AU2009203886B2

AU2009203886B2 - Improvements in heat exchangers for dispensing sub-zero beer

Info

Publication number: AU2009203886B2
Application number: AU2009203886A
Authority: AU
Inventors: Benjamin Paul Baker
Original assignee: Tempak International Pty Ltd
Current assignee: Tempak International Pty Ltd
Priority date: 2008-01-04
Filing date: 2009-01-02
Publication date: 2014-01-30
Anticipated expiration: 2029-01-02
Also published as: CA2711492A1; NZ586788A; EP2238399A4; EP2238399A1; AU2009203886A1; US20110011569A1; WO2009086589A1

Abstract

A heat exchanger (10) comprises a coolant line (11) and a beverage line (13), embedded in a solid block of Aluminium (15). The coolant line (1 l)is in the form of a first helical coil defining a plurality of turns typically located in the centre of the block. The beverage line (13) is in the form of a second helical coil defining a plurality of turns extending around the first coil. The coolant line defines a cold zone (12), typically in the centre of the block, with the volume outside the central zone carrying the beverage line ratio defining an designated beverage cooling zone (14). The volume ratio of the designated zone to the cold zone is about 150: 100. The heat exchanger allows for cooling of beer to precise temperatures and even temperatures close to freezing point, using direct expanded Freon refrigeration methods. The complete system including the refrigeration equipment to be packaged into a small area, such as is available under bars and dispensing counters etc., which removes the need for large installations and the associated costs and maintenance of the same. In a variant an additional beverage cooling zone may be located inside the cold zone. The positions of the coolant and beverage lines may also be reversed in certain applications.

Description

WO 2009/086589 PCT/AU2009/000002 "Improvements in heat exchangers for dispensing sub-zero beer" Cross-Reference to Related Applications The present application claims priority from Australian Provisional Patent Application No 2008900054 filed on 4 January 2008, the content of which is 5 incorporated herein by reference. Field of the Invention This invention relates to an improved apparatus for dispensing cooled fluids, in particular beverages, such as beer. 10 Background of the Invention In most commercial establishments where beer is served, the beer is supplied in barrels or kegs. The kegs are stored in a refrigerated cold room or cellar at a temperature range of between 3 and 10 degrees C. The beer is normally dispensed 15 through beer dispensing valves/taps located away from the -cold room. A heat exchanger or some form of extra cooler is also normally included in the system to further cool the beer in line between the cold room and the tap. The beer is delivered to the taps from the kegs through a conduit containing the beer delivery lines. The conduit also contains coolant transfer lines for recirculation of 20 cold water or water containing a percentage of antifreeze components such as glycol. In practice, the beer is moved through the beer delivery lines by means of CO 2 gas pressure applied to the barrel or keg. Recently, due to changes in customer preferences and fashions, it has become desirable to serve beer at temperatures below 0 degrees C. 25 Existing systems using heat exchangers installed in line between the cold room and the beer dispensing tap, have relied on an external cold source being supplied to circulate coolant at closely controlled temperatures through the conduit and heat exchanger to cool the beer to the sub zero temperature. These systems have high maintenance costs associated with the external cold 30 source and a high initial installation costs involving extensive site alterations to the beer system. The present invention seeks to provide a lower cost and preferably more efficient beverage cooling system. Any discussion of documents, acts, materials, devices, articles or the like which 35 has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of 2 these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application. 5 Summary of the Invention According to a first aspect of the present invention there is provided a heat exchanger comprising a first line and a second line embedded in a solid block of a material having a high thermal conductivity with the first line in the form of a first helical coil defining a plurality of turns, and the second line in the form of a second 10 helical coil defining a plurality of turns and extending around the first coil, wherein the angle between a plane defined by a turn of the second coil and a plane defined by a turn of the first coil is between 15 and 120 degrees. In one embodiment, the first line is a coolant line and defines a cold zone in the centre of the block, with the volume outside the zone carrying the second line which is 15 a beverage line defining a designated beverage cooling zone. The location of the coolant line typically in the centre of the aluminium block and the physical arrangement of the coolant line in the form of a coil provides a cold core or central cold zone in the solid block. The resultant outer area provides a designated beverage cooling zone in which 20 the beer/beverage line is located. Alternatively, the first line is a beverage line and defines a designated cooling zone in the centre of the block, with the volume outside the zone carrying the second line which is a coolant line defining a designated cold zone outside the cooling zone. In a second related aspect, the invention provides a heat exchanger comprising a 25 coolant line and a beverage line embedded in a solid block of a material having a high thermal conductivity with the beverage line in the form of a first coil having a plurality of turns being located in the centre of the block and defining a designated beverage cooling zone and the coolant line in the form of a second coil defining a plurality of turns and extending around the first coil and defining a cold zone. 30 The ratio of the volumes of these two distinct zones within the solid is an important relationship when dispensing beer at critical temperatures, often as low as -2 degrees C. In a preferred embodiment the volume ratio of the designated zone to the cold zone is about 150:100. 35 2a The cold zone acts as a thermal storage of energy. This thermal storage is used to maintain controlled beverage outlet temperatures and avoid the fluctuations that are typical with existing heat exchangers. 5 The coil is typically in the form of a helical coil. As used herein "helical" is not to be taken as inferring that the coils of each turn of the helical coil need be circular. The coils may be any shape and will typically comprise semi-circular curved ends separated by straight lengths of tubing. The coolant used is typically a Freon refrigerant, however the invention can 10 easily be adapted for use with recirculating glycol.

WO 2009/086589 PCT/AU2009/000002 3 The coolant tubes are arranged in a helical pattern through the cold zone. The distance between the tubes is varied to control the rate of heat transfer from the coolant into the solid material of the cold zone. In the preferred embodiment the distance between adjacent tubes is between 3 and 10 mm. 5 The diameter of the coolant tubes used in the cold zone for transfer of cold from the coolant to the cold zone is selected based on the energy requirement of the system. Typically the range of tube diameters would be from 6 to 13 mm. The distance between the tubes/coils in the beverage line is varied to control the rate of heat transfer from the designated zone into the beverage. In the preferred 10 embodiment the distance between adjacent tubes is from 3 to 8 mm. The diameter of the beverage tubes used in the designated zone for transfer of heat from the beverage to the solid material is also selected based on the energy requirements of the system. Typically, the diameter may be between 7 to 11 mm. The distance between the coolant tubes located in the cold zone and the 15 beverage tubes located in the designated zone affects the heat flow between the two defined solid areas. The preferred distance is from 2 to 6 mm. This allows for predetermined heat transfer effects with in the solid to facilitate the heat transfer from the coolant to the solid and then across the solid and into the beverage. 20 The relationship between the plane of the beverage tube coils and the coolant tube coils ("the angle between the tubes") is important in maximising the heat transfer rate across the solid. Adjusting the angle controls the heat transfer rate across the solid. In a preferred embodiment this angle is between 80 and 110 degrees, however the angle is adjustable 25 between 15 and 120 degrees. The angle provides three dimensional heat flux within the solid areas and acts as a means of inducing turbulence to the heat flow through the solid areas and maximising the available transfer of cold through the system. The efficiency control that is available through the present invention allows for 30 cooling of beer to precise temperatures and even temperatures close to freezing point, using direct expanded Freon refrigeration methods. The present invention allows for a complete system including the refrigeration equipment to be packaged into a small area, such as is available under bars and dispensing counters etc., which removes the need for large installations and the 35 associated costs and maintenance of the same.

WO 2009/086589 PCT/AU2009/000002 4 The present invention may also eliminate or ameliorate the problems associated with freezing of subzero beverages which has limited the dispensing of low alcohol beverages at temperatures less that 0 degrees C using existing heat exchanger systems. There may be a plurality of beverage lines in the designated zone. There may 5 also be a plurality of coolant lines in the cold zone. The cold zone may include more than one coolant line, for example two coolant lines in parallel, or two coolant lines in series. In one embodiment one or more additional lines may pass through the first coil. The additional lines may include one or more lines for cooling glycol. Alternatively 10 the additional lines may include one or more lines for pre-chilling soft drinks, soda or the like. The additional lines are generally located in a central zone inside the inner cold zone. The ratio of the central zone to the inner cold zone to the outer zone is typically about 150: 100: 150. 15 Brief Description of the Drawings A specific embodiment of the present invention will now be described, by way of example only, and with reference to the accompanying drawings, in which: Figure 1 is a schematic view of an embodiment of a solid block heat exchanger 20 embodying the invention; Figure 2 is a schematic view of part of the heat exchanger illustrating the gaps between the tubes in the beverage lines; Figure 3 is a schematic view of part of the heat exchanger illustrating the gaps between the tubes in the coolant lines; 25 Figure 4 is a schematic view illustrating the concepts of the inner cold zone and the designated zone; Figure 5 is a schematic view illustrating a variant of the heat exchanger of Figures 1 to 4 in which there are two parallel beverage lines; Figure 6 is a schematic view illustrating a yet further embodiment of a heat 30 exchanger in which there are two coolant lines in series; Figure 7 is a schematic view of a variant of the solid block heat exchanger of Figures 1 to 4 in which the locations of the cold zone and cooling zones are reversed. Figure 8 is a schematic view illustrating a variant of the heat exchanger of Figures 1 to 4 in which there is and additional cooling zone; and 35 Figure 9 is a schematic view of part of the heat exchanger of Figure 8.

WO 2009/086589 PCT/AU2009/000002 5 Detailed Description of a Preferred Embodiment Referring to the drawings Figure 1 shows a solid block heat exchanger 10 comprising a first coolant line or tube (typically formed from stainless steel) in the form of a "helical" coil arrangement 11 having a plurality of turns/coils. As shown the 5 coils are generally rectangular in plan view having semi-circular curved ends separated by straight lengths of tubing. However other coil shapes could be used. This coil arrangement locates generally within an cold zone 12 of the heat exchanger 10 within a rectangular box shaped volume also shown in Figure 4. In this embodiment, the coil 11 is an inner coil as, extending around the outside of the coil 10 arrangement 11 is a second "helical" coil arrangement 13 (also typically formed from stainless steel tubes) which in use carries beverage, typically beer, or other carbonated alcoholic drink of a similar alcohol content to beer. As shown, the coils are generally rectangular in plan view having semi-circular curved ends separated by straight lengths of tubing. Again, other coil shapes could be 15 used. This "outer" coil arrangement locates in a zone 14 (the designated cooling zone) outside of the cold zone 12 of the heat exchanger and between that cold zone 12 and the exterior of the heat exchanger. The heat exchanger 10 is formed by locating the coils 11 and 13 in a rectangular 20 mould in the arrangement shown and pouring molten aluminium over the coils to form a solid block 15. Such casting techniques are well known for forming solid block heat exchangers and accordingly will not be described in detail herein. When cast, the open ends of the coils 11 and 13 form coolant inlets Ila and coolant outlets 11 b, and beverage inlets 13a and beverage outlets 13b, respectively. 25 The ratio of the volume of the two zones 12, 14 within the solid block is an important relationship when dispensing beer at critical temperatures, often as low as 2C. In a preferred embodiment the volume ratio of the designated beverage cooling zone 14 to the cold zone 12 is about 150:100. In use, the cold zone 12 or core acts as a thermal storage of energy. This thermal 30 storage is used to maintain controlled beverage outlet temperatures to avoid the fluctuations that are typical with the heat exchangers described in the prior art. The distance between the coils of the coolant coil arrangement may be varied to control the rate of heat transfer from the coolant into the solid core. With reference to Figure 3, in the preferred embodiment the distance "b" between the exteriors of the 35 tubes is between 3 and 10 mm.

WO 2009/086589 PCT/AU2009/000002 6 The diameter of the tubes used in the coolant coil for transfer of cold from the coolant to the cold zone is selected based on the energy requirement of the system. Typically, the diameter range would range between 6 and 13 mm. With reference to Figure 2, the distance "a" between the tubes in the beverage 5 coil arrangement 13 is varied to control the rate of heat transfer from the beverage into the defined cold zone 12. Typically the distance between the tubes is from 3 to 8 mm. The diameter of the tubes used in the designated cooling zone for transfer of cold from the solid to the beverage is also selected based on the energy requirement of the system. Typically the diameter range for the beverage line tubes would be between 10 7 and ll mm. The distance between the coolant tubes located in the cold zone and the beverage tubes located in the designated zone is a significant factor in determining the heat flow between the two defined solid areas. With reference to Figure 3, the preferred distance "c" is between 2 and 6 mm. 15 This allows for predetermined heat transfer effects within the solid to facilitate the heat transfer from the cold zone 12 to the coolant and also from the beverage into the solid. The relationship between the plane of the beverage tube coils and the coolant tube coils ("the angle between the tubes") is important in maximising the heat transfer 20 rate across the solid. Adjusting the angle controls the heat transfer rate across the solid. As shown in the described embodiment the angle between the plane of the coils in the coolant coil and the beverage coil is 90*. It is preferred that the angle is between 80 and 110 degrees, however the angle may be anywhere between 15 and 120 degrees. 25 The angle provides three dimensional heat flux within the solid areas and acts as a means of inducing turbulence to the heat flow through the solid areas and maximising the available transfer of cold through the system. Although the foregoing describes the beverage being dispensed as being alcoholic, it will be appreciated that the system may also be used to dispense other 30 beverages, particularly soft drinks, such as sodas and the like. Although the above describes a heat exchanger having a single beverage line, and single coolant line, it will be appreciated that more than one beverage line may be provided in the designated cooling zone 14 and more than one coolant line in the cold zone 12.

WO 2009/086589 PCT/AU2009/000002 7 For example, Figure 5 shows a variant 110 of the heat exchanger of Figures 1 to 4 in which there is a second beverage line 113 running parallel to the first beverage line 13. Figure 6 shows a further variant 210 in which there are two coolant lines "in 5 series" defining the (inner) cold zone 12. A first coolant line 213 comprises a helical coil and a coolant inlet 213a and a coolant outlet 213b and defines one part 12a of the inner cold zone 12. A second coolant line 223 following on in series from the first coolant line, comprises a helical coil and a coolant inlet 223a and a coolant outlet 223b and defines the other part 12b of the inner cold zone 12. The coolant inlet 223a is on 10 the opposite side of the block 210 to the coolant outlet 213b of the first coolant line. Although in the preferred embodiment, as described above, the cold zone 12 is inside the designated beverage cooling zone 14 which has the beverage lines passing though it, it is possible to manufacture a heat exchanger in which the location of the coolant tube coils 311 and beverage line 313 coils are reversed, so that the cold zone 15 312 lies outside the beverage coils 313. In this embodiment, the ratio of the volume of the cold zone 312 to the beverage line zone 314 remains 100::150, and the coolant and beverage pipe dimensions and spacings remain in the ranges described above as does the relationship between the plane of the beverage tube coils and the coolant tube coils. In a typical embodiment the angle is 900 as shown in Figure 7, although this angle can 20 be varied between 80 and 110 degrees, even between 15 and 120 degrees. It is also possible for additional lines to be present in the centre of the cold core block forming a third or central zone. This is illustrated in Figures 8 and 9, where the central zone is referenced 20 and shown as rectangular parallelepiped in broken lines. With reference to Figure 6 also, the central zone is used for cooling as is the outer 25 designated zone. It may have one or more lines 22 passing through it - see Figure 6. In one embodiment the line 22 may be a glycol line for cooling glycol, used to cool a beer transfer conduit, and/or beer font or the like. In an alternative application there may be up to twenty additional lines 22 for pre-chilling e.g. soda or soft drinks. As shown in Figures 8 and 9, where the central zone is present and used for 30 cooling, the volume ratio of the central zone 20 to the inner cold zone 12 to the outer zone 14 is typically about 150: 100: 150. It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the scope of the invention as broadly described. 35 The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

1. A heat exchanger comprising a first line and a second line embedded in a solid block of a material having a high thermal conductivity with the first line in the form of 5 a first helical coil defining a plurality of turns, and the second line in the form of a second helical coil defining a plurality of turns and extending around the first coil, wherein the angle between a plane defined by a turn of the second coil and a plane defined by a turn of the first coil is between 15 and 120 degrees. 10

2. A heat exchanger as claimed in claim 1 wherein the first line is a coolant line and defines a cold zone in the centre of the block, with the volume outside the zone carrying the second line which is a beverage line defining a designated beverage cooling zone. 15

3. A heat exchanger as claimed in claim 1 wherein the first line is a beverage line and defines a designated cooling zone in the centre of the block, with the volume outside the zone carrying the second line which is a coolant line defining a designated cold zone outside the cooling zone. 20

4. A heat exchanger as claimed in any one of claims 2 to 3 wherein the volume ratio of the designated cooling zone to the cold zone is about 150:100.

5. A heat exchanger as claimed in any one of claims 2 to 4 wherein the distance between adjacent turns in the coolant line is between 3 and 10 mm. 25

6. A heat exchanger as claimed in any one of claims 2 to 5 wherein the coolant line comprises tubes having a diameter between 6 to 13 mm.

7. A heat exchanger as claimed in any one of claims 2 to 6 wherein the distance 30 between adjacent turns in the beverage line is from 3 to 8 mm.

8. A heat exchanger as claimed in claim 7 wherein the diameter of the tubes used in the beverage line is from 7 to 11 mm. 9

9. A heat exchanger as claimed in any one of claims 7 to 8 wherein the distance between the coolant tubes located in the cold zone and the beverage tubes located in the designated zone is from 2 to 6 mm. 5

10. A heat exchanger as claimed in any preceding claim wherein the angle between a plane defined by the second coil turns and a plane defined by the first coil turns is between 80 and 110 degrees.

11. A heat exchanger as claimed in any one of claims 2 to 10 wherein the coolant 10 line carries a Freon refrigerant.

12. A heat exchanger as claimed in any one of claims 2 to 11 wherein there are a plurality of beverage lines in the designated cooling zone. 15

13. A heat exchanger as claimed in any one of claims 2 to 12 wherein there are a plurality of coolant lines in the cold zone.

14. A heat exchanger as claimed in any one of claims I to 2, or claims 5 to 13 when dependent on claims 1 or 2, wherein one or more additional lines pass through the first 20 coil.

15. A heat exchanger as claimed in claim 14 wherein the additional lines include one or more lines for cooling a secondary cooling media. 25

16. A heat exchanger as claimed in claim 14 wherein the additional lines include one or more lines for cooling soft drinks, soda or the like.

17. A heat exchanger as claimed in any one of claims 14 to 16 wherein the additional lines are generally located in a central zone inside the cold zone. 30

18. A heat exchanger as claimed in claim 17 wherein the volume ratio of the central zone to the cold zone to the designated zone is about 150: 100: 150.

19. A heat exchanger substantially as hereinbefore described with reference to 35 Figures 1 to 4, or Figure 5, or Figure 6, or Figure 7 or Figures 8 and 9 of the accompanying drawings.