BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to beverage cooling systems and has particular reference to beverage cooling systems used in connection with so-called python systems.

2. Background

A python comprises a large diameter (10 cm) insulated plastics tube containing a plurality of beverage lines which are used to interconnect a series of beverage storage containers with a series of beverage dispense points. The python prevents the beverages, or beverage components such as beer, carbonated water and syrup, from being over-heated in their passage from a temperature stabilized cellar to the beverage dispense point. Typically, in a bar or restaurant, the beverage dispense lines pass through the bar area which area can be very warm relative to the desired dispensing temperature of the beverage. Where the beverage is dispensed intermittently, and in the absence of an insulated python, the beverage would become over-warm in the beverage lines.

Normally, the small diameter beverage lines are placed concentrically around a central, larger diameter, pipe through which cold water is pumped to maintain the product temperature. This water is re-circulated via a chiller.

In order that the re-circulation system can provide the initial lift for the water, a large pump is necessary to pump the water through the larger pipe and back to the water chiller. However, once the initial lift of water has been provided, a quantity of chilled water far in excess of the system's usual requirements continues to be pumped around the system.

Normally, the chilled water is obtained from a water bath containing an ice bank, the ice bank having been formed on an evaporator of a refrigeration system. The ice bank builds up during periods of low demand and is used to even out the refrigeration load requirement.

Unfortunately, with high water flow rates, the excess of water slowly eliminates the ice bank, thus reducing the efficiency of the cooler unit. Furthermore, the high flow rate of chilled water can over-chill the drinks in the python and the initial drinks served after the python has been standing for some while can be at too low a temperature.

SUMMARY OF THE INVENTION

By the present invention, there is provided a beverage cooling system including a water bath, a refrigerator evaporator in the water bath, an insulating tube containing a plurality of beverage lines, and a re-circulating coolant line, a pump for pumping water from the water bath through the re-circulating coolant line and back into the water bath, characterized in that there is provided means to vary the output (i.e., the volumetric flow rate) of the pump so as to have at least two output volumes.

The output of the pump may be varied manually such that the output is reduced after the original lift of water has occurred. Alternatively, the output may be varied automatically such that after the initial lift has been achieved, a timer operates to reduce the pump speed to a lower level.

In a further alternative, the pump output may be varied in response to variations of temperature of the interior of the insulating tube, or of the water returning from the insulating tube or reaching the distal end of the insulating tube, or of the temperature of the beverage passing through the beverage lines, preferably at or near the outlet of the beverage lines.

The output of the pump may be increased with an increase in sensed temperature.

The pump output may be varied by varying its speed. The pump is preferably driven by an electric motor, and the motor speed may be variable continuously or in discrete steps. The motor may be controlled by phase angle control. The pump may be a regenerative pump or a centrifugal pump. The output of the centrifugal pump may be varied by throttling the cooling in flow.

BRIEF DESCRIPTION OF THE DRAWING

By way of example, embodiments of the present invention will now be described with reference to the accompanying drawing, wherein:

FIG. 1 shows a schematic view of a beverage cooling system in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the drawing, there is shown an insulated container 1 forming a water reservoir 2 for cooling water. An evaporator coil 3 forms an ice bank 4 in the water reservoir. A refrigeration system of conventional form including a compressor pump 5 to compress refrigerant, a condenser 6 and a fan 7 acts in the normal manner to provide a flow of refrigerant to the evaporator coil 3. The thickness of the ice bank 4 can be controlled by any suitable means.

The pump 8 draws water from the water reservoir 2 via a dip tube 9 and passes it to an outlet pipe 10 that extends through an insulating tube 11, which insulates a portion of a python system P. Python system P is formed of a plurality of beverage lines passing through insulating tube 11 in close heat exchange contact with a portion of coolant line 10. A representive beverage line B is shown and provides for fluid communication of a beverage from a source S thereof to a dispensing valve V. Coolant line 10 is of conventional form wherein the chilled water is re-circulated through loop 12 and back via outlet end 13 thereof into the water reservoir 2. A temperature sensor 14 senses the return temperature of water emerging from the python system and controls the speed of pump 8 via control box 15. The sensor 14, as indicated in phantom outline, may also be located on a beverage line under insulation tube 11.

When the system is switched on initially, the water in outlet end portion 13 will be warm. This will be sensed by sensor 14 and the control box 15 will operate pump 8 at its maximum speed. As the water circulating through line 10 chills the beverage in line B, the return water temperature falls and this is sensed by sensor 14.

With the fall in the temperature, control box 15 reduces the speed of pump 8. This reduction causes a reduction in the power requirement of the system, a reduction in the noise of the system, a reduction in the excessive water flow over the ice bank 4 and also reduces the wear on pump 8 and its drive motor.

Controlling the speed of pump 8 thus has a number of significant advantages compared to existing systems. The noise levels are lower, the wear on the pump is lower, and the power requirement for the pump is reduced, hence the electrical costs are lower. There is also a hidden benefit in that the refrigeration costs are lowered. By reducing over cooling, the amount of chilled water required for re-circulation is lowered, and hence the refrigeration load is lowered. There is thus a double power saving.

The pump 8 may be a centrifugal pump, but is preferably a regenerative pump. It is preferably driven by an electric motor--typically a 1/4 horsepower AC induction motor rated 180 W. Control may be by phase angle control or by chopping the wave form. An electronic control circuit can be used to chop the form of the AC wave for power control purposes. If a centrifugal pump is used, the power output can be controlled by throttling the coolant inflow, which will reduce output and electric motor load.

It will be appreciated by those of skill in the art that various sources of cold water can be used other than through the provision of a water bath 2, as described herein. It can also be understood that the water does not necessarily need to be recycled. In addition, various liquid or otherwise fluid coolants could be used other than water.