EP3255368A1

EP3255368A1 - Heat exchanger, especially a gas radiator or a condenser for a car

Info

Publication number: EP3255368A1
Application number: EP16173746.5A
Authority: EP
Inventors: Grzegorz Romanski; Dawid Szostek
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2016-06-09
Filing date: 2016-06-09
Publication date: 2017-12-13

Abstract

The object of the present invention is the heat exchanger (1), especially a gas radiator or a condenser for a car, comprising manifolds arranged on both sides of the heat exchanger and plurality stacked parallel and spaced relative to each other flattened tubes, the ends of which are arranged in the manifolds. The flattened tubes (2) are elongated in the transverse direction (X) and have rounded outer side walls (2a). Furthermore, the heat exchanger comprises ribbed separators (3) formed of curved wavy ribs having flat outer side walls (3a). The ribbed separators (3) are arranged between the flattened tubes (2). The heat exchanger according to the invention is characterized in that the (B) width of the ribbed separator (3) is larger than the (A) width of the flattened tube (2) in the range of 0% to 20%, while the flattened tube (2) is positioned symmetrically with respect to the ribbed separator (3) across the width of the ribbed separator (3) and forms equal distances the ribbed separator (3) projects on both sides beyond the outer surface of the side walls (2a) of the flattened tube (2). The (B) width of the ribbed separator (3) is measured between its outer flat side walls (3a) in the transverse direction (X), while the width of the flattened tube (2) is measured in the same transverse direction (X) and between the outer surfaces of its side walls (2a).

Description

Technical Field

The present invention relates to a heat exchanger, especially a gas radiator or a condenser for a car, comprising manifolds arranged on both sides of the heat exchanger and plurality stacked parallel and spaced relative to each other flattened tubes, the ends of which are arranged in the manifolds. The flattened tubes are elongated in the transverse direction and have rounded outer side walls. The heat exchanger further comprises ribbed separators in the form of wavy curved ribs having flat outer side walls. The ribbed separators are arranged between the flattened tubes.

TECHNICAL BACKGROUND OF THE INVENTION

There are known heat exchangers such as condensers or radiators for car made up of plurality parallel arranged flat tubes between which the separators are arranged in the form of wavy curved ribs. The pipe ends are connected to two manifolds in which the refrigerant is gathered. Typically, the width of the ribs is equal to the width of the flat tubes, which causes that the assembly of the radiator elements is simplified. It is also known an arrangement wherein the width of the flat tube is slightly greater than the ribbed separator.
From DE 102004042692 patent description a heat exchanger with at least one manifold and one separator made of wavy formed ribs is known. Between the separators the flat tubes are disposed which have twisted end sections arranged in the longitudinal slots of the manifold. Said flat tubes are provided with the formed outer side walls. At one side of the heat exchanger the wavy formed ribs are exactly closed in the plane of the outer side walls of the flat tubes, while on the other side they project beyond the plane of the flat wall and form the protrusion. Such asymmetrical arrangement of the ribs in relation to the flat pipe, in which the ribs are longer than the flat tube, is to provide a protection of the flat pipes against impacts of stones and corrosion. However, this solution is disadvantageous due to the complicated process of assembling of the individual elements of the heat exchanger.
Taking into account the prior art, the inventors proposed a heat exchanger whose design does not have the prior art disadvantages, because the ribs are symmetrically wider relative to the flat tube. This results in improving of the mechanical strength of a heat exchanger because the tubes are not exposed to direct impact of stones or other objects.

Summary of the Invention

The object of the invention is to improve of the heat exchanger structure, which would be still more efficient and more protected against impact of stones and corrosion.
This object is achieved by using features set forth in claim 1.
According to the invention, the ribbed separators formed of the wavy curved ribs are provided with two-sided protrusion, which is caused by suggestion of using the ribbed separator having greater width in relation to the width of the flattened tube. The ribbed separator is symmetrically wider on both sides in relation to the flattened tube. Thanks to said two-sided protrusions, higher heat exchange efficiency is provided due to increased heat transfer surface. Furthermore, there is provided a still better protection against impact of stones and still better corrosion protection with respect to known solutions. This is very important because typically a condenser or a radiator for R744 gas is placed in the vehicle in the first row i.e. as a first heat exchanger of a cooling module consisted of several sequentially arranged heat exchangers. In addition, the chemical composition of the cooling fins is selected so that the galvanic corrosion potential caused privileged corrosion of ribs rather than tubes, and therefore the larger the surface of the ribs the higher corrosion resistance. The increased surface area of ribs improves heat transfer between the air (cooling medium) and ribs. However, from the production point of view a symmetry of ribs does not complicate the manufacturing process and does not cause increasing of the manufacturing cost of a heat exchanger.
The object of the invention is achieved by a heat exchanger which is characterized in that the width of the ribbed separator is greater than the width of the flattened tube in the range from 0% to 20%. In addition, the flattened tube is positioned symmetrically with respect to the ribbed separator across the width of said separator and forms equal distances the ribbed separator projects on both sides beyond the outer surface of the side walls of the flattened tube. The width of the ribbed separator is measured between its outer flat side walls in the transverse direction, while the width of the flattened tube is measured in the same transverse direction and between the outer surfaces of its side walls.
According to the invention the tube is produced by extrusion process, and preferably it is formed by winding.
Preferably, the distance the ribbed separator projects beyond the outer surfaces of the side walls of the flattened tube is in the range from 10 mm to 22 mm.

Brief description of the Drawings

These and other features of embodiments of the invention will now be described in detail with reference to the accompanying drawing, in which

Figure 1 shows a heat exchanger according to the invention in a perspective view;
Figure 2 shows a fragment of the heat exchanger of Fig. 1 in cross section through the flat tube of the radiator.

Description of the embodiment of the invention

The present invention will be described in more detail hereinafter with reference to the accompanying drawings in which a preferred embodiment of the invention is shown.
Referring to FIG. 1 the heat exchanger 1 comprises manifolds (not shown) which are arranged on both of its sides. The heat exchanger further comprises plurality flattened tubes 2 arranged in parallel and spaced relative to each other, the ends of which are placed in the manifolds (not shown). As illustrated in Fig. 1 the flattened tubes 2 are elongated in the transverse direction X (indicated in Fig. 1 by the arrow). The flattened tubes 2 have rounded outer side walls 2a, which are connected to each other with parallel flat upper and lower walls. The transverse direction X is determined by the planar top and bottom walls. The heat exchanger 1 further comprises ribbed separators 3 formed of wavy curved ribs, wherein the ribbed separators 3 have outer flat side walls 3a. As illustrated in Fig. 1 the ribbed separators 3 are arranged between the flattened tubes 2. It should be noted that for clarity the Fig. 1 shows a fragment of the heat exchanger in the form of a block comprising several flat tubes and ribbed separators arranged in between.
Fig. 2 shows the mutual positioning of the flattened tube 2 of the heat exchanger in relation to the ribbed separator 3. The width of the ribbed separator 3, marked by B value in Fig. 2, is measured between its outer flat side walls 3a and in the transverse direction X. However, the width of the flattened tube 2, marked in Fig. 2 by A value, is measured in the same transverse direction X and between the outer surfaces of its side walls 2a. According to the invention the B width of the ribbed separator 3 is larger than the A width of the flattened tube 2 in the range of 0% to 20%. The flattened tube 2 is positioned symmetrically with respect to the ribbed separator 3 across the width of the ribbed separator 3 and forms equal distances the ribbed separator 3 projects on both sides beyond the outer surface of the side walls 2a of the flattened tube 2. Preferably, the distance the ribbed separator 3 projects beyond the outer surfaces of the side walls 2a of the flattened tube 2 is in the range from 10 mm to 22 mm.
The individual blocks of the heat exchanger, especially gas radiator or condenser for the car are carried out in a known manner by forming firstly flattened tubes preferably from a brass sheet, which are then trimmed by cutting into lengths depending on the radiator type and that are subjected to well known protective treatment against corrosion. However the ribbed separators are formed of wavy curved ribs. The ribbed strips are stacked one above the other and separated by flattened tubes. The flattened tubes are produced in the process of press forming or by corrugation. The protruding ends of the flattened tubes are mounted in the two heads disposed on both sides of the radiator. The heads are provided with manifolds for the cooling agent. The flattened tubes are mounted symmetrically across the width of the ribbed separator to ensure equal distances the ribbed separator projects on both sides beyond the outer surface of the side walls of the flattened tube. According to the invention the tests were carried for different B widths of a ribbed separator with respect to the A width of the flattened tube 2. As a result of these tests, the most preferred result was obtained for improvement of the heat exchanger performance and protection against impacts of stones, and it was found that the B width of the ribbed separators have to be greater than the A width of the flattened tube 2 in the range of 0% to 20%. The best possible result meeting the expectations was obtained for the flattened tube having width 12 mm and ribbed separator having width 14 mm.

Claims

A heat exchanger (1), in particular gas radiator or a condenser for a vehicle comprising:
manifolds located on both sides of the heat exchanger (1), and

plurality flattened tubes (2) arranged in parallel and spaced relative to each other, the ends of which are placed in the manifolds,

wherein the flattened tubes (2) are elongated in the transverse direction (X) and have rounded outer side walls (2a),

and the heat exchanger further comprising the ribbed separators (3) formed of curved wavy ribs having outer flat side walls (3a), wherein the ribbed separators (3) are arranged between the flattened tubes (2)

characterized in that:
the (B) width of the ribbed separator (3) is larger than the (A) width of the flattened tube (2) in the range of 0% to 20%, and

the flattened tube (2) is positioned symmetrically with respect to the ribbed separator (3) across the width of the ribbed separator (3) and forms equal distances the ribbed separator (3) projects on both sides beyond the outer surface (2a) of the side walls (2a) of the flattened tube (2), wherein

the (B) width of the ribbed separator (3) is measured between its outer flat side walls (3a) and in the transverse direction (X), and

the width of the flattened tube (2) is measured in the same transverse direction (X) and between the outer surfaces of its side walls (2a).
The heat exchanger according to claim 1, characterized in that the flattened tube (2) is produced by a press forming process.
The heat exchanger according to claim 1, characterized in that the flattened tube (2) is produced by a corrugation process.
The heat exchanger according to claim 1, characterized in that the distance the ribbed separator (3) projects beyond the outer surfaces of the side walls (2a) of the flattened tube (2) is in the range from 10 mm to 22 mm.