FR2754885A1 - Condenser with integral reservoir for motor vehicle air conditioning - Google Patents

Abstract

The condenser has a number of parallel tubes (12), with one end communicating with a first collecting chamber (18) and the other end communicating with a second collection chamber (38), and with a reservoir (40). The reservoir extends vertically upward over part of the height of the second collecting chamber, and is divided internally by a vertical wall (54). The vertical wall forces the condensed fluid to travel firstly over a vertically ascending path (60) then over a vertically descending path (62), improving separation of the gas and liquid phases under the effect of gravity.

Description

Integrated reservoir condenser for refrigeration circuit, in particular for motor vehicle
The invention relates to a condenser with integrated reservoir for a refrigeration circuit intended in particular for the air conditioning of a motor vehicle.

It relates more particularly to a condenser comprising a bundle of tubes, of which a first end communicates with a first manifold in a generally vertical direction and of which a second end communicates with a second manifold and with a reservoir in generally vertical direction, and in which the bundle of tubes includes an upper part for condensing the refrigerant and a lower part for subcooling the condensed refrigerant.

In a refrigeration circuit of this type, the refrigerant is first compressed by means of a compressor in order to be in the superheated vapor phase, then sent to the condenser where it is successively "desuperheated", condensed into a liquid phase hot, and cooled to a cold liquid phase. The fluid in the cold liquid phase is then sent, via a pressure reducer, to an evaporator where it exchanges heat with an air flow intended for the passenger compartment of the vehicle and transforms into the vapor phase before returning to the compressor, And so on. The tank connected to the condenser contains a desiccant to absorb the moisture existing in the refrigerant.

A condenser of this type is known from French Patent Application No. 96 04881.

In this known condenser, the second manifold and the reservoir are separated, so that there is no communication of the refrigerant between the reservoir and the second manifold.

This makes it possible to carry out a circulation in several passes, that is to say in several circulation paths, of the refrigerant in the upper part of the bundle of tubes, and consequently to improve the thermal performance.

This solution has proven to be advantageous for improving thermal performance, compared to condensers of the prior art, in particular compared to the condenser according to US Pat. No. 4,972,683, in which the refrigerant circulates in a single pass from the first box. manifold to the second manifold.

One of the aims of the invention is to further improve the thermal performance of a condenser according to the aforementioned French patent application, and in particular to improve the separation of the gaseous and liquid phases of the refrigerant.

To this end, the invention provides a condenser of the type defined in the introduction, in which the reservoir extends vertically upward over at least part of the height of the second manifold, and in which the reservoir is divided internally by a partition. substantially vertical to force the condensed fluid, during sub-cooling, to move first along an upward vertical path and then along a downward vertical path, which makes it possible to promote the separation of the gaseous and liquid phases of the refrigerant by effect of gravitation.

Thus, the separation of the gaseous and liquid phases is reinforced by the ascending path of the refrigerant, which allows the gravitational effect to be all the more effective as the height of the ascending path and, consequently, the height of the downward path is more important.

This is the reason why it is particularly preferred that the reservoir extends vertically upwards over the entire height of the second manifold.

Thus, the gravitational effect can fully play its role and contribute to a better separation of the gaseous and liquid phases of the refrigerant.

Advantageously, the reservoir has a lower part into which the lower part of the tube bundle opens and an upper part forming a vertical extension and extending along the second manifold.

This characteristic makes it possible in particular to reduce the overall size of the condenser.

Advantageously, the lower part of the tank has a cross section whose area is larger than that of its upper part.

According to another characteristic of the invention, the vertical partition is attached to a transverse partition to divide the flow of the lower part of the beam and distribute it between the upward path and the downward path.

In a preferred embodiment of the invention, the second manifold and the reservoir are delimited by a first cylindrical wall and by a second cylindrical wall with parallel generators, which intersect, so that the first cylindrical wall delimits the second manifold, that the second cylindrical wall defines the vertical downward path and that the intersection of the two walls delimits the vertical upward path.

Advantageously, the first cylindrical wall and the second cylindrical wall are of circular or substantially circular section.

It is particularly preferred that the second cylindrical wall has a diameter greater than that of the first cylindrical wall.

In the description which follows, given solely by way of example, reference is made to the appended drawing, in which - FIG. 1 is a view in vertical section of a condenser according to a preferred embodiment of the invention; and - Figure 2 is a sectional view along line II-II of Figure 1.

The condenser shown in FIG. 1 comprises a bundle 10 formed from a multiplicity of parallel and horizontal tubes 12, preferably of non-circular section, between which are placed corrugated inserts 14 forming heat exchange fins.

The bundle 10 communicates at a first end with a first manifold 16 which extends in a generally vertical direction and which comprises a cylindrical wall 18, preferably of circular section, into which the tubes 12 open at one of their ends .

The manifold 16 extends over the entire height of the bundle 10. It comprises two end walls 20 and 22 placed respectively in the upper part and two intermediate partitions 24 and 26.

The manifold 16 is thus divided into three chambers, namely an inlet chamber 28, an intermediate chamber 30 and an outlet chamber 32. The manifold 16 is provided with two pipes 34 and 36 to allow the entry of a refrigerant in vapor or gas phase (flow che F1) and the exit of the same fluid in liquid phase (flow che F2) after condensation.

The tube bundle can be divided into two parts, namely an upper part PS and a lower part PI which, in the example, comprise respectively 17 and 8 tubes.

On the side of the other end of the bundle, the tubes of the upper part SP communicate with a second manifold 38, while the tubes of the lower part PI communicate with a reservoir 40, the manifold 38 and the reservoir 40 being completely separated from each other.

The second manifold 38 extends over the entire height of the upper part PS of the bundle and is limited by a side wall 42, as well as by an upper wall 44 and a lower wall 46.

The reservoir 40 comprises a lower part 48 which extends over a height corresponding to that of the lower part PI of the bundle and an upper part 50 forming a vertical extension which extends over the entire height of the second manifold 38. The reservoir 40, including its extension, is closed in the lower part by a wall 52 and in the upper part by the above-mentioned wall 44. The lower part 48 of the tank has a cross section whose area is larger than that of the upper part 50.

Inside the tank is placed a vertical partition 54 which extends over part of the height of the tank.

This vertical partition is connected in the lower part to a transverse partition 56 to divide the lower part PI of the bundle into two sub-beams PIS and PII which each include four tubes, in the example considered.

The vertical partition 54 stops at a distance from the upper wall 44 to provide a communication passage 58. The vertical partition 54 and the transverse partition 56 make it possible to delimit, inside the tank 40, two circulation paths, namely a path vertical up 60 and a vertical down 62.

The reservoir 40 is capable of containing a desiccant capable of absorbing the moisture existing in the refrigerant passing through the reservoir 40.

The condenser of Figure 1 is intended to be mounted in an air conditioning circuit further comprising a compressor, an expansion valve and an evaporator (not shown).

The refrigerant is first compressed by the compressor in order to be in the superheated gas phase. I1 then enters the inlet chamber 28 of the manifold 16 through the tubing 34. I1 then circulates in a portion of the upper part PS of the bundle 10 to reach the second collector chamber 38. Then, the fluid circulates in the opposite direction in another sub-part of the upper part PS of the bundle 10 to reach the intermediate chamber 30. The upper part PS, also called "upstream part", constitutes a part of the bundle which allows the condensation of the refrigerant.

The refrigerant then leaves the intermediate chamber 30 and circulates in the sub-beam PIS of the lower part PI of the beam to reach a chamber 64 delimited in the lower part 48 of the tank 40. The previously condensed refrigerant is forced to move vertically upwards following the vertical upward path 60. Then it gains the downward vertical path 62 passing through the passage 58. When the fluid follows the downward vertical path 62, it undergoes the effect of gravitation, which facilitates the separation of the gaseous and liquid phases, the gaseous phase tending to rise and the liquid phase tending to descend. Is then collected, in a chamber 66 located in the lower part of the lower part 48 of the tank 40, only refrigerant in liquid phase, previously condensed and which is being sub-cooled.

Then, this fluid during sub-cooling reaches the outlet chamber 32 of the manifold 16 by the sub-beam PII of the lower part PI of the beam. During this journey, the condensed refrigerant is further sub-cooled. There is thus obtained, in chamber 32, a sub-cooled condensed fluid which then leaves the heat exchanger through the outlet pipe 36, as shown by arrow F2.

Referring now to Figure 2 which shows, in section, the embodiment of the second manifold 38 and the reservoir 40. The latter are obtained by two nested housings which include a first cylindrical wall 42 of circular section and a second cylindrical wall 68, also of circular section, which intersects with the wall 42 along two parallel generatrices 70 and 72. The diameter of the wall 68 is greater than that of the wall 42.

The wall 42 thus internally delimits the second collecting chamber 38, while the second cylindrical wall 68 internally delimits the downward vertical path 62. The upward vertical path 60 is delimited at the intersection of the walls 42 and 68.

Of course, the end walls or partitions are provided in the appropriate places, as shown in FIG. 1.

The invention thus makes it possible to promote the separation of the liquid and gaseous phases from the refrigerant during its journey through the tank. This separation effect is all the better as the height of the vertical upward path of the fluid is greater, which has the consequence of increasing the height of fall of the liquid in its downward path.

The invention finds particular application to air conditioning installations of motor vehicles.

Claims (8)

Claims 1. Condenser for a refrigeration circuit traversed by a refrigerant, comprising a bundle (10) of tubes (12), a first end of which communicates with a first manifold (16) in a generally vertical direction and a second end of which communicates with a second manifold (38) and with a reservoir (40) in a generally vertical direction, and in which the bundle of tubes (12) comprises an upper part (PS) serving for the condensation of the refrigerant, and a lower part (PI) for sub-cooling the condensed refrigerant, characterized in that the reservoir (40) extends vertically upwards over at least part of the height of the second manifold (38), and in that the reservoir (40 ) is internally divided by a substantially vertical partition (54) to force the condensed fluid, during sub-cooling, to move first along a vertical path ascending (60) then along a descending vertical path (62), which makes it possible to promote the separation of the gaseous and liquid phases of the refrigerant by gravitation effect. 2. Condenser according to claim 1, characterized in that the reservoir (40) extends vertically upwards over the entire height of the second manifold (38). 3. Condenser according to one of claims 1 and 2, characterized in that the reservoir (40) has a lower part (48) into which the lower part (PI) of the tube bundle opens, and an upper part (50) forming a vertical extension and extending along the second manifold (38). 4. Condenser according to claim 3, characterized in that the lower part (48) of the reservoir (40) has a cross section whose area is larger than that of its upper part (50). 5. Condenser according to one of claims 1 to 4, characterized in that the vertical partition (54) is attached to a transverse partition (56) to divide the flow from the lower part (PI) of the bundle and distribute it between the upward path (60) and downward path (62). 6. Condenser according to one of claims 1 to 5, characterized in that the second manifold (38) and the reservoir (40) are delimited by a first cylindrical wall (42) and by a second cylindrical wall (68) to parallel generators, which intersect, so that the first cylindrical wall (42) delimits the second manifold (38), that the second cylindrical wall (68) delimits the downward vertical path (62) and that the intersection of the two walls defines the upward vertical path (60). 7. Condenser according to claim 6, characterized in that the first cylindrical wall (42) and the second cylindrical wall (68) are of circular section. 8. Condenser according to claim 7, characterized in that the second cylindrical wall (68) has a diameter greater than that of the first cylindrical wall (42).