GB1598097A

GB1598097A - Absorption refrigeration unit

Info

Publication number: GB1598097A
Application number: GB5282577A
Authority: GB
Original assignee: Benteler Deustchland GmbH
Current assignee: Benteler Deustchland GmbH
Priority date: 1977-12-19
Filing date: 1977-12-19
Publication date: 1981-09-16

Description

(54) ABSORPTION REFRIGERATION UNIT (71) We, BENTELER-WERKE AKTIEN GESELLSCHAFT, a Company of the Federal Republic of Germany, of 4794 Schloss Neuhaus, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a continuously operable absorption refrigeration unit for cooling water, drinks and draught beer, the unit comprising a metal container for receiving the material to be cooled and an evaporator tube associated with the metal container.

Absorption refrigeration units of this kind are known and operate quietly.

An object of the invention is to improve the efficiency of the aforementioned continuously operable absorption units for cooling water, drinks and draught beer.

Accordingly, the present invention provides a continuously operable absorption refrigeration unit for cooling water, drinks and draught beer, the unit comprising a metal container for receiving the material to be cooled and an associated evaporator tube for cooling the container, in which unit the evaporator tube has a flat oval cross-section presenting a flat portion which operatively engages the container wall and the area of contact between the evaporator tube and the container is increased by a layer of contact material applied to the wall of the container so that the evaporator tube is embedded in the contact material.

The evaporator tube of flat, oval crosssection is cheap to manufacture and ensures efficient heat transfer, since its flat portion bears on the metal container and is embedded in the layer of contact material.

In an advantageous embodiment of the invention, the evaporator tube and/or an absorber tube of the unit is provided with steel wire gauze adjacent the inner surface of the tube. This capillary-forming means enhances evaporation in the evaporator tube and/or condensation in the absorber tube.

Cold-storage means may be associated with the container and, in the case of a double-walled container, may be contained within the space between the walls.

According to another preferred feature of the invention a condenser of the absorption unit extends approximately at right angles to a boiler of the unit or to a gas and vapour tube extending from the boiler. The condenser may be in the form of a finned tube, such as a Trufin (Registered Trade Mark) tube having aluminium tube walls and fins.

Alternatively, the condenser may be a coiled tube which, in the upper region of the container, is separated therefrom by ther mally insulating material and is accessible to a flow of external air. Advantageously, a cooling plate is provided, and surrounds the sides of the coiled condenser tube.

An absorption unit embodying the invention is compact and light-weight.

In order that the invention may be readily understood, embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which: FIGURE 1 shows an absorption refrigeration unit embodying the invention and comprising a container (shown in vertical section) for holding a material to be cooled; FIGURE 2 is a front view of the refrigeration unit of Figure 1, without the container; FIGURE 3 shows, in cross-section, a first container and evaporator arrangement for incorporation in the refrigeration unit of Figures 1 and 2; FIGURE 4 is a similar view to Figure 3, showing a second container and evaporator arrangement; FIGURE 5 shows an absorption refrigeration unit with a container suitable for cooling draught beer; FIGURE 6 is a plan view of the absorption refrigeration unit of Figure 5;; FIGURE 7 shows, in cross-section, a sump of a gas heat exchanger of the unit which drains into a storage tank; FIGURE 8 is a section along line X-X in Figure 7; FIGURE 9 shows an absorber tube, partly in section; and FIGURE 10 is a view in the direction of arrows X11--X11 in Figure 9.

Figure 1 shows an absorption refrigeration unit comprising a boiler 1, a gas and vapour pipe 2, a condenser 3, an evaporator 4, an absorber 5 and a storage tank 6. Tank 6 is connected to boiler 1 by a pipe 7.

Boiler 1 can be heated electrically or by LP gas or kerosene.

The material to be cooled is held in a container 8 which is made of light metal, preferably aluminium, and is surrounded by thermal insulation 9, covering the side wall and the bottom of container 8. The insulation also partly screens from the container the heat-radiating parts of the absorption unit, i.e. condenser 3 and absorber 5, but allows the necessary heat exchange to occur between the condenser and absorber and the external air.

As shown in Figures 1 and 2, the device is compact and the heat-radiating parts of the absorption unit are at the back of the unit, so that heat can be radiated outwards when the device is incorporated in a housing with an open back.

In the embodiment of Figures 1 and 2, the condenser 3 extends approximately at right angles to the boiler 1 and the gas and vapour pipe 2. The condenser tubes may be Trufin (Registered Trade Mark) tubes equipped with aluminium tube walls and fins. Container 8 has an outlet 10 for withdrawing cooled material from the bottom 11 of container 8. A second outlet 12 is connected to an internal feed pipe 13. A supply bottle (not shown) is placed upside-down at the top end of pipe 13, so that drinks can be withdrawn through the outlet 12 from the bottle.

Figure 3 shows first container and evaporator arrangement without thermal insulation 9. The side wall 14 of the container 8 has several turns of flat oval evaporator tube 15 therearound. One flat surface of tube 15 is operatively secured to wall 14, thus ensuring optimum heat transfer from the container wall 14 to the wall of the evaporator tube 15, or optimum cold transfer from tube 15 to container wall 14. As shown in Figures 3 and 4, a layer of contact material 1 6a which is a good conductor of heat is applied to the wall of the container so that the evaporator tubes is embedded in the contact material and the area of contact between the wall 14 and the tube 15 is increased.

In a second container and evaporator arrangement illustrated in Figure 4, the cooled material is enclosed in a doublewalled container 8a. The internal wall is of light metal, preferably aluminium, whereas the outer jacket 16 can be made e.g. of steel.

As shown in Figure 4, the turns of the evaporator tube 15 are permanently secured to the outerjacket 18 of the container and are embedded in a layer of contact material. A cold-transmitting and storage medium is poured into the space between the inner container and the outer jacket 16.

Figures 5 and 6 show an absorption refigeration unit embodying the invention having a storage container suitable for cooling draught beer.

A beer keg, preferably a substantially cylindrical metal vessel is placed in a container 18 which is surrounded by the turns of a coiled evaporator tube 19 having a flat oval cross-section. The evaporator tube 19 is enclosed and sealed by thermal insulation 20.

In the embodiment of Figures 5 and 6 the condenser is a coiled tube 21 which is disposed, in the neighbourhood of the top edge of the container 18 and is isolated from the container by thermal insulating material whilst being accessible to external air. A heat conducting plate 22 extends around the periphery of the coil 21.

In the present embodiment, storage tank 23 of the absorption unit is disposed below the bottom of container 18. The absorber tube coil 24 surrounds the container 18, leaving space for insulation 20 between container 18 and coil 24, and providing for a flow of external air as before.

Figures 7 and 8 show means whereby a sump of the gas heat exchanger is drained into the storage tank.

A gas heat exchanger 26 surrounds the descending portion of an evaporator tube 25 extending from evaporator 4 or 19 to the storage tank 6 or 23. A drainage tube 27 is sealingly disposed between the external wall of the tube 25 and the internal wall of the tube of the gas-heat exchanger 26, and the portion of the gas heat exchanger tube surrounding the evaporator and drainage tubes is sealed off, so that the sump of the gas heat exchanger can drain into the storage tank. As shown in Figures 7 and 8 the end portion of the tube 25 is compressed in order to accommodate the tube 27.

Figures 9 and 10 show an absorber tube in which steel wire gauze 28 is inserted adjacent the inner wall to form a capillary means which enhances condensation. The same feature can be applied to the evaporator tube, to enhance evaporation therein.

Attention is hereby drawn to our Copending Patent Application No. 21076/80 which also relates to an absorption refrigeration unit and which has been divided out of the present Application.

WHAT WE CLAIM IS:- 1. A continuously operable absorption refrigeration unit for cooling water, drinks and draught beer, the unit comprising a metal container for receiving the material to be cooled and an associated evaporator tube for cooling the container, in which unit the evaporator tube has a flat oval cross-section presenting a flat portion which operatively

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Figure 1 shows an absorption refrigeration unit comprising a boiler 1, a gas and vapour pipe 2, a condenser 3, an evaporator 4, an absorber 5 and a storage tank 6. Tank 6 is connected to boiler 1 by a pipe 7. Boiler 1 can be heated electrically or by LP gas or kerosene. The material to be cooled is held in a container 8 which is made of light metal, preferably aluminium, and is surrounded by thermal insulation 9, covering the side wall and the bottom of container 8. The insulation also partly screens from the container the heat-radiating parts of the absorption unit, i.e. condenser 3 and absorber 5, but allows the necessary heat exchange to occur between the condenser and absorber and the external air. As shown in Figures 1 and 2, the device is compact and the heat-radiating parts of the absorption unit are at the back of the unit, so that heat can be radiated outwards when the device is incorporated in a housing with an open back. In the embodiment of Figures 1 and 2, the condenser 3 extends approximately at right angles to the boiler 1 and the gas and vapour pipe 2. The condenser tubes may be Trufin (Registered Trade Mark) tubes equipped with aluminium tube walls and fins. Container 8 has an outlet 10 for withdrawing cooled material from the bottom 11 of container 8. A second outlet 12 is connected to an internal feed pipe 13. A supply bottle (not shown) is placed upside-down at the top end of pipe 13, so that drinks can be withdrawn through the outlet 12 from the bottle. Figure 3 shows first container and evaporator arrangement without thermal insulation 9. The side wall 14 of the container 8 has several turns of flat oval evaporator tube 15 therearound. One flat surface of tube 15 is operatively secured to wall 14, thus ensuring optimum heat transfer from the container wall 14 to the wall of the evaporator tube 15, or optimum cold transfer from tube 15 to container wall 14. As shown in Figures 3 and 4, a layer of contact material 1 6a which is a good conductor of heat is applied to the wall of the container so that the evaporator tubes is embedded in the contact material and the area of contact between the wall 14 and the tube 15 is increased. In a second container and evaporator arrangement illustrated in Figure 4, the cooled material is enclosed in a doublewalled container 8a. The internal wall is of light metal, preferably aluminium, whereas the outer jacket 16 can be made e.g. of steel. As shown in Figure 4, the turns of the evaporator tube 15 are permanently secured to the outerjacket 18 of the container and are embedded in a layer of contact material. A cold-transmitting and storage medium is poured into the space between the inner container and the outer jacket 16. Figures 5 and 6 show an absorption refigeration unit embodying the invention having a storage container suitable for cooling draught beer. A beer keg, preferably a substantially cylindrical metal vessel is placed in a container 18 which is surrounded by the turns of a coiled evaporator tube 19 having a flat oval cross-section. The evaporator tube 19 is enclosed and sealed by thermal insulation 20. In the embodiment of Figures 5 and 6 the condenser is a coiled tube 21 which is disposed, in the neighbourhood of the top edge of the container 18 and is isolated from the container by thermal insulating material whilst being accessible to external air. A heat conducting plate 22 extends around the periphery of the coil 21. In the present embodiment, storage tank 23 of the absorption unit is disposed below the bottom of container 18. The absorber tube coil 24 surrounds the container 18, leaving space for insulation 20 between container 18 and coil 24, and providing for a flow of external air as before. Figures 7 and 8 show means whereby a sump of the gas heat exchanger is drained into the storage tank. A gas heat exchanger 26 surrounds the descending portion of an evaporator tube 25 extending from evaporator 4 or 19 to the storage tank 6 or 23. A drainage tube 27 is sealingly disposed between the external wall of the tube 25 and the internal wall of the tube of the gas-heat exchanger 26, and the portion of the gas heat exchanger tube surrounding the evaporator and drainage tubes is sealed off, so that the sump of the gas heat exchanger can drain into the storage tank. As shown in Figures 7 and 8 the end portion of the tube 25 is compressed in order to accommodate the tube 27. Figures 9 and 10 show an absorber tube in which steel wire gauze 28 is inserted adjacent the inner wall to form a capillary means which enhances condensation. The same feature can be applied to the evaporator tube, to enhance evaporation therein. Attention is hereby drawn to our Copending Patent Application No. 21076/80 which also relates to an absorption refrigeration unit and which has been divided out of the present Application. WHAT WE CLAIM IS:-

1. A continuously operable absorption refrigeration unit for cooling water, drinks and draught beer, the unit comprising a metal container for receiving the material to be cooled and an associated evaporator tube for cooling the container, in which unit the evaporator tube has a flat oval cross-section presenting a flat portion which operatively

engages the container wall and the area of contact between the evaporator tube and container is increased by a layer of contact material applied to the wall of the container so that the evaporator tube is embedded in the contact material.

2. A refrigeration unit according to claim 1, wherein the container is provided with cold-storage means.

3. A refrigeration unit according to claim 2, wherein the container is double-walled, the space between the walls containing a cold-transmitting and storing medium.

4. A refrigeration unit according to claim 3, wherein the evaporator tube is permanently secured to the outer jacket.

5. A refrigeration unit according to claim 3 or 4, wherein the outer jacket of the doublewalled container is made of steel.

6. A refrigeration unit according to any preceding claim, wherein the evaporator tube and/or an absorber tube is or are provided with steel wire gauze adjacent the inner surface of the tube.

7. A refrigeration unit according to any preceding claim, wherein an end portion of the evaporator tube extending to a storage tank of the unit is surrounded by a gas heat exchanger tube and drainage tube for draining off a sump into the storage tank is disposed between the exterior wall of the evaporator tube and the internal wall of the gas heat exchanger tube.

8. A refrigeration unit according to claim 7, wherein the end portion of the evaporator tube is compressed to accommodate the drainage tube and the portion of the gas heat exchanger tube surrounding the evaporator and drainage tubes is sealed off.

9. A refrigeration unit according to any preceding claim, wherein a condenser of the refrigeration unit extends approximately at right angles to a boiler of the unit or to a gas and vapour tube extending from the boiler,

10. A refrigeration unit according to claim 9, wherein the condenser is in the form of a finned tube.

11. A refrigeration unit according to any one of claims I to 8, wherein the condenser is in the form of a coiled tube which is located Jt the top edge of the container and is separated therefrom by thermal insulating material whilst being accessible to a flow of external air.

12. A refrigeration unit according to claim 11, wherein a heat conducting plate extends around the periphery of the coiled condenser tube and is accessible to a flow of external air.

13. A refrigeration unit according to any preceding claim, wherein the container has an outlet means for withdrawing cooled material at the bottom and a second outlet means is connected to an internal feed pipe associated with a storage bottle for withdrawing water or drinks from the bottle through the second outlet means.

14. An absorption refrigeration unit substantially as hereinbefore described with reference to Figures 1, 2 and 3 of the accompanying drawings.

15. An absorption refrigeration unit substantially as hereinbefore described with reference to Figures 1, 2 and 4 of the accompanying drawings.

16. An absorption refrigeration unit substantially as hereinbefore described with reference to Figure 3 or 4 and Figures 5 and 6 of the accompanying drawings.

17. An absorption refrigeration unit according to any one of claims 14 to 16, having an evaporator tube draining arrangement substantially as hereinbefore described with reference to Figures 7 and 8 of the accompanying drawings.

18. A absorption refrigeration unit according to any one of claims 14 to 17, having an evaporator and/or absorber tube construction substantially as hereinbefore described with reference to Figures 9 and 10 of the accompanying drawings.