GB2153008A - Liquid dispensing apparatus - Google Patents

Abstract

Apparatus 2 for dispensing liquid from a container 1 comprises a housing 3 adapted for attachment to the container as at 5, and a piston 4 slidably mounted in the housing and adapted to effect a seal against a rim 15 of an opening in the container by means of a sealing washer 14. A flow passage 17 extends through the piston 4 for admitting gas under pressure to the interior of the container 1, liquid being forced up tube 16. The gas pressure acts upwardly on the sealing washer 14 over a surface area smaller than that of the surface of the piston 4 subject to the same downward pressure, resulting in a net downward force on the piston so as to effect the seal. <IMAGE>

Description

SPECIFICATION Liquid dispensing apparatus This invention relates to liquid dispensing apparatus for use in situations where liquid is dispensed under pressure.

Apparatus for dispensing soft drinks and other beverages in bars generally involves the use of a re-usable container from which the beverage is discharged under pressure. For some applications it is preferable to have smaller, disposable containers and it is now possible through use of for example, P.E.T., to have disposable plastics bottles capable of withstanding gas pressures of several pounds per square inch. It has been proposed to dispense beverages from such bottles, and in particular orange juice concentrate stored and transported in two litre disposable P.E.T. bottles. The concentrate has to be diluted before serving and the diluting process takes place at a mixer tap. In order to get the concentrate from the bottle to the mixer tap a dispenser attachment is used to discharge the concentrate under pressure.This attachment provides an inlet for introducing pressurized gas and in addition has a tube through which the concentrate flows to the mixer tap. It is important to obtain a good seal between the mouth of the bottle and the dispensing attachment which fits on to the mouth, since neither the gas under pressure nor the concentrate should be allowed to escape. In the past proposal, this has been done by making use of the thread usually provided on the neck of a bottle. The cap is removed from the bottle and the dispensing attachment is screwed into position. The seal is then provided by the compression of a washer between the mouth of the bottle and the dispensing attachment srewed down on to the bottle.

Such an arrangement does not always guarantee good sealing properties as it is dependent on the quality of the thread and the care with which the operator screws on the attachment. The operator must ensure that it goes on straight so as to avoid cross threading and must also be careful not to overtighten the attachment. This system is rather messy and laborious to operate. In addition, the quality of the seal depends on the plane in which the mouth of the bottle lies being perpendicular to the neck of the bottle on which the thread is formed, so as to ensure uniform compression of the sealing washer.

A further disadvantage with the known arrangement is that there is no positive interlock between the attachment and the bottle, which would ensure that the attachment could not be inadvertently unscrewed whilst the gas is still turned on. That is a desirable feature from the point of view of both convenience and safety.

Thus a need exists for a more effective and easy to use apparatus for dispensing liquid under pressure from a container.

Accordingly, the present invention provides apparatus for dispensing liquid from a container, comprising a housing adapted for attachment to the container, a piston slidably mounted in the housing and adapted to effect a seal around an opening in the container, and a flow passage extending through the piston for admitting gas under pressure to the interior of the container, wherein the piston has a surface exposed to the pressure of the gas in such a way that in use there is a net force acting on the piston to effect the seal around the opening.

With such an arrangement, the piston is forced against e.g. the rim of the opening in a P.E.T. bot tle so as to form a seal through which neither the gas nor the liquid can pass. The seal is achieved by virtue of the gas pressure operating on the piston, so that the gas serves the dual purposes of providing the sealing force on the piston and also providing the pressure necessary to dispense the liquid. Sealing is not dependent on the operator correctly screwing apparatus to the container.

Preferably, the force moving the piston into engagement with the rim of the opening and holding it there to form a seal is provided by an arrangement in which the surface area of the face of the piston remote from the rim and subjected to the gas pressure is greater than the surface area of the opposite face of the piston which is subject to the same gas pressure. The face engaging the rim preferably includes a sealing washer of a suitable material.

Any suitable means may be provided to hold the apparatus in place relative to the container against the gas pressure, such as brackets, clamps, bolts or a bayonet fitting. If the container is of a type having a threaded part adjacent the opening which normally receives a screw-down closure member, it would also be possible to provide the apparatus with a suitable mating thread to enable it to be held in place. Such a connection does not provide a particularly good location of the apparatus for the reasons mentioned above, although the sealing would not suffer from the same disadvantages since the force on the sealing washer comes from the piston rather than screwing down the apparatus. Thus as long as the apparatus is held in some way relative to the container, sealing engagement may be achieved by the piston arrangement.

Preferably, however, said holding means comprises a hook-like shoe provided on the apparatus and adapted to hook under and engage an appropriate part of the container, such as its base or a projecting flange or the aforementioned threaded part.

The apparatus according to the invention is particularly suitable for use with standard P.E.T. bottles which have a flange extending circumferentially about their neck portion to support them during filling. Therefore no new bottles need to be designed. The hook-like shoe may then hook under the flange and abut against it to hold the apparatus in place. The shoe may be pivotally mounted to the housing about a horizontal axis, so as to swing into position beneath the flange. In this position it may fit loosely, but when the gas is subsequently admitted, the gas pressure causes the shoe firmly to abut the flange in a positive inter lock and hold the apparatus in place relative to the opening.If it is desired, the shoe may be provided with an extension which ensures that a gas connector may only be connected to dispensing apparatus positioned on a container when the shoe is in position beneath the flange. This extension also ensures that the gas connector must be disconnected from the dispensing apparatus before the shoe can move out of its position abutting the flange. Thus the positive interlock between the shoe and the flange ensures that the apparatus cannot be inadvertently removed from the bottle while the gas is still turned one, as in the case of the prior art devices.

A further advantage of the hook-like shoe member is that its pivotal mounting to the housing ensures that the apparatus is self-centering, automatic ally adjusting its position on the rim even if this is at an angle to the flange. Thus a sealing washer for example is always forced into uniform engagement with the rim, regardless of whether or not the rim and neck of the bottle are perpendicular to one another. This system therefore has advantage over the prior art devices.

In a preferred embodiment, the housing includes a cylindrical chamber formed in its lower portion, which contains the piston in sliding sealing relationship by means of at least one 0-ring extending circumferentially around the piston, a tube for discharging the liquid extending through the housing and through the piston, a radially extending passage adapted at its outward end to receive the gas connector to supply the gas under pressure, and a centrally located axial passage connecting the gas supplied via the radial passage to the cylindrical chamber, wherein the piston also includes a centrally located axial passage connecting the cylindrical chamber with the interior of the bottle, and said tube extends centrally through both the passage in the housing and that in the piston, and wherein the bottom face of the piston comprises a substantially cylindrical recess receiving a washer for sealing engagement with the rim of the bottle neck.

In order to avoid an undesirable build up in pressure in the system, a relief value may be included in the line supplying gas to the apparatus. Alternatively, or in addition, a system for relieving excess pressure may be incorporated in the dispensing apparatus. Such a system could comprise a further piston also mounted in the housing and spring biased away from the first piston so as to give relative movement between the two pistons when a maximum pressure set by the spring is exceeded, thereby communicating the system with atmosphere and lowering the pressure. This is particularly advantageous when the apparatus is used with certain beverages such as fruit juice concentrates which may undergo fermentation with the consequent evolution of carbon dioxide.

The apparatus may be suitable for dispensing any type of beverage alcoholic, non-alcoholic etc.

A preferred embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional view of a dispensing apparatus in accordance with the invention; Figure 2 is a plan view of the shoe shown in Figure 1; Figure 3 is a cross-section taken along the lines 3-3 of Figure 2; and Figure 4 is a front elevation of the shoe.

Figure 1 of the drawings shows a disposable bottle 1 made of P.E.T. or a similar material capable of withstanding pressure, the bottle 1 having been filled in sterile conditions with a liquid such as orange juice concentrate requiring dilution by 5 to 1. Disposed on top of the bottle is a dispensing apparatus 2 which comprises a housing 3 in which a piston 4 is slidably carried and a shoe member 5 pivotally connected to the housing 3 at the horizontal axis 6.

The housing 3, made of nylon-66 or any other food grade high strength plastic material, is of generally cylindrical shape. It has a downwardly facing cylinder chamber 6 in which the piston 4, made of a similar material to the housing 3, is slidably disposed for vertical movement. The piston 4 includes two spaced apart circumferentially extending grooves 7 and 8, respectively retaining 0ring seals 9 and 10. The seals 9 and 10 ensure that the cylinder chamber 6 is sealed from atmosphere and that the piston 4 is free for vertical movement guided by the cylindrical wall 11. Formed in the lower face of the piston 4 is a frustum shaped recess 12 of a diameter sufficiently large at all points to enable the piston 4 to fit loosely over the neck 13 of the bottle 1.A sealing washer 14 made of neoprene or a similar resilient material is secured in the recess 12 so as to be capable of forming an air-tight seal between the rim 15 of the neck 13 and the piston 4. The sealing washer 14 takes up any small irregularities or imperfections in the rim 15.

The sealing washer 14, piston 4 and housing 3 each have vertically extending and centrally disposed passages to accommodate a vertically extending tube 16 for dispensing liquid from the bottle. The inlet (not shown) of the tube 16 is in the lower region of the bottle 1 and it then extends vertically through the dispensing apparatus 2 and leads to a mixer tap downstream, at which point the orange juice concentrate is diluted. The passage 17 through the washer 14, piston 4 and housing 3 is at all points of wider diameter than the tube 16, so that the interior 18 of the bottle 1, the cylinder chamber 6 and a radially extending passage 19 in the housing 3 are all in fluid communication by means of the annular space around the tube 16. In use, all of these regions are at an operating pressure of about 20psi. At the point where the tube 16 leaves the housing 3, an O-ring seal 20 ensures that the annular space around the tube 16 is sealed off from atmosphere.

A connecting member 21 fits in the radial passage 19 by means of a force fit or other secure connection. The connecting member 21 is symmetrical about an annular flange 22 engaging an external surface 23 of the housing 3, and it includes a further O-ring seal 24 to seal passage 19 from atmosphere. A standard gas connector 25, shown in outline, fits on to the connecting member 21 on the other side of the flange 22, with a sealing connection similarly ensured by an O-ring 26.

The shoe member 5, made of stainless steel or other suitable material, is further illustrated in Figures 2, 3, and 4. This includes a lower plate 27 formed with a recess 28 which in use receives the neck of the bottle so that the recessed part of the lower plate 27 can engage a flange 29 extending circumferentially around the neck of the bottle.ql Such flanges are formed on P.E.T. bottles to support them during the filling process. On either side of the lower place 27 are two vertical plates 30 and 31 which are pivotally connected to the housing 3 by joints at 32 and 33 to allow rotation of the shoe member 5 about the horizontal axis 6. On a third side of the lower plate 27 another vertical plate 34 extends upwards and is provided with an extension 35 which projects away from the housing 3.

The extension 35 includes a recess 36 through which the gas connector 25 passes so as to fit onto the connecting member 21.

In use, the apparatus 2 is placed loosely on the rim 15 of the neck 13 of the bottle with the shoe member 5 pivoted in an upward position not shown. In this position the gas connector 25 cannot be fitted onto the connecting member 21 as it is obstructed by the extension 35 and/or the vertical plate 34. The shoe member 5 is then allowed to swing into the position shown in Figure 1, when the recess 28 fits around the neck 13 of the bottle and under the flange 30. In this position the recess 36 in the extension 35 allows connection of the gas connector 25 to the connecting member 21. Thus the arrangement is such that gas may only be supplied to the dispensing apparatus 2 when the shoe member 5 has moved into its downward position and the lower plate 27 is located beneath the flange 29.Equally, the gas connector 25 must be removed from the apparatus before the shoe member 5 may be moved out of engagement with the flange 29 of the bottle. This arrangement therefore makes the apparatus easier and safer to use.

When gas is admitted under pressure the piston 4 is moved downwards by the pressure communicated by passage 17 to cylinder chamber 6 so as to force the sealing washer 14 into sealing engagement with the rim 15. The same pressure is further communicated to the interior of the bottle by the continuation of passage 17 through the piston 4 and sealing washer 14. This pressure acts upwardly on the sealing washer 14 over a surface area considerably smaller than that of the surface of the piston 4 subjected to the same downward pressure, resulting in a net downward force on the piston 4. There is a positive interlock between the lower plate 27 and the flange 29 which provides the necessary reaction force to hold the apparatus 2 in position.ql Because of the pivoted mounting of the shoe member 5 to the housing 3 the apparatus is self-centering, automatically adjusting its sealing position on the rim 15 even if this is at an angle to the flange 29.

Beverages such as fruit juice concentrates may tend to ferment while stored in the bottle 1, leading to an undesirable build-up of pressure. This may be released by a relief valve in the gas connector 25, or alternatively a relief valve may be built into the dispensing apparatus itself.

The apparatus 2 and equipment downstream thereof is easy to clean by loading detergent solution or some other cleaning solution into the bottle 1 and then discharging it in the usual way.

Claims (11)

1. Apparatus for dispensing liquid from a container, comprising a housing adapted for attachment to the container, a piston slidabiy mounted in the housing and adapted to effect a seal around an opening in the container, and a flow passage extending through the piston for admitting gas under pressure to the interior of the container, wherein the piston has a surface exposed to the pressure of the gas in such a way that in use there is a net force acting on the piston to effect the seal around the opening.

2. Apparatus as claimed in claim 1, wherein the surface area of the face of the piston remote in use from a rim of the opening and subject to the gas pressure is greater than the surface area of the opposite face of the piston which is subject to the same gas pressure, whereby the force is provided to move the piston into engagement with said rim and to hold it there to form the seal.

3. Apparatus as claimed in claim 2, wherein the apparatus is adapted to receive a gas connector to supply said gas under pressure.

4. Apparatus as claimed in claim 3, further comprising a housing including a cylindrical chamber formed in its lower portion, which contains the piston in sliding sealing relationship by means of at least one O-ring extending circumferentially around the piston, a tube for discharging the liquid extending through the housing and through the piston, a radially extending passage adapted at its outward end to receive the gas connector to supply the gas under pressure, and a centrally located axial passage connecting the gas supplied via the radial passage to the cylindrical chamber, wherein the piston also includes a centrally located axial passage connecting the cylindrical chamber with the interior of the container, and said tube extends centrally through both the passage in the housing and that in the piston, and wherein the bottom face of the piston comprises a substantially cylindrical recess receiving a washer for sealing engagement with the rim of the opening.

5. Apparatus as claimed in claim 3 or 4, including means for holding the apparatus in place relative to the container against the gas pressure.

6. Apparatus as claimed in claim 5, wherein said holding means comprises a hook-like shoe provided on the apparatus and adapted to hook under and engage an appropriate part of the container.

7. Apparatus as claimed in claim 6, wherein said hook-like shoe is pivotally mounted to the apparatus about a horizontal axis and is adapted to swing into position under a flange of the container.

8. Apparatus as claimed in claim 7, wherein said shoe is provided with an extension adapted to ensure that the gas connector may only be connected to the apparatus when the shoe is in position beneath the flange.

9. Apparatus as claimed in claim 8, wherein said extension includes a recess adapted to receive said gas connector.

10. Apparatus as claimed in any of the preceding claims, wherein the piston is in two parts and includes a first piston portion adapted to effect the seal around the container opening, and a second piston portion exposed to the gas pressure upstream of the container and spring biassed away from the first piston portion so as to give relative movement between the two portions when a maximum pressure set by the spring is exceeded, thereby communicating the system with atmosphere and lowering the pressure.

11. Apparatus for dispensing liquid from a container substantially as hereinbefore described with reference to the accompanying drawings.