LIQUID DISPENSING APPARATUS

Abstract: A dispensing apparatus (10) for dispensing metered quantities of a liquid. The apparatus comprises a peristaltic pump (11) having a pump inlet (13) adapted for connection to a liquid supply (17) and a pump outlet (15). Flow from the pump outlet (15) is controlled by a control valve (45) having a valve intake (47) for receiving liquid from the pump outlet and two valve outlets one being a return outlet (48) communicating with the pump inlet and the other being a discharge outlet (49) communicating with a dispensing handpiece (21). The control valve (45) has two modes of operation, one being a recirculating mode in which liquid entering the intake is directed to the return outlet and the other being a discharge mode in which liquid entering the valve intake is directed to the discharge outlet. A control means including a key pad (25) on the dispensing handpiece (21) is provided for controlling operation of the control valve in the two modes and for controlling operation of the pump.

Description: LIQUID DISPENSING APPARATUS FIELD OF THE INVENTION The present invention relates to a liquid dispensing apparatus and relates particularly, though not exclusively, to a drink dispensing apparatus. BACKGROUND TO THE INVENTION Drink dispensing apparatus are known for dispensing a drink by means of a pump into a glass or cup. In general, the volume of liquid dispensed is controlled manually and relies on the user ascertaining visually when the required volume has been dispensed. The known apparatus do not permit a metered volume of liquid to be dispensed accurately and consistently. SUMMARY OF THE INVENTION The present invention was developed with a view to providing a dispensing apparatus which can dispense metered quantities of liquid accurately. According to the present invention there is provided a liquid dispensing apparatus comprising: a pump having a pump inlet adapted for connection to a liquid supply, and a pump outlet; a control valve having a valve intake for receiving liquid from the pump outlet, and two valve outlets one being a return outlet communicating with the pump inlet and the other being a discharge outlet, said control valve having two modes of operation, namely a recirculating mode in which liquid entering the intake is directed to the return outlet and a discharge mode in which liquid entering the valve intake is directed to the discharge outlet; and, a control means for controlling operation of the control valve in said two modes of operation and for controlling operation of the pump whereby, in use, a controlled quantity of liquid can be dispensed from the discharge outlet of the control valve. The control means may incorporate a time delay whereby the control valve is caused to move from the recirculating mode into the discharge mode a predetermined time interval after commencement of operation of the pump. The purpose of this is to allow the pump to develop liquid pressure at the pump outlet before operation of the control valve. Conveniently, the pump comprises a peristaltic pump having a resiliently deformable liquid transport line along which a movable member passes to progressively deform the transport line and propel the liquid through the line. The dispensing apparatus may further comprise a dispensing line, one end of which communicates with the discharge outlet of the control valve. A dispensing handpiece may be fitted to the other end of the dispensing line. The control means may include an actuating means incorporated in the dispensing handpiece whereby operation of the pump and the control means can be initiated from the handpiece. The dispensing apparatus may be adapted to dispense various types of liquid. For this purpose, the peristaltic pump may have a plurality of such resiliently deformable.liquid transport lines each extending between a respective pump inlet and pump outlet, and a plurality of such control valves each associated with a respective one of the transport lines. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described with particular reference to drink dispensing apparatus, however it is to be understood that it has wider application to the dispensing of other liquids, for example, in the food processing industry or medical field. The nature of the invention will be better understood from the following detailed description of specific embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which:- Fig. 1 is a schematic view of one embodiment of a dispensing apparatus according to the invention; Fig. 2 is a schematic elevational view of a housing for a peristaltic pump forming part of the dispensing apparatus illustrated in Figure 1; Fig. 3 is a fragmentary view of the peristaltic pump of Figure 2 illustrating a plurality of transport tubes and a rotor having rollers which pass in succession over the transport tubes ' ; Fig. 4 is a perspective view of an alternative embodiment of the rotor; Fig. 5 is a perspective view of a stationary part of the peristaltic pump including the transport tubes; Fig. 6 is a schematic view of a control valve, the control valve being shown in a recirculating mode; Fig. 7 is a view similar to Fig. 6 except that the control valve is shown in a discharge mode; and Fig. 8 is a schematic view of a reservoir which is provided in the dispensing apparatus of Figure 1; Fig. 9 is a schematic view of a second embodiment of a dispensing apparatus according to the invention; Fig. 10 is a schematic view of a third embodiment of a dispensing apparatus according to the invention; Fig. 11 is a schematic view of a fourth embodiment of a dispensing apparatus according to the invention; Fig. 12 is an enlargement of a discharge nozzle employed in the apparatus of Fig. 11. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Figures 1 to 8 illustrate a first embodiment of a liquid dispensing apparatus 10 for selectively dispensing drinks of various types. In particular, the dispensing apparatus 10 is adapted to dispense metered quantities of bottled alcoholic liquor. The dispensing apparatus 10 comprises a pump 11 illustrated most clearly in Figures 3, 4 and 5 having a plurality of pump inlets 13 and an equivalent number of pump outlets 15. Each inlet 13 receives liquid from one of a plurality of bottles 17 mounted in inverted fashion on a rack 19. Each outlet 15 communicates with a dispensing handpiece 21 on the outer end of a flexible conduit 23 as illustrated in Fig. 1. The handpiece 21 incorporates a dispensing nozzle 24 and an actuating means in the form of a key pad 25 having a series of keys, one corresponding to each of the bottles 17. With this arrangement, actuation of any one of the keys causes the pump 11 to deliver a metered quantity of alcoholic beverage .from the corresponding bottle 17 to the dispensing handpiece 21 from where it can be dispensed into a glass or other vessel. As illustrated most clearly in Figures 3, 4 and 5 the pump 11 is in the form of a peristaltic pump having a stationary part 27 and a rotatable part 29. The stationary part 27 comprises a base 31 and a plurality of liquid transport lines 33 mounted on the base 31. The liquid transport lines 33 are each in the form of a length of resiliently deformable tube one end of which defines a respective one of the plurality of pump inlets 13 and the other end of which defines a respective one of the plurality of pump outlets 15. The liquid transport tubes are typically manufactured from a hard- wearing, long-life material, such as a latex based or synthetic plastics material of known composition. The liquid transport tubes 33 are secured to the base 31 by securing bracket 35. The base 31 is provided with a concave depression 38 which accommodates the rotor 29 and an intermediate portion of each of the liquid transport lines 33. The radius of curvature of the concave depression 38 corresponds to, and is slightly larger than, the radius of the circular path of movable members 37 on the rotor 29. The difference in the radii is approximately equal to the thickness of the liquid transport tubes 33 when deformed to a fully flattened condition, typically 2 to 4mm. The shape of the base 31 is designed to ensure a proportional relationship between rotation angle of the rotor and volume of the displaced liquid. The rotor 29 comprises a plurality of circumferentially spaced longitudinal members 37 supported between supporting rotor discs 39. While not apparent from the drawings, the longitudinal members 37 are preferably in the form of rollers each of which can rotate about its central longitudinal axis on a shaft mounted between the discs 39. The rollers 37 on the rotor illustrated in Fig. 3 are coaxially mounted on common shafts (not illustrated) that pass through all three discs 39. Figure 4 illustrates a more preferred form of the rotor 29 in which each roller 37 is offset with respect to it's neighbour and is rotatably supported on it's own shaft between two of the discs 39. This is a more preferred arrangement as it reduces the load on a motor driving the rotor, and also reduces the noise produced during operation of the peristaltic pump 11. The angular spacing of the rollers is selected so that as one roller 37 commences its passage over the deformable transport tubes 33, the immediately preceding roller is still in contact with the transport tubes 33 as illustrated, for example, in Fig. 2. This ensures that peristaltic pressure is maintained in the tubes 33 between successive passes of the rollers 37. A drive motor 41 drives the rotor by way of a belt and pulley transmission 43 as illustrated in Fig. 2. Advantageously the belt and pulley transmission comprises a timing belt having a plurality of teeth provided thereon which engage with the teeth on a pair of sprockets provided on the rotor drive shaft and motor shaft respectively. A sensing means, typically in the form of a photodetector 44, senses the movement of the teeth of the timing belt and/or one of the sprockets and generates an electrical signal in the form of a pulse train indicative of the number of teeth passing the photodetector 44. The number of teeth passing the photodetector 44 is directly proportional to the volume of liquid being pumped through the tubes. During operation of the pump, the longitudinal members 37 pass successively along the intermediate portions of the liquid transport lines 33 as the rotor rotates and progressively deform (squeeze) the intermediate portions so as to pump liquid from the inlets 13 to the outlets 15. The dispensing apparatus has a plurality of control valves 45, one associated with each transport line 33. The control valves 45 each comprise a sliding-spool 46 directional flow valve having an intake 47 connected to the respective pump outlet 15, and two outlets, one being a return outlet 48 and the other being a discharge outlet 49. The return outlet 48 is connected to the respective pump inlet 13, and the discharge outlet 49 communicates with the dispensing nozzle 24 of the dispensing handpiece 21 via a respective dispensing tube 51. The return outlet 48 communicates with the respective pump inlet 13 by way of a return line 50. Each control valve 45 has two modes of operation, one being a recirculating mode in which liquid entering the intake 47 is directed to the return outlet 48 and the other being a discharge mode in which liquid entering the valve intake 47 is directed to the discharge outlet 49. Movement of the control valve 47 between the recirculating mode and the discharge mode is effected by sliding of the valve spool 46 in conventional manner. Each control valve 45 is typically a solenoid valve in which sliding movement of the valve spool 46 is effected by a solenoid actuated by an electrical signal, and normally resting in the recirculating mode prior to actuation. A control means (not illustrated) is provided for controlling operation of each control valve 47 and the peristaltic pump 11. The control means comprises an electronic control circuit having an actuating means defined by the key pad 25 incorporated in the dispensing handpiece 21. The control circuit incorporates a time delay whereby the control valve is caused to move from the recirculating mode (as shown in Fig. 7) into the discharge mode (as shown in Fig. 6) a predetermined time interval, for example, 0.2 to 2.0 seconds, after commencement of operation of the pump. Typically, the time delay is approximately 0.5 seconds. The time delay allows the pump to operate and produce liquid pressure at the various pump outlets 15 prior to operation of the control valve. It also allows the motor 41 to develop full torque and attain a constant speed. The control circuit may provide analogue signal processing, and typically also involves digital signal processing to effect some of the control functions. A suitable programmable logic array (PLA) and/or a microprocessor based controller may be employed to effect the digital signal processing. The control circuit is responsive to actuation of a key on the key pad 25 to activate the pump 11 and a corresponding control valve 45. The photodetector 44 provides a feedback signal to the control circuit in the form of the pulse train which is indicative of the volume of liquid being pumped through the tubes. The control circuit counts the pulses and compares the count with a preset number. Each liquid transport line has a unique number, which may differ from line to line, reflecting the difference in the physical properties such as viscosity of the liquids, displaced volume and pressure drop in a line. The preset number typically represents a predetermined standard volume of spirits, for example, 30ml, known in the liquor industry as a "nip", or possibly 15ml, or a "half nip". As soon as the number of pulses equals the preset number the control circuit deactivates the control valve which returns to the recirculating mode. The control valves 45 are rapid acting and can move from the discharge mode to the recirculating mode and vice versa practically instantaneously. Hence the valve can dispense a metered quantity of liquid accurately, typically to within 0.05ml per 10ml of spirits of a predetermined volume. If desired, the operator can obtain a double dose or double "nip" of the spirits by depressing the key on key pad 25 twice. In this embodiment there are a plurality of dispensing lines 51 housed within the flexible conduit 23, one dispensing line corresponding to each pump outlet 15. Each dispensing line 51 is connected at one end to the discharge outlet 49 of the respective control valve 45. The other end of the dispensing line 51 opens into the dispensing nozzle 24 of the dispensing handpiece 21. There are a plurality of liquid reservoirs 61 housed in the rack 19, one corresponding to each of the pump inlets 13. Each pump inlet 13 communicates with a respective one of the reservoirs 61 by way of a delivery line 63 having an intake portion 64 opening into the reservoir adjacent the bottom thereof. As illustrated in Fig. 8 the top wall 66 of the reservoir has an inlet 65 adapted to receive a spigot 67 which is received in the mouth of a respective one of the inverted bottles 17 mounted on the rack. The spigot 67 has a spring loaded ball valve therein, and as the spigot 67 is pushed down into the inlet 65 a pin forces the ball upwards, thus opening the valve and allowing the liquor to flow into the reservoir. The contents of the bottle 17 progressively drain into the reservoir as liquid is pumped from it. A vent 70 is incorporated in the reservoir to facilitate this action. A level sensor including a probe 71 is associated with the reservoir such that when the liquid in the reservoir falls below a predetermined level, the pump can no longer be operated. The purpose of the reservoir is to ensure that there is sufficient liquid available for a metered quantity of the liquid to be dispensed on operation of the pump. The reservoir also ensures a smooth liquid discharge from a bottle and eliminates the influence of a head pressure in the bottle. When the liquid level in the reservoir falls below the predetermined level, the corresponding control valve 45 is deactivated and the empty bottle 17 must be removed and replaced with a full bottle. The dispensing apparatus according to the embodiment allows a measured quantity of alcoholic liquor from any one of the bottles 17 to be dispensed at the handpiece 21 simply by pressing the appropriate key on the key pad 25. When one of the keys on the key pad 25 is pressed, the motor 41 is actuated so as to cause the rotor 29 to rotate. As the rotor rotates, the rollers 37 successively pass along the various transport lines 33 and so transport liquid through the lines from the inlets 13 to the outlets 15 and thus develop liquid pressure at the outlets. After the predetermined time interval, which is typically 0.5 seconds, the particular control valve 45 corresponding to the pressed key is caused to move from the recirculating mode into the discharge mode so allowing liquid to be delivered along the dispensing line 51 to the handpiece 21. Metering of the dispensed liquid is controlled by the control circuit as described above. The control valve is returned to the recirculating mode and rotation is terminated once the metered quantity has been dispensed. At the time when the particular control valve is in the discharge mode, the other control valves remain in the recirculating mode so that liquid transported along the transport lines 33 as a result of rotation of the rotor is returned to the various pump inlets 13. Figure 9 illustrates a second embodiment of the liquid dispensing apparatus according to the invention. This embodiment of the liquid dispensing apparatus 10 is similar to that illustrated in Figure 1 except that the pump, electric motor and control valves are now housed within the base 80 of the rack on which the inverted bottles are mounted. In this embodiment of the drink dispensing unit a single dispensing hand piece 21 on the outer end of a fixable conduit 23 is provided, similar to that of Figure 1. The construction and operation of the drink dispensing unit 10 illustrated in Figure 9 is otherwise substantially identical to that of Figure 1 and will not be described again here. Obviously, the drink dispensing unit 10 can be designed to accommodate any number of bottles 17, eight bottles being a preferred number from the point of view of the size of the unit and the range of spirits generally offered at most bars. Figure 10 illustrates a third embodiment of the drink dispensing unit 10 similar to that illustrated in Figure 9, except that two dispensing hand pieces 21 are provided on the outer end of respective flexible conduits 23. In general, only one hand piece can operate at a time for dispensing a metered quantity of drink. Typically, there is approximately a one second operational time to complete the discharge of the metered quantity of drink, and during this time the other hand piece is locked out, but can be activated immediately after discharge is completed with the first hand piece. This only applies if both hand pieces are being used to dispense the same liquor, however if different liquors are required then both hand pieces can be operated simultaneously. The unit may also be designed to allow the use of two sets of discharge tubes operating from two sets of solenoid valves for each liquid transport line, so that liquor from the same bottle can be dispensed simultaneously with both hand pieces. Figure 11 illustrates a fourth embodiment of a drink dispensing unit according to the invention, which is similar to the embodiment of Figure 10 except that the hand pieces have been removed and the respective dispensing lines connected to the discharge outlets 49 of the control valves communicate with specially designed outlet nozzles 90. The outlet nozzles 90 comprise a plastic cone-shaped block, having a plurality of outlet apertures, eight of which are connected to the dispensing lines 51. The other outlet apertures in the outlet nozzle 90 may be connected to an external supply or supplies of soft drink, mixers or other liquids. Between the nozzle 90 and the external supply or supplies, a set of external solenoid valves are provided, the external solenoid valves also being connected to the control circuit to regulate the supply of external products on demand. Advantageously, the outlet nozzle 90 is mounted about the discharge tube of an ice dispenser 92, the operation of which is also controlled by the control circuit of the drink dispensing unit 10. In this embodiment, actuating means in the form of key pads 94 are provided to enable a user to select a metered quantity of a desired liquor, and/or an external supply of product or ice. The electronic control circuit can be preprogrammed so that by pressing a single key on key pad 94 the user can select a particular mixed drink, for example, ice, spirit and mixer in metered quantities. Now that numerous embodiments of the liquid dispensing apparatus according to the invention have been described in detail, it will be apparent that the invention provides significant advantages over prior art liquid dispensing apparatus. The described drink dispensing unit enables accurate and rapid dispensing of metered quantities of liquid. Furthermore, the apparatus ensures a high degree of accuracy and repeatability regardless of variations and atmospheric pressure, head pressure represented by the level of a liquid in a bottle and reservoir, and physical properties of the liquid. The provision of control means to control the operation of the control valves and pump gives the apparatus an inherent versatility as to the manner in which liquids are dispensed in metered quantities. The control means can also be used to provide stock control and may be provided with memory means and adapted for connection to an external computer . Numerous variations and modifications will suggest themselves to persons skilled in the relevant arts, in addition to those already described, without departing from the basic inventive concepts. For example, although each of the described embodiments employs a peristaltic pump, any suitable pumping system may be employed. A peristaltic pump is preferred as it provides a convenient means of pumping a plurality of liquids separately between a plurality of pump inlets and respective pump outlets. Furthermore any suitable means for sensing the quantity of liquid displaced by the pump and providing a feedback signal to the control means of the apparatus can be employed. For example, a liquid flow sensor may be incorporated in each of the discharge outlets of the control valves. All such variations and modifications are to be considered within the scope of the present invention, the nature of which is to be determined from the foregoing description and the appended claims.

Claims: THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:- 1. A liquid dispensing apparatus comprising: a pump having a pump inlet adapted for connection to a liquid supply and a pump outlet; a control valve having a valve intake for receiving liquid from the pump outlet and two valve outlets one being 'a return outlet communicating with the pump inlet and the other being a discharge outlet, said control valve having two modes of operation, namely a recirculating mode in which liquid entering the intake is directed to the return outlet and a discharge mode in which liquid entering the valve intake is directed to the discharge outlet; and, a control means for controlling operation of the control valve in said two modes of operation and for controlling operation of the pump whereby, in use, a controlled quantity of liquid can be dispensed from the discharge outlet of the control valve. 2. A liquid dispensing apparatus as claimed in claim 1, wherein the control means incorporates a time delay whereby the control valve is caused to move from the recirculating mode into the discharge mode a predetermined time interval after commencement of operation of the pump. 3. A liquid dispensing apparatus as claimed in claim 2, further comprising sensing means for sensing the operation of said pump and for generating a feedback signal indicative of the quantity of liquid transported through the pump, said control means being responsive to said feedback signal to return the control valve to the recirculating mode when a metered quantity of liquid has been dispensed from the discharge outlet of the control valve. 4. A liquid dispensing apparatus as claimed in claim 1, wherein the pump comprises a peristaltic pump having a resiliently deformable liquid transport line and a movable member for progressively deforming the liquid transport line whereby the liquid is transported through the line. 5. A liquid dispensing apparatus as claimed in claim 4, wherein said liquid transport line is one of a plurality of such resiliently deformable liquid transport lines each extending .between a respective pump inlet and pump outlet, and wherein said control valve is one of a corresponding plurality of such control valves each associated with a respective one of the liquid transport lines. 6. A liquid dispensing apparatus as claimed in claim 5, wherein said movable member is one of a plurality of rollers rotatably mounted on a motor driven rotor, and wherein as the rotor rotates the rollers successively roll over an intermediate position of each of said transport lines whereby said intermediate portion is progressively deformed to transport the liquid through the lines. 7. A liquid dispensing apparatus as claimed in claim 6, further comprising a plurality of dispensing lines one end of each of which communicates with the discharge outlet of a respective one of the control valves, and wherein the other end of the or each dispensing line opens into a dispensing nozzle. 8. A liquid dispensing apparatus as claimed in claim 7, wherein the control means further comprises an actuating means whereby operation of the pump and the control means can be initiated manually by operating the actuating means. 9. A liquid dispensing apparatus as claimed in claim 1, wherein the liquid supply comprises a liquid reservoir connected to the pump inlet whereby a sufficient supply of liquid can be made available for a metered quantity of liquid to be dispensed on operation of the pump. 10. A liquid apparatus as claimed in claim 9, wherein the reservoir has a level sensing means whereby the control means can prevent operation of the control valve when the liquid level in the reservoir falls below a predetermined level.

Inventors: GUTTERIDGE DOROTHY MAE, GUTTERIDGE LANCELOT PHILLIP, GUTTERIDGE, DOROTHY, MAE, GUTTERIDGE, LANCELOT, PHILLIP
Applicants: GUTTERIDGE DOROTHY MAE, GUTTERIDGE LANCELOT PHILLIP, LANGOULANT BRUCE LE BER, LANGOULANT JENNIFER MAE, GUTTERIDGE, DOROTHY, MAE, GUTTERIDGE, LANCELOT, PHILLIP, LANGOULANT, BRUCE, LE BER, LANGOULANT, JENNIFER, MAE
Application year: 1992
Main classification: B67D5
IPC codes: B67D1, B67D5, G01F11