GB2275912A

GB2275912A - Flow control valve for a drink dispenser

Info

Publication number: GB2275912A
Application number: GB9304942A
Authority: GB
Inventors: Paul Pavey
Original assignee: GRANADA VENDING SERVICES LIMIT; P & O Vending Services Ltd
Current assignee: GRANADA VENDING SERVICES LIMIT; P & O Vending Services Ltd
Priority date: 1993-03-11
Filing date: 1993-03-11
Publication date: 1994-09-14
Also published as: GB9304942D0

Abstract

A control valve for a liquid dispenser comprising a flexible outlet tube 5 through which the liquid flows, a pivotally mounted closure member 26 which squeezes the tube 5 against a support 28 under the action of a cam 21 to close the tube. Biasing means biases the closure member away from the tube when not being forced by the cam. The shape of the closure member conforms to the shape of the tube (see fig 4 not shown). Several such outlet tubes with associated closure members, stops and cams lie alongside each other, the cams all being driven by a common shaft (8, figure 1 not shown). The position of the shaft and hence the condition of the tubes (open or closed) is determined by an optical sensing means (10, figure 1 not shown). <IMAGE>

Description

DRINK DISPENSING APPARATUS This invention relates to drink dispensing apparatus in particular a system for controlling fluid supply e.g. the supply of water or milk, in drink dispensing apparatus.

Drink dispensing machines are to be found in public places and places of work, where they usually take the form of vending machines used by the public, as well as in cafes, restaurants and hotels, where catering staff use them to provide drinks for their customers. Drink dispensing machines may dispense either hot or cold drinks or both. Drink dispensing machines generally comprise at least one tank or container for a fluid, which is usually water but occasionally is another fluid such as milk, in which container the fluid is stored and if required heated.

Other ingredients are usually stored in the form of a dry powder and include coffee, tea, hot chocolate, sugar, or dried milk powder. The apparatus usually comprises a separate mixing chamber in which the optionally hot fluid is mixed with the other ingredient(s) for the drink to be dispensed. Several separate mixing chambers may be available for a variety of drinks or a single chamber can be used.

Alternatively mixing can take place in the cup in which the drink is to be dispensed. The apparatus will also comprise means for dispensing the prepared drink from the apparatus as well as means for supplying the fluid and the other ingredient(s) to wherever they are to be mixed.

In certain apparatus the route the fluid takes through the machine will depend on the drink being dispensed and a variety of fluid outlets will be available. In such cases means are required to control the route taken by the fluid so that the right outlet is used in each case. Such control may be obtained by supplying the fluid to a manifold having a plurality of outlets controlled by a plurality of valves which allow or prevent fluid from leaving the manifold by their particular outlet. In the past solenoid valves have been used for this purpose in drink dispensing machines. The solenoid valves, which are electrically controlled, work by the lifting up of a valve seat from a fluid outlet when power is supplied to the valve, with the valve seat returning to block off the outlet when the power is switched off, for example by means of spring biasing.The use of solenoid valves for this purpose leads to several disadvantages. First, solenoid valves are liable to blockages caused by the deposition of scale when used for the supply of hot water. Further, each outlet requires a separate solenoid valve each of which takes up a considerable volume of space so that the overall fluid control system is bulky. Moreover, the provision of solenoid valves is considerably expensive.

The present invention overcomes or mitigates some or all of the problems associated with conventional drink dispensing machines.

According to the present invention there is provided a fluid control system for drink dispensing apparatus which comprises: a fluid inlet; more than one fluid outlet; a flexible outlet tube connected to each fluid outlet; means associated with each fluid outlet for closing/opening the outlet tube, which means comprises a closure member movable with respect to the flexible tube so as to close or open it and a pressure member capable of exerting force on the closure member so as to cause it to open or close the tube.

To be movable with respect to the tube the closure member is movably, preferably pivotally, mounted with respect to the outlet tube. The closure member preferably takes the form of a lever which can be pushed down on to the outlet tube to close it. The part of the closure member which contacts the outlet tube is preferably shaped so that it corresponds in shape to the part of the tube it contacts. Hence, with a tube of circular cross-section the closure member is provided, where it contacts the tube, with a profile corresponding to the tube, i.e. having a cross-section which is a part of a circle, e.g. a sector. In this way when the closure member is forced down on the tube to close it it does not contact the tube at a point of contact but over a line or area of contact. This distributes the pressure being applied to the tube so that wear on the tube is reduced.Furthermore, it allows the tube to be closed more quickly and accurately. The closure member may also be shaped so as to assist the pressure member to exert the required force.

Means may be provided for biasing the closure member either away from or towards the flexible outlet tube, e.g. the closure member may be biased in a position to either open or close the tube. Preferably the closure member is biased away from the tube when not being forced by the pressure member.

The pressure member may take any suitable form as long as it is able to exert force on the closure member so as to close and open the tube. It could, for example, take the form of a piston arrangement which during the stroke of the piston forces the closure member down on to the tube and releases it upon withdrawal of the piston.

The pressure member preferably takes the form of a cam, which by its rotation is able to both force the closure member to push down on to the tube so as to close it as well as to reduce the pressure on the closure member to allow the tube to be opened. Closing and opening of the tube can thereby be controlled by controlling the movement of the cam. The cam may be shaped to provide the desired pattern of opening and closing of the tube upon rotation of the cam. The cam could, for example, be provided with a recess in its outer surface and be mounted above the closure member so that when the non-recessed outer surface of the cam is in contact with the closure member it is forced down on to the tube and when the recessed part of the cam is in contact with the closure member it is allowed to lift away from the tube to allow the tube to be opened.

It may be advantageous where the closure member is a lever and the pressure member a cam for the cam to be provided with a roller which rolls over the closure member and evens out the resistance experienced by the cam during its movement over the lever and thereby assists in the closing/opening of the tube. Such a roller could be positioned at either end of any recess in the cam's contact surface. The closure member could be shaped so as to assist the movement of the cam, for example, it could include surfaces particularly adapted for a roller.

The action of the cam and lever is preferably a simulation of a person squeezing or pinching the flexible tube between their fingers.

Each outlet has its own closure member and pressure member, for example each outlet has associated with it a cam and lever. A particularly compact arrangement is obtained where the flexible outlet tubes extend in parallel and a series of cams and levers are stacked one against the other lying over those flexible tubes. Each cam and lever may be a separate independent component which can be added or taken away from the system as desired leading to great flexibility.

Concerted control of the individual closure and pressure members will allow control over the number of flexible outlet tubes open or closed at any given time.

It is preferred that only one outlet tube is open at any given time, with all other tubes being closed. If, for a particular drink to be dispensed, fluid has to be passed through more than one outlet this may be effected by sequential opening and closing of the outlets concerned, although it would be possible for those outlets to be opened simultaneously. In the case where the pressure member is a cam concerted control can be obtained by mounting each of the individual cams on a common drive shaft so that rotation of the drive shaft causes rotation all of the cams simultaneously.

The cams may then be shaped and so positioned relative to each other that rotation of the drive shaft leads to the desired combinations of open and shut outlets.

Hence, in a preferred embodiment, the various rotational positions of a common cam shaft will always relate to the opening of a single though differing individual outlet while the remaining outlets are held closed. In a preferred embodiment all of the cams are of an identical shape but their relative positioning on the drive shaft is such that as the drive shaft is rotated only one of the cams is in a position which corresponds to an open outlet tube at any given time.

The drive shaft and corresponding passage through the cam are preferably non-circular, e.g. polygonal, in cross-section to prevent relative rotation of the cams and the drive shaft. The relative positioning or orientation of the cams can in such a case be easily effected by control of the orientation of their noncircular opening through which the drive shaft passes, as different orientations of the opening will lead to differing positions of the cams on the drive shaft. A particularly advantageous arrangement is for the cam openings to form an eight point star in cross-section and the drive shaft to be a suitably sized square in cross-section.Each cam can then be mounted in eight different positions on the cam shaft leading to a large number of combinations of relative cam orientations and in particular allows for up to eight different outlet tubes to be used and for it still to be possible to have only one tube open at a given time.

The fluid control system is preferably provided with a tube support mounted with respect to one or more of the tubes so that the tube is pressed against the support by the closure member. The closure member may be shaped to correspond to the support to assist quick and accurate closure. The tube support may take the form of a rod extending perpendicularly to the tubes and the closure member may have a profile perpendicular to the tube corresponding to the cross-section of the rod.

Sensors may be provided to assist in the concerted control of the individual closure and pressure members.

Sensing apparatus may be used to detect the positioning of the closure and pressure members at any given time.

Optical sensors are preferred. Where the closure and pressure members take the form of a series of cams and levers on a common drive shaft an optical sensor may be provided which is able to detect the position of the drive shaft on which the cams are mounted. In such a case the sensing apparatus may include a position marker rotatably mounted on the cam shaft between an infrared light emitter and sensor. Slots provided in the marker, which allow the light to pass through from the emitter to the sensor, are provided at positions which relate to the opening of different tubes. As the cam shaft and marker rotates the sensing apparatus is able to measure the transition time between each slot.

An index slot which has a shorter transition time could be provided to act as an initial or starting position to be recognised by the sensor when the apparatus is first switched on and from which the other positions can be calculated.

Closure and opening of the tube could be carried out manually, e.g. using a ratchet system to effect movement between the various opening and closing combinations, or more preferably such control is carried out automatically. Preferably such control is carried out by a microprocessor able to control the positioning of the closure and pressure members.

Indeed the whole control of the drink dispensing apparatus is preferably automatically controlled by a microprocessor.

The fluid control system is preferably such that after the delivery of fluid it returns to the same rest position. At least one of the tubes is preferably open in the rest position to allow for drainage of any excess fluid. Preferably in the rest position the outlet tube which corresponds to the most popular drink to be dispensed is open so that the apparatus is ready to dispense the most popular drink directly from the rest position.

The fluid control system may be provided with more than one fluid inlet, which would allow for the delivery of more than one fluid, e.g. milk and water.

Each inlet should be connected to a fluid storage container, e.g. a water tank. The fluid may be gravity fed from the storage container to the fluid control system. Preferably, however, the fluid is pumped from the fluid storage tank to the fluid control system.

This arrangement allows the fluid storage container to be mounted other than above the fluid control system, e.g. at the bottom of the drink dispensing apparatus, which allows for a compact arrangement. Any suitable fluid pump can be used, but for a drink dispensing apparatus which dispenses hot drinks, it should be capable of running at high temperatures, as in such machines water, for example, may be transferred from the storage tank at a temperature of around 95 to 96"C.

When a fluid pump is present the fluid control system is preferably positioned above the fluid storage container so that fluid which is not required to be dispensed can drain back into the fluid storage container under gravity. This prevents, in the case of water, scale building up in the fluid control system.

Any number of outlets may be provided from the fluid control system, and this will depend in part upon the variety and number of drinks which may be dispensed from the apparatus. In the case of a drink dispensing apparatus which is able to dispense black coffee, white coffee and cappuccino coffee four outlets would be suitable to allow the fluid to be delivered to the various ingredients for mixing as well as to allow the dispensing of fluid, e.g. hot water, on its own.

The flexible outlet tubes are preferably arranged in parallel to each other and may be positioned in fixed channels to prevent their relative movement particularly during opening and closing. The flexible outlet tubes may pass from the fluid control system to where the fluid is mixed with the other ingredients of the drink to be dispensed. It is preferable for the flexible outlet tube which is closed and opened by the closure and pressure members to be separable from other tubing so that it may be easily replaced upon wear without the need for large pieces of tubing to be replaced which might involve considerable disassembly of the apparatus. The outlet tube may be made of any suitable material which allows sufficient flexibility for the tube to be squeezed close by the closure member. A suitable material is silicon plastic.The dimensions of the tube will be such as to allow for flexible closure, for example tubing with an inner diameter of between 6 and 8 mm and an outer diameter of 8 to 10 mm will be suitable.

According to the present invention there is also provided a drink dispensing apparatus which comprises a fluid control system as described above.

The present invention has many advantages, e.g.

the fluid control system of the present invention is much smaller than comparable conventionally used systems including solenoid valves, which allows the drink dispensing apparatus to be smaller and generally more compact. In general the fluid control system of the present invention having a specific number of outlets can take up to about 25% of the room taken up by a similar number of solenoid valves. Furthermore, the expense of including solenoid valves is avoided in the present invention. Also, the fluid control system of the present invention is much less liable to blockages caused by scale and the like. In general the present invention provides a simple, cost effective system for controlling fluid flow in drink dispensing apparatus.

For a greater understanding of the present invention, and to show how the same may be put into effect, reference will now be made to the accompanying drawings in which: Figure 1 is a schematic front view of a fluid control system according to the present invention; Figure 2 is a side view to an enlarged scale of part of the system of Figure 1 when in an open position; Figure 3 is a side view to an enlarged scale of part of the system of Figure 1 when in a closed position; Figure 4 is a section along the line A to A of Figure 2; and Figure 5 is a section along the line B to B of Figure 3.

A fluid control system which is part of a drink dispensing apparatus is shown in Figure 1. The fluid control system 1 comprises a manifold 2 having a water inlet 3 and four parallel directed water outlets 4. On each of the four water outlets a flexible tube 5 is connected so that they extend in parallel from the manifold. Pivotally mounted above each flexible tube 5 is a lever 6. Mounted above each of the levers 6 is a cam 7. The cams 7 are stacked together upon a common drive shaft 8 upon which they are mounted which extends perpendicularly to the tubes. The cam shaft 8 is driven by a motor 9. At one end of the cam shaft 8 optical sensing equipment 10 is mounted.The optical sensing equipment includes an infrared beam source 10a and an infrared receiver 10b between which a slotted identification disc 10c is mounted so as to rotate with the cam shaft 8.

The water inlet 3 is connected via a hose connection 11 to a water tank 12 which is equipped with an element 13 for heating the water 14 stored therein.

The temperature to which the water 14 is heated can be measured via a thermometer 15 also provided in the tank. Water 14 is supplied to the tank 12 via a mains water supply 16 which is connected to a water inlet 17 on the tank 12. A water pump 18 is provided in the tank 12 by which the water 14 is pumped via a water outlet 19 from the water tank 12 to the fluid control system 1.

The route by which the water 14 leaves the fluid control system 1 will depend on which of the four tubes 5 is open. Opening and closure of the flexible tube is effected by squeezing and release of the flexible tube 5 by the levers 6 which act as fingers. Each lever 6 can be individually pressed down on to its flexible tube 5 by its cams 7. The cams 7 are arranged on the cam shaft 8 so that in each rotational position of the cam shaft only one of the flexible tubes 5 is opened and the remaining tubes are closed. Which of the tubes 5 is open is detected by the optical sensing equipment 10 which is able to detect the position of the identifier disc 10c. The entire system is controlled by a microprocessor which is not shown.

The means of opening and closing the tubes 5 is shown in more detail in Figures 2 to 4.

Each of the cams 7 is a circular disc having a central opening 20 of an eight point star cross-section which is mounted on the drive shaft 8 which is of square cross-section. In the circumference 21 of each cam 7 a recess 22 is provided. A roller 23 is positioned at each end of the recess 22.

The lever 6 is mounted below the cam 7 and on its upper surface is provided with two flat surfaces 24,25 which act as a cam roller ramps. On its under surface it is provided with a spherically shaped recess 26 into which the tube 5 can be accommodated. The lever 6 is pivotally mounted at a pivot point 27.

A rigid support rod 28 is mounted so as to extend perpendicularly behind the tubes 5. The support rod 28 is circular in cross-section.

In use the motor 9 drives the cam shaft 8 to the desired position as detected by the sensing equipment 10a,b,c. In the desired position one of the flexible tubes 5 is open and the others remain closed. Water 4 is then pumped by the pump 18 from the water tank 12 into the manifold 2. The water 4 enters through the manifold inlet 3 and passes out of the manifold outlet 4 which corresponds to the open flexible tube 5. The water 4 passes through the flexible tube to the place where it is to be mixed with the other ingredient of the drink to be dispensed. Opening and closing of a tube 5 is effected as follows. The circumference 21 of each cam 7 is in contact with its associated lever 6.

When the cam 7 is in a position where the recess 22 is in contact with the lever 6 the lever 6 is not forced down on to the tube 5 which is open. Rotation of the cam 7 will cause one of the rollers 23 to come into contact with one of the roller ramps 24 or 25 of the lever 6. The lever 6 is being pushed down on to the tube 5 in this position so the tube is nearly fully pinched between the lever 6 and the support rod 7.

Further rotation will lead the outer circumference 21 of the cam 7 to take the full load and fully close the tube 5 in the recess 26 of the lever 6.

Claims

1. A fluid control system for drink dispensing apparatus which comprises: a fluid inlet; more than one fluid outlet; a flexible outlet tube connected to each fluid outlet; means associated with each fluid outlet for closing/opening the outlet tube, which means comprises a closure member movable with respect to the flexible tube so as to close or open it and a pressure member capable of exerting force on the closure member so as to cause it to open or close the tube.

2. A fluid control system according to claim 1, wherein the closure member is pivotally mounted with respect to the outlet tube.

3. A fluid control system according to claim 1 or 2, wherein the closure member takes the form of a lever which can be pushed down on to the outlet tube to close it.

4. A fluid control system according to any preceding claim, wherein the part of the closure member which contacts the outlet tube is preferably shaped so that it corresponds in shape to the part of the tube it contacts.

5. A fluid control system according to any preceding claim, wherein means are provided for biasing the closure member either away from or towards the flexible outlet tube.

6. A fluid control system according to any preceding claim, wherein the pressure member takes the form of a cam, which by its rotation is able to both force the closure member to push down on to the tube so as to close it as well as to reduce the pressure on the closure member to allow the tube to be opened.

7. A fluid control system according to claim 6, wherein the cam is shaped to provide the desired pattern of opening and closing of the tube upon rotation of the cam.

8. A fluid control system according to claim 7, wherein the cam is provided with a recess in its outer surface and is mounted above the closure member so that when the non-recessed outer surface of the cam is in contact with the closure member it is forced down on to the tube and when the recessed part of the cam is in contact with the closure member it is allowed to lift away from the tube to allow the tube to be opened.

9. A fluid control system according to any one of claim 6, 7 or 8, wherein the closure member is a lever and the cam is provided with a roller which rolls over the closure member and evens out the resistance experienced by the cam during its movement over the lever and thereby assists in the closing/opening of the tube.

10. A fluid control system according to claim 1, wherein the closure member is a lever and the pressure member is a cam and the flexible outlet tubes extend in parallel and a series of cams and levers are stacked one against the other lying over those flexible tubes.

11. A fluid control system according to claim 10, wherein each of the individual cams is mounted on a common drive shaft so that rotation of the drive shaft causes rotation of all of the cams simultaneously.

12. A fluid control system according to claim 11, wherein all of the cams are of an identical shape but their relative positioning on the drive shaft is such that as the drive shaft is rotated only one of the cams is in a position which corresponds to an open outlet tube at any given time.

13. A fluid control system according to claim 11 or 12, wherein each of the cam openings is in the form of an eight point star in cross-section and the drive shaft has a correspondingly sized square cross-section.

14. A fluid control system according to any preceding claim, wherein there is further provided a tube support mounted with respect to one or more of the tubes so that the tube is pressed against the support by the closure member.

15. A fluid control system according to claim 14, wherein the tube support takes the form of a rod extending perpendicularly to the tubes and the closure member has a profile perpendicular to the tube corresponding to the cross-section of the rod.

16. A fluid control system according to any preceding claim, which is further provided with sensing apparatus which is able to detect the positioning of the closure and pressure members at any given time.

17. A fluid control system according to any preceding claim, which is further provided with more than one fluid inlet.

18. A drink dispensing apparatus which comprises a fluid control system according to any preceding claim.

19. A fluid control system substantially as hereinbefore described, with reference to and as illustrated in Figures 1 to 5 of the accompanying drawings.

20. A drink dispensing apparatus substantially as hereinbefore described, with reference to and as illustrated in Figure 1 of the accompanying drawings.