This invention relates to apparatus for cleaning systems for dispensing beer and like carbonated beverages, or other systems in which a pressurised gas is used to expel a liquid from a container into a fluid containing system, for example in dairy plant. The system is described with reference to beer dispensing systems, but is not limited to such application.

An important factor in maintaining the condition of keg beer as dispensed to the customer is to ensure that the pipework and fittings of the dispensing system which come into contact with the beer are cleaned regularly. Such systems must also be cleaned periodically for reasons of hygiene. Cleaning is effected by disconnecting the coupling head from the keg closure valve and connecting the coupling head to a, so-called, wash socket that is in communication with a pressurised source of cleaning fluid. The wash socket must mimic the keg closure valve with which the coupling head usually mates. There are relatively few, effectively standard, types of coupling head enclosure valves; in the United Kingdom the most common are the slide-on, the tri-lobe and the well type.

Usually, the valve using the wash socket is a modified keg closure valve; such valves have two, concentric passages or ports, one for the ingress of pressurising gas into the top

of the keg and the other for the egress of beer from the bottom of the keg, via a spear depending from the closure valve. When disconnected, both the coupling head and the closure valve seal their gas and beer ports. For hygiene, the closure valve must isolate the keg beer port at or close to the interface between the closure valve and the coupling head. In adapting a closure valve as a wash socket valve, discharge of gas from the coupling head into the cleaning system must be prevented and this is achieved by forming blind gas passages in the wash socket body. Also, it is inevitable that the wash socket cleaning fluid port will be sealed at the wash socket/coupling head interface.

It is an object of the present invention to provide a purpose-designed wash socket valve that is simpler than a modified keg closure valve and thus more economic to manufacture; whilst performing at least as effectively as a modified keg closure valve.

According to the present invention a wash socket for a beverage, pressure-dispense system, comprises a body, adapted to mate with a coupling head of a given type, and housing a normally-closed valve adapted to be opensad by operation of said coupling head; wherein the valve has a movable member that is:- configured to cooperate with a coupling head/wash socket interface to seal the coupling gas port, arranged to open a port for cleaning fluid, and provides a passage for cleaning fluid to the coupling head beer port;

when the wash socket valve is opened by said given coupli head.

A wash socket in accordance with the present invention i thus different from modified keg closure valve wash sockets i that the gas passage or port of the coupling head is sealed a the interface of the coupling head with the wash socket. I addition, it is not necessary for the cleaning fluid port to b sealed at the coupling head/wash socket interface.

In a preferred embodiment of the invention, the movabl valve member is a piston slideable in a bore formed in the was socket, the piston having a cleaning fluid passage passin therethrough. The piston may have a head provided with peripheral sealing member to the bore and a stem which extend through a valve seat, the cleaning fluid passage comprising a axial bore passing through the piston head and communicatin with longitudinal grooves in the piston stem, the upstream end of the grooves being sealed by an 0-ring about the piston ste and cooperating with the valve seat. The piston may be biasse by a spring operative between a downstream face of the valv seat and the upstream face of the piston head, the sprin acting to force the O-ring into sealing engagement with th valve seat. A wash valve socket in accordance with thi embodiment of the present invention therefore has the cleanin fluid valve some distance upstream of the wash socket/cleanin coupling head interface; this is of no consequence as onl cleaning fluid would be exposed to atmosphere within the was socket.

In one form of this embodiment, the piston seal has

flexible sealing lip which is evertable to seal the piston an the bore of the wash socket body against external gas pressur when a coupling head is connected to the wash socket. In a alternative form of this embodiment, the piston head is cu shaped and is provided with a O-ring to seal with a cylindrica bore of the socket body.

In a further embodiment of the present invention the was socket comprises an adaptor, housing the valve and having a integral coupling flange, removably fitted to a mountin fixture; the fixture being provided with a cleaning flui passage to connect with the valve cleaning fluid port in th adaptor.

The above and other features of the present invention ar illustrated, by way of example, in the Drawings wherein:- Fig. 1 is a sectional view of a wash socket in accordance wi the first embodiment of the present invention and for a tri-lo coupling head;

Fig. 2 is a similar view to the wash socket of Fig. 1, but for well type coupling head; and

Fig. 3 is a sectional view of a wash socket in accordance with second embodiment of the present invention, the wash sock having a two-part body; the two sides of the wash socket bei sectioned along planes at 90° to one another.

Referring to Fig. 1 there is shown a wash socket 10 havi a connecting flange 12 for mounting a beer keg coupling head standard form, (for example a tri-lobe coupling flange or round flush-top) which coupling heads are provided with central fluid connection or port for receiving fluid from t

beer keg for supply to the pipework of the dispensing system

The central fluid connection of such a coupling head i surrounded by a co-axial annular gas connection or port, throug which pressurised carbon dioxide may be supplied to the keg fo expulsion of beer therefrom.

The wash socket 10 has a body formed from pressed stainles steel and comprises a coupling flange pressing 12, cylindrica wall portion 14, line connection 16, a base pressing 18 and a intermediate wall 20; all joined by welding.

The wash socket body 14 houses a piston 22 having a head 2 that carries a peripheral seal 26, whose upper face 28 i adapted to seal against the annular gas port of a coupling head which carries an evertable sealing lip 30 to engage the inne wall of the cylindrical wall portion 14.

The piston also comprises stem 32, the distal end of whic passes through an aperture in the intermediate wall 20, whic aperture is surrounded by a collar 34 forming a valve seat The distal end of the piston stem is formed with a seating fo an O-ring 36 which is biassed into engagement with the valv seat 34 by means of a compression spring 38 disposed about th piston stem 32 and acting between the underside of the pisto head 24 and the intermediate wall 20. During assembly, the O ring 36 may be compressed within its retaining groove on th piston stem by a ring 40, slideable on the piston stem so tha the stem and O-ring can be fed through the collar 34, whereupo the O-ring expands to retain the piston stem captive within th collar 34; the ring 40 thereafter being retained on the pisto stem between the piston head and the intermediate wall.

The piston stem 32 is formed with four longitudinal groove

46 whose upstream ends communicate with the O-ring seating an whose downstream ends communicate with an axial bore 48 o cruciform section formed through the piston head 24. Th grooves 46 and bore 48 thus form a flow passage through th piston and valve seat, which is closed when the coupling head i removed from the mounting flange 12; allowing spring 38 to bia

O-ring 36 into sealing engagement with valve seat 34. Suc upwards bias of the piston also everts the sealing lip 30 t provide a seal against the escape of any fluid between th piston head 24 and the bore 14. Whilst piston bore 48 is no sealed, the upstream ends of grooves 46 are sealed by O-ring 3 cooperating with valve seat 34.

When the coupling head (not shown) is fitted to the mounting flange 12, the piston 22 is depressed against th action of the spring 38 by engagement of the seal face 26 wit the coupling head beer port. In this manner O-ring 36 i disengaged from valve seat 34, establishing a fluid flow pat between chamber 42, formed beneath the intermediate wall 20, a the central beer port of the coupling head; for supply o cleaning fluid to the pipework of the dispensing system. the same time, such movement of the piston everts the seali lip 30 to provide a seal between the piston head 24 and the bo 14 against external gas pressure applied via the gas port of t coupling head.

Flange 18 may be provided with screw holes (not shown) fo mounting the wash socket to the wall of a beer cellar.

Figure 2 shows a wash socket 10 including a modified

generally cylindrical coupling flange 50, and a modified pisto

52 provided with a cup shaped head 54, to form a well-typ connection for SANKEY-type coupling heads. As is apparent fro the figure, the wash socket is otherwise similar to that show in Figure 1; except that the seal 26 of Figure 1 is replaced b an O-ring 56, which seals between the piston head 54 and surrounding collar 58 attached to the flange 50. other modifications that may be made to the wash socket shown in Figure 1 would be to replace the tri-lobed flange 12 with a circular flange to accept a slide-on coupling head.

Figure 3 shows an embodiment of the present invention wherein the wash socket comprises an adaptor 70 suitable for us in combination with a fixture 72 which may be mounted on the wall of a beer cellar for example.

The adaptor 70 has a cylindrical bore 73 formed therein an housing a piston essentially the same as the piston 22 shown b Fig.l; consequently, like parts bear the same reference numerals.

The piston head 24 carries a peripheral seal 26 whose upper face 28 is adapted to seal against the beer port of a coupling head and which carries an evertable sealing.lip 30 in engagement with the wall of the bore 73.

The piston 22 also comprises a stem, the distal end of which enters the hollow interior of a tubular extension 74 of the adaptor 70, which interior communicates with the bore 73. A concentric valve seat 76 is formed within the tubular extension 74 and through which the distal end of the piston stem 32 passes. This end of the piston is formed with a seating for

an O-ring 36 which is biassed into sealing engagement with th valve seat 76 by means of a spring 38 disposed about the pisto stem 32. One end of spring 38 engages a shoulder 78 forming downstream face of valve seat 76 and the other end of the sprin engages the upstream face 80 of piston head 24.

Fixture 72 has an externally threaded neck 82 which provides a mechanical engagement with the adaptor 70. Th fixture 72 also has ^" a through passage 84, one of whose ends 8

(only one shown) is connected to a fixedly installed pressurise cleaning fluid supply conduit. The other end of the passage 8 may be used to connect further fixtures to the conduit series o may be blanked off. A side branch 88 communicates with th through connection 84 for sealed engagement with the extensio

74 of the adaptor 70 by means of an O-ring 90.

The adaptor 70 is also provided with a skirt portion 9 which is internally threaded for engagement with the externall threaded neck 82 of fixture 72. The adaptor is sealed to t neck by means of a gasket 94.

Thus, pressurised cleaning fluid may be supplied to coupling head mounted upon flange 12 of the adaptor 70. Up removal of the coupling head from the flange, piston 24 wi move upwardly so that O-ring 36 seals against the valve seat 7 preventing escape of cleaning fluid. Various differe attachments may be fitted to any given fixture, to suit vario coupling heads.

In each of the above described embodiments, the gas sea between the coupling head and the wash socket is maintained the coupling head is operated to open the wash socket. T

depth of the bore 14, 58 or 73, in which the piston head 24, 5 slides, enabling seal 26 or 56 to stay in sealing contact wit the bore even when the piston 22 has been fully depressed by th coupling head. Thus, even though the shape of the interfac between the coupling head and wash socket changes as th coupling head is operated, sealing of the coupling head ga passage is maintained.