Thermosyphon radiators

Abstract: A thermosyphon radiator comprising a sealed panel containing a reservoir of water in a lowermost part of the panel and a heating member, e.g. a hot water pipe, extending through the lowermost part of the panel, the member being at least partially immersed in the liquid.

Description: This invention relates to thermosyphon radiators of the type claimed in the preamble of claim 1. Thermosyphon radiators are the type in which a vaporising liquid contained within a sealed panel is heated, in use, by a heated pipe extending with clearance through the lowermost part of the panel. The liquid is vaporised and travels upwardly to the colder upper parts of the radiator where the vapour condenses giving out its latent heat of vaporisation into the radiator surface which is then convected to the air in a space, e.g. a room. In one such type of radiator described in one embodiment of GB-A-2099980, the heating pipe is provided with a wick means in the form of a metal gauze depending therefrom, the pipe itself lying wholly above the level of a reservoir of the liquid. The wick dips into the liquid and continuously supplies a thin film of the liquid around the pipe for evaporation by the heated pipe to the upper parts of the radiator where the vapour condenses to give out its latent heat of evaporation to the radiator surface. The condensed liquid then trickles down the inside of the radiator and returns to its reservoir. One problem with this type of system is that it is necessary to provide a wick to impart the necessary capillary action to draw the liquid up to the pipe increasing the cost of system. It is therefore an object of the present invention to provide a thermosyphon radiator without a wick. According to the present invention, we provide a thermosyphon radiator as defined in claim 1. The vaporising liquid may be water, but ammonia, methanol or acetone are viable alternatives. The member is a pipe for carrying a second liquid. The pipe is covered externally with a fine metallic mesh, compacted metallic wool, fibrous material or a polymeric coating. Alternatively the pipe is coated with a porous material such as a sintered metallic or ceramic material. Conveniently the pipe is immersed in the vaporising fluid, e.g. water to a depth of no less than three-quarters of the diameter of the pipe. The panel may be of roll-bonded aluminium, which may be pretreated to inhibit corrosion. The panel may be hermetically sealed and preferably is evacuated except for the vaporising liquid. The radiator may be externally finned to increase the heat transfer to the space to be heated. Suitably the water is distilled water and may contain corrosion inhibitors. An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which:- Figure 1 is a perspective view of the radiator, and Figure 2 is a cross-sectional view of the radiator. Referring to the drawings, the radiator comprises a conventional sealed panel 1 having a lowermost part 2 through which a pipe 3 enters at one side 4 and leaves by the other side 5. The pipe 3 may be a hot water pipe supplied with hot water from a boiler (not shown) and is joined to the panel 1. The panel 1 itself is hermetically sealed and evacuated except for the vaporising liquid. The lowermost part 2 of the panel contains a reservoir 6 of water (Figure 2) and the pipe 3, which as shown extends with clearance through the internal panel sides formed by the lowermost part 2, is immersed in the water to a depth of no less than three-quarters of the diameter of the pipe 3. The radiator is filled and then sealed for life by means of a preformed opening 7 at the bottom of the radiator. The opening is closed by using heat and pressure to bond the metal surfaces together. When hot water at near boiling point passes through the pipe 3 the water 6 begins to boil extracting latent heat from the pipe 3 and the vapour so produced rises to the upper part of the radiator panel where it condenses on the inside surface to give out its latent heat to the panel surface and therefore the space to be heated. The condensate then trickles back down to the reservoir 6. While not shown the external surface of the radiator panel 1 may be finned to assist heat transfer to the space to be heated.

Claims: A thermosyphon radiator comprising a sealed panel (1) containing a reservoir of vaporising liquid in a lowermost part (2) of the panel and a heating member (3) extending through the lowermost part (2) of the panel with clearance, the member (3) being at least partially immersed in the vaporising liquid, in which the member is a pipe (3) for carrying a second liquid characterised in that the pipe is covered externally with a fine metallic mesh, compacted metallic wool, fibrous material or polymeric coating, or the pipe is coated with a porous material. A thermosyphon radiator as claimed in claim 1 in which the liquid comprises either water, ammonia, methanol or acetone. A radiator as claimed in claim 1 in which the liquid is water. A radiator as claimed in claim 3 in which the pipe (3) is immersed in the vaporising liquid to a depth of no less than three-quarters of the diameter of the pipe. A radiator as claimed in any of the preceding claims in which the panel (1) is of roll-bonded aluminium. A radiator as claimed in any or the preceding claims in which the panel (1) is hermetically sealed. A radiator as claimed in any of the preceding claims in which the panel (1) is evacuated except for the vaporising liquid. A radiator as claimed in any of claims 2 to 6 in which the water is distilled water. A radiator as claimed in any of the preceding claims in which the panel (1) is externally finned.

Inventors: SHIRET ALAN REGINALD, TAYALI NKOLE ENOCK, SHIRET, ALAN REGINALD, TAYALI, NKOLE ENOCK
Applicants: BRITISH GAS PLC, BG PLC
Application year: 1995
Main classification: F28D5
IPC codes: F28D15, F28D1