DEHYDRATING AND FILTERING UNIT FOR A REFRIGERANT CIRCUIT

Abstract: A dehydrating and filtering unit for a compression refrigerant circuit, comprising a body (1) having a first end connected to the condenser (3) and a second end connected to the vacuum service conduit (4) and to the capillary (2). The capillary (2) is intimately associated with the body (1) by means of a single solder joint (12). The end portion of the capillary (2) may be located in a seat formed on the service conduit (4). Alternatively, the service conduit (10) is integrally formed with the body (1) and formed with an opening (11) for insertion of the end portion of the capillary (2). Application particularly in domestic refrigerators.

Description: Dehydrating az Filtering Unit for a Refrigerant Circuit The present invention relates to a dehydration filter for use in domestic refrigerators employing an evacuation system in the high pressure part. More particularly, the invention concerns a dehydration filter to be inserted in the refrigerant circuit between the condenser and the capillary tube of the evaporator and connected to the service conduit employed for creating a vacuum within the refrigerant circuit prior to introducing thereinto the refrigerant fluid. The dehumidifying filters of the above defined kind and the associated inlet and/or outlet conduits are usually made of copper, it being generally known that considerable difficulties are encountered in connecting the filter with the respective conduits by brazing. These brazed or soldered connections are relatively fragile and expensive due to the employ of noble metal brazing alloys, and have to be made unter suitable conditions in order to avoid refrigerant losses due to imperfect, porous and/or irregular seams. The main object of the present invention is therefore the provision of a filter which its connected to the respective refrigerant circuit by a reduced number of soldered connections and presents maximum safety, structural simplicity, ruggedness and reliable sealing function. According to tile invention, this object is attained by a filtering AnU dehydrating unit adapted to be inserted in a refrigera=t circuit between the condenser and the capillary tube of the evaporator thereof, and connected to a service vacuum conduit, said filter unit being characterized by the fact that the capillary is intimately associated with the service vacuum conduit, and that the connection of the capillary and the service conduit to the body of the filter unit is established by a single solder joint. In a first embodiment of the invention, the connection between the end of the capillary tube and the service conduit is established by partially compressing the latter to form a seat for the end of the capillary, so as to facilitate the insertion ofthe two conduits together into the respective port of the filter unit and to reduce the section to be filled with the solder material. In a second embodiment of the invention, the end of the capillary is partially inserted into an opening formed in the service conduit, the latter being formed as an extension of the filter body. Tile characteristics and advantages of the invention will be better understood upon reading of the following description of exetnplary and non-limitative embodiments with reference to the accompanying drawings, wherein: fig. I shows a diagrammatic longitudinal sectional view of a dehydration filter according to prior art, fig. 2 and 3 show diagrammatic longitudinal sectional views of two embodiments of a filter unit according to the invention. As shown in fig. 1, the cylindrical body I of a known filter has one of its ends formed with a port for connection to a capillary 2, while its other end portion is laterally compressed to form two tubular ports for receiving therein a condensed conduit 3 and a vacuum service conduit 4, respectively. In this system the gaseous refrigerant, after having been compressed and subsequently cooled in condenser conduit 3, flows through the filter in the liquid state, the main function of said filter being to retain any humidity so as to avoid the formation of ice in capillary 2 with consequent blocking of the flow within the refrigerant circuit. In order to meet these requirements, the filter body 1 contains an absorbent material 7 such as silica gel or the like acting as a chemical filter, and mechanical filters 5, 6 disposed adjacent the inlet and the outlet of body 1, respectively, for retaining any solid contaminants and for preventing absorbent material 7 from being carried out of filter body 1 by the refrigerant fluid. After passing through the filter, the refrigerant enters capillary 2 which funstions to control the amount of the fluid flowing towards the evaporator, wherein it develops its refrigerating effect due to evaporation and expansion in the gaseous phase. During evacuation of the refrigerant circuit preparatory to introducing the refrigerant thereinto, the air aspirated through service conduit 4 may enter thereinto directly from condenser conduit 3 without passing through filter body 1, thus avoiding any contamination or moistening of absorbent material 7. Fig. 2 shows a first embodiment of the filter unit according to the invention adapted to achieve the advantages described above. The filter unit shown comprises a tubular body 1 having two outwardly procecting hemispherical end portions for connection to an end portion of a condenser conduit 3 and the end portions of a service conduit 4 and a capillary 2, respectively. he latter connection is preferably formed by locating the end portion of capillary 2 in a seat 8 formed in vacuum service conduit 4 by partially compressing its end portion. In this manner it is possible to connect both conduits together to the fikter body with minimum consumption of solder material by a single solder joint 12, so as to achieve maximum safety and reliability of the connection. Diagrammatically shown in fig. 3 is a second embodiment of the invention further simplified with respect to the one shown in fig. 2 and comprising a cylindrical filter body 1 having two end portions for connection to con- denser conduit 3 and the combination of service conduit als capillary, respectively. In this embodiment the service tube 10 is formed as an integral extension of cylindrical body 1, the end portion of capillary 2 being inserted in to a port 11 formed in service conduit 10 and affixed thereto by a single solder joint 13. In both embodiments of the invention, the refrigerant circuit functions in the well-known classical manner, i.e. the liquid refrigerant provenient from the condenser flows through the absorbent material 7 contained within filter body 1, and enters capillary 2 on its way towards the evaporator. he above described construction results in a difference, however, with regard to the flow ratL Qf the air aspirated from the circuit during evacuati 3t thereof. In both embodiments of the invention, the aevirated air passes through the absorbent filter material, in contrast to what happens in the case of prior art constructions. This feature could be disadvantageous, if the air originally contained in the C'-Clit containes a certain degree of humidity sufficient to partially saturate the filter material. Extensive and repeated tests have shown, however, that this inconvenient phenomenon occurs very rarely indeed, and scarcely to such a degree as to impair the efficiency of the filter. Any inconveniencey of this kind are fully compensated by the technical and economical advantages obtained by having only a single solder connection of reduced dimensions for the outlet conduits of the filter, i.e. the capillary and the vacuum service conduit. The filter unit according to the invention may obviously be modified in various manners. Thus the diameters and wall thicknesses of the filter body and the various conduits as well as the materials employed may be selected in accordance with the characteristics of the refrigerant circuit.

Claims: Claims: 1. A filtering and dehydrating unit adapted to be inserted in the refrigerant circuit of a domestic refrigerator between the condenser and the capillary of the evaporator thereof, and connected to a service vacuum conduit, characterized in that said capillary (2) is intimately associated with the service vacuum conduit (4), and in that the connection of the capillary and the service vacuum conduit to the body (1) of the filter is established by a single solder joint (12, 13). 2. A unit according to claim "1, characterized in that the end portion of said capillary (2) is located in a seat (8) formed on said service conduit (4) so as to facilitate the assembly and insertion thereof into a single port of the filter 3. A unit according to claim 1, characterized in that said service conduit (10) is integrally formed with said body (1) as an extension thereof, an end portion of said capillary (2) being inserted into an opening (11) formed in said extension. 4. A unit for a refrigerant circuit, substantially as described with reference to the accompanying drawings and for the purpose indicated.

Inventors: BOBBO, LUCIANO
Applicants: INDUSTRIE ZANUSSI S.P.A.
Application year: 1981
Main classification: F25B43
IPC codes: F25B41, F25B43