GB1561877A

GB1561877A - Refrigerating apparatus

Info

Publication number: GB1561877A
Application number: GB3152/78A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-03-05
Filing date: 1978-01-26
Publication date: 1980-03-05
Also published as: IT7820459A0; DE2709670B2; FR2382658B1; FR2382658A1; IT1094245B; DE2709670A1; DE2709670C3

Description

(54) IMPROVEMENTS IN OR RELATING TO REFRIGERATING APPARATUS (71) We, BOSCH-SIEMENS HAUSGERATE GMBH with seat in Stuttgart, of Hochstrasse 17, 8000 München 80, Federal Republic of Germany, a limited liability company organised under the laws of the 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: The present invention relates to refrigerating apparatus.

Refrigerating apparatus, especially a refrigerating cabinet having compartments at different temperatures, is provided with a heat-insulated housing and a refrigerating machine, the evaporator of which cools the compartment or possibly compartments of lowest operating temperature, such as for example a deep-freezing compartment, while at least one compartment of higher temperature is cooled by a heat pipe extending between the compartments.

According to the invention, there is provided a refrigerating apparatus comprising a heat-insulated housing provided with a first compartment to be maintained at a first temperature and at least one further compartment to be maintained at a second temperature higher than the first temperature, a heat pipe containing a working fluid and having a working section extending between the two compartments, the heat pipe being in thermal contact with an evaporator in the first compartment, a heatable container housing an adsorption medium for a gas which will not react with the working fluid, the container being located externally of the housing and being in open communication with the heat pipe, thermal energy transferred by the heat pipe being regulable by thermal expulsion of the non-reactive gas from the adsorption medium, and heater means to heat the container in dependence upon the temperature in the further compartment.

Preferably, the non-reactive gas is hydrogen.

Advantageously, the evaporator and the heat pipe are provided in a roller-welded plate with two channel system separated from each other.

Using a heatable container arranged externally of the refrigerating apparatus, only a small proportion of the heat energy required for the regulation of the heat pipe enters the part of the refrigerating apparatus enclosed by the heat insulation so that the energy balance of the apparatus is hardly influenced at all by the heat energy required for the expulsion of the nonreactive gas.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawing in which: - Fig. 1 shows a refrigerating apparatus embodying the invention; and Fig. 2 shows in three-dimensional illustration, an evaporator plate produced by a roller-welding process with an integrated heat pipe.

Referring to the drawing, Fig. 1 shows a two-temperature refrigerating cabinet 10 equipped with a heat-insulated housing 11, in which a deep-freezing compartment 12 and a main refrigerating compartment 13 are arranged one above the other and are separated by a heat-insulated intermediate wall 14. The deep-freezing compartment 12 lying at the top as well as the main refrigerating compartment 13 lying thereunder have separate heat-insulated doors 15 and 15', respectively.

The two-temperature refrigerating cabinet 10 is equipped with a refrigerating machine (not shown), which is operated by a single compressor unit and in the coolant circuit of which, apart from a condenser, lies an evaporator 16 associated with the deep-freezing compartment 12. The cooling machine is controlled by a thermostat (not shown), the sensor of which is arranged in the deep-freezing compartment 12.

A heat pipe 17 containing a working fluid extends out of the deep-freezing compartment 12 through the heat-insulated intermediate wall 14 downwardly into the main refrigerating compartment 13. The upper section of the heat pipe 17 where heat is given off, bears in heat-exchanging contact against the evaporator 16 of the deep-freezing compartment 12. While its heat-absorbing lower section extends into the main refrigerating compartment 13. For better heat exchange, the lower section of the heat pipe 17 may be equipped with cooling ribs 18.

A heatable container 20, which is equipped with a heating device 21, illustrated schematically as an electric coil, is connected by a connecting pipe 19 to the heat pipe 17 in its middle section lying in the region of the heat-insulated intermediate wall 14. The heatable container 20 is arranged externally of the space enclosed by the heat insulation, and its entire surface is exposed to the room air surrounding the refrigerating cabinet. The interior of the container 20 contains an adsorption medium shown schematically as projections 22, for a gas which will not react with the working fluid.

The heating device 21 is connected to a current network by way of feed conductors 23 and 24. Lying in the conductor branch 23 is a thermostat switch 25, which switches in dependence upon the temperature in the main refrigerating compartment 13 and which for this purpose is equipped with a heat sensor 26, which bears against the lower section of the heat pipe 17 extending into the normal refrigerating compartment.

The thermostat switch 25 can however also be constructed, as indicated by dotdashed lines, with a heat sensor 26' freely arranged in the useful space of the main refrigerating compartment 13 and in this case picks up the air temperature therein.

In Fig. 2, an evaporator 16' for the deep freezing compartment and a heat pipe 17' are integrated in a contiguous roller-welded plate provided with two channel systems separated one from the other. This plate is shaped by incising and bending in such a manner that its upper section forms the Ushaped evaporator 16', while its lower section associated with the rear wall of the normal refrigerating compartment 13 together with a channel running in the edge of the upper limb of the evaporator 16' forms the heat pipe 17'. A container 20' for the non-reactive gas serving for the regulation of the heat transfer is connected through a pipe 1Y to the heat pine 17'.

The operation of the illustrated two teninerature refrigerating cabinet 10 is as follows: - The heat pipe 17, filled with a working fluid, is heat-conductingly connected at its upper section with the evaporator 16 of the freezing compartment 12. A non-reactive gas is adsorbed by the adsorption medium present in the container 20 as long as the container 20 is cold and the heating device 21 is switched off by opening of the thermostat switch 25. Hydrogen is preferably used in this case as the non-reactive gas, while ferric hydride serves as adsorption medium.

When the evaporator 16 in the freezing compartment 12 is cold, the upper section of the heat pipe 17 connected therewith is so cooled that the working fluid present in the heat pipe 17 is condensed and, as indicated in Fig. 1 by a downwardly directed arrow, flows downwardly into the section associated with the main refrigerating compartment 13. The liquid working fluid evaporates here through heat absorption and thereby withdraws heat from the main refrigerating compartment. The arising working fluid vapour rises upwardly then to condense anew at the upper section of the heat pipe 17.

When the temperature in the normal refrigerating compartment 13 is lowered by the evaporation of the refrigerant to the lower switching point of the thermostat switch 25, then this has the effect that the thermostat switch 25 closes. Hereby, the heater device 21 bearing against the container 20 is heated and the non-reactive gas stored in the adsorption medium 22 is thereby expelled. In consequence, the nonreactive gas expelled from the container 20 passes into the working fluid vapour in the heat pipe 17 and by its presence reduces the material flow of the working fluid appreciably. In this manner, little or no heat is withdrawn from the main refrigerating compartment 13 since the lower section of the heat pipe associated with the main refrigerating compartment 13 can warm up. On attainment of the upper switching temperature of the thermostat switch 25, this opens and switches the heating device 21 off. The room air now cools the container 20, whereby the non-reactive gas is again adsorbed and the normal refrigerating process continues in the main refrigerating compartment 13.

It is also possible to use a negative temperature coefficient resistance or a positive temperature coefficient resistance in place of the thermostat switch 25. The resistance continuously controls the heater current circuit for the heater element 21 by means of an electronic circuit. In the case of the use of a heat pipe with wick effect, the main refrigerating compartment 13 can be arranged above the deep-freezing compartment 12 in the two-temperature refrigerating cabinet.

Claims

WHAT WE CLAIM IS: -

1. A refrigerating apparatus comprising a heat-insulated housing provided with a first compartment to be maintained at a first temperature and at least one further compartment to be maintained at a second temperature higher than the first temperature, a heat pipe containing a working fluid and having a working section extending between the two compartments, the heat pipe being in thermal contact with an evaporator in the first compartment, a heatable container housing an adsorption medium for a gas which will not react with the working fluid, the container being located externally of the housing and being in open communication with the heat pipe, thermal energy transferred by the heat pipe being regulable by thermal expulsion of the non-reactive gas from the adsorption medium, and heater means to heat the container in dependence upon the temperature in the further compartment.

2. An apparatus as claimed in Claim 1, wherein the adsorption medium comprises ferric hydride.

3. An apparatus as claimed either in Claim 1 or Claim 2, wherein the non-reactive gas comprises hydrogen.

4. An apparatus as claimed in any one of the preceding claims, the evaporator and the heat pipe are provided in a roller-welded plate with two channel systems separated from each other.

5. A refrigerating apparatus substantially as hereinbefore described with reference to the accompanying drawings.