GB2124340A - A fluid delivery system and valve therefor - Google Patents

Abstract

A fluid delivery system for delivering fluid from either of two containers (14, 15) has a source (26) of fluid under pressure, pipelines (22, 23, 24, 25) interconnecting the source to each container and primary delivery lines (17, 16) interconnecting each container with a commutation valve having a single outlet port (24) and a single delivery line (13) to a dispensing outlet (30). The valve (20) permits the flow of fluid under pressure from one of the containers (14, 15) to the delivery line (13) and can be caused to commute to allow delivery from the other of the containers (14, 15) by applying a pressure signal along the delivery line (13) in the reverse direction from a source (32) of signal pressure applied by a valve (31) located at or adjacent the dispersing outlet (30). <IMAGE>

Description

SPECIFICATION A fluid delivery system and valve therefor The present invention relates to a fluid control valve and to a system incorporating such a valve.

The present invention will be particularly described in relation to an application in a beer delivery system operable to dispense beer or other like liquid from a container or keg housed in a cylinder to a tap or other outlet in a bar room or hotel lounge. It is to be understood, however, that the valve of the present invention is not limited to such application, and can be employed in a wide range of different circumstances where its effective operation to select flow paths from a number of predetermined such flow paths is of considerable value.

One of the problems encountered in a public house or other location where beer is dispensed, is the difficulty of exchanging one container or keg for another when the keg in use becomes empty.

Because of the pressures to which such kegs are subject they are made from strong and opaque materials so that the quantity remaining in the keg cannot be determined. If the keg should become empty during a busy period it is necessary for the barman or other supervisor to leave the bar or other dispensing point and to physically exchange the empty keg for a full one from a store in the cellar. The absence of the barman from the dispensing point for the time taken to manoeuvre a new keg into position and to make the necessary connections both to the beer delivery line and to the fluid pressure source, usually a carbon-dioxide bottle, is a considerable disadvantage both from the point of view of security and convenience.To solve this problem attempts have been made to provide a system allowing one keg to be exchanged for another when the said one keg becomes empty by acting solely at the bar on a suitable control valve. Conventional pneumatic or hydraulic systems, however, require at least three and possible four pipelines between the bar and the cellar in order to be able to exchange just one keg for another, and furthermore would require at least two complex three port or five port valves.

Attempts to provide such systems have also run into difficulties due to the particular sugary nature of the liquid concerned since this reacts with the neoprene seals conventionally used in pneumatic and hydraulic control circuits causing these to clog or gum jamming the valve or valves and rendering them inoperable or inoperative.

Because the cellar may be some considerable distance from the beer delivery point the cost of supplying and installing the additional pipelines required for such a system, even if the problem of valve jamming could be overcome, is considerable and the present invention seeks to provide a system in which keg interchange can be effected without requiring the installation of additional pipelines between cellar and beer delivery point, and to provide a valve which makes such a system possible.

According to one aspect of the present invention, therefore, there is provided a valve having two inlets and an outlet and means defining fluid flow paths through the valve from each of the said two inlets to the said outlet, the valve being commutable between a first condition and a second condition in the former of which the flow path between a first inlet and the outlet is open and the flow path between a second inlet and the outlet is closed and in the latter of which the flow path between the said second inlet and the outlet is open whilst the flow path between the first inlet and the outlet is closed, commutation between the two conditions being controlled by signals in the form of predetermined pressure variations applied to the valve through the outlet.

Thus, by applying such pressure variations to the beer delivery line at the dispensing point they are transmitted in the reverse flow direction to the outlet of the valve the two inlets of which are, in this application, connected to the outlets of respective kegs, one being in use at any one time and the other being in reserve. Preferably indicator means are provided to provide indication of which condition the valve is in so that upon commutation an empty keg can be disconnected and replaced with a full one to continue the automatic exchange process when the keg in use becomes empty.

The application of a pressure signal along the beer delivery line can be effected by means of a suitable control valve connected to a small pressurised gas canister which can be located in the beer delivery line close to the dispensing point.

In a preferred embodiment the control valve is a simple open/shut valve of suitable construction so as not to become clogged or jammed by contact with the beer, which is operated by a push button to open communication between the gas bottle and the beer delivery line when the push button is depressed. When a keg becomes empty, therefore, the barman or bar supervisor has only to depress the push button to effect automatic exchange of the empty keg for a new one which has been preliminarily connected into the system, and beer dispensing can continue with only a small hiatus for the beer delivery pipe again to fill. It is envisaged that this should take only a matter of seconds.Moreover, exchange of one keg for another can take place before the keg in use becomes empty if this should be required for any reason, for example if the beer being dispensed is unsatisfactory or becomes polluted since the pressure fluctuation can be transmitted equally by the beer in the delivery line when the control valve is opened to allow communication between the control pressure source and the delivery line.

In a preferred embodiment of the invention which will be described in greater detail below the valve comprises a body having a fixed flow passage or passages and a rotatable valve member having openings therein which are brought into register with different flow passages at different angular positions thereof. Movement of the valve member between one angular position and the next is effected by the fluid pressure applied upon operation of the control valve, the rotatable member being adapted to turn through a predetermined angle to effect interchange of the two flow paths each time the pressure exceeds a predetermined control pressure.

The present invention also comprehends apparatus for deliverying beer from one of a plurality of kegs in a cellar and having means for changing the connection between one beer keg and another comprising a source of fluid pressure, pipelines interconriecting the said source to each keg, an individual beer delivery line extending from each keg to a common valve operable to allow the flow of beer from one keg to pass whilst blocking the other or others, and a common beer delivery pipeline extending from the valve to a beer delivery point, the valve operation to commute to a different position to allow beer arriving on a different individual beer delivery line to pass to the common beer delivery line upon reception of pressure fluctuation signals arriving along the beer delivery pipeline in a reverse flow direction.

As will be appreciated from the preceding statement, although exchange of one keg for another is envisaged in the specific embodiment to be described herein below, it is possible for the apparatus of the invention to incorporate a valve specifically set up to select one keg for delivery from a number greater than two, for example three, four or more kegs may be connected to a valve having three, four or more positions correspondingly so that the valve can select each keg in sequence for delivery each time the control valve is operated. In a public house having a large consumption, where three or four barrels of a given beer may be consumed in one session, such a delivery valve would allow the barman to set up four kegs in advance so that each can be dispensed in turn and then replaced by the next in sequence.

The particular construction which allows the valve disc to turn through a predetermined angle to effect the required interchange of flow paths may be achieved by providing a helical track which is engaged by transverse projections on a plunger which is caused to displace axially by the controlling pressure signal applied along the delivery line to the valve outlet. If the plunger is allowed to turn in only one directional sense it therefore causes the valve disc to turn by sliding along the helical tracks as it moves in one axial direction, whilst it turns itself in the said one rotary direction when displacing axially in the opposite direction from the first mentioned.

Unidirectional rotation of the plunger can be effected simply by means of a conventional ratchet arrangement comprising a ring of asymmetrical teeth and one or more resiliently biased ratchet pawls.

It is important if a valve is to be used for dispensing beer that it should be hygienic and that the seals which allow relative movement of the movable parts should not be degraded by contact with the beer. For this reason it is preferred that the seals are made from silicone rubber and have polytetrafluoroethylene contact surfaces bonded thereto. Such a valve is preferably of all plastics construction using acetal as a suitable material with stainless steel being employed for any components which are unavoidably of metal.

Conveniently the valve body is made of transparent plastics material allowing visual checking of the flow passages for cleaning purposes. Regular cleaning of beer delivery pipes has to be undertaken and the valve of the present invention conveniently allows this operation in a manner which will be described in more detail below.

Two embodiments of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a fluid circuit diagram illustrating the connection of a valve according to the present invention in a beer delivery circuit; Figure 2 is an axial section of a first embodiment of the valve; Figure 3 is an end vievv of the valve illustrated in Figure 2; Figure 4 is a scrap section on the line lV--lV of Figure 3; Figure 5 is a cut-away isometric view of a part of the valve body illustrated in Figure 2; Figure 6 is a sectional view taken on the line VI--VI of Figure 2; and Figure 7 is a sectional view similar to that of Figure 2, of a second embodiment of the invention.

Referring first to Figure 1 this shows a fluid delivery circuit for delivering fluid, such as beer, from a storage area, generally indicated by the broken line 11 to a delivery area generally indicated within the broken line 12, which two areas are interconnected by a delivery line 13. At the storage area there are provided two containers 14, 1 5 of the liquid to be dispensed, which each have individual delivery lines 1 6, 1 7 connected to respective inlets 1 8, 1 9 of a commutation valve 20 which constitutes the subject of the present invention. An outlet 21 of the valve 20 is connected to the delivery line 1 3.

Pressure for dispensing liquid from the kegs 14, 1 5 is supplied by a pressure line 22 having branch lines 23, 24 leading to respective kegs 1 5, 14 respectively and itself supplied along a line 25 from a fluid pressure source 26 which in this embodiment is a canister of carbondioxide under pressure.

At the beer dispensing station the delivery line 1 3 is connected to a T-coupling 27 from which branch pipelines 28, 29 lead to a beer delivery tap 30 and a control valve 31 respectively. The control valve is in turn connected to a small gas bottle 32 containing carbondioxide under pressure.

In operation, therefore, the compressed gas source 26 pressurises the two kegs 14, 1 5 and liquid such as beer is urged to flow out of the kegs along the individual delivery lines 1 6, 17 to the inlets 1 8, 1 9 of the flow control valve 20 which allows liquid from one or the other inlet to pass to the outlet 21. Supposing, therefore, that the valve is in a condition to allow the flow of liquid from the inlet 1 8 to the outlet 21 the keg 14 will gradually empty as the liquid is dispensed through the tap 30 until no more liquid is present in which condition only compressed gas flowing through the system from the compressed gas source 26 will flow out of the tap 30. The compressed gas source 26 has a pressure regulator 33 which determines the pressure at which the system operates.By now depressing the push button on the control valve 31 to open communication between the compressed gas bottle 32 and the line 29 the delivery line 1 3 receives a pressure signal at a higher pressure and this causes commutation of the valve 20 to now allow a flow of liquid from the inlet 1 9 to the outler 21, blocking the inlet 1 6. The keg 1 5 will now automatically start delivering liquid to the delivery line 13 and continued operation of the tap 30 will allow beer to be dispensed without the barman having to leave the delivery area.

Referring now to Figures 2 to 6 a presently preferred construction for the valve 20 of the circuit illustrated in Figure 1 is shown. The valve comprises a valve body 34 having an aperture 35 for receiving a coupling constituting the outlet coupling 21, and the apertures 36, 37 for receiving couplings constituting the two inlets 18, 1 9 illustrated in Figure 1.

Secured to the valve body 34 is a valve cover 38 which has a cylindrical extension 39 projecting transverse the general plane of the cover 38. The cover 38 is secured to the valve body 34 by screws or other fixing means which are not illustrated in the drawings. The cover 38 has a peripheral flange 40 which contains a seal 41 which seals a chamber 42 defined between an upper face of the valve body 34 and the flange 40 of the cover 38.

The inlet port 36 is illustrated in Figure 4. This includes a unidirectional valve 43 comprising a valve plate 44 biased into contact with a rim of a valve body member 45 by a conical spring 46. The port 36 communicates via a transverse passage 47 with the upper face of the valve body 34. At the entrance to the passage 47, where it communicates with the upper face of the valve body 34 ("upper" being used in this specification to identify the valve in the orientation illustrated in the drawings, it being understood that the valve can in fact be positioned in use in any convenient orientation in which case the orientation references in this description will not necessarily be the same) there is a cylindrical sealing element 48 of stainless steel which is resiliently supported by the silicone rubber ring 49.The construction of the inlet port 37 is exactly identical with that of the port 36, with the exception that the transverse passage leading to the upper face of the valve body 34 is angularly offset by 300 with respect to a centre line X-X for reasons which will become apparent from the following description.

Centred on the line X-X the valve body 34 has a cylindrical recess 50 in which is housed a cylindrical boss 51 of a valve disc 52 which overlies the upper face of the valve body 34 and is held in the chamber 42 defined between the valve body 34 and the cover 38. The valve disc 52 is pressed against the upper face of the valve body 34 by a set of pressure pads 53 only one of which can be seen in Figure 2.

The valve disc 52 has a set of six equally spaced holes 54 at the same radial distance from the centre line X-X as the transverse passages 47 which allow the ports 36, 37 to communicate with the upper face of the valve body 34. The angular separation of these passages is thus one half of the angular separation of the holes 54 so that when one of the holes 54 is in register with one of the passages 47 the other passages 47 is blocked by the valve disc 52 between two adjacent holes 54.

The outlet port 35 communicates via a transverse passage 55 with the chamber 42 at a greater radial distance than the radius of the disc 52 so that the outlet port is always in communication with the chamber 42 regardless of the angular position of the valve disc 52.

Passing through a central opening in the valve disc 52 is a central shaft 56 which carries at one end a plunger 57 and at the other has an enlarged head 58 through which passes a transverse pin 59 which projects slightly from diametrically opposite points of the head 58. The ends of the pin 59 extend into respective opposite helical grooves 60,61 in the cylindrical boss 51 of the valve disc 52.

The plunger 57 is sealed within the bore in the cylindrical turret 39 by means of a silicone rubber seal 62 having a polytetrafluoroethylene facing 63 a spring 64 biases the plunger 57 downwardly.

Finally, the shaft 56 has an axial slot 65 engaged by a pin 66 of a ratchet mechanism generally indicated 67. This ratchet mechanism is illustrated in greater detail in Figure 6 and comprises a ring 68 which is a press fit within the bore on the turret 39 and which has a set of asymmetrical ratchet teeth 69 on the inner surface thereof. Within this ring 68 there is housed a ratchet pawl-housing 70 through which the pin 69 extends to secure the ratchet pawlhousing 70 to the shaft 56 (by engagement of the pin 66 in the slot 65) for rotation therewith. A ratchet 71 is housed in an offset slot in the ratchet pawl-housing 70 and is resiliently biased in a radially outward direction by a circlip spring 72 housed in a radially inward facing groove of the pawl-housing 70. The ratchet mechanism 67 thus allows the shaft 66 to slide axially with the plunger 57 whilst allowing rotation of the shaft 56 in only one direction (clockwise as viewed in Figure 6).

The valve described above operates as follows: the valve disc 52 acts as a face valve in cooperation with the stainless steel inserts 48 in the passages 47 leading to the two inlet ports 36, 37. Initially, it can be supposed that the inlet port 36 illustrated in Figure 4 is open with a hole 54 of the disc 52 in register therewith as illustrated in Figure 4. Liquid arriving at the inlet port 36 can thus flow through the passage 47 and the hole 54 into the chamber 42 from where it can flow around the upper region of the valve disc 52 into the transverse passage 55 and out through the outlet port 35.The liquid is also in communication via passages in the ratchet mechanism 67 with the underface of the plunger 57, but since the normal operating pressure in the liquid (in the specific example given above this is beer being dispensed at a pressure of 15-20 PSI) the spring 64 maintains the plunger 57 in its lowermost position. Because of the angular offset of 300 between the transverse passages 47 associated with the inlet ports 36, 37 respectively the port 37 is closed. When the change in position is required a pressure signal generated as described above in relation to Figure 1 is applied to the outlet port 35 and this passes backwards through the transverse passage 55 into the chamber 42. Transmission of this pressure through the hole 54 into the outlet port 36 is prevented by the unidirectional valve 43.The pressure does reach, however, through the ratchet mechanism 67 to the undersurface of the piston 57 and since this pressure is now greater than the resistance offered by the spring 64 the piston 57 rises along the bore in the turret 59 taking with it the shaft 56 which is allowed to slide axially with respect to the ratchet mechanism 67 by the slot 65 which is engaged by the pin 66.

The pin 59 which traverses the enlarged head 58 at the lower end of the shaft 56 travels in the helical grooves 60, 61 causing the shaft to turn through 30 as it rises between its lowermost position and an upper position defined by contact of the enlarged head 58 with the undersurface of the cover 38 or by total compression of the spring 64. As the shaft 56 rotates clockwise as viewed in Figure 5 the ratchet pawl 71 is carried by the carrier 70, again clockwise as viewed in Figure 6 through the angular separation of one pair of ratchet teeth 69.When the pressure arriving along the delivery line at the outlet port 35 is released the spring 64 urges the piston 57 downwardly, but now the ratchet mechanism 67 prevents the anticlockwise rotation of the shaft 56 which would be required if the pin 59 were to follow the helical grooves 60, 61. Since the pin 59 is now constrained to travel straight down in an axial direction the helical grooves 60, 61 react to generate a turning movement on the boss 51 and hence on the valve disc 52 causing it to turn through 300, being the angular separation of adjacent ratchet teeth 69. This angular movement of the valve disc 52 carries a hole 54 into register with the passage 47 of the inlet port 37 and at the same time locks the passage 47 associated with the inlet port 36 which had previously been open.

Liquid arriving at the inlet port 37 can now flow through the valve whilst the port 36 is closed.

When required to commute back to the original condition it is only necessary to apply another pressure signal to the outlet port 35 whereupon the valve disc will turn again through an angle of 300, this time bringing a new hole 54 in register with the passage 47 associated with the port 36 and blocking the port 37. This process can be repeated indefinitely allowing continuai change of kegs between the two positions illustrated in Figure 1.

Other modifications and variations to the invention can be envisaged. For example, by providing three or more inlet ports and positioning the holes 54 in the valve disc 52 at appropriate angular separations it can be arranged that one port only is open at a time. The length of the spring 64 may be considered a disadvantage, in which case the length of the turret 39 may be shortened by applying a tension spring housed within the valve rather than the compression spring on the reverse side of the piston 57 as illustrated in the drawing.

By using polytetrafluoroethylene facings to the silicone rubbers seals the problem of clogging or jamming of the valves by contact with a liquid such as beer is avoided.

Figure 7 illustrates a modified embodiment of the present invention which operates in substantially the same way as the embodiment of Figures 1-6, but in which various components have been simplified for the purpose of enabling the valve to be made by injection moulding techniques. In Figure 7 those components which fulfil the same or similar functions to corresponding components in the embodiment of Figures 2-6 have been identified with the same reference numerals. Thus, a valve disc 52 having a plurality of holes 54 (not visible in Figure 7) and a cylindrical boss 51 is housed between a valve body 34 to the upper face of which it is pressed by pressure-applying means 53 in the form of spring loaded balls the springs of which react against a cover 38 fixed to the valve body 34.The cylindrical boss 51 has helical grooves 60, 61 therein within which are housed radial projections 59 of an enlarged head 58 on the lower end of a stem 56 having an axial key way 65. The stem 56 is slidable through a ratchet wheel 76 held axially immovably between a retainer plate 77 and a shoulder 78 of the cover 38.

The end of the stem 56 is force fitted into a recess in a diaphragm clamping member 79 which is itself force fitted into a cooperating retainer 80 with a flexible diaphragm 81 being clamped between them. The diaphragm 81 has its outer periphery clamped between the cylindrical projection 39 of the cover 38 and an end cover 82 screwed to the projection 39 by screws 83. A helical spring 64 is compressed between the member 80 and the end of the cover 82. The diaphragm 81 replaces the sliding seal 63 and ensures a perfect gas tight and water tight closure of the valve despite high operating pressures.

The ratchet wheel 76 has radially outwardly extending asymmetrical teeth which engage a ratchet pawl 66 mounted in this embodiment in the cover 38 and resiliently biased radially inwardly towards the stem 56 in order to ensure uni-directional rotation thereof.

Finally, a safety cap 85 sealed by a sealing ring 86 and having a cylindrical skirt 87 with a radially outwardly extending snap-engaging peripheral rim 88 is housed in the opening at the lower end of the bore 50 in the valve body 34 housing the cylindrical boss 51 of the valve disc 52. The operation of the valve illustrated in Figure 7 is exactly the same as that of the embodiment of Figures 2-6 with the exception that the two clamping members 79, 80 and diaphragm 81 replace the piston assembly so that no sliding friction is generated in effecting the seal, the diaphragm 81 acting as a rolling seal for this purpose.The ratchet wheel 76 and pawl 66 act in the same way as the ratchet in the embodiment of Figures 2-6 to ensure uni-directional rotation of the stem 56 and consequent rotation of the valve disc 52 to effect changeover of the valve ports when a high pressure feedback signal along the delivery line is received at the delivery port 35 causing the stem 56 to be displaced axially untii such excess pressure is removed, following which the stem displaces axially back to its original position, the linear stroke of the stem 56 in one direction being constrained against rotation by the ratchet and consequently causing rotary movement of the valve disc 52, and linear movement in the opposite direction following the helical grooves 60, 61 in the valve disc's cylindrical boss 51.

The interconnection between the stem 56 and the clamping member 79 is effected by means of a symmetrical dovetail connection allowing the stem 56 to turn about its own axis with respect to the member 79 whilst nevertheless axially interconnecting the two components for linear movement parallel to the length of the stem 56.

Claims (18)

1. Apparatus for delivering a liquid such as beer from one of a plurality of containers, and having means for changing the connection between one container and another, comprising a source of fluid pressure, pipelines interconnecting the said source to each container, an individual liquid delivery line extending from each container to a common valve operable to allow the flow of liquid from one container to pass whilst blocking the other or others, and a common liquid delivery pipeline extending from the valve to a liquid delivery point, the valve operating to commute to a different position to allow liquid arriving on a different individual liquid delivery line to pass to the common liquid delivery line upon reception of a pressure fluctuation signal arriving along the said common liquid delivery line in a reverse flow direction.

2. A valve suitable for the liquid delivery apparatus of Claim 1, and having two inlets and an outlet, means defining fluid flow paths through the valve from each of the said two inlets to the said outlet, the valve being commutable between a first position and a second position in the former of which the flow path between the first inlet and the outlet is open and the flow path between the second inlet and the outlet is closed, and in the latter of which the flow path between the said second inlet and the outlet is open whilst the flow path between the first inlet and the outlet is closed, commutation between the said two positions being effected by signals in the form of predetermined pressure variations applied to the valve through the outlet.

3. A valve as claimed in Claim 2, in which the valve body has fixed flow passages therein and houses a rotatable valve member having openings which can be brought into register with different flow passages at different angular positions of the valve member with respect to the valve body.

4. A valve as claimed in Claim 3, in which the valve disc has an axially extending portion with a helical track formed therein engaged by a transverse projection on a plunger which is axially displaceable with respect to the valve disc.

5. A valve as claimed in Claim 4, in which the said plunger is rotationally constrained so that it can only rotate in one directional sense about an axis parallel to the direction of axial displacement of the plunger so that when moving in a first axial sense with respect to the valve disc the plunger can turn by virtue of the interengagement of the helical track with the transverse projections, but when dispiaced axially in the opposite directional sense the valve disc is caused to turn.

6. A valve as claimed in Claim 5, in which the said uni-directional rotation of the plunger is effected by means of a ratchet mechanism.

7. A valve as claimed in any of Claims 2 to 6, in which all the seals between the components of the valve are made from silicon rubber with polytetrafluoroethylene contact surfaces bonded thereto.

8. A valve as claimed in any of Claims 2 to 7, in which all components of the valve apart from the seals are made from plastics material.

9. A valve as claimed in any preceding Claim, in which at least some components of the valve are transparent allowing visual inspection of the commutation state of the valve.

10. A system as claimed in Claim 1, incorporating a valve as claimed in any of Claims 2 to 9, in which the pressure signal for commutation of the valve is applied to the delivery line via a T-junction connector at a point between the said valve and a delivery outlet.

11. A system as claimed in Claim 10, in which the pressure signal is applied to said delivery line from a source of compressed gas via a manually controllable valve.

12. A system as claimed in Claim 11, in which the said manually controllable valve is a push button valve resiliently biased to a closed position and openable upon depression of an operating member.

13. A system as claimed in any of Claims 10 to 12, in which the T-junction connector includes a uni-directional valve allowing the pressure signal to enter the delivery line but preventing escape of fluid from the delivery line to the signal line.

14. A valve as claimed in any of Claims 2 to 9, in which the said plunger is sealed in the housing by a diaphragm seal.

15. A valve as claimed in Claim 14, in which the said diaphragm seal is a rolling diaphragm seal.

16. A valve as claimed in Claim 14 or Claim 15, in which the interconnection between the plunger and the diaphragm permits axial displacement of the plunger and rotary displacement of the plunger with respect to the diaphragm.

1 7. A valve substantially as hereinbefore described with reference to the accompanying drawings.

18. A fluid delivery system substantially as hereinbefore described with reference to Figure 1 and any of Figures 2-7 of the accompanying drawings.