GB2235968A

GB2235968A - Heat exchange between fluids

Info

Publication number: GB2235968A
Application number: GB8918405A
Authority: GB
Inventors: Frank Worth
Original assignee: Booth Dispensers Ltd
Current assignee: Booth Dispensers Ltd
Priority date: 1989-08-11
Filing date: 1989-08-11
Publication date: 1991-03-20
Anticipated expiration: 2009-08-11
Also published as: GB2235968B; GB8918405D0

Abstract

In apparatus for heat exchange between fluids the temperature at a lower region of the first fluid in which the second is heat exchanged is at a higher temperature than an upper region. As described a cooling unit chills the water 12 at the top thereof to maintain a controlled ice bank 22. Water is at its highest density at 4 DEG C and accordingly the water 12 at the bottom is always at or in the region of 4 DEG C. Liquid e.g. a drink passes through a pipe 14 in the bottom region of the water to cool that water and is available for dispensing. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO HEAT EXCHANGE.

The present invention relates to a method of heat exchange between two or more fluids and to heat exchange apparatus and Is particularly, although not exclusively, applicable to the cooling of liquids such as drinks.

It Is desirable to cool or maintain certain liquids in the region of 40C in order that they may be enjoyed at their optimum temperature and In order that they do not suffer damage through being overheated or over chilled to any great degree. However, the cooling of such liquids or the maintaining of such liquids at the desired temperature is difficult where the room temperature exceeds 40C, and it is difficult to maintain a heat exchange system which can hold or cool the liquid to the desired temperature.

According to one aspect of the present invention a method of heat exchange between a first fluid and a second fluid comprises exchanging heat between the fluids at a lower region of the first fluid the temperature of which lower region of the first fluid is at a higher temperature than the temperature at an upper region of the first fluid.

The method may comprise cooling the upper region of the first fluid. The method may comprise maintaining the temperature differential between the upper and lower regions of the first fluid. The method may comprlse maintaining the upper region of the first fluid generally at the freezing point of the fluid.

The first fluid may comprise water. The method may comprise maintaining ice in the upper region, either automatically or manually.

The density of the fluid at the lower region may be greater than the density at the higher region, and the method may comprise maintaining the temperature at the bottom of the fluid substantially constant as the density of fluid at the bottom thereof is generally the greatest density that the fluid can have.

The second fluid may comprise a liquid. The second fluid may be cooled. The second fluid may comprise a drink.

The present invention also includes a method of cooling a drink or maintaining a drink at a required temperature by exchanging heat as herein referred to in which the second fluid comprises the drink.

According to another aspect of the present invention a heat exchange apparatus includes first fluid retaining means and second fluid retaining means, the second fluid retaining means being located at a lower region of the first fluid retaining means, and means for enabling the temperature of fluid located in the first fluid retaining means to be at a lower temperature at the lower region than at a higher region.

The present Invention includes any combination of the herein described features.

The present invention may be carried into practice In various ways but one embodiment will now be described, by way of example and with reference to the accompanying schematic sectional diagram which shows an insulated container 10 which is filled with water 12, which comprises the cooling medium, and a U-shaped pipe 14 extending through sealed connectlons 16 in the lower region of the water 12.

Drink to be cooled flows through the pipe 14 and heat exchange occurs between the drink and the water at or near the bottom of the contalner 10.

A cooling unit 18 is located towards the top of the water 12, the unit 18 being connected to a refrigeration plant 20. The unit 18 chills the water at the top to maintain a controlled Ice bank 22. When the ice bank 22 reaches a certaln predetermined maximum size the cooling of the water Is halted and, conversely, when the bank Is sufficiently reduced in size the refrigeratlon plant 20 is operated agaln to activate the cooling unit 18 and increase the size of the bank 22.

Thus there is always some Ice present at the top of the water at OOC.

Water Is at Its highest density at 40C and so accordingly the water 12 at the bottom of the container 10 is always at or in the region of 40C. Should the water increase In temperature at the bottom region then the density decreases and the hot water will rlse and be cooled. Alternatively should the water decrease In temperature at the bottom of the contalner then the density will again decrease and the cooler water will rise thereby ensuring the substantlally constant temperature at the bottom region of the tank.

Thus the liquid being cooled in the pipe 14 is always maintained at, or cooled to, the temperature in the region of the water at the bottom of the contalner 10, i.e. in the region of 40 and, where the liquid being cooled is a drink, the liquid Is able to be dispensed at Its optimum temperature and maintained above freezing point in the region of 40C to ensure that the liquid does not suffer from adverse temperatures if left to stand In the cooling medium for a considerable perlod of time.

Thus by perlodlcally switching the refrigeratlon plant 20 on and oFf in accordance with the size of the bank a generally constant temperature is able to be malntalned at the bottom of the water. The size of the Ice bank can be monitored by temperature sensors (not shown) or some other means if desired.

In an alternative embodiment the cooling unit 18 and the plant 20 are omitted and are replaced by ice which Is placed In the tank 10. When the ice melts elther completely or partially, further Ice can be added.

The Ice may be located in a separate contalner to the container 10 if desired and may, for instance, be located In a bucket.

Claims

1. A method of heat exchange between a first fluid and a second fluid comprising exchanging heat between the fluids at a lower region of the first fluid, the temperature of which lower region of the first fluid is at a higher temperature than the temperature at an upper region of the first fluid.

2. A method as claimed in Claim l comprising cooling the upper region of the first fluid.

3. A method as claimed in Claim 1 or 2 comprising maintaining the temperature differential between the upper and lower regions of the first fluid.

4. A method as claimed in any preceding claim comprising maintaining the upper region of the first fluid generally at the freezing point of the fluid.

5. A method as claimed in Claim 4 comprising maintaining ice in the upper region of the first fluid.

6. A method as claimed in Claim 5 comprising maintaining ice in the upper region of the first fluid automatically.

7. A method as claimed in Claim 5 comprising maintaining ice in the upper region of the first fluid manually.

8. A method as claimed in any preceding claim in which the density of the first fluid at the lower region is greater than the density at the higher region.

9. A method as claimed in Claim 8 comprising maintaining the temperature at the bottom of the fluid substantially constant.

10. A method as claimed in any preceding claim in which the second fluid is cooled.

11. A method of heat exchange substantially as herein described with reference to, and as shown in the accompanying drawings.

12. A method of cooling a drink or maintaining a drink at a required temperature by exchanging heat by a method as claimed in any preceding claim in which the second fluid comprises the drink.

13. A method of cooling drink or maintaining a drink at a required temperature substantially as herein described with reference to, and as shown in the accompanying drawing.

14. A heat exchange apparatus including first fluid retaining means and second fluid retaining means, the second fluid retaining means being located at a lower region of the first fluid retaining means, and means for enabling the temperature of fluid located in the first fluid retaining means to be at a higher temperature at the lower region than at a higher region.

15. Apparatus as claimed in Claim 14 in which the first fluid comprises water.

16. Apparatus as claimed in Claim 12 or 13 in which the second fluid comprises a liquid.

17. Apparatus as claimed in Claim 16 in which the second fluid comprises a drink.

18. A heat exchange apparatus substantially as shown and described with reference to, and as shown in the accompanying drawing.

19. A heat exchange apparatus as claimed in any of Claims 14 to 18 when used in a method as claimed in any of Claims 1 to 13.