GB2440202A

GB2440202A - Multi-Compressor Cooling Apparatus with Current Start-up Control and Used for Cooling Beverages

Info

Publication number: GB2440202A
Application number: GB0614056A
Authority: GB
Inventors: Michael John Filmer
Original assignee: M F REFRIGERATION Ltd
Current assignee: M F REFRIGERATION Ltd
Priority date: 2006-07-14
Filing date: 2006-07-14
Publication date: 2008-01-23
Anticipated expiration: 2026-07-14
Also published as: GB2440202B; GB0614056D0

Abstract

A cooling system for beer or the like has a chill tank 22 for a liquid coolant such as water with conduits for a liquid refrigerant located in or around the tank to chill the liquid therein. The liquid refrigerant is supplied to the tank by a twin compressor system comprising a first compressor 26 arranged to operate by its own to supply cooled refrigerant to the tank during a start up period and a second compressor 28 operating in tandem with the first and arranged to start up after the first compressor to increase the flow of refrigerant and/or reduce its temperature, while reducing the overall initial current draw of the system. The beverage such as beer from a supply 10 may be passed to a cooling coil 24 within the tank and thence via a beverage line 30 to a dispensing point, passing through a sub-cooling unit 40 through which coolant from the tank 22 is also passed. The cooling module may include an associated cooling coil (50 fig 2) for cooling the beverage, and the cooled beverage is further cooled as it passes through the coil en-route to the dispense site.

Description

* 2440202

COOLING APPARATUS FOR BEER AND THE LIKE

This invention relates to apparatus for cooling liquids, particularly beverages such as beer.

Beer is often sold on draft for immediate consumption, for example from a pump at a bar, supplied from a keg which may be some distance from the bar. Many beers, particularly lagers, are intended to be drunk chilled to a temperature only a few degrees above 0 C.

Many cooling systems for draft beverages are known. For example GB-A-2198218 discloses a cooling system in which water is chilled in an ice tank and circulated to a number of heat exchangers close to a beverage dispensing point, some going through a cooling bath for chilling bottled beverages, and some through a heat exchanger through which draft beer is passed to a pump.

EP-A-1510499 discloses a system in which draft beer itself is passed through an ice bank cooler, at some distance from the dispensing point, and thence to a beer pump via a subsidiary heat exchanger nearer the pump. Water may be circulated through the secondary heat exchanger from the ice bank cooler, and conduits for water and beer may be bundled together within an insulating sheath known as a "python".

In recent years, demand for chilled beers has increased, and preferred serving temperatures have decreased. There is therefore a requirement for more efficient cooling systems.

Ice bank chillers, such as that disclosed in GB-A-2419176, generally comprise a water bath with refrigerant pipes, usually of copper, running around the inner surfaces. A compressor circulates a refrigerant through these pipes to freeze water in the tank and form an ice bank around the sides of the tank. The water in the tank may be agitated, causing it to circulate to encourage the growth and maintenance of a uniform ice bank. One problem which arises with the trend towards lower temperatures is that the compressors used draw a high current, particularly on start up, with which an ordinary mains electricity supply may not be able to cope.

According to a first aspect of the present invention, a cooling system for beverages and the like is provided comprising a chill tank for a liquid coolant, with conduits for a liquid refrigerant located in or around the tank to chill the liquid therein, wherein the liquid refrigerant is supplied to the tank by a twin compressor system comprising a first compressor arranged to operate on its own to supply cooled refrigerant to the tank during a start up period, and a second compressor operating in tandem with the first and arranged to start up after the first compressor to increase the flow of refrigerant and/or reduce its temperature, while reducing the overall initial current draw of the system.

The second compressor may be arranged to start up after a predetermined time delay from the start up of the first compressor, or may be activated thermostatically when a predetermined temperature is sensed within the tank.

In order to cool the beverage further on its way between the chiller and the dispensing point, it may be passed through a subsidiary cooling module at an intermediate position, preferably near to the dispensing point. Typically the subsidiary cooling module will consist of a container such as a cylinder, with a heat exchange coil of stainless steel or the like within it, a cooling fluid, such as water from the chiller tank, passing through the module and the beer passing through the heat exchange coil to cool it further. Typically the beverage line runs between the chiller tank and the subsidiary cooling module together with outward and return lines for water from the chiller tank, the three lines being incased in a flexible insulating sheath known as a "python", so that the beer line is not only insulated from room temperature but is in close proximity with cold water lines.

According to a further aspect of the invention, there is provided a sub-cooling module for a beverage cooling system comprising an elongated fluid-tight container with an inlet and an outlet for a cooling fluid and a heat exchange conduit within the container with an inlet and an outlet for a beverage to be cooled, wherein all said inlets and outlets into the container at one end thereof while the inlet and outlet for cooling fluid being arranged to convey the cooling fluid to one end of the container and remove it from the other end.

The heat exchanger is preferably in the form of a stainless steel coil extending between the two ends of the container. By passing the beverage from one end of the container to the other and back again before it leaves the container, improved cooling efficiency is achieved. In one preferred embodiment the coil comprises several loops extending parallel to the longitudinal direction of the container.

Preferred embodiments of the invention will now be described with reference to the accompanying drawing wherein: Figure 1 shows schematically a beverage cooling system in accordance with the present invention; Figure 2 shows a cutaway view through a subsidiary cooling module in the accordance with the invention, forming part of the cooling system shown in Figure 1; Figure 3 shows a perspective view of a second embodiment of a coil assembly of a subsidiary cooling module in accordance with the invention and Figure 4 shows an end view of the second embodiment of a coil assembly of Figure 3.

Referring first to Figure 1, beer or the like from a keg 10 is drawn by a pump (not shown) through a supply tube 12 to a main chilling unit generally indicated by 20. This may for example comprise an ice bank cooler of the type disclosed in GB-A- 2419176, wherein a tank full of water or other refrigerant such as a glycol solution has around at least some of its side walls a bank of heat exchange tubes for the circulation of a fluid refrigerant. The refrigerant is cooled and circulated through the heat exchange tubes (not shown) by twin compressors 26 and 28, which will be described in more detail below.

A coolant feed line 32 runs from the main cooler unit 20 to a sub-cooling module 40 which will be described in more detail with reference to Figure 2, and a coolant return line 36 runs back from the sub-cooling module to the main cooling unit 20. A pump 34 is provided for circulating the water or other coolant from the main cooling unit 20 to the subsidiary cooling module 40.

The subsidiary cooling module 40 is shown in more detail in Figure 2. This comprises a fluid-tight cylindrical container with a thermally insulating wall 42 and insulating end caps 44, 46.

The beverage inlet line 30 connects to one end 52 of a heat exchanger coil 50 made of a material of high thermal conductivity such as stainless steel. The coil extends to the opposite end of the module, with a return pipe 48 extending back to and through the end cap 46 where its end 54 connects to the beverage line 45 which in turn is connected to a beverage dispensing point such as a beer pump or tap.

A suitable twin compressor system is the Danfos SC21 universal twin compressor comprising two 550 W motors with an operating current after 4 seconds of 21.8 A and a cut-in current for the second compressor also of 21.8 A. When the system is switched on, the first compressor 26 starts up, drawing an initially high current. Refrigerant is circulated around the sides of the coolant bath 22, which is filled with water or another coolant such as a glycol-water mixture. After an initial start up period, when the current drawn by compressor 26 has fallen to its normal running value, the second compressor 28 is automatically started up, again drawing a high current, but one such that the total current draw of the two compressors is one which can be accommodated by an ordinary mains supply.

As the coolant in the tank 22 is cooled to its working temperature on a typically from 0 to -3 C and preferably about 3 C, the pump 34 can be started to circulate coolant through the sub-cooling module 40. Coolant runs through the feed line 32, connecting to an inlet pipe 56 which passes through the end cap 46 and extends to the far end of the module, adjacent end cap 44, where a coolant is discharged into the module chamber 43.

As coolant is pumped in, it passes back along the length of the e coolant chamber to an outlet 47 which passes through the end cap 46 and connects to a coolant return line 36.

The beer or other beverage to be cooled is drawn as required from a keg 10 through a feed line 12 to a cooling coil 24 immersed in the coolant tank 22. After passing through the coolant coil and being cooled to its serving temperature, the beer passes through a feed line 30 connected to the outlet end of the coil and thence to a pipe connection 52 of the subsidiary cooling module. The beverage is cooled further as it passes through cooling coil 50, which is immersed in more liquid coolant being circulated from the main cooling tank 22. The beverage then returns to line 48, passing through end cap (46), where the outlet end 54 of the coil is connected to a feed line which in turn connects to a beer pump or the like.

The twin compressors 26, 28 are, together, more compact than a single compressor offering the same capacity, and can therefore be fitted conveniently into the main cooling unit 20, reducing the overall size of the apparatus.

The maximum current draw of the twin compressors 26, 28, when operated in sequence with a time delay, is less than that which would be drawn by a single compressor of similar capacity, which might draw too high a starting current to be usable with an ordinary AC mains supply.

The construction of the sub-cooler unit 40, with all the inlet and outlet pipes at one end, means that the unit can take up less space, being fitted into a elongate space, for example under a bar counter, all the pipe connections being conveniently accessible in a small area.

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Referring now to Figure 3, an alternative heat exchanger coil 58 is shown, separated from the subsidiary cooling module. Heat exchanger coil 58 differs from the first embodiment 50 in that the coils form a series of loops, each loop extending along the longitudinal axis of the subsidiary cooling module. The insulating end cap 70 is shown, through which pass the inlet pipe 66 through which coolant is pumped and the outlet pipe 62 through which coolant leaves the subsidiary cooling module. This end cap also accommodates the inlet pipe connection 64 of the heat exchanger coil 68 through which the beverage is pumped and the return pipe connection 60 through which the cooled beverage leaves the cooling module.

Figure 4 shows an end view of heat exchanger coil 58 showing the end cap 70, the inlet pipe 66, the outlet pipe 64 and the inlet pipe connection 60 of the heat exchanger coil 62 and the return pipe 60.

Claims

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CLAIMS

1. A cooling system for beverages and the like comprising a chill tank for a liquid coolant and conduits for a liquid refrigerant located in or around the tank to chill the liquid therein, wherein the liquid refrigerant is supplied to the tank by a twin compressor system comprising a first compressor arranged to operate on its own to supply cooled refrigerant to the tank during a start up period and a second Q compressor operating in tandem with the first and arranged to start up after the first compressor to increase the flow of refrigerant and/or reduce its temperature, while reducing the overall initial current draw of the system.

2. A cooling system according to claim 1 wherein the second compressor is arranged to start up after a predetermined time delay from the start up of the first compressor.

3. A cooling system according to claim 1 wherein the C second compressor is arranged to be activated thermostatically when a predetermined temperature is sensed within the tank.

4. A cooling system according to any preceding claim further comprising a heat exchange coil located in the tank through which a beverage can be passed from a beverage supply and thence to a dispensing point via a beverage line.

5. A cooling system according to claim 4 wherein the beverage line is encased in a flexible insulating sheath together with outward and return lines for coolant from the chiller tank. I_i

7. A cooling system according to claim 6 wherein the subsidiary cooling module comprises an elongate fluid-light container with an inlet and an outlet for a cooling fluid and a heat exchange conduit within the container with an inlet and an outlet for a beverage to be cooled, wherein all said inlets and outlets into the container are located at one end thereof while the inlet and outlet for cooling fluid are arranged to convey the cooling fluid to one end of the container and remove it from the other end.

O 8. A cooling system according to claim 7 wherein the heat exchanger is in the form of a stainless steel coil extending between the two ends of the container.

9. A cooling system according to claim 8 wherein the coil comprises several loops extending parallel to the longitudinal direction of the container.

10. A sub-cooling module for a beverage cooling system comprising an elongated fluid-type container with an inlet and an outlet for a cooling fluid and a heat exchange conduit within the container with an inlet and an outlet for the beverage to be cooled, wherein all said inlets and outlets c into the container are located at one end thereof while the inlet and outlet for cooling the fluid are arranged to convey the cooling fluid to one end of the container and remove it from the other end.