IES20020867A2 - Liquid dispense valves - Google Patents

Abstract

The present invention relates to a liquid dispense valve comprising: (a) a body (2) having a bore (15) defining a cylindrical chamber therein and having a beverage inlet port (24) and a beverage outlet port (25) in communication with the chamber; (b) a rotatable valve member (3) comprising a generally cylindrical barrel of plastics material rotatably mounted in the chamber in the body (2) so as to be movable between open and closed positions of the valve, the said barrel having a channel (14) therein to provide a fluid conduit between the inlet port (24) and the outlet port (25) when the valve is in an open postion, and having a sealing surface portion (21) to seal one of the ports when the valve is in the closed position, the external diameter of the barrel being minimally less than the internal diameter of the bore in the body (2); (c) handle means (8) to rotate the valve member (3) beteween the open and closed position; (d) at least one plug (5) of plastice material receivable in a recess (27) in the barrel diametrically opposite to the sealing surface portion (21); and (e) spring means (23) in the recess (27) to urge the plug radially outwardly of the barrel against the surface of the bore (15) and thus press the sealing surface portion (21) of the barrel against the surface of the bore surrounding the port to be sealed. The liquid dispense valve described herein is particularly useful, inter alia, in the field of beverage dispensing equipment, particularly for dispensing beers, including stout, especially draught beers supplied from a pressurised container.

Description

This invention relates to liquid dispense valves for dispensing liquids of all kinds. It is useful, inter alia, in the field of beverage dispensing equipment, particularly for dispensing beers, including stout, especially draught beers supplied from a pressurised container.

The background of the invention will be discussed with reference to beverage dispensing taps, but the invention is not so limited. Draught beers are generally dispensed via taps attached to mounting fixtures which are mounted at the rear of a bar counter or the like. Bar staff working behind the counter operate such taps to dispense beers which are then handed to customers standing at the front of the counter. Many conventional beer taps have a vertical handle which is pulled by the staff member to dispense the beer. Such tap handles generally have a cam surface at the lower end thereof and are linked to a spindle by a pin which passes through both the handle and the spindle. As the handle is pulled away from the vertical position, interaction of the cam surface against a top surface of the tap body causes the spindle to lift and open a valve inside the body by longitudinal movement. However, this operation depends entirely upon the pin, which often has a diameter of only about 4mm. Such pins tend to break or become loose and fall out as a result of repeated usage. There is therefore a need for taps which do not have the cam pin as a point of weakness.

It has been proposed to make beer taps with a rotary valve. The handle is attached (for example by means of a forked lower end) to a cylindrical barrel which is rotatable in a generally cylindrical cavity inside the tap body. A beer inlet port and a beer outlet port in the body can be put into communication with each other by means of a channel in part of the surface of the barrel, when the handle is pulled away from the vertical position. However, when the handle is vertical, there is no communication between the inlet and outlet ports, and the inlet port is sealed by a plug which is urged radially outwardly from the barrel. The plug is one of a pair of plugs installed at either end of a passage extending across the barrel. One known product used a coil spring between the plugs to urge them both outwardly. However, the use of a coil spring had certain disadvantages, as set out in Irish Patent Specification No. S81460JIE^M460) OTO._1 i/z?a : ----2 ¢0208 6 7 which shares a common inventor with the present application, and whose contents are incorporated herein by reference. IE S81460 describes a beverage dispensing tap comprising: a) a body defining a cylindrical chamber therein and having a beverage inlet port and a beverage outlet port; b) a rotatable valve member comprising a generally cylindrical barrel fitting closely in the said chamber in the body and having a channel therein to provide a conduit between the inlet port and the outlet port when the valve is in an open position; c) handle means to rotate the valve member between closed and open positions; d) sealing means receivable in a cylindrical passage in the valve member and comprising a pair of plugs which fit slidably at either end of the passage, and spring means between the two plugs urging them outwardly of the valve member, characterised in that the spring means comprises a plurality of disc springs.

Beverage dispensing taps with a rotary valve as described above were made with a body and a rotatable valve member of stainless steel while the diametrically-opposed plugs of the sealing means were of plastics material. In order to facilitate smooth rotary movement, and to reduce wear of one metal component on the other, it was necessary to provide a reasonable clearance between the external surface of the valve member and the internal surface of the chamber in the body, i.e. there was a significant difference of about 0.5mm between the external diameter of the valve member and the internal diameter of the body, as shown in Figures 3 and 4 of the drawings of IE S81460. Sealing was achieved by one of the plugs being spring-urged against the portion of the body defining the beverage inlet port. When the tap was opened by rotating the valve member, the plug slid away from the inlet port to open the conduit between the ports, and when the tap was closed again the plug slid back across the inlet port to close the conduit.

It was found that problems arose with the plug (made of polytetrafluoroethylenePTFE) wearing inconsistently. This was believed to be due to the passage of the springurged plug across the inlet port, which was a circular hole cut in a cylindrical surface. When the plug surface started to move across the port, the two diameters would form a counter elliptical shape which would put uneven pressure on the sealing plug as it moved between open and closed positions. ΙΕβ 2 Οβ 6 Ί Because one of the plugs provided the sealing surface at the inlet port, it was necessary for the plugs to have a substantially greater diameter than the inlet port. In practice the plug was 12mm in diameter and the inlet port was 6.5mm in diameter. The large diameter of the plugs relative to the diameter of the valve member had the consequence that the channel providing the conduit between the ports had to be of small dimensions. Therefore as seen in Figure 4 of IE S81460, the channel was restricted and the liquid flow encountered a "step" when it entered the conduit. In later development of the tap of IE S81460, the diameter of the inlet port was reduced to 4mm, which had the effect of reducing the "Step" but also limiting the flow into the valve.

In the tap of IE S81460, 4-lipped seals of the kind sold under the Trademark QUAD-RING® were applied around the cylindrical barrel of the valve member, as shown particularly in Figures lb and 5 of IE S81460. However, because of the significant clearance between the valve member and the body core, the pair of lips on each seal projecting into this clearance space tended to twist during assembly of the tap and to wear inconsistently during operation.

There are other known types of beverage dispense tap with a rotary valve. In one type a ball with a central bore is turned through 90° to align the bore with opposed inlet and outlet ports. However this form of valve suffers from turbulent flow as the valve is being opened. Another type of valve uses a ball with an arcuate channel which provides a conduit between inlet and outlet ports orientated at 90° to each other. However in this form of valve the ball is rotatably housed in plastics shell components that are machined to fit the ball surface and then secured tightly around it. This form of valve is difficult to dis-assemble for maintenance purposes.

It is an object of the present invention to provide liquid dispense valves in which the problems described above are reduced or eliminated. It is also an object of this invention to provide a reliable and attractive liquid dispense valve which is smaller than the conventional beverage dispense taps that are currently used, with a reduced thermal mass which causes less heat gain as a beverage is dispensed, and which is convenient both to assemble and to dis-assemble for maintenance.

The present invention provides a liquid dispense valve comprising: (a) a body having a bore defining a cylindrical chamber therein and having a beverage inlet port and a beverage outlet port in communication with the chamber; £02006? (b) a rotatable valve member comprising a generally cylindrical barrel of plastics material rotatably mounted in the chamber in the body so as to be movable between open and closed positions of the valve, the said barrel having a channel therein to provide a fluid conduit between the inlet port and the outlet port when the valve is in an open position, and having a sealing surface portion to seal one of the ports when the valve is in the closed position, the external diameter of the barrel being minimally less than the internal diameter of the bore in the body; c) handle means to rotate the valve member between the open and closed positions; d) at least one plug of a plastics material receivable in a recess in the barrel diametrically opposite to the sealing surface portion; and e) spring means in the recess to urge the plug radially outwardly of the barrel against the surface of the bore and thus press the sealing surface portion of the barrel against the surface of the bore surrounding the port to be sealed.

Suitably the sealing surface portion seals the inlet port. Most suitably the sealing surface portion of the barrel seals against the surface portion of the bore defining the perimeter of the inlet port.

The bore in the body suitably defines an open-ended cylindrical chamber. Preferably the chamber is open at both ends so that the valve member can be pushed out of it if the unit is to be dis-assembled. The chamber may suitably be closed by covers applied to the sides of the body at each end of the bore. Most suitably the covers are associated with the handle means and preferably form part of the handle means. In the preferred embodiments the extent of angular movement of the handle means is governed by cut-out portions of the body that are inward of the covers.

The barrel may suitably be provided with one recess receiving a spring-urged plug diametrically opposite to and aligned with the sealed port in the closed position of the valve. In another suitable arrangement, the barrel may be provided with two recesses receiving spring-urged plugs diametrically opposite to the said port but placed side-by -side in an axial direction.

The minimal difference between the external diameter of the barrel and the internal diameter of the bore should preferably provide the smallest clearance that permits smooth rotation of the barrel in the bore upon manual activation of the handle. ΙΕθ 208 6 7 The said difference in diameters is preferably less than 0.10mm, and may suitably be in the range from 0.04 to 0.08mm, particularly from 0.048 to 0.069mm.

Preferably the body and the valve member are of different materials. Suitably the body is of metal while the valve member is of plastics material. If the body is of plastics material also, it is preferably of a different plastics material from the valve member. Suitably the valve member is of a plastic material with very good creep resistance, low and constant co-efficient of friction and physically inert.

Preferably the spring means comprises a plurality of disc springs, suitably two.

As discussed in IE S81460, disc springs are conically-formed annular discs which are loaded in the axial direction. Variable spring characteristics can be achieved by the arrangement of disc springs into stacked columns. Disc springs achieve greater force under less compression and surface area than a coil spring. Disc springs are designed for pre-load conditions where, once compression is engaged, the spring offers greater capacity to maintain pressure, reducing the opportunity for setting, which can occur with coil springs. The disc springs also require less compression force than a comparable coil spring when the plug is being pushed into the recess in the valve member, which facilitates assembly and reassembly of the tap. With disc springs, only manual pressure is required when the valve member is being assembled, whereas a coil spring has to be compressed with a tool which makes the assembly operation awkward.

A coil spring also has to be ground flat for a full rotation at each end in order to seal against flat faces. Satisfactory sealing requires an equilibrium of pressure which is difficult to achieve with the tolerances resulting from the grinding flat of coil springs. Disc springs do not require grinding in order to seal against flat faces in a predictable manner to achieve accurate sealing. Disc springs are commercially available with bearing flats and it is preferred to use such disc springs in the present invention.

Suitably, the disc springs are arranged in a pair with the individual elements facing in opposite directions. This enhances the ability to provide a greater force rating in a confined area. Desirably the disc springs are of stainless steel. This is preferred for an installation in contact with a beverage.

In the preferred embodiments, the valve member comprises a generally cylindrical barrel having two circumferential grooves carrying a pair of 4-lipped seals such as those sold under the trademark QUAD-RING ®, one on each side of the plug6 MB 0 ?08 s 1 receiving recess. This provides an improvement over a prior art tap having a rotary valve member in which the tap journal is sealed with two nitrile O-rings and back-up PTFE seals. By using 4-lipped sealing rings, the preferred embodiment of the present invention has eliminated the need for back-up seals and facilitated easier handle action due to lower friction.

Four-lipped seals are in annular form with a four-lipped sealing profile. In contrast to an o-ring, a QUAD-RING ® Seal has a double sealing function. It requires a lower initial squeeze, which results in reduced friction during dynamic applications. Furthermore, it has a number of other advantages over the O-ring: Low Friction - QUAD-RING ® Seal requires less radial squeeze than a comparable O-ring. Less squeeze means less friction, less wear and thus a longer service life.

Very good sealing efficiency - Due to an improved pressure profile over the QUAD-RING ® Seal cross-section, a high sealing effect is achieved.

Lubrication - A lubricant reservoir formed between the sealing lips improves start up.

Unlike an O-ring, the mould line flash lies in the trough, between and away from the critical sealing lips.

Two embodiments of the invention are illustrated in the accompanying drawings in which: Fig. 1 is a front elevation of the liquid dispense valve (LDV) of both embodiments; Fig. 2 is a horizontal cross-section of the first embodiment of the LDV, without its handle means, on the line C-C in Fig. 4; Fig. 3 is a vertical cross-section of the second embodiment, again without its handle means, on the line B-B in Fig. 5 or the line D-D in Fig. 4, showing the valve in the closed position; Fig. 4 is a cross section of the first embodiment on a line equivalent to A-A in Fig-3; Fig. 5 is a cross section of the second embodiment, on the line A-A in Fig. 3; •Ε 0 2e β j Fig. 6 is a vertical cross section, similar to Fig. 3 on the line D-D in Fig. 4 or the line B-B in Fig. 5 (or the line B-B in Fig. 4 and 5) but with the handle means and showing the valve in the open position; Fig. 7 is a view similar to Fig. 6, showing the valve in the closed position, with a fragment shown in an enlarged view; Fig. 8 is a side view of the LDV, omitting the limb of the handle fork and the external wall of the body of the LDV, the valve being in the open position similar to Fig. 6; Fig. 9 is a side view similar to Fig. 8, showing the valve in the closed position.

Fig. 10 is a side view of the LDV without one fork and cover plate, in the open position of Fig. 8 but with a threaded attachment system; Fig. 11 is a side view of the LDV similar to Fig. 10, but in the closed position; Fig. 12 is a top exploded view of the valve member barrel of the LDV; Fig. 13 is a side exploded view of the valve member barrel of the LDV.

As shown in the drawings, an LDV comprises a handle (8), a body (2) and a valve member (3). The length of the valve member (3) is equal to the width of the body (2). The handle has a forked lower end with a pair of forks (1) which embrace the flatsided body and the flat-ended valve member (3). Each fork (1) has an enlarged portion which forms a cover plate for the respective side of the body and valve member(see Fig. 10 and 11). Locating screws (7) pass through the forks (1) into wear plates (11), to be described below. As indicted in Fig. 2, the wear plates (11) are designed to be inserted in slots (9) at the ends of the valve member. The screws (7) secure the forks (1) to the wear plates (11) which are held in the slots (9) so that the valve member (3) rotates when the handle (8) is moved.

The body (2) has an open-ended bore (15) which defines a cylindrical chamber housing the valve member (3). An inlet port (24) is located at the rear of the body (2), communicating with the chamber. An inlet body portion (16) defines a funnel leading to the inlet port (24). The LDV can be mounted to any form of receiver by means of a splined attachment as shown in Fig. 6 at Numeral 17 (or by means of a threaded attachment (31) as shown is Fig. 10 and 11). The inlet body portion can be sealed from leakage of liquid by means of a location seal (18) as shown in Fig. 6 and 7. ΙΕο β J The body also has an outlet port (25) in the lower part thereof, communicating with a liquid outlet (6). It is possible to use various forms of outlet configuration to suit different liquids being dispensed. These may include detachable outlets in the form of plastic or metallic spouts which may contain flow straighteners or restrictor disks, these being examples of attachments that are used widely in the drinks dispense industry.

The valve member (3) is a generally cylindrical barrel which fits within the bore (15) of the body (2), so as to be rotatable therein. Due to the open ends of the bore, the barrel can be inserted into the bore from either end and can be pushed out again if disassembly of the valve becomes necessary for maintenance purposes.

The valve member (3) has a channel (26) providing a liquid conduit between the inlet port and the outlet port in the open position of the valve. The base of the channel (26) forms a chord to the circumference of the valve member (3).

The inlet port (24) is suitably within a diameter range of 3mm to 8.5mm and the outlet port (25) is suitably within a diameter range of 4mm to 12mm, dependant on the liquid to be dispensed. The channel (26) has a diameter corresponding to that of the outlet port, for example in the range of 4mm to 12mm. As seen in Fig. 4 and 5, the channel (26) is approximately semi-circular in profile.

The valve member (3) also has a pair of circumferential grooves to receive a pair of 4-lipped sealing rings (4) and (4a) which seal against the internal wall of the bore (15).

The body (2) can be made of any suitable food-grade plastic material or foodgrade metal, for example nickel or chromium-plated brass, or preferably a grade of Austenitic stainless steel S304 or S316. The valve member (3) can be made from any food-grade plastic with high wear resistance, suitably PTFE or preferably "Ultra High Molecular Weight Polyethylene" (UHMWPe). The liquid outlet (6) can be constructed from any food-grade plastic or food-grade metal, for example nickel or chromium-plated brass or preferably a grade of Austenitic stainless steel S304 or S316.

In the embodiments of Fig. 2 and 4, the valve member (3) has a pair of recesses (27) whereas in the embodiment of Fig. 5 the valve member has a single recess (27).

The plug or plugs (5, 5a and 5b) of plastics material are slidably received in the recess or recesses. Each recess has a flat base (29) and the inner surface of each of the plugs is squarely located parallel to the base so that two disc springs (23) can be trapped between £020867 the base of the plug (24) and the base of the recess (29). Each of the disc springs (23) is a frustoconically-formed annular disc of stainless steel and they are placed with their narrow ends in contact with each other. The disc springs urge the plug(s) radially outwardly. The plug(s) have arcuate external surfaces corresponding to the internal surface of the cylindrical bore (15). Suitably the extent of potential projection of the plug surface beyond the barrel surface may be up to 0.1mm (see Fig. 7 - enlarged portion where the small clearance is shown).

The plug(s) are located in the valve member (3) diametrically opposite to the sealing surface portion (21) of the valve member. In the embodiment of Fig. 2 and 4, the two plugs (5) and (5a) are located diametrically across the valve member (3) from the inlet port (24) when the valve member is in the closed position. The plugs (5) and (5a) are located side-by-side in an axial direction along the valve member. The 4-lipped Quad Ring® seals (4) and (4a) are located in grooves spaced apart beyond the plugs (5) and (5a) in an axial direction. In the embodiment of Fig. 5 the single plug (5) is aligned with the inlet port in the closed position of the valve member. The 4-lipped seals (4) and (4a) are located on either side of the plug.

Each plug (5) is generally cylindrical and slides in a cylindrical recess (27). An O-ring seal (10) held in a groove on the surface of the plug prevents liquid from entering the area of the disc springs (23).

Each plug (5), (5a), (5b) may suitably be made from a plastic material with very good creep resistance, low and constant co-efficient of friction and physically inert (suitable for food contact), suitably PTFE or preferably "UHMWPe" as described above.

Each plug is urged radially outwardly by the disc springs and is pressed against the internal surface of the bore (15). Diametrically opposite to the plug(s), the external surface of the valve member (3) forms a sealing surface (21). The external diameter of the valve member (3) and the internal diameter of the bore (15) are so closely matched that a sealing contact is made between the respective surfaces, under pressure of the spring-urged plug acting against the opposite surface of the bore. As the actual surface of the valve member (3) performs the sealing function, the inlet port can be substantially larger than in the tap of IE S81460 e.g. with a diameter of 8.5mm which is desirable for the beverage industry. •Ε 0 2 0β6 7, In the open position of the LDV, shown in Fig. 6, the valve member (3) has been rotated by use of the handle (8) to the orientation in which the liquid channel (14) connects the inlet port (24) and the outlet port (25), in the same manner as in IE S81460 but without the "step" encountered in the flow path of IE S81460. The inlet flow of liquid is indicated by the arrow (12) and the outlet flow is indicated by the arrow (13) in Fig. 6. The outlet port (25) is substantially closer to the inlet port (24) than in the tap of IE S81460 so that the length of travel of the fluid in the channel (14) is shorter.

In Fig. 7, the valve member has been rotated by means of the handle (in a clockwise direction, as seen in this figure) to the closed position. The angular rotation is about 50 degrees. The sealing surface (21) of the valve member is pressed into sealing contact with the internal surface of the bore, particularly at the perimeter (30) of the inlet port (24). Due to the close diameters of the valve member and the bore, the inner surface of the bore is virtually tangential to the cylindrical surface of the valve member at and around the perimeter of the inlet port. The valve member is pressurised into sealing contact by means of the spring-urged plug or plugs. Liquid supplied towards the inlet port in the direction of the arrow (12a) at a pressure of the order of 45 psi (3 bar) is prevented from passing through the valve by the sealing contact between the valve member and the bore having matching diameters with only very close tolerances.

Due to the plastics material of the valve member (3) and the plug or plugs (5), the valve member can be rotated with low friction and therefore low wear. Lateral sealing is achieved by the 4-lipped Quad Ring® seals (5), to ensure that liquid cannot exit the LDV body through the sides.

In a preferred embodiment, the valve member (3) has an external diameter of 22.3mm with a tolerance in the range from -0.02 to -0.041mm. The bore (15) has an internal matching diameter of 22.3mm with a tolerance in the range from +0.028 to +0.007mm. Therefore the maximum difference in the diameters is 0.069mm and the minimum difference in the diameters is 0.027mm, giving a mean difference of 0.048mm. The radial difference is 50% of these figures. As the sealing surface (21) of the valve member is pressured against the internal surface of the bore (15) by the action of the plug or plugs (5), the separation at the perimeter of the inlet port is effectively reduced to zero, the cylindrical valve member being slightly offset from a concentric position in the cylindrical bore by the pressure action of the plug. ΝΕΟ 208 6 7 In the preferred embodiment, having a valve member with an external diameter of 22.3mm, the inlet port suitably has a diameter of about 8.5mm. If the diameter of the inlet port is increased significantly above 8.5mm, the tangential sealing contact at the perimeter of the inlet port may be affected. The plug or plugs (5) have a diameter of the order of 8mm.

The foregoing measurements relate to the preferred embodiment. In practice these measurements can vary in relation to the physical overall size of the LDV.

Fig. 8 and 9 show the device for limiting the angular rotation of the valve member. In IE S81460, the body had an open slot in which the handle moved. However, there was a risk of dirt becoming trapped in the slot, restricting the movement of the handle and giving rise to potential hygiene problems. In the LDV of the present invention, wear plates (11) are located on either side of the body (2) and are rotated by means of four screws (7) which are located through the handle forks (1), threading into the wear plates at four positions (1 la, 1 lb, 1 lc and 1 Id). The wear plates are inserted in slots in the valve member (3) and enter into profiled cut-outs (28) formed in the edges of the body where it defines the ends of the bore. The cut-outs (28), which are arcuate in shape, have end walls which define stop positions for the wear plates. In the open position of Fig. 8, the wear plate (11) has been rotated inside the body (2) so that its end comers rest against the lower fixed position (20) and the upper fixed position (20a). In the closed position of Fig. 9, the wear plate has been rotated in the clockwise direction inside the body (2) to rest against the upper fixed position (19) and the lower fixed position (19a).

As shown in Fig.2, the ends of the valve member (3) are flush with the sides of the body (2). The wear plates (11) are sunk into the slots (9) and the cut-out portions (28). As shown in Fig. 10 and 11, the cover plate portions (29) of the handle forks can be placed against the sides of the body (2) so as to cover the end of the valve member and the cut-outs. Thus the cut-outs are enclosed and are not prone to collecting dirt, unlike the slots of IE S81460.

Fig. 10 and 11 show side views of an LDV having a threaded attachment (31). A standard coupling unit having a threaded nut may be used to mount the LDV in communication with a liquid supply source, for example as shown in IE S81460. ¢020(67 When assembling the LDV, the disc springs (23) and plug(s) (5) are inserted into the recess(es) (27), and the 4-lipped seals are placed around the valve member. The valve member is then pushed into the bore (15). The wear plates (11) are pushed into the slots (9) with the ends of the wear plates extending into the cut-outs (28). The forks (1) of the handle are then slid around the sides of the body and the screws (7) are used to secure the forks to the wear plates. Rotational movement of the handle is then transmitted to the valve member within the angular limitations set by the end positions (19) and (20) of the cut-outs.

The LDV can easily be dis-assembled by reversing the above-described procedure.

As compared to the tap of IE S81460, the LDV of the present invention gives significantly improved performance. As the sealing surface (21) is a part of the cylindrical surface of the valve member, the contact points of the valve member are more evenly distributed when the valve is open and closed, thus eliminating the excessive wear as experienced in the tap of IE S81460. Furthermore, as the valve member (3) can now be much closer in diameter to the internal bore of the body, the 4lipped Quad Ring® seals operate with full effect, eliminating the twisting and inconsistent wear experienced during assembly and operation of the tap of IE S81460.

Claims (5)

1. A liquid dispense valve comprising: 5 (a) a body having a bore defining a cylindrical chamber therein and having a beverage inlet port and a beverage outlet port in communication with the chamber; (b) a rotatable valve member comprising a generally cylindrical barrel of plastics material rotatably mounted in the chamber in the body so as to be movable between open and closed positions of the valve, the said barrel having a channel therein to 10 provide a fluid conduit between the inlet port and the outlet port when the valve is in an open position, and having a sealing surface portion to seal one of the ports when the valve is in the closed position, the external diameter of the barrel being minimally less than the internal diameter of the bore in the body; c) handle means to rotate the valve member between the open and closed positions; 15 d) at least one plug of plastics material receivable in a recess in the barrel diametrically opposite to the sealing surface portion; and e) spring means in the recess to urge the plug radially outwardly of the barrel against the surface of the bore and thus press the sealing surface portion of the barrel against the surface of the bore surrounding the port to be sealed. 20

2. A liquid dispense valve according to claim 1 wherein the sealing surface portion seals the inlet port.

3. A liquid dispense valve according to either of the preceding claims wherein the barrel is provided with two recesses receiving spring-urged plugs diametrically opposite to the inlet port in the closed position of the valve but placed side-by-side in an axial 25 direction.

4. A liquid dispense valve according to any of the preceding claims wherein the difference between the external diameter of the barrel and the internal diameter of the bore is less than 0.1mm.

5. A liquid dispense valve substantially as described herein with reference to and/or as 30 illustrated in the accompanying drawings.