CN1370263A - Evaporator for household refrigerator - Google Patents

Abstract

This invention relates to an evaporator household refrigerating appliances such as a refrigerator and refrigerator-freezer combis or the like, with a pipe-like, refrigerant line (13) which is embodied at least approximately in a heat conducting manner and is at least approximately shaped like a zig-zag and substantially in contact in a heat-conductive manner with a more or less heat-conducting carrier tray (11). It also comprises an aluminum carrier tray to which a zig-zag shaped aluminum pipe is subsequently brought into thermal by means of welding or sticking using an aluminum adhesive tape. The disadvantage of securing the pipe in this manner is the relatively high amount of labor involved and the unreliable thermal contact between the pipe and the carrier tray. According to the invention, the pipe is fixed to the carrier tray by foaming using polyurethane foam.

Description

Evaporators for domestic refrigeration installations

The present invention relates to a heat exchanger, in particular to an evaporator for domestic refrigeration devices, such as refrigerators, combined cooling and freezing devices, etc., which has a tubular refrigerant medium pipeline at least approximately designed for heat conduction, Such lines are at least approximately meander-shaped and fastened to a base plate of at least approximately thermally conductive design, at least largely in thermally conductive contact.

It is known for evaporators used in domestic refrigerators to apply seam welding or section welding (Z-Bond-Verfahren) to the refrigerating-medium channel for conducting the refrigerating medium in a chip-free forming method. Embedded in an aluminum substrate. Refrigerators also use such evaporators, which consist of an aluminum base plate and separate aluminum tubes prefabricated in a meandering shape, which are fastened to the base plate in thermally conductive contact. For fastening the refrigerant line to the base plate, it is known, for example, to fasten the prefabricated tubes to the base plate with a soldered connection. For this purpose, for example, one of the welded parts is coated with a thin layer of brazing material, which is joined to the other welded part intended for brazing when the welded part is heated, so that the substrate and the preform The tubes are connected to form thermal contact. This method of fastening the refrigerant lines to the base plate is not only labor-intensive and therefore expensive to manufacture, but also has the danger that the heat-conducting connection of the two parts of the evaporator is also subject to the degree of care and care of the employees in the manufacturing department. Influence. Another method that has been implemented in practice for the thermally conductive connection of aluminum refrigerant lines to an aluminum base plate is the provision of an aluminum-coated adhesive tape, by means of which the heat-conducting contact is Lay out the pipes that are pressed against the aluminum base plate with a certain pressing force to overlap them along their zigzag lines, and fix them on the base plate with the lapped end of the adhesive tape. A precondition for this type of fastening is also the fact that the two connecting parts are at least to a certain extent free from dust and grease, which is relatively complex in terms of processing technology, in order to be able to achieve a guaranteed heat conduction between the two parts. The retention force of the contact, this force is produced by the adhesive tape clad in aluminum. In addition, the precisely positioned application of the adhesive tape, which is suitable for large quantities, is only possible with great effort in terms of processing technology.

It is the object of the invention to avoid the disadvantages currently present for a heat exchanger according to the preamble of claim 1 with simple constructional measures.

According to the invention, this task is solved by holding the refrigerant medium line positively and/or non-positively fixed by an at least essentially adhesive holding medium that has been processed in the liquid initial state, which A holding medium in a hardened state at least substantially fixes the refrigerant medium line to the base plate, wherein the holding medium is at least essentially separated from the contact point, ie the contact point of the refrigerant line and the base plate.

Due to the use of a retaining medium which is liquid during its processing for fastening, for example, a pipe made of aluminum to a base plate also made of aluminum, it is ensured that the retaining medium of fluid follows the meanders The profile of the curved refrigerant line is such that, due to the adhesive effect of the retaining medium, the refrigerant line remains functionally particularly reliable over its entire length in heat-conducting contact with the base plate, wherein the entire retaining surface on the base plate can be coated with liquid The retaining medium is used to fix the lines, which are pressed against the retaining surface in thermally conductive contact with a certain retaining force before the retaining medium is applied. At the same time, pressing the prefabricated refrigerating medium pipeline on the holding surface of the base plate ensures that the liquid holding medium is separated from the heat-exchanging contact portion between the refrigerating medium pipeline and the base plate. Due to the formation of this coating layer on the holding surface of the base plate with the liquid holding medium, the refrigerating medium line is at least buried in the holding medium as far as possible after the liquid holding medium has hardened, thus resulting in On the one hand, the cooling medium line is fastened firmly to the mounting surface of the base plate with a particularly strong heat-conducting contact and, on the other hand, with a particularly precise position. Due to the use of an adhesive liquid holding medium, the holding force is not lost between the two components to be connected and the cleaning process of the two components is avoided, which is very troublesome, whereas for example for brazing Solder connections must be cleaned. In the existing methods of manufacturing evaporators, such as the seam welding method and the section welding method (Z-Bond-Verfahran), or the brazing of the refrigerant medium pipeline on the substrate, these methods will have some problems, that is, they are affected Manufacturing constraints can lead to warping of the evaporator, and with the evaporator according to the invention these problems are at least eliminated as far as possible. The evaporator plate used as a cold-wall evaporator thus has a particularly reliable two-dimensional and heat-conducting contact on the insulating surface of a coolant container.

In the absence of additional auxiliary means, the prefabricated refrigerating medium line of the evaporator with the following refrigerating medium line is held particularly firmly on the holding surface of the base plate, the cross-section of this refrigerating medium line For a deformed circular shape with at least one approximately flat contact surface, if, according to a preferred embodiment of the subject matter of the invention, the surface of the holding medium is located above the center of gravity of the area of the deformed circular section in the hardened state , the approximately planar contact surface of the refrigerant line rests at least largely on the base plate in a heat-conducting manner. Since the refrigerant line is designed with, for example, a D-shaped cross-section or an elliptical cross-section, and its dimension is hardened to maintain the layer height of the medium, the refrigerant line is shaped without additional measures. Connectively held on the holding surface of the substrate. Furthermore, due to the volumetric contraction of the holding medium in the hardened state, the line is pressed against the holding surface of the base plate under pretensioning, in order to achieve a particularly strong transfer of heat between the base plate and the refrigerant line. Furthermore, the formation of a flat contact surface on the refrigerant line ensures a particularly effective and positive contact of the refrigerant line on the mounting surface of the base plate, resulting in a particularly intensive heat transfer.

An ellipse is here meant to be an area extending along an axis of symmetry and having limit lines bent at both ends. These surfaces can be, for example, an ellipse or two opposite flat circles or semi-ellipses with a rectangle in between.

If according to the next advantageous technical solution of the present invention, the circular cross-section of the deformation of the refrigerant pipe is designed to be at least approximately semicircular, then the flat contact surface of the refrigerant pipe can be made particularly conveniently .

According to a further preferred embodiment of the subject matter of the invention, provision is made for the media to be designed as heat-resistant materials processed in the liquid initial state.

Due to such a fastening method of the refrigerant medium line on the holding surface of the base plate, the cooling release of the base plate can be influenced in a targeted manner. Evaporators produced in this way are particularly suitable for use as so-called cold-wall evaporators, since the heat-insulating material only insignificantly reduces the insulating effect of the wall on which the cold-wall evaporator is mounted.

According to a preferred embodiment of the subject matter of the invention, it is provided that the heat-insulating material is formed from a foamed heat-insulating material.

Due to the use of foamed insulation for fixing the refrigerant medium lines on the holding surface of the base plate, an evaporator can be produced in a simple manner, which is particularly suitable for use as a so-called cold wall of a domestic refrigerator Evaporator. Also, the walls of the fridge with the cold wall evaporator will at best reduce insulation somewhat, but this is a negligibly small reduction. In addition, since the pressure is formed in the pressing tool that presses the refrigerant medium line to the base plate when the insulating material is foamed, it is also ensured that the insulating material wets the base plate and the base plate at least to a great extent. Free surfaces outside the contact points between the refrigerant lines and thus a particularly effective fastening of the refrigerant lines to the base plate is achieved.

According to another preferred embodiment of the subject matter of the invention, provision is made for the thermal insulation to be formed from polyurethane foam.

On the one hand, due to the adhesion of the polyurethane foam material in the liquid state, and on the other hand, due to the relatively high mechanical strength of the foam material, the refrigerant medium pipeline on the evaporator base plate maintains thermal contact with the base plate, especially in mass production. Reliable and mechanically stable in position.

If, according to another advantageous technical solution of the subject of the present invention, it is provided that the holding medium covers the refrigerant medium line at least partially along the meandering curve of the refrigerant medium line, then the position of the line on the base plate is particularly Solid and reliable.

According to a further preferred embodiment of the subject matter of the invention, it is provided that the partial covering of the refrigerant line is produced by an at least approximately mesh-like surface pattern.

Since the refrigerant medium pipeline is covered in a mesh shape on the outer surface of the pipeline away from the base plate, it is ensured that the refrigerant medium pipeline is firmly fixed on the base plate, and the use of the least amount of material is significantly reduced. The hardening time of the foamed insulating material of the retaining agent and thus the production time of the evaporator are optimized.

According to a last preferred embodiment of the subject matter of the invention, it is provided that the refrigerant medium line and the retaining medium are covered on their side facing away from the base plate by a film-shaped material which at least approximately has the outer dimensions of the base plate. The material is held in place by a hardened holding medium.

Since the entire surface is covered with a holding medium for fixing the refrigerant medium pipeline on the base plate, such as a foamed heat insulating material, the porous and loose heat insulating material itself in the hardened state prevents mechanical wear, For example wear due to the operation of the evaporator in a refrigerator up to the assembly of the evaporator. Furthermore, such a covered evaporator is also suitable as a so-called rear wall evaporator in the cooling cavity of a refrigerator. The sealing film, which acts as a water vapor trap, is particularly suitable for covering the foamed thermal insulation material.

The following description describes the invention on the basis of an exemplary embodiment which is simplified and shown in the drawing. The picture shows:

Fig. 1: the plate evaporator of the present invention represented by the perspective view seen from the front;

Figure 2: Partial cross-sectional view of the evaporator indicated by section line II-II in Figure 1.

FIG. 1 shows a plate-shaped evaporator 10, for example used as a so-called cold-wall evaporator, which has a base plate 11 made of a heat-conducting material, such as aluminum or also corrosion-resistant steel sheet or the like. The base plate 11 has a holding surface 12 on one side of its large area, on which a zigzag-shaped pipeline used as a refrigerant medium pipeline 13 is placed in heat conduction contact. The material is a thermally conductive material such as aluminum or corrosion-resistant steel or similar. In order to form the best heat conduction from the refrigerant medium pipeline 13 to the base plate 11, the cross section of the refrigerant medium pipeline 13 with a circular cross section is changed in shape, so that the refrigerant medium pipeline basically It has a D-shaped cross-section, and its supporting surface 14 is basically flat. The supporting surface 14 of the refrigerant medium pipeline 13 is in thermal contact with the base plate 11 (see FIG. 2 ). In order to make the refrigerant medium pipeline 13 fixed on the base plate 11 in thermal contact, the pipeline is buried in the heat insulating material with adhesive effect used as the holding medium 15, thereby forming a sandwich-like evaporator structure . This insulating material is coated at least on the portion of the holding surface 12 in the initial liquid state, which has been pressed against the base plate 11 with a certain preload before the liquid holding medium is applied. Occupied by medium line 13. Since there is a pre-tightening force on the refrigerant medium pipeline 13, the plane heat conduction contact of the pipeline 13 on the base plate 11 is ensured, and the liquid initial shape holding medium 15 is also prevented from entering the supporting surface 14 and corresponding parts. between the retaining surfaces 12. However, the liquid state of the holding medium 15 at the start of the process ensures that, due to its fluidity, the intermediate cavity formed by the meandering refrigeration line 13 is at least completely filled without shrinkage cavities. After filling, the shape of the cross-section of the refrigerant line 13 embedded in the holding medium is positively fixed not only along the holding surface 12, but also vertically to the holding medium 15 after the adhesive holding medium 15 has hardened. Inside. The compression of the refrigerant line 13 within the holding medium 15 is additionally ensured by at least completely covering the refrigerant line 13 with a mesh plan pattern 16, which surface pattern covers the line facing the holding surface 12 face. Due to this net-like surface structure of the holding medium 15 at the same time it is ensured that the refrigerant medium line 13 is only partially covered with the holding medium 15 on its face facing the support surface 14, and thus the refrigerant medium line The cooling medium circulating in the channel 14 is possible both to the base plate 11 and also to a so-called rear wall evaporator which is arranged, for example, freely suspended in a cooling chamber of a refrigerator.

In addition to the thermal insulation material described in the embodiment as the holding medium 15, such as foamed polyurethane foam or similar materials, thermosetting plastics that can be injection molded are suitable for molding and injection molding materials. Fixed on the base plate 11, wherein the thermosetting plastic injection molding material and molding material can ensure the thermal expansion of the base plate 11 on the one hand, and the thermal expansion of the refrigerant pipeline 13 on the other hand in view of its adhesive effect and the refrigerant medium pipeline. 13 such properties as the required holding force on the substrate 11 must be selected.

Another solution of the refrigerant medium pipeline 13 shown in the embodiments can also be a refrigerant medium pipeline with a circular cross section. In addition to being designed as an evaporator, the design according to the invention is also suitable for the design and manufacture of a condenser.

It is also possible for the refrigerant medium line and/or the base plate to have projections, with which the hardened holding medium cooperates in a positive manner.

The refrigerant medium pipeline and the base plate can also be fixed and connected to each other only by the adhesion of the medium.

Claims (9)

1. be used for household refrigerating device, evaporimeter as refrigerator, refrigeration and freezing composite set or other similar device, it have a kind of tubulose, be similar to the refrigerant pipeline of heat conduction design at least, this pipeline makes meander-shaped at least approx and is fixed on the substrate that is similar to heat conduction design at least, at least largely be the heat conduction contact, it is characterized in that

Refrigerant pipeline (13) shape connects ground and/or power has maintenance medium (15) sticking action, through processing under liquid original state to be maintained fixed by a kind of with connecting at least approx, this medium the sclerosis after refrigerant pipeline (13) is fixed on the substrate (11), wherein keep medium and be positioned at pipeline (13) and substrate (11) between the contact site separate at least in essence.

2. by the described evaporimeter of claim 1, has a refrigerant pipeline, it has a kind of circular cross sections through distortion, and has the bearing-surface of a near flat at least, the refrigerant pipeline just abuts on the substrate with this bearing-surface at least largely with heat conduction, it is characterized in that, keep the hardened surface of medium (15) to be positioned on the area center of gravity of passing through the circular cross sections of being out of shape of refrigerant pipeline (13).

3. by the described evaporimeter of claim 2, it is characterized in that the circular cross sections through distortion of refrigerant pipeline (13) is designed to approximate half-circular at least.

4. by any described evaporimeter among the claim 1-3, it is characterized in that, keep medium (15) to be designed to thermal resistance material under liquid original state through processing.

5. by the described evaporimeter of claim 4, it is characterized in that the thermal resistance material is made of the heat-barrier material of foaming.

6. by the described evaporimeter of claim 5, it is characterized in that heat-barrier material is formed by foamable urethane foam material.

7. by any described evaporimeter among the claim 1-6, it is characterized in that, keep medium (15) along the curve of the meander-shaped of refrigerant pipeline refrigerant pipeline (13) to be covered at least partly.

8. by the described evaporimeter of claim 7, it is characterized in that it is to produce by a kind of approximate at least netted plane pattern (16) that the part of refrigerant pipeline (13) covers.

9. by any described evaporimeter among the claim 1-8, it is characterized in that, refrigerant pipeline (13) and maintenance medium (15) are covered by a kind of approximate at least film shape material with substrate (11) appearance and size on their face that deviates from substrate (11), and the maintenance medium (15) that this material is hardened is maintained fixed.

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