Improvements in and relating to taps for pressurised casks and bottles

Abstract

 A tap for pressurised casks and bottles is shown which has a body portion with an outlet. A valve element controls the outlet and co-operates with the body so that at least one double seal (12, 14) is formed at the valve seat when the valve element is positioned to close a tap. The body of the tap comprises a chamber (6) with one end of which is the outlet (4) and at the other end of which an expansion chamber is attached. The smaller end (22) of the expansion chamber is aligned and connected to a small bore tube (24) for insertion into the bottle or cask. The arrangement is such that there are no discontinuities in the flow both from the tube to the outlet of the chamber. The tap is capable of withstanding the pressure in the container, maintaining a liquid in the container at an acceptable carbonation level and dispensing the liquid without an unacceptable amount of froth being produced.

Description

[0001] This invention relates to taps and more particularly to taps for pressurised casks and bottles.

[0002] Any gaseous liquid for example beer or carbonated soft drinks is difficult to dispense satisfactory without producing an unacceptable amount of froth. The pressures at which such liquids have to be maintained prior to dispensing are high. Barrels of lager and beer require relatively sophisticated tapping devices to provide a pressure reduction between the container and the tap. These tapping devices additionally restrict the tendancy of the liquid to 'froth'. Whilst it is known to provide means whereby liquid may be poured from smaller containers these are often found to be unsuccessful at preventing frothing. The general object of this invention is therefore to provide a relatively simple tap which will withstand the pressure of the gaseous liquid in a normally pressurised cask or bottle while allowing the liquid to be poured without excessive frothing and which may be provided for the cask or bottle without greatly adding to the cost to the consumer.

[0003] Furthermore, customers often wish to buy in bulk but do not intend to consume all the liquid at one time. The tap must therefore be able to maintain the remaining liquid in a container at a carbonation level acceptable to the customer even when it has been used to dispense part of the contents of the container.

[0004] According to one aspect of the invention a tap for attachment comprises a chamber which has an outlet at one end controlled by a valve element and an expansion chamber coaxially aligned with and attached to the other end of the chamber, the smaller end of the expansion chamber being aligned and connected to a tube for insertion into the bottle or cask, the arrangement being such that there are no discontinuities in the flow path from the tube to the outlet of the chamber.

[0005] Such a tap has two advantages which reduce the amount of frothing. Firstly, it provides a smooth flow path for the liquid thereby reducing the nucleation of gas bubbles in the liquid being dispensed. Secondly, the small bore tube provides a restriction, so that there is only a small pressure drop across the tap itself, which minimises gas breakout at this point. The expansion section between the tube and the tap effects a smooth transition in cross-section minimising the production of gas bubbles in this zone.

[0006] According to a further aspect of the invention a tap for attachment to a pressurised cask or bottle comprises a body portion with an outlet and a valve element to control the outlet, the valve element co-operating with the body so that at least one double seal is formed at the valve seat when the valve element is positioned to close the tap.

[0007] The advantage of this arrangement is that it enables the tap to withstand the pressure inside the container.

[0008] The valve element is preferably cylindrical and is preferably positioned transversely to the flow passage, a double seal being provided on each side of the flow passage when the valve element is in the closed position.

[0009] The valve member may alternatively be positioned parallel to the flow passage and a double seal provided on each side of the outlet when the valve element is in the closed position. This increases the ease of operation of the tap.

[0010] Conveniently a cylindrical pipe of flexible material is attached between the expansion chamber and the tube to restrict the liquid flow rate when the container pressure is high so that the flow rate will always by substantially uniform over a wide range of container pressure.

[0011] The invention will now be described by way of example with reference to the accompanying drawings in which:

Figure 1 is a side view of a tap according to the invention; and

Figure 2 is a sectional side view of another embodiment of the tap of Figure 1.

[0012] The tap shown in Figure 1 has a body formed from a plastic material for example polypropylene or high density polyethylene consisting of a screw cap 2, by which it may be fitted to a correspondingly threaded open end of a pressurised cask or bottle, and an outlet 4 which are joined by a chamber 6. The body extends above the outlet to form an annular wall 7 to hold a valve element for movement transverse to the axis of the chamber 6 to control fluid flow through the outlet 4. The valve element may be formed from a semi-flexible elastomer material and is joined to a handle 10 in screw engagement with the annular wall 7.

[0013] In the position shown, the valve is closed and two double seals are formed between the valve and the annular wall.

[0014] The first double seal is formed (a) between a cylindrical face 12 of the valve 8 engaging against the inner face of the wall of the outlet 4, and (b) between a conical seat 14 on the valve engaging against a corresponding seat found on the upper edge of the outlet 4. A second double seal is produced above the chamber 6 (a) between a bead 16 on the upper end of the valve engaging against a taper face 18 on the tubular extension 7 and (b) between a second bead 17 engaging against the inner wall of the tubular extension.

[0015] Another embodiment of the tap is shown in Figure 2 in which like numerals refer to like parts. The body extends from the chamber 6 transversly to and across the outlet 4 to form an annular wall 25 to hold the valve element 8 for movement parallel to the axis of the chamber 6. In the closed position shown two double seals are again formed, however in this embodiment a double seal is provided on either side of the outlet 4.

[0016] The first double seal is formed (a) between a bead 26 on the cylindrical face 12 of the valve 8 engaging against the wall of chamber 6 and (b) between the conical seat 14 on the valve engaging against a corresponding seat on the shoulder between the chamber 6 and the outlet 4. The second double seal is produced on the other side of the outlet 4 (a) between the bead 16 on the outer end of the valve engaging against a taper face 28 on the tubular extension 25 and (b) between the second bead 17 engaging against the inner wall of the tubular extension 25.

[0017] In both embodiments the two double seals enable a significant amount of pressure to be held within the container to which the tap is attached.

[0018] The screw engagement between the handle 10 and the tubular body 7 or 25 is formed with a large angle screw thread. This gives a rapid movement of the valve on rotating the handle, reducing the time when the valve restricts the outlet and causes a consequent high pressure drop and thus minimising the froth dispensed on opening and closing. Alternative means may be provided to move the valve but preferably the outlet is always opened and closed rapidly.

[0019] The axial valve arrangement shown in Figure 2 has the advantage that the opening and closing of the valve by rotation of the handle 10 is facilitated since the handle is distanced from the cap 2. Ratchet teeth may be provided on the cap 2 and the container neck to prevent accidental unscrewing of the tap from the container.

[0020] The cylindrical chamber 6 extends through the screw cap and is joined to an expansion chamber 20. The cross-sectional area of the expansion chamber is a maximum at this point and is exactly equal to the cross-sectional area of the cylindrical chamber. The expansion chamber converges continuously to a minimum at an included angle of 10° to 20° and then extends at constant diameter to form a small tube 22. This allows a capillary tube 24 to be attached either internally or externally to the cylindrically tapering expansion chamber as shown in Figures 1 and 2 respectively. Again the internal cross-sectional area of the capillary tube is equal to that of the expansion chamber at the point where the liquid will pass from a capillary tube to the expansion chamber.

[0021] Thus a smooth flow path is provided for the liquid as it passes from the container to the outlet. The internal surface finish of the capillary tube, expansion chamber and main tap body are carefully controlled to prevent as far as possible any discontinuities in the flow pattern of the liquid being dispensed. Any such discontinuities, sharp edges or sudden divergences in cross-sectional area will provide nucleation sites for gas bubbles and cause decarbonation and consequent frothing.

[0022] The tap of the present invention is preferably fitted to the cask or bottle as soon as it has been filled with liquid. For this reason, if the cap is viewed from the front looking along the axis of the cap screw thread, it is preferred that there are no projections of the tap beyond the outer diameter of the screw cap which is used to attach the fitment to the container neck. This is to maintain the simplicity of the capping equipment in line with that conventionally used.

[0023] The capillary tube is preferably arranged to extend to the bottom of the container to which the tap is attached. This means that all the liquid in the container will be available for dispensing even if the container is lying on its side and also ensures that the valve is flooded with the liquid at all times after the initial moments of the first dispensing operation.

[0024] In an alternative arrangement a piece of flexible tubing may be added to the capillary tube. This length of flexible tubing formed for example from silicon rubber is preferably attached between the expansion chamber and the capillary tube. The pressure of the liquid within the capillary tube will decrease as it passes along the tube so that there will be a discernable pressure difference across the length of flexible tubing. This will cause it to contract thus restricting the flow from the container to the outlet. When the container is full and the internal pressure is therefore at a maximum, the flow rate of the liquid along the capillary tube will tend to be high. However, the high pressure will also cause the length of flexible tubing to collapse inwards thus restricting the flow. As the container empties and the pressure and therefore the flow rate falls, the pressure difference across the length of tubing will decrease causing it to expand and allow more liquid through. In this way the flow rate remains substantially uniform over a wide range of container pressure.

[0025] The tap is relatively cheap to manufacture, but will operate successfully with gaseous liquids such as beer, lager, sparkling white wine and carbonated soft drinks and will maintain the liquid in good condition.

Claims

1. A tap for attachment to a pressurised cask or bottle comprising a body portion with an outlet and a valve element to control the outlet, the valve element co-operating with the body so that at least one double seal is formed at the valve seat when the valve element is positioned to close the tap.

2. A tap for attachment to a pressurised cask or bottle has a body comprising a chamber which has an outlet at one end controlled by a valve element and an expansion chamber coaxially aligned with and attached to the other end of the chamber, the smaller end of the expansion chamber being aligned and connected to a small bore tube for insertion into the bottle or cask, the arrangement being such that there are no discontinuities in the flow path from the tube to the outlet of the chamber.

3. A tap as claimed in Claim 2 wherein the valve element co-operates with the body portion so that at least one double seal is formed at the valve seat when the valve element is positioned to close the tap.

4. A tap as claimed in either Claim 1 or 3 wherein a second double seal is formed at the other end of the valve element when the valve element is positioned to close the outlet.

5. A tap as claimed in either Claim 3 or Claim 4 when dependent of Claim 3 wherein the valve element is positioned transversly to the flow passage and a double seal is provided on either side of the flow passage when the valve element is in the closed position.

6. A tap as claimed in Claim 5 wherein the body extends above the outlet transversly to the chamber to form an annular wall, one double seal being formed between the valve element and the outlet and the other double seal being formed between the valve element and the annular wall.

7. A tap as claimed in either Claim 3 or Claim 4 when dependent on Claim 3 wherein the valve element is positioned parallel to the flow passage and a double seal is provided on either side of the outlet when the valve element is in the closed position.

8. A tap as claimed in Claim 7 wherein the body extends across the outlet parallel to the chamber to form an annular wall one double seal being formed between the valve element and the chamber and the other double seal being formed between the valve element and the annular wall

9. A tap as claimed in any one of Claims 2 to 8 wherein a cylindrical pipe formed from a flexible material is attached between the expansion chamber and the small bore tube to regulate the flow rate of the liquid as it passes from the container to the outlet.

10. A tap as claimed in any one of Claims 2 to 9 wherein the cross-sectional area of the expansion chamber is equal to the cross-sectional area of the chamber at the point where they are attached.

11. A tap as claimed in any one of Claims 2 to 10 wherein the internal cross-sectional area of the expansion chamber decrease continuously from the point of attachment to the chamber until it is equal to that of the small bore tube.

12. A tap as claimed in any one of Claims 2 to 11 wherein the expansion chamber includes an integral tubular portion to which the small bore tube may be attached either internally or externally, the integral tubular portion having an interior dimensioned such that there are no discontinuities in flow path from the small bore tube to the expansion chamber.

13. A tap as claimed in any preceding claim wherein the position of the valve element is controlled by handle to which it is attached, the handle being in screw engagement with the body.

14. A tap as claimed in any one of Claims 1 to 6 and 9 to 13 subsequently as herewith described with reference to Figure 1 of the accompanying drawings.

15. A tap as claimed in any one of Claims 1 to 4 and 7 to 13 subsequently herewith described with reference to Figure 2 of the accompanying drawings.

Drawing