WO2003052333A1

WO2003052333A1 - Condenser for refrigeration systems

Info

Publication number: WO2003052333A1
Application number: PCT/BR2002/000147
Authority: WO
Inventors: Estevão Marino ESPÍNDOLA; Jean Marcelo Ferreira; Ademar Testoni; Alexandre Cury Schmid; Sthefan Verjas De Almeida; Tadeu Vicente Bonassa
Original assignee: Multibrás S.A. Eletrodomésticos
Priority date: 2001-11-20
Filing date: 2002-11-05
Publication date: 2003-06-26
Also published as: PL369460A1; JP2005513397A; AU2002339275A1; AR037540A1; RU2004118504A; US20050016203A1; CN1589386A; MXPA04004748A; EP1451512A1

Abstract

A condenser for refrigeration systems containing a refrigerant gas and applied to refrigeration appliances of the type comprising an internally refrigerated cabinet (G) presenting external walls (20) which are at least partially defined in a metallic plate and comprise at least one condensation coil (S) formed by a plurality of tube extensions (10) for conducting refrigerant gas and which are generally rectilinear and mutually coplanar, each of said tube extensions (10) being seated and retained inside a respective groove (21), which is formed by bending the metallic plate of a respective external wall (20) of the cabinet (G).

Description

CONDENSER FOR REFRIGERATION SYSTEMS Field of the Invention

The present invention refers to a condenser of the tube-plate type to be used in the refrigeration system of appliances, such as refrigerators and freezers presenting an internally refrigerated cabinet with external walls that are at least partially defined in a metallic plate. Prior Art There are well known in the prior art the refrigeration appliances presenting a cabinet with external walls made of a metallic plate and a refrigeration system comprising a condenser of the tube-plate type that uses at least one of said external walls of the cabinet as a heat dissipating fin, against which is internally seated the tubing for conducting the refrigerant gas pumped by the compressor and which will be condensed before entering an evaporator of the refrigeration system. As it can be noted from figures 1-2 of the enclosed drawings, in the condensers of the presently known tube-plate type, the tube 10 that defines the metallic condensation coil is simply seated against the inner face of a respective external wall 20 of the cabinet G of the refrigeration appliance, said tube 10 being retained against the external wall 20 by a tape 30, made of aluminum or any other thermally conductive material, which is medianly applied to the tube 10 and has end portions that are glued or otherwise affixed to said external wall 20. The tube 10 and the tape 30 are afterwards covered by the thermal insulation of the cabinet G, which insulation is generally defined by a filler 50 of polyurethane contained between the external wall 20 and an internal wall 40 of the cabinet G. However, this known condenser construction of the tube-plate type presents some disadvantages, one of which resulting from the fact that the cylindrical tube 10 is seated against the flat surface of the external wall 20, whereby only one tangential contact line is formed between the tube 10 and the external wall 20, requiring the provision of the tape 30 in order to assure not only the fixation of the tube 10, but a greater thermal contact between these two condenser parts, namely the tube 10 and the respective external wall 20.

Another great disadvantage of the known construction results from the high cost of the adhesive aluminum tape 30. Yet a further disadvantage of said tube-plate condenser construction results from the slow assembly process thereof . Objectives of the Invention Due to the above mentioned deficiencies related to the constructive system of the condensers of the tube- plate type, it is an object of the present invention to provide a condenser of the type considered herein, with a construction that is simple and rapid to produce, requiring reduced manual operations and eliminating the usual tapes for affixing the tube to the respective external wall of the cabinet . It is a further object of the present invention to provide a condenser as mentioned above, which allows an efficient thermal exchange between the compressed refrigerant gas and the external environment of the cabinet, without requiring the provision of elements projecting outwardly from the contour of the external walls of the cabinet. Summary of the Invention In order to attain the objectives mentioned above, the present invention proposes a condenser comprising at least one condensation coil formed by a plurality of tube extensions for conducting the refrigerant gas, which are seated and retained in respective grooves formed by bending the metallic plate of a respective external wall of the cabinet.

Each groove is configured and dimensioned to tightly "embrace" preferably more than half the perimeter of the outer face of the respective tube extension, so as to maximize the contact area between the tube extensions and the metallic plate that defines the respective external wall of the cabinet. The retention of the tube extensions is now made by interference, dispensing the fixation tapes. Brief Description of the Drawings

The invention will be described now, with reference to the enclosed drawings, in which:

Fig. 1 is a cross-sectional view of a tube extension of a condensation coil affixed against the inner face of an external wall of a cabinet according to the prior art construction;

Fig. 2 is a similar view to that of figure 1, but illustrating only an enlarged small portion of a corner of the cabinet ; Fig. 3 is a similar view to that of the previous figure, but illustrating a preferred form of carrying out the present invention; and

Fig. 4 is a somewhat schematic perspective view of a condenser of the tube-plate type comprising a condensation coil, which is mounted, according to the present invention, to a rear external wall of an internally refrigerated cabinet; and an additional condensation coil that is conventionally adapted to the inner face of the top external wall of the cabinet. Description of the Illustrated Embodiment As already mentioned, the present condenser of the tube-plate type is applied to the refrigeration system of different refrigeration appliances, such as refrigerators and freezers presenting a cabinet G to be internally refrigerated and which has external walls 20, generally in a metallic plate, and internal walls 40 usually defined in a single piece of plastic material and denominated inner box. Between the internal walls 40 and the external walls 20 a filler 50 of polyurethane foam is inserted to provide the required thermal insulation to the cabinet G. In order to eliminate the disadvantages of the prior art construction already discussed at the introduction of the present application jointly with figures 1 and 2, the invention proposes a construction, according to which the condenser comprises at least one condensation coil S, which is formed by a plurality of tube extensions 10, for conducting the refrigerant gas, which are arranged in series relative to each other and to the refrigeration system to which the condenser is applied, each tube extension 10 being seated and retained inside a respective groove 21, formed by bending the metallic plate of a respective external wall 20 of the cabinet G. As a function of the construction of the cabinet G, the groves 21 are generally rectilinear and mutually coplanar. However, it should be understood that other arrangements could be provided in which the grooves 21 are not rectilinear and coplanar.

In the illustrated embodiment, the grooves 21 are opened to the outside of the respective external wall 20 of the cabinet G. The external wall 20 used can be the one that defines the rear closing part of the cabinet G, considering that this external wall 20 is generally made of a steel plate as a separate piece from the single metal sheet that defines the lateral and upper external walls of a parallelepipedic cabinet G. It should be understood that the grooves 21 can open to the interior of the respective external wall 20, which would present ribs on the outer face thereof, resulting from the bottom of the grooves 21 projecting outwardly from the plane of said external wall 20. Aiming at maximizing the contact area between each tube extension 10 and the respective groove 21, the latter presents a cross section that is configured and dimensioned to tightly "embrace" the tube extension 10, by preferably contacting more than half the external perimeter of the latter.

In order to form the condenser, the tube extensions 10 of the condensation coil S are lodged inside the respective grooves 21 of an external wall 20, whose metallic plate is previously stamped. Subsequently, the metallic plate is submitted to a localized pressing, in order to partially close the grooves 21 around the tube extensions 10, embracing the latter and assuring a larger contact area and the retention of the tube extensions 10 inside the grooves 21, since the opening 21a of the latter now presents a width that is smaller than the largest transversal dimension of the tube extension 10, taken according to a direction parallel to the respective external wall 20. However, it should be understood that the tube extensions 10 can be seated inside the grooves 21 and affixed therein by an additional common fixation element, which is coupled to the external wall and acts against the exposed surface portion of the tube extensions 10. The tube extensions 10 generally present a circular cross section, making the grooves 21 present the same cross section shape, in order to operate as a cradle, in which the respective tube extensions 10 will be tightly seated. In the illustrated embodiment, the grooves 21 present a depth that is substantially equal to the largest transversal dimension of the tube extension 10, taken at a direction that is orthogonal to the respective external wall 20. Thus, the external surface of the tube extension 10 is generally arranged in a tangential way in relation to the plane of the external wall 20, allowing the formation of a condenser that is entirely contained in the external contour of the cabinet and with the constructive and assembly advantages mentioned above.

The increase in the thermal efficiency of the construction proposed herein allows this condenser of tube-plate type to have its positioning changed from the lateral external walls of the cabinet G of a refrigerator or a freezer to be associated to the rear external wall 20 of said cabinet G, avoiding the problem of leaving marks on the lateral external walls upon injection of polyurethane in the conventional constructions, in which the tube extensions are internally affixed to said lateral external walls.

Depending on the characteristics of the refrigeration system, the provision of one or more additional condensation coils SI, S2 may be required, arranged in series with the condensation coil S and associated with the top and bottom external walls 20 of the cabinet G. In this case, the tube extensions 10 can be seated and affixed against the flat inner face of the external walls 20 that define the top and bottom of the cabinet G, according to the prior art construction, as illustrated in figure 4, in which the additional coil S2 seated against the inner face of the bottom external wall 20 is represented in dashed lines .

Although only one form of carrying out the invention has been described, it should be understood that the invention can have different embodiments, resulting in the same advantageous effects over the solutions known up to now. Thus, the protective scope of the invention should not be limited to the described illustrated form, but solely to the constructive concept contained in the appended claims .

Claims

1. A condenser for refrigeration systems containing a refrigerant gas and applied to refrigeration appliances of the type comprising an internally refrigerated cabinet (G) presenting external walls (20) which are at least partially defined in a metallic plate, characterized in that it comprises at least one condensation coil (S) formed by a plurality of tube extensions (10) for conducting a refrigerant gas, each of said tube extensions (10) being seated and retained inside a respective groove (21) , which is formed by bending the metallic plate of a respective external wall (20) of the cabinet (G) .

2. The condenser as set forth in claim 1, characterized in that each groove (21) presents a cross section that is configured and dimensioned to contact more than half the external perimeter of the tube extension (10) that is seated and retained inside said groove (21) .

3. The condenser as set forth in claim 2, characterized in that each groove (21) presents an opening (21a) with a width smaller than the largest transversal dimension of the tube extension (10) , taken at a direction that is parallel to the respective external wall (20) .

4. The condenser as set forth in claim 3, characterized in that the tube extensions (1) and the grooves (21) present a circular cross section.

5. The condenser as set forth in claim 1, characterized in that the depth of the groove (21) is substantially similar to the largest transversal dimension of the tube extension (10) , taken at a direction that is orthogonal to the respective external wall (20) .

6. The condenser as set forth in claim 1, characterized in that the groove (21) opens to the outside of the respective external wall (20) of the cabinet (G) .

7. The condenser as set forth in claim 1, characterized in that it comprises a condensation coil (S) , whose tube extensions (10) are seated and retained in grooves (21) , which are defined on an external wall (20) provided at the rear part of the cabinet (G) .

8. The condenser as set forth in claim 7, characterized in that it comprises an additional condensation coil (SI) arranged in series with the condensation coil (S) and whose tube extensions (10) are seated and affixed against the flat inner face of an external wall (20) that defines the top of the cabinet (G) .

9. The condenser as set forth in any one of claims 7 or 8, characterized in that it comprises an additional condensation coil (S2) arranged in series with the condensation coil (S) and whose tube extensions (10) are seated and affixed against the flat inner face of an external wall (20) that defines the bottom of the cabinet (G) .

10. The condenser as set forth in claim 1, characterized in that the grooves (21) are rectilinear and mutually coplanar.