Exchange arrangement for heat produced by gas combustion

Abstract

 The arrangement comprises a heater (18) with a condensation cavity (20); a boiler (2) with an evaporator (10); an outgoing and return communication circuit (24) between the evaporator (10) and each cavity (20) and a thermal fluid which may be vaporized in the evaporator (10) and which is condensable in the condensation cavities (20). In the evaporator (10), the circuit (24) and the cavities (20), further to the vaporizable fluid, there is a gas which is non-condensable at room temperature, preferably an inert gas and there is a chamber (38) for non-condensable gas and lines (40) for communicating the cavity (20) with the non-condensable gas chamber (38).

Description

[0001] The invention relates to an exchange arrangement for heat produced by gas combustion, applicable particularly for cooking and which comprises: at least one heater in which there is a condensation cavity; a boiler with a burner for gas combustion and with an evaporator adapted to receive heat produced by said combustion; a closed circuit establishing outgoing and return communication between the evaporator and each of the condensation cavities, said circuit comprising first return lines, each of which is provided with a first port in one of said condensation cavities; and a thermal fluid which may be vaporized in said evaporator, adapted to flow along at least a part of said circuit and which may be condensed in said condensation cavities.

[0002] The arrangements to which the foregoing paragraph relates have been described in Spanish patent of invention 8801114; particularly in their culinary applications, they avoid the existence of flames on the cooker hob, achieving the avoidance of an undesired propagation of said flames. Likewise, with the combustion being removed from the site of immediate use of the heat, it facilitates good channelling and exhausting of the combustion gases and furthermore there is a saving in gas consumption.

[0003] For good operation of these arrangements, once they have been charged with the required amount of thermal fluid, a vacuum is formed. In the consequent start up in which vaporization and subsequent condensation takes place, a stabilization process occurs, which is relatively slow and noisy.

[0004] To overcome this slowness and reduce the noises, the invention provides an arrangement of the type first mentioned above, which is characterized in that in said evaporator, said circuit and said cavities, further to the vaporizable fluid, either in liquid or in gas phase, there is substantially only a gas which is non-condensable at room temperature, preferably an inert gas and in that there is at least one chamber for the non-condensable gas and a network of lines for communication of each cavity with at least one chamber for non-condensable gas, said network comprising second return lines, each of which is provided with a second port in one of said condensation cavities.

[0005] Preferably according to the invention, in each condensation cavity the first port is at a lower level than the second port.

[0006] Further advantages and features of the invention will be appreciated from the following description in which without any limiting nature there is described a preferred embodiment of the invention, with reference to the accompanying drawing.

[0007] The Figure is a schematic view, partly in perspective and partly in cross section of the heat exchange arrangement of the invention.

[0008] The arrangement is based on the combustion of a gas which accedes to a boiler 2 through a pipe 4 which, inside the boiler 2, reaches a burner 6 provided with orifices 8 through which the gas may flow to form flames. The burner 6 may be of any known type and may both have the linear form shown schematically and be of any other adequate configuration.

[0009] Also within the boiler 2 in a suitable position for receiving a maximum amount of heat generated by the gas combustion, there is an evaporator 10 preferably comprising a plurality of plates 12 or similar elements adapted to be heated; said plates are traversed by a pipe 14. The boiler 2 is provided with a stack 16, also shown schematically cut away, which is adapted duly to exhaust the combustion gases.

[0010] Furthermore, the device comprises at least one heater 18 in which there is a condensation cavity 20; preferably the upper plate 22 enclosing the cavity 20 is flush with the upper surface of the heater. Nevertheless, the invention also comprises the case, not shown, of pairs of like cavities forming therebetween an oven where the products to be heated or the foodstuffs to be cooked may be placed.

[0011] The arrangement also comprises a closed circuit 24 establishing outgoing and return communication between the evaporator 10 and each of the condensation cavities 20; the circuit comprises outgoing lines 26 and 28 (the latter shown only in part) and first return lines 30, 32 (the latter also shown only in part). Each first return line is provided with a first port 34 located in a condensation cavity 20.

[0012] There is also a thermal fluid occupying the evaporator 10 and which is heated by the burner 6; the fluid is adapted to flow along the whole or part of the closed circuit 24, the flow being regulated possibly by valves 36.

[0013] The thermal fluid is vaporized by the action of the burner 6 and on reaching certain cavities 20 selected by operation of the appropriate valves 36, gives up its heat and condenses and in the liquid phase it flows through the first port 34 and returns to the burner 6 along the line 30.

[0014] For better operation of this known arrangement, once the required amount of thermal fluid has been charged, a vacuum is formed by removal of the air. Nevertheless, as stated above, drawbacks arise, since the start up of the installation produces a relatively slow and undesirably noisy stabilization process.

[0015] To overcome such drawbacks, after the said vacuum has been formed, a gas which is non-condensable at room temperature, preferably an inert gas and more preferably nitrogen or dehydrated air is introduced.

[0016] Nevertheless, during the start up phase, it is necessary for the said gas to be removed from the places where heat transfer occurs, i.e. from the evaporator 10 and the condensation cavities 20 and for it to be stored in such a way as not to hinder operation of the circuit.

[0017] To this end, the invention contemplates the existence of a chamber 38 for non-condensable gas and a network of lines for placing each cavity 20 in communication with at least one chamber 38. This network of lines comprises second return lines 40, each of which is provided with a second port 42 in the corresponding condensation cavity 20.

[0018] As said above, it is necessary for the non-condensable gas to be stored in the gas chamber or chambers 38. To such end, to avoid joint return flow of the thermal fluid and the non-condensable gas, it is contemplated that in each condensation cavity 20 the first port 34 should be at a lower level than the second port 42. In this way, the condensed thermal fluid reaches the first port 34 and returns substantially independently of the gas.

[0019] Preferably the bottom 44 of a condensation cavity 20 slopes down to a lower portion where the first port 34 is located.

[0020] A further preferred feature of the invention which may be alternative to or simultaneous with the feature described in the foregoing paragraph, is that all or some of the second ports 42 are surrounded by a lip 46 extending upwardly from the bottom 44 of the condensation cavity 20. In other cases, it is contemplated that the second port 42 should be in a side or upper wall of the condensation cavity 20.

[0021] In this way, the displacement of the non-condensable gas, initially stored in the cavity 20, by the vaporized thermal fluid and storage thereof in the chamber 38 is promoted.

[0022] Preferably there is a communication between each gas chamber 38 and the evaporator 10 and this communication is useful for the recirculation of the thermal fluid which may have entered the chamber 38. Nevertheless, this communication is provided with means such as a siphon 48 to prevent gas flow.

[0023] The only objective of the reference symbols inserted after the technical features mentioned in the claims is to facilitate the understanding of the latter and it no way limits the scope thereof.

Claims

1. An exchange arrangement for heat produced by gas combustion, applicable particularly for cooking and which comprises: at least one heater (18) in which there is a condensation cavity (20); a boiler (2) with a burner (6) for gas combustion and with an evaporator (10) adapted to receive heat produced by said combustion; a closed circuit (24) establishing outgoing and return communication between the evaporator (10) and each of the condensation cavities (20), said circuit comprising first return lines (30), each of which is provided with a first port (34) in one of said condensation cavities (20); and a thermal fluid which may be vaporized in said evaporator (10), adapted to flow along at least a part of said circuit (24) and which may be condensed in said condensation cavities (20), characterized in that in said evaporator (10), said circuit (24) and said cavities (20), further to the vaporizable fluid, either in liquid or in gas phase, there is substantially only a gas which is non-condensable at room temperature, preferably an inert gas and in that there is at least one chamber (38) for the non-condensable gas and a network of lines (40) for communication of each cavity (20) with at least one chamber (38) for non-condensable gas, said network comprising second return lines (40), each of which is provided with a second port (42) in one of said condensation cavities (20).

2. The arrangement of claim 1, characterized in that in each condensation cavity (20), the first port (34) is at a lower level than said second port (42).

3. The arrangement of claim 2, characterized in that at least one condensation cavity (20) has a bottom (44) sloping towards a lower region in which said first port (34) is located.

4. The arrangement of any one of claims 1 to 3, characterized in that at least one of said second ports (42) is surrounded by a lip (46) extebnding upwardly from the bottom (44) of the condensation cavity (20).

5. The arrangement of claim 2, characterized in that in at least one of said condensation cavities (20) there is a second port (42) is situated in a side or upper wall.

6. The arrangement of any one of claims 1 to 5, characterized in that there is a communication with each non-condensable gas chamber (38) with said evaporator (10) and said communication comprises means to prevent the flow of gas.

7. The arrangement of claim 6, characterized in that said means comprise a siphon (48).

8. The arrangement of any one of claims 1 to 7, characterized in that said inert gas is nitrogen.

9. The arrangement of any one of claims 1 to 7, characterized in that said non-condensable gas is dehydrated air.

Drawing