the port (7) in the bottom of the valve housing is in communication with means (2) for displacing the medium. The so constructed dispensing device can thus be used for a quick and accurate dispensation, because the valve body (5) has no volume displacing effect and moreover can be shifted qwickly. A plurality of the above mentioned devices can be used simultaneously for a particularly quick dispensation of a plurality of different liquid media.

Description

DEVI CE AND METHOD FOR DOSI NG A LIQU I D FLUID

The present invention relates to a device for dosing , i . e. metering and dispensing a liquid medium, said device comprising a valve, displacement means, and means for shifting the valve and holding it in position . More particularly, the invention relates to a device suitable for quick and exact dispensation of small quantities .

Such a device may be used within the automobile industry, or by paint retailers or others, who by means of the device can dispense the exact quantity of tinting colorant necessary for obtaining a desired hue of a basic color composition . The desired hue is obtain¬ ed by adding one or more tinting colorants to the basic color composi¬ tion , which is as a rule white. The tinting colorants are ordinarily added in very small quantities and must therefore be dispensed with great accuracy in order to obtain the desired hue. The device will therefore in most cases be used together with other corresponding devices, each of these being used in connection with a tinting colorant. I n many cases up to 16-20 devices are used in an apparatus.

The device according to the invention may, however, also be used for other applications where an accurate and speedy dispens¬ ing is desired.

Several metering and dispensing devices of the kind refer¬ red to are known . However, these are disadvantageous, because, due to the elements used , they do not deliver an accurately metered quan¬ tity. Thus, a small quantity is displaced by the shifting of the valves employed , and this results in an inaccurate dϊspending . To remedy this problem it has been proposed to use vacuum devices for pro¬ ducing a suction at the end of the dispensing step . This, however, will make the apparatus excessively complicated and also expensive to produce.

Thus, apparatus of the kind referred to are known, in which the problem in respect of the accuracy of dispensing has been solved . Thus, an apparatus is known , in which a cam control is used for the movement of the dispensing apparatus. Moreover, an appara¬ tus is known, in which a step motor is used for controlling the dis- pensation . However, it is a common feature of all these known appa¬ ratus that they do not make it possible to obtain a quick dispensation of the liquid medium. Thus, cam controlled dispensing devices, which are capable of dispensing a small minimum quantity of liquid , must necessarily perform a great number of cycles, which is time consum¬ ing . In the other known type, the step motor used for dispensation must be caused to engage sequentially with each valve/displacement member. After the engagement with each valve/displacement member the desired dispensation from this valve/displacement member is ef¬ fected and thereafter the motor is brought into engagement with the next following valve/displacement member. Thereafter the dispensation is effected from this valve/displacement member, etc. , until the desi- red number of valves/displacement members has delivered their quanti¬ ty of liquid . Thus, a quick dispensation of the liquid medium is not obtainable by this device, either.

It is the object of the present invention to provide a devi¬ ce, in which the above mentioned problems are remedied, and which at the same time provides the possibility of a simple construction and a quick dispensation of the liquid medium .

To achieve this, a device of the kind referred to is, accord¬ ing to the invention , characterized in that the valve, the displacement means and the shifting and holding means are built together to form a unit, that the valve comprises a valve body rotatably mounted in a valve housing and having a flow passage, the latter having a mouth opening at the bottom as well as a mouth opening at the top or on the side of the valve body, that the valve housing has a port provided at its bottom and communicating with the mouth opening of the flow passage at the bottom of the valve body, and at least two lateral ports communicating with a storage container for the medium to be dispensed , and with at least one container into which the medium is to be dispensed , respectively, that the valve body is adapted, by means of the shifting and holding means, which are firmly connected with the valve, to be rotated to a position in which a pre-selected port is brought into communication with the other mouth opening at the top or on the side of the valve body and is held in a position such that the port at the bottom of the valve housing communicates with the displacement means, the latter being constituted by a cylϊn- der, which is directly connected with the valve housing, and an indexable piston being connected with a servomotor or similar means capable of ensuring an accurate displacement of the piston .

With a device constructed as specified a very accurate dϊs- pensation is obtained by constructionally simple means, since the val¬ ve body, when shifted by rotation about its axis , does not displace any liquid that might disturb the accuracy of the dispensation . More¬ over, the servomotor will index the piston very accurately so that accurate dispensation is obtained as a function of the stroke of the piston . This accurate dispensation can be performed quickly, because all that is required , after a desired quantity has been dispensed, is to rotate the valve body in order to cut off the flow towards the container into which the medium is to be dispensed . Preferably the valve body is rotated to a position where communication is established between the volume above the piston and the storage container, because a continued displacement of the piston will then return any remaining liquid to the storage container and thereby produce an advantageous stirring/movement therein . This operation can be perform- ed concurrently for a desired number of dispensing devices, each of these constituting an independent unit. Thus, it is possible to avoid the delay inherent in a sequential operation of an array of dispensing devices, and in this manner the total time consumed for dispensing from a plurality of devices is considerably reduced by the construction according to the invention .

An advantageous embodiment of the device according to the invention is characterized in that a connecting member is provided be¬ tween the servomotor or other operating means and the piston , which connecting member may be connected with a plurality of pistons of corresponding devices, so that all the devices are activated simultane¬ ously by one servomotor. Hereby the advantage is obtained that the servomotor or other corresponding operating member can simultaneous¬ ly dispense a plurality of media, whereby the time consumption for dispensation can be further reduced . A further advantageous embodiment of the device according to the invention is characterized in that the valve housing comprises an upper part, in which the ports are provided, said ports extending through the side and the bottom of the upper part, and a lower part, in which the port is provided , the valve body comprising a substan- tially cylindrical body which is in sealing engagement with the bottom of the upper part and has a flow passage, the mouth opening of which at the top can be brought into registry with the mouth openings of the ports at the bottom of the upper part. This construction is particularly advantageous when very high pressures are used for the dispensation, because the pressure on the underside of the valve body will urge this against the upper part of the valve housing and will thereby produce a sealing effect which is increased with increasing pressure exerted by the displacement means .

A further advantageous embodiment is characterized in that the substantially cylindrical body comprises two superposed parts, of which the upper part, which is intended for engagement with the bot¬ tom of the housing upper part, is made from a plastics material , pre- ferably molytron, which creates a low friction between the valve body and the housing upper part, while the lower part is made from steel , and that the surfaces of the housing upper part and the body upper part intended for engagement with one another are plane-polished to secure a sealing connection . Hereby it becomes possible in a construc- tionally simple manner to obtain a sealing connection between the up¬ per side of the valve body and the underside of the upper part of the valve housing , while keeping the friction low, so that the requirement of power for rotating the valve body is as small as possible. According to a further embodiment, the device is characte- rized in that a spiral spring is arranged between the lower housing part and the valve body, said spring urging the valve body against the housing upper part by way ^'of a plastics spring support, said spring having a spring force sufficient for overcoming the force act¬ ing on the valve body in a direction away from its engagement with the housing upper part during the aspiration phase of the piston , where a pressure below that of the atmosphere prevails under the valve body. Hereby it is ensured that no leakage occurs when the piston draws in liquid during an aspiration phase. The spiral spring has preferably a spring force which is capable of withstanding a pressure of 2 atmospheres, which should provide adequate security against leakage.

A further advantageous embodiment of the device according to the invention is characterized in that the valve body is connected with the shifting and holding means by means of a pin-and-hole con- nection of non-circular cross section . Hereby certainty is obtained that the valve is precisely set in the desired^' position by means of the shifting and holding means so that the desired dispensation is effect¬ ed through the correct port in the side of the valve housing . A further advantageous embodiment of the device according to the invention is characterized in that it comprises a unit for the automatic control of the shifting and holding means, and that the shifting and holding means comprises means providing an accurate, preferably electronic return message to the control unit about the po¬ sition of the valve body . Hereby dispensing errors can be avoided , because a return message about incorrect position can be used for preventing or interrupting the dispensing .

According to a further embodiment, the device is characte- rized In that the return message means comprises a scanning print board, which is firmly connected with a carrier and comprises a print indicating the position of the valve body, and springs mounted in a cover of the valve housing and adapted to scan the print plate, said springs being connected with the control unit which registers the position of the valve on the basis of the scanning signal . Hereby the advantage is obtained that, since the print board is non-rotatably connected with the valve body, it becomes possible in a simple way to obtain a reliable signal for indicating the position of the valve body, and by suitably designing the strips of the print board it is possible to control the valve body in such a manner that there will never occur an unintentional registry between the flow passage of the valve body and the port communicating with the container into which the medium is to be dispensed . This provides a further security of cor¬ rect dispensation . . - A further advantageous embodiment of the device according to the invention is characterized in that the shifting and indexing means are so constructed as not to require power supply for holding the valve body in an adjusted position . Hereby a device is obtained which is inexpensive in operation , and the holding of the valve body in position can be ensured by its frictional engagement with the valve housing , because the medium urges these against one another when the displacement means are activated .

The invention also relates to a dispensing apparatus for use in the tinting of colorants, said apparatus being characterized in that it comprises a plurality of devices constructed as above described . Hereby an apparatus is obtained which with great accuracy, quickly and preferably automatically can be used for the dispensing of a plu¬ rality of tinting colorants, corresponding to the number of devices, into a basic color composition . The invention also relates to a method of metering and dis¬ pensing a liquid medium by means of a device as described above.

This method is characterized in

I . that the device is primed, I I . that the valve body is positioned with its lateral mouth opening in communication with a first lateral port of the housing , said port being connected with a storage container for the liquid medium to be dispensed,

I I I . that the displacement means are activated for drawing the medium into the device,

I V. that the lateral mouth opening of the valve body is brought into communication with another lateral port of the housing , said port being connected with a first container into which the medi¬ um is to be dispensed, V. that the displacement means are reactivated for displa¬ cing a predetermined quantity of medium through said second port towards the first container into which the medium is to be dispensed,

VI . that the valve body is rotated to bring the lateral mouth opening into communication with a further lateral port of the housing, said port being connected with a further container into which the medium is to be dispensed, or that the first container is replaced by a further container into which the medium is to be dis¬ pensed, and

VI I . that the two last mentioned steps are repeated a desir- ed- number of times .

Hereby a plurality of successive accurate and quick dispensing operations is obtained, in which the medium can selectively be dispensed into different containers either by shifting the valve for discharge from different ports or by exchanging the container into which the medium is to be dispensed .

An advantageous embodiment of the method according to the invention, where a plurality of devices is used simultaneously, is cha¬ racterized in

VI I I . that all these devices are subjected to steps I -IV for dispensing a predetermined quantity corresponding to the smallest common quantity to be dispensed by the devices employed,

IX. that the valve body of the device or devices to dispen¬ se this smallest common quantity is shifted back so that the lateral mouth opening is again brought into communication with the first la¬ teral port of the housing ,

X . that al l devices are reactivated for dispensing the now smal lest common quantity for the remaining devices that have not been shifted back, and

XI . that the steps IX and X are repeated a desired number of times until only one device has dispensed its last desired quantity .

Hereby a particularly advantageous method of dispensing by means of the said devices is obtained , where simultaneous dispensation of a plurality of different media is effected , which makes it possible substantially to reduce the time consumed for dispensation .

Though not specifically mentioned in the beforegoing text it is to be understood that the valve body and the valve housing are produced with so fine tolerances that no leakage occurs along and around the valve body.

I n the present description and in the claims the term " li¬ quid medium" is to be understood to mean flowable media in the range from light flowing water to high viscous paste .

The invention will now be described in further detail with reference to the accompanying drawing , in which

Fig . 1 diagrammatϊcally shows an exploded sectional view of an embodiment of a device according to the present invention , Fig . 2 a longitudinal section through a valve housing - ^* according to the invention ,

Fig . 3 a cross section through the valve housing of Fig .

2 taken along the line I l l - I l l , Fig . 4 a longitudinal section through a valve body accord¬ ing to the invention for use together with the valve housing of Figs . 2-3,

Fig . 5 a diagrammatical illustration of a color tinting ap¬ paratus according to the present invention, and Fig . 6 a longitudinal section on a different scale through another embodiment of a valve according to the invention .

Fig . 1 shows a device, which is intended for the metering and dispensing of a liquid medium , and which consists of a valve 1 , displacement means 2 and means 3 for shifting the valve 1 and hold- ing it in position . The device illustrated is constructed for use in connection with a color tinting apparatus .

The valve 1 , which is shown more clearly in Figs . 2-4, com¬ prises a valve housing 4 and a substantially cylindrical valve body 5 which is mounted for rotation about an axis of rotation 6. The valve housing 4 has a port 7 at its bottom and , in the embodiment illustrat¬ ed , three ports 8, which are arranged in the side of the valve hous¬ ing 4. These ports 8 are intended to be connected to a storage con¬ tainer 27 for the medium to be dispensed, with a container 28 into which the medium is to be dispensed, while the third port can be used for connection to a desired sensor (not shown) .

The valve housing is closed by means of a disc shaped co¬ ver 9, which by means of screws is fastened in threaded holes 10 of the valve housing 4, thereby to cover a mounting opening 11 through which the valve body is mounted in the valve housing . The valve housing 4 has a cylindrical bore 12 with a diameter substantially cor¬ responding to the outer diameter of the cylindrical valve body 5. The cover 9 is provided at its upper side with a recess 13 and has a cen¬ tral through-bore 14. The recess 13 serves for the accurate position- Jn of the means 3 for shifting and holding the valve, while the central through-bore 14 is provided for establishing a pin-and-hole connection which will be mentioned later.

The valve body 5 has a substantially cylindrical portion 15 and a collar 16 which is intended to be accomodated in a recess 17 o the valve housing . The collar 16 is held in position in this recess 17 after the mounting of the cover 9 on the valve housing 5, the col¬ lar 16 having a thickness such as to fill the recess 17. In the sub- statϊally cylindrical portion 15 of the valve body two bores are provid¬ ed at right angles to one another, the two bores combining to form a flow passage 18 which has a mouth opening 19 at the bottom and a mouth opening 20 on the side. The mouth opening 19 can be brought into communication with the port 12 of the valve housing , and the mouth opening 20 may by rotation of the valve body 5 be brought in¬ to communication with a selected one of the ports 8. The valve body 5 is moreover provided with a hexagonal hole 21 intended for engagement with a hexagonal drive pin 22 asso¬ ciated with the means 3 for shifting and holding, thereby establishing the above mentioned pin-and-hole connection , which owing to its non- rotational ly symmetric construction ensures a correct positioning of the valve body in accordance with the desired shifting .

The means 3 for shifting and holding are provided in the form of a motor 23 and a gear box 24. The gear box 24 comprises optical registering means (not shown) for indication of the position of the drive pin . Such registering means may, however, comprise other registering means capable of delivering an electronic signal to a control unit. When the motor 23 has placed the valve body 5 in a desired position , the power supply is switched off and the valve body 5 is held in its position owing to the friction between the upper side of the valve body 5 and the underside of the cover 9, the valve body 5 being urged against the cover 9 by the pressure of the medium in the device .

The displacement means 2 are In this embodiment constitut- ed by a cylinder 25 and a piston 26, which is arranged for an index¬ ing movement in the cylinder 25. Alternatively, the displacement means 2 may be constituted by a reversible pump . When the device has been primed , the downward movement of the piston 26 may be used for drawing medium from the storage container 27 when the valve body 5 has beforehand been set for connection of the mouth opening 20 with that one of the ports 8 which is connected to the storage container 27. After rotation of the valve body 5 to bring the mouth opening 20 in communication with that one of the ports 8 which is connected to the container 28 into which the medium is to be dispensed , the piston 26" may be reactivated for movement in the opposite direction , thereby to dispense the medium .

I n Fig . 5 it will be seen that the piston 26 is connected with a connecting member in the form of a circular plate 29 which through an element 30 is connected with a servomotor 31 , which con- trols the travel of the pistons and thereby the amount of liquid being dispensed . I n the apparatus il lustrated a desired number of devices are provided , only two of which are il lustrated , the pistons 26 of which are symmetrically connected with the circular plate 29 in order to obtain a symmetrical load when the servomotor 31 is activated . The operation of the apparatus illustrated in Fig . 5 is as follows :

When the devices have been primed , the valve body 5 in each of the devices employed is so positioned that the lateral mouth opening 20 is in communication with that one of the ports which Is connected to the associated storage container 27. Thereafter the pistons 26 are activated so that medium is drawn from the storage containers 27 into the devices in a quantity corresponding to the volume in the cylinders 25 swept by the pistons . Obviously, this drawn-In volume can be determined by suitably dimensioning the piston and the cylinder and by selecting a suitable stroke of the pistons . Thereafter each valve body 5 is again shifted so that the mouth opening 20 is brought into communication with the port 8 connected to the container 28. Thereafter the piston 26 is reactivated for movement in the opposite direction so as to displace the smallest common quantity to be displaced by all the devices, i n that one or those of the devices which are to deliver this quantity only, the valve body 5 is shifted back so that the mouth opening 20 is again brought into communication with that one of the ports 8 which is connected with the storage container 27, and the pistons are thereaf¬ ter displaced by the servomotor 31 so as to displace the now smallest common quantity for the devices that have not been shifted back. Thereafter the valve body 5 is shifted back in those ones of the remaining devices that are to deliver only the now smallest common quantity, etc. , until the last device has delivered its last desired quantity. At this point the container 28 has received the desired proportion , and the apparatus can again be shifted for drawing liquid from the storage containers 27. - - Fig . 6 shows a section through another embodiment of a valve 1 ' . This valve 1 ' is intended for use in combination with dis¬ placement means 2 and shifting and holding means 3, such as previ¬ ously described . This valve Is likewise constructed for use in con¬ nection with a color tinting apparatus . i n this embodiment, the housing of the valve V comprises an upper part 4a and a lower part 4b . In the upper part 4a of the housing three ports are again provided . These extend through the side 32 of the upper part and are angularly bent so that each port also has an opening in . the bottom 33 of the upper part. I n the lower part 4b, the port 7 Is provided, and like before this is intended to be connected to displacement means 2 in the form of a cylinder 25 and a piston 26.

In the valve housing there is mounted a substantially cylin¬ drical valve body 5¹ , which sealϊngly engages the bottom 33 of the housing upper part 4a . The sealing effect is established by means of a spiral spring 39 which through a valve guide 40 urges the valve body 5¹ into engagement with the upper part 4a of the housing . More¬ over, this sealing engagement is strengthened when the piston in the process of delivery of liquid exerts a pressure on the underside of the valve body 5, the latter being then urged towards the upper part 4a of the housing at a higher force.

The spiral spring 39 is dimensioned to be capable of with¬ standing a force of 2 atmospheres, thereby ensuring that no leakage occurs between the valve body 5' and the housing upper part 4a when the piston 26 draws in liquid during an aspiration phase . Hereby adequate security is obtained that the low pressure under the valve body 5' does not cause the valve body 5' to move away from its posi¬ tion in engagement with the upper part 4a of the housing . In order to obtain optimum sealing , the surfaces of the up- part and of the valve body intended for engagement with one another are plane-polished so that no additional sealing means are required between these surfaces .

The substantially cylindrical valve body 5' comprises two superposed parts 34, 35, of which the upper part 34 is made from a plastics material , preferably molytron , so as to create a low friction between the valve body 5¹ and the upper part 4a of the housing when the valve body is rotated relatively to the valve housing . The lower part 35 of the valve body 5¹ is made from steel with a view to the rigidity of the valve body, ensuring distribution of the pressure over the whole cross sectional area of the valve body when the valve guide 40, which is also made from a plastics material , preferably molytron, exerts a central pressure on the lower part 35.

The valve guide 40 is preferably constructed with a rounded surface resting in a corresponding rounded surface in the lower part 35 so that a correct positioning is always obtained, even when the valve body is rotated . A screw or pin fitting in a bore 41 extending through the lower part 35 and partly through the upper part 34 positively prevents mutual displacement of the two parts . In the valve body 5' there is provided a flow passage, the mouth opening 20 of which in the top can be brought into registry with the mouth openings of the ports 8 in the bottom 33 of the upper part when the valve body 5' is rotated . The valve body 5' is rotated by means of a pin-and-hole connection 21 , 22, preferably of hexagonal cross section . Thus, a hexagonal hole 21 is provided in the valve body 5' .

A hexagonal pin 22 is mounted on a carrier 37, which ex- tends through the upper part 4a of the housing and is provided at its top with a hole 42 for engagement with a pin associated with the shifting and holding means 3. This pin-and-hole connection can like¬ wise be constructed with a non-circular cross section , but since an output shaft of a motor is frequently used, this output shaft may be constructed with a face, and a screw is then fitted in a threaded hole 43 extending radially through the carrier, whereby the carrier 37 is secured to such a substantially circular shaft by tightening the screw against the face.

In a recess in the top of the carrier a scanning print board is arranged, which forms part of return message means for the shift¬ ing and holding means . The scanning print board 36 is firmly con¬ nected with the carrier 37 and is thus rotational ly firmly connected with the valve body 5' . The print board 36 comprises a print indi¬ cating the position of the valve body 5, and in a recess 44 on the underside of the cover 9 springs 38 are provided, which scan the print board 36 and are connected with the control unit which thus re¬ gisters the position of the valve on the basis of the scanning signal .

By suitably designing the print strips it is thus possible to obtain an accurate indication of the position of the valve at any time, and it is therefore possible to establish an electronic control of a DC -servomotor. The construction of the electronic control and the layout of the print strips are carried out depending on the man¬ ner, in which it is desired to control the valve. However, the valve body 5' should always be controlled in such a manner that the flow passage 18 is always moved away from the port 8 connected to the container into which liquid is to be dispensed , so as to prevent dosa¬ ge errors .

The valve V can be used instead of the valve 1 , and thus can be used in the apparatus shown in Fig. 5. The same advantage will be obtained , viz. a quick and precise delivery, seeing that also with the valve V a simultaneous delivery from a plurality of storage containers 27 can be obtained so that the total time of a cycle will substantially correspond to the time of a cycle for the maximum quan- tity to be delivered by any of the devices, in contrast to the known apparatus where the time of the cycle corresponds to the cumulated times of the cycles of delivery of all the devices .

Claims

P a t e n t C l a i s.

1. Device for metering and dispensing a liquid medium, said device comprising a valve, displacement means, and means for shifting the valve and holding it in position, c h a r a c t e r i z e d in that the valve, the displacement means and the shifting and holding means are built together to form a unit, that the valve (1) comprises a valve body (5) rotatably mounted in a valve housing (4) and having a flow passage (18), the latter having a mouth opening (19) at the bottom as well as a mouth opening (20) at the top or on the side of the valve body, that the valve housing has a port (7) provided at its bottom and communicating with the mouth opening (19) of the flow passage at the bottom of the valve body, and at least two lateral ports (8) communicating with a storage container (27) for the medium to be dispensed, and with at least one container (28) into which the medium is to be dispensed, that the valve body is adapted, by means of the shifting and holding means (3), which are firmly connected with the valve, to be rotated to a position in which a pre-selected port (8) is brought into communication with the other mouth opening (20) at the top or on the side of the valve body (5) and is held in a position such that the port (7) at the bottom of the valve housing communicates with the displacement means (2), the latter being consti¬ tuted by a cylinder (25), which Is directly connected with the valve housing (4), and an indexable piston (26) being connected with a servomotor (31) or simitar means capable of ensuring an accurate displacement of the piston,

2. Device according to claim 1, c h a r a c t e r i z e d in that a connecting member (29) is provided between the servomotor (31) or other operating means and the piston (26), which connecting member may be connected with a plurality of pistons (26) of corre- spondϊng devices, so that all the devices are activated simultaneously by one servomotor.

3. Device according to claim 1, c h a r a c t e r i z e d in that the valve housing (4) comprises an upper part (4 a), in which the ports (8) are provided, said ports extending through the side (32) and the bottom (33) of the upper part, and a lower part (4 b_), in which the port (7) is provided, the valve body (5¹) comprising a substantially cylindrical body which is in sealing engagement with the bottom (33) of the upper part (4 a) and has a flow passage (18), the mouth opening (20) of which at the top can be brought Into registry with the mouth openings of the ports (8) at the bottom (33) of the upper part.

4. Device according to claim 3, c h a r a c t e r i z e d in that the substantially cylindrical body comprises two superposed parts

(34,35), of which the upper part (34), which is intended for engage¬ ment with the bottom (33) of the housing upper part (4 a), is made from a plastics material, preferably molytron, which creates a low friction between the valve body (5¹) and the housing upper part (4 a), while the lower part (35) is made from steel, and that the sur¬ faces of the housing upper part (4 a) and the body upper part (34) intended for engagement with one another are plane-polished to secure a sealing connection.

5. Device according to claim 3 or 4, c h a r a c t e r i z - e d in that a spiral spring (39) is arranged between the lower hous¬ ing part (4 b_) and the valve body (5¹)_/ said spring urging the valve body (5¹) against the housing upper part (4 a) by way of a plastics spring support (40), said spring having a spring force sufficient for overcoming the force acting on the valve body (5¹) in a direction away from its engagement with the housing upper part (4 a) during the aspiration phase of the piston (26), where a pressure below that of the atmosphere prevails under the valve body (5¹).

6. Device according to any of the beforegoing claims, c h a r a c t e r i z e d in that the valve body (5) is connected with the shifting and holding means (3) by means of a pin-and-hole connection (21,22) of non-circular cross section.

7. Device according to any of the beforegoing claims, c h a r a c t e r i z e d in that it comprises a unit for the automatic control of the shifting and holding means (3), and that the shifting and holding means comprise means providing an accurate, preferably electronic return message to the control unit about the position of the valve body (5).

8. Device according to claim 6 or 7, c h a r a c t e r i z ¬ e d in that the return message means comprise a scanning print board (36), which is firmly connected with a carrier (37) and com¬ prises a print Indicating the position of the valve body (5¹), springs (38) mounted in a cover (9) of the valve housing and adapted to scan the print plate (36), said springs being connected with the control unit which registers the position of the valve on the basis of the scanning signal.

9. Device according to claim 7 or 8, c h a r a c t e r i z ¬ e d in that the shifting and indexing means (3) are so constructed as not to require power supply for holding the valve body (5) in an adjusted position.

10. Metering and dispensing apparatus for use in the tint¬ ing of colorants, c h a r a c t e r i z e d in that it comprises a plurality of devices according to any of the beforegoing claims.

11. Method of metering and dispensing a liquid medium by means of a device according to any of claims 1-9, c h a r a c t e r i - z e d in

I. that the device is primed,

II. that the valve body (5) is positioned with its lateral mouth opening (20) in communication with a first lateral port (8) of the housing, said port being connected with a storage container (27) for the liquid medium to be dispensed,

III. that the displacement means (2) are activated for drawing the medium into the device,

IV. that the lateral mouth opening (20) of the valve body is brought Into communication with another lateral port (8) of the housing, said port being connected with a first container (28), into which the medium is to be dispensed,

V. that the displacement means (2) are reactivated for displacing a predetermined quantity of medium through said second port (8) towards the first container (28) into which the medium is to be dispensed,

VI. that the valve body Is rotated to bring the lateral mouth opening (20) into communication with a further lateral port, said port being connected with a further container, into which the medium is to be dispensed, or that a first container is replaced by a further container into which the medium is to be dispensed, and

VII. that the two last mentioned steps are repeated a desir¬ ed number of times.

12. Method according to claim 11, where a plurality of devi¬ ces are used simultaneously, c h a r a c t e r i z e d in VIII. that all these devices are subjected to steps I -IV for dispensing a predetermined quantity corresponding to the smallest common quantity to be dispensed by the devices employed,

IX. that the valve body (5) of the device or devices to dispense this smallest common quantity is shifted back so that the la¬ teral mouth opening (20) is again brought into communication with the first lateral port (8) of the housing ,

X. that all devices are reactivated for dispensing the now smallest common quantity for the remaining devices that have not been shifted back, and

XI . that the steps IX-X are repeated a desired number of times until only one device has dispensed its last desired quantity.