A CONDENSER

Abstract

 A condenser 1 comprising a series of tubes 20 communicated fluidly with and interposed between two tubular header boxes 10, 11, and further comprising a cylinder 30 adapted to receive and contain a fluid used for heat exchange, wherein the cylinder 30 is communicated fluidly with the header box 11 through plurality of openings 31, wherein at least one of the openings 31 has an oblong shape.

Description

FIELD OF THE INVENTION

[0001] The invention relates to heat exchangers for automotive application. In particular, it relates to condensers comprising a condenser cylinder.

BACKGROUND OF THE INVENTION

[0002] Generally, a heat exchanger for an air-conditioning heat loop of comprises a bundle of parallel tubes and two headers to which the corresponding ends of the parallel tubes are connected in a fixed and sealed way. Thus the fluid can flow through the tubes, being made to pass from the vapor phase to the liquid phase by the external forced air flow which sweeps the tubes whose surface area, increased by the addition of disrupters or dividers in the tubes and/or between the tubes, and optimizes the heat exchange.

[0003] In the present case, the exchanger can be of the type produced by brazing, and the headers used may be designed in two parts, being known as "two-part headers" or "two-part header boxes".

[0004] This type of header, which has a tubular overall shape, includes: a header plate with a longitudinally open wall, provided with slots intended to receive the corresponding ends of the parallel fluid flow tubes; and a cover which, after assembly, closes the longitudinal opening of the header plate, and which has a wall including at least one external collar delimiting a hole for the flow of fluid.

[0005] Typically in an air-conditioning system, the stages of evaporation, compression, condensation and expansion take place one after another by using a suitable fluid such as a fluid of the R134 or 1234YF type. After the condensation stage, the fluid is maintained in a liquid state inside a reservoir. This reservoir may be integrated into a condenser or may stand alone and be connected to the outlet of said condenser.

[0006] When the fluid is condensed in the condenser, said fluid circulates at the saturation temperature of said fluid towards a reservoir such as a condenser cylinder. A condenser cylinder has the function of separating the liquid and gas phases in a fluid in order to allow only the fluid to exit in its liquid state. At the same time, the condenser cylinder may be used with the aim of sub-cooling the fluid, i.e. of reducing the temperature of the fluid to below the saturation temperature corresponding to the defined condensation pressure.

[0007] According to the prior art, the condenser cylinder has a first function of maintaining the fluid used in the loop. Additional functionality consists, for example, in absorbing humidity by virtue of the presence of a material such as a suitable gel. The condenser cylinder may also serve to filter the fluid present in the loop, thus preventing particles having a larger size than a set threshold value from circulating within the air-conditioning system.

[0008] In the automotive industry, the air conditioning systems of vehicles have substantial influence on the emissions and fuel consumption of said vehicles. New requirements are continuously set for new vehicles, demanding reduction of the fuel consumption, which in turn often requires better efficiency and performance of the air conditioning systems. This means for example that the thermal performance and the subcooling plateau length on the condenser are to be increased, as many solutions applied today fail to meet the ever-increasing requirements. By the plateau length it is meant here the length of the constant pressure, temperature, superheat and sub cooling level, while the system is charged with coolant. The plateau has an aim to ensure the system operation with the same cooling performance during lifetime.

[0009] The aim of the invention is to improve efficiency and performance of the condenser assembly. This aim is to be achieved at low cost and with minimum modifications to the existing design.

SUMMARY OF THE INVENTION

[0010] The object of the invention is, among others a condenser comprising a series of tubes communicated fluidly with and interposed between two tubular header boxes, and further comprising a cylinder adapted to receive and contain a fluid used for heat exchange, wherein the cylinder is communicated fluidly with the header box through plurality of openings, wherein at least one of the openings has an oblong shape.

[0011] Preferably, all openings communicating the cylinder with the header box have an oblong shape.

[0012] Preferably, each oblong opening has a rectangular shape with rounded corners, wherein at least two opposite second walls are parallel and longer than the two opposite first walls.

[0013] Preferably, each oblong opening has a shape defined by two half-circles, the free ends of which are connected by parallel lines.

[0014] Preferably, the header box comprises collar of oblong shape corresponding to each oblong opening in the cylinder.

[0015] Preferably, the header box comprises a base and a cover, wherein said cover comprises collars.

BRIEF DESCRITPTION OF DRAWINGS

[0016] Examples of the invention will be apparent from and described in detail with reference to the accompanying drawings, in which:

Fig. 1 shows a condenser in a front view;

Fig. 2 shows the bottle of the condenser in a perspective view;

Fig. 3 shows a closer view of the cylinder;

Fig. 4a shows a header box of the cylinder in a perspective view, while Fig. 4b shows the cross-section of the header box.

DETAILED DESCRIPTION OF EMBODIMENTS

[0017] Fig. 1 shows a heat exchanger in a front view. In particular, a condenser 1 is shown. In structural terms, the condenser 1 comprises, in a known way, a bundle of parallel tubes 20 whose ends are connected in a fixed and sealed way to the upstream and downstream headers or header boxes, numbered 10 and 11 respectively, in the direction of flow of the working fluid flowing in the loop in question. An inlet fluid connecting flange and an outlet fluid connecting flange are attached to these headers respectively, as are attachment plates for attaching the heat exchanger to other elements of the vehicle.

[0018] In particular, the tubes 20 in which the fluid flows have an oblong cross section, and dividers are arranged between them, thereby increasing the surface for heat exchange between the fluid flowing in the exchanger 1 and the external air flow passing through the exchanger 1. The inside of the tubes 20 may also include disrupters which, like the dividers, increase the heat exchange surface and also the mechanical strength of the tubes. Extruded tubes may also be used. Each tube 20 forms, for example, a plurality of parallel internal channels for the flow of fluid.

[0019] The condenser 1 further comprises a condenser cylinder 30 attached to one of the header boxes - in this case to the header box 11. The header box 11 is divided internally by portioning walls so that the flow of the fluid can be redirected to make a U-turn within the bundle of tubes. The condenser cylinder 30 is connected to the header box 11 through inlet and outlet openings 31, so that the fluid can enter and exit the condenser cylinder 30. Said inlet and outlet openings 31 are fluidly separated within the header box 11 by the partitioning walls, so any mixing of the fluids before and after entering the cylinder 30 is prevented.

[0020] Fig. 2 shows the cylinder of the condenser in a perspective view. The inlet and outlet openings 31 of the condenser cylinder 30 are located in the lower portion of the cylinder 30. In this example, the openings 31 are located in the mounting flange 32 of the cylinder 30. However, they could be located directly on the cylinder 30 without said mounting flange 32.

[0021] Fig. 3 shows a closer view of the condenser cylinder 30. In particular, the details of the opening 31 can be observed. According to the invention, the opening 31 has an oblong shape, i.e. cross-section. In particular, the oblong opening 31 has a rectangular shape with rounded corners, wherein at least two opposite walls 31b are parallel and longer than the two remaining walls 31a. In this example, the oblong opening 31 has a shape defined by two first walls 31a in form of half-circles, the free ends of which are connected by two second walls 31b in form of parallel lines. In particular case, the oblong shape can be an oval shape, with both first walls 31a and second walls 31b substantially rounded.

[0022] It was observed by the applicant that such shape of the opening allows to improve the efficiency and thermal performance of the condenser in a substantial manner, especially in comparison to a standard round hole applied in the condenser cylinder. In particular, changing shape from to oblong effectively allows to enlarge one of its dimensions in the longitudinal direction of the header box without enlarging the dimension in the traverse direction. This improves the thermal performance, while at the same time decreases the pressure drop. Further, is has been observed a significant improvement in the plateau length of the condenser.

[0023] Fig. 4a shows the header box 11 of the condenser 1 in a perspective view, while Fig. 4b shows the cross-section of the header box 11. The header box 11 comprises collars 14 for cooperation with openings 31 in the condenser cylinder 30, that is to enable flow between the header box 11 and the cylinder 30. These preferably have an oblong shape corresponding to each oblong opening 31 in the cylinder 30. In particular, the collars 14 are located on the cover 22 of the header box 20. The cover 22 is attached to the base 21, into which tubes 20 protrude. A secure connection is thus facilitated.

[0024] Not all openings 31 between the header box 11 and the cylinder 30 have to be of oblong shape. In particular, in some cases where requirements regarding the efficiency are less strict, at least one of the openings 31 has to be oblong - other opening or openings can remain circular.

[0025] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of drawings, the disclosure, and the appended claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to the advantage.

Claims

1. A condenser 1 comprising a series of tubes 20 communicated fluidly with and interposed between two tubular header boxes 10, 11, and further comprising a cylinder 30 adapted to receive and contain a fluid used for heat exchange, wherein the cylinder 30 is communicated fluidly with the header box 11 through plurality of openings 31, characterized in that at least one of the openings 31 has an oblong shape.

2. A condenser 1 according to claim 1, wherein all openings 31 communicating the cylinder 30 with the header box 11 have an oblong shape.

3. A condenser according to any preceding claim, wherein each oblong opening 31 has a rectangular shape with rounded corners, wherein at least two opposite second walls 31b are parallel and longer than the two opposite first walls 31a.

4. A condenser 1 according to any preceding claim, wherein each oblong opening 31 has a shape defined by two half-circles, the free ends of which are connected by parallel lines.

5. A condenser 1 according to any preceding claim, wherein the header box 11 comprises collar 14 of oblong shape corresponding to each oblong opening in the cylinder 30.

6. A condenser according to claim 5, wherein the header box 11 comprises a base 12 and a cover 13, wherein said cover 13 comprises collars 14.

Drawing