GB2167845A - Drive arrangement for a pump/agitator in a cooler - Google Patents

Abstract

A cooler comprises a tank (31, Fig. 2 not shown) containing liquid and a motor/pump/agitator unit 200, the motor 12 producing a magnetic drive which is transmitted to a magnetic slug 60 connected to pump impeller 19 and/or agitator 24. As described, the motor 12 has its own plastics housing 13 and causes an annular magnet (not shown) to rotate, the magnet surrounding part of a plastics housing 16 for the slug. The impeller 19 pumps water from the tank round a recirculation system. The motor 12 is sealed off from the tank and there is therefore no need for a drive shaft to pass through the housing 13 as in the prior art. <IMAGE>

Description

SPECIFICATION Coolers The present invention relates to coolers and more particularly to coolers for flowing media such as drinks.

In existing coolers for drinks, it has been normal practice to fit a small open frame motor with a stainless steel shaft and plastic propeller into the top of the water tank of a cooler to provide agitation of the water in the bath in order to effect an efficient heat exchange between the evaporator coil of the refrigeration system and product coil which contains the drink being cooled, thus using the water as a heat exchange medium.

In some cases a small semi submersible pump is fitted to the same motor in addition to the propeller to provide a water recirculation facility to maintain a given temperature of the lines connecting the cooler to a dispense point.

It has been proved that, due to the heat generated by the motor being conducted along the motor shaft which is in contact with the water, the tendency is for this heat, over a period of time, to evaporate water from the tank mainly through the clearance hole for the motor shaft in a mounting tray and through other orifices, e.g. in the tank lid.

The present invention seeks to overcome or reduce the above disadvantage.

According to a first aspect of the present invention there is provided a cooler comprising a tank containing a liquid, agitating means and/or pump means for the liquid in the tank, and a motor, the motor having a magnetic driving member and said means having a magnetic driven member, the magnetic drive between said members being across a gap.

The motor is preferably mounted within a separate compartment within the tank.

The tank is preferably sealed air-tight.

According to a second aspect of the present invention there is provided a drive unit comprising a motor which is arranged to rotate an annular magnet, the motor and the magnet being accommodated in a common compartment, a magnetic slug located outside said compartment but adjacent to the annular magnet to be rotated thereby, and an impeller andtor agitator fixedly connected to the magnetic slug.

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 shows a motor/pump/agitator unit of a prior art cooler; Figure 2 shows a partly-exploded and partly broken away perspective view of a cooler unit in accordance with the present invention; Figure 3 shows a cross-sectional view of part of Fig. 2; and Figure 4 shows an exploded view of a motor/pump/agitator unit of a cooler in accordance with the present invention.

Referring to Fig. 1, a prior art unit comprises a motor 101 connected to a shaft 102.

The motor is located in a mounting tray 103 which defines a separate compartment for the motor in the top of a water tank. The shaft 102 emerges from the tray and enters the water through a clearance hole 107. Mounted on the shaft are the impeller (not shown) of a water recirculating pump 104 and a propeller 105 for agitating the water. Since shaft 102, the impeller of pump 104 and the propeller 105 are in contact with the water, heat from the motor 101 is conducted to the water by these components. Thus water in the tank evaporates and escapes via hole 107 and various other apertures in the lid of the tank. This means that the water must be replenished at intervals if the cooler is to operate correctly.

Fig. 2 shows a cooler in accordance with the present invention comprising a housing 30 defining a tank 31 which contains water 32, Fig. 3, and has a generally rectangular lid 40 of plastics material. Passing through the water are two sets of coils: coils 35 containing beer to be cooled and coils 33 containing coolant supplied by a refrigeration unit. Beer enters the cooler at inlet 10 passes through coils 35 and emerges at outlet 38 where it passes through a pipe (not shown) to a beer dispenser.

A motor/pump/agitator unit 200 is located in the tank 31. A detailed exploded view of a preferred unit 200 is shown in Fig. 4. The unit comprises a motor 12 in a water-tight compartment formed by a plastics tray 13 which in use is located within the tank near the top. The motor incorporates an annular ceramic magnet (not shown) for producing a rotating magnetic field. An electrical connection block 27 and an in-line fuse 26 are provided for the motor 12.

The tray 13 is mounted in a circular aperture in the lid 40, a seal being formed therewith by a gasket 14.

A ceramic magnetic slug 60 has a plastics housing 16 which is sealingly connected to the bottom of the tray 13 by a gasket 15.

The closed cylindrical part 1 7 of the housing 16 is encircled by the annular magnet of the motor 12 and thus serves to separate the two magnets; it thus forms a thermal break between the motor and the slug 60.

Impeller 19 of pump 50 is fixedly connected to slug 60 to be rotated thereby. The impeller is located within a pump housing 21 sealed to slug housing 16 by an O-ring gasket 18. The pump 50 pumps water along a pipe 25. Bolts 22, having washers 23 thereon, serve to secure housings 21 and 16 to the bottom of tray 13. Fixed to the shaft 20 of impeller 19 is an agitator 24 in the shape of a propeller.

Pump 50 serves to recirculate water to keep the beer cool as it is supplied to the dispenser. To this end, pipe 25 is connected to a cooling water outlet 36 from which the water passes along outward and return pipes extending alongside and in thermal communication with the beer pipe connected to outlet 38. Water returns to the tank 31 via inlet 37.

The water 32 in tank 31 serves as a heat exchange medium between beer coils 35 and the coolant coils 33, and agitator 24 serves to improve the efficiency of this process.

The tank 31 is provided with a number of seals to restrict the escape of water vapour therefrom. Its lid 40 is tightly sealed to tank wall 42, Fig. 3. by a gasket 44. Water is initially supplied to tank 31 via an aperture 46 in the tank lid. The water reaches aperture 46 via a tube 47 depending from an aperture 48 in a metal lid 210 of the cooler unit. A rubber ring 49 is provided on the outside of tube 47 to provide a further air-tight seal against the upper edge of aperture 46.

A bung 211 closes aperture 48 when the tank has been filled.

Also after filling a plug is provided in the end of an overflow pipe 11 of the tank.

The above-described embodiment has the advantage that a thermal break (i.e the spacing between the two magnets occupied by housing part 17) is provided between the motor and the water. Thus evaporation is reduced. Furthermore, no sealing of moving parts is necessary between the motor and the tank; accordingly it is easier to assure an airtight seal between the compartment for the motor and the tank. Gaskets 14 and 44, sealing ring 49, bung 211 and the plug for pipe 11 all serve to prevent evaporation of water from the tank. Accordingly once the cooler unit is operational, the tank does not require periodic topping-up as with existing coolers.

Various modifications may be made to the above-described arrangement. For example housing 16 may be made integral with tray 13 to avoid the need for gasket 15 Also, different magnetic drive arrangements can be employed; for example motor 12 may comprise an electromagnetic winding arrangement producing a suitable rotating magnetic field to drive the pump and agitator.

Claims (9)

1. A cooler comprising a tank containing a liquid, agitating means and/or pump means for the liquid in the tank, and a motor, the motor having a magnetic driving member and said means having a magnetic driven member, the magnetic drive between said members being across a gap.

2. A cooler according to claim 1, wherein the motor is mounted within a separate compartment within the tank.

3. A cooler according to claim 1 or 2, wherein the tank is air-tight.

4. A cooler according to any preceding claim, wherein magnetic driving member comprises an annular magnet and the magnetic driven member comprises a slug connected to said means.

5. A cooler according to any preceding claim, wherein the magnetic driven member has a non-magnetic housing which serves to separate the two magnetic members.

6. A cooler according to claims 4 and 5, wherein the housing is surrounded by the annular magnet.

7. A cooler according to claim 2 and claim 5 or 6 wherein the housing is integral with the walls of the motor compartment.

8. A cooler according to any preceding claim wherein the pump means pumps water out of the tank to a recirculation system from which it returns to the tank.

9. A cooler substantially as herein de scribed with reference to Figs 2 to 4 of the accompanying drawings.

9. A cooler substantially as herein described with references to Figs 2 to 4 of the accompanying drawings.

10. An an independent invention the additional feature of any of claims 2 to 8.

11. A drive unit comprising a motor which is arranged to rotate an annular magnet, the motor and the magnet being accommodated in a common compartment, a magnetic slug located outside said compartment but adjacent to the annular magnet to be rotated thereby, and an impeller and/or agitator fixedly connected to the magnetic slug.

CLAIMS Amendments to the claims have been filed, and have the following effect: New or textually amended claims have been filed as follows:

1. A cooler comprising a tank containing a liquid, agitating means and/or pump means for the liquid in the tank, and a motor, the motor having a magnetic driving member and said means having a magnetic driven member, the magnetic drive between said members being across a gap which constitutes a thermal break between the magnetic driving and magnetic driven members.

2. A cooler according to claim 1, wherein the motor is mounted within a separate compartment within the tank.

3. A cooler according to claim 1 or 2, wherein the tank is air-tight.

4. A cooler according to any preceding claim, wherein magnetic driving member comprises an annular magnet and the magnetic driven member comprises a slug connected to said means.

5. A cooler according to any preceding claim, wherein the magnetic driven member has a non-magnetic housing which serves to separate the two magnetic members.

6. A cooler according to claims 4 and 5, wherein the housing is surrounded by the annular magnet.

7. A cooler according to claim 2 and claim 5 or 6 wherein the housing is integral with the walls of the motor compartment.

8. A cooler according to any preceding claim wherein the pump means pumps water out of the tank to a recirculation system from which it returns-to the tank.