EP1319907A2

EP1319907A2 - Heat exchanger

Info

Publication number: EP1319907A2
Application number: EP02258119A
Authority: EP
Inventors: Kenichi c/o Sanden Corporation Wada; Hirotaka C/O Sanden Corporation Kado
Original assignee: Sanden Corp
Current assignee: Sanden Corp
Priority date: 2001-12-14
Filing date: 2002-11-26
Publication date: 2003-06-18
Also published as: JP2003185296A; EP1319907A3; CN1424550A

Abstract

A heat exchanger (1) has a first header pipe (3), second header pipe (2), a plurality df tubes (4), and a plurality of fins (5). The first header pipe (3) and a second header pipe (2) are provided in a row arrangement. The first header pipe (3) has a desiccant member (12). The plurality of tubes (4) are provided in communication with the first header pipe (3) and the second header pipe (2). Both end of each tube (4) is inserted into the first header pipe (3) and the second header pipe (2), respectively. Each of the plurality of fins (5) is disposed between said tubes (4). A centre of cross-sectional area of the first header pipe (3) is offset toward one side of the heat exchanger (1) in an air flow direction, and an entire width of the end of each tube (4) is inserted into the first header pipe (3), such that a clearance is created between the end of each tube (4) and the desiccant member (12).

Description

The present invention relates to a heat exchanger including a desiccant unit inserted into one of header pipes for use in an air conditioner for vehicles. In particular, the present invention relates to a heat exchanger suitable use as a condenser in an air conditioner for vehicles.
Heat exchangers for use in an air conditioner for vehicles, which include a pair of header pipes and a plurality of heat exchanger tubes communicated therebetween, are known in the art. As shown in Figs. 4 and 5, a heat exchanger 100 has a pair of header pipes 101 and 102. The pair of header pipes 101 and 102 is communicated by a plurality of heat exchanger tubes 103. A diameter of header pipe 102 is larger than that of header pipe 101. A desiccant unit 104 is inserted into herder pipe 102.
As shown in Fig. 4, in such heat exchanger 100, because header pipe 102 having desiccant unit 104 protrudes toward both sides of heat exchanger 100 in a thickness direction (in a longitudinal direction of Fig. 4), the space of the installation of heat exchanger 100 is increased due to a portion protruding from the both sides of heat exchanger 100. Therefore, if heat exchanger 100 is used as a condenser for use in an automotive air conditioner, following problems may arise. For example, if such heat exchanger 100 is used as a condenser installed in an engine room of a vehicle, heat exchanger 100 and a radiator 105 are installed in the engine room in this order from the direction of an air flow direction as shown in an arrow A'. In this condition, an air flow route of air flowing radiator 105 after passing through heat exchanger 100 is lengthened. As a result, a leakage of air between heat exchanger 100 and radiator 105 may arise. If the air between heat exchanger 100 and radiator 105 is leaked, the amount of air passing through radiator 105 may decrease. In addition, if a suction fan (not shown) disposed at the downstream of radiator 105 is activated, the amount of the air bypassing heat exchanger 100 and flowing directly to the radiator 105 may increase. As a result, the amount of the air passing through heat exchanger 100 may decrease.
In addition, as shown in Fig. 5, a centre of a surface in a cross section of header pipe 102' is simply decentred toward an anti-radiator side in order to shorten the air flow route between heat exchanger 100 and radiator 105. In this condition, an inserting portion of each heat exchanger tube 103 into header pipe 102' is increased because the centre of a surface in a cross section of header pipe 102' is decentred. As a result, each heat exchanger tube 103 and desiccant unit 104' may be interfered each other. Specifically, if the size of desiccant unit 104', e.g., a diameter of a surface in a cross section of desiccant unit 104, is decreased in order to prevent desiccant unit 104' from interfering with each heat exchanger tube 103, the function of removing water from refrigerant in desiccant 104' may be decreased.
Therefore, a need has arisen for heat exchangers for use in air conditioners for vehicles that overcome these and other shortcomings of the related art. A technical advantage of the present invention is to decrease a protruding portion of a header pipe from one side of the heat exchanger in a thickness direction, so that a radiator is disposed adjacent to the heat exchanger. A further technical advantage of the present invention is to provide a heat exchanger preventing decrease of the amount of air passing through a radiator due to the air leakage between the heat exchanger and the radiator.
According to an embodiment of the present invention, a heat exchanger comprises a first header pipe, second header pipe, a plurality of tubes, and a plurality of fins. The first header pipe and a second header pipe are provided in a row arrangement. The first header pipe has a desiccant member. The plurality of tubes are provided in communication with the first header pipe and the second header pipe. Both end of each tube is inserted into the first header pipe and the second header pipe, respectively. Each of the plurality of fins is disposed between said tubes. A centre of cross-sectional area of the first header pipe is offset toward one side of the heat exchanger in an air flow direction, and an entire width of the end of each tube is inserted into the first header pipe, such that a clearance is created between the end of each tube and the desiccant member.
Objects, features, and advantages of embodiments of this invention will, be apparent to persons of ordinary skill in the art from the following detailed description of the invention and the accompanying drawings.
The present invention may be more readily understood with reference to the following drawings, in which:
Fig. 1 is a front view of a heat exchanger, according to a first embodiment of the present invention;
Fig. 2 is a cross-sectional view of the heat exchanger depicted in Fig. 1;
Fig. 3 is a cross sectional view, which corresponds to Fig. 2, of a heat exchanger, according to a second embodiment of the present invention;
Fig. 4 is a cross-sectional view, which corresponds to Fig. 2, according to a known heat exchanger; and
Fig. 5 is a cross-sectional view, which corresponds to Fig. 2, according to another known heat exchanger.
Referring to Figs. 1 and 2, a heat exchanger according to a first embodiment is described. In the embodiment, the present invention applied to a condenser having a function as a receiver, in particular to a subcool-type condenser, is described.
As shown in Fig. 1, a subcool-type condenser 1 comprises a second header pipe 2, a first header pipe 3, and a plurality of heat exchanger tubes 4. Second header pipe 2 and first header pipe 3 are vertically arranged in parallel with each other. The plurality of heat exchanger tubes 4 extend in parallel with each other, communicating between header pipes 2 and 3. Pluralities of corrugated fins 5 are provided between heat exchanger tubes 4 and on their outer layers. Second header pipe 2 has an inlet pipe 6 for introducing refrigerant at an upper portion and an outlet pipe 7 for discharging the refrigerant at a lower portion in a vertical direction.
A partition plate 8 is provided within second header pipe 2. Partition plate 8 divides the inside of second header pipe 2 into an upper compartment (an upper header pipe portion 2a) and a lower compartment (a lower header pipe portion 2b). Partition plate 8 also divides the area, in which the plurality of heat exchanger tubes 4 are located, into a refrigerant condensing core 9 and a subcool core 10. Refrigerant condensing core 9 condenses the refrigerant introduced into condenser 1. Subcool core 10 supercools the condensed refrigerant from condensed refrigerant from refrigerant condensing core 9. Specifically, partition plate 8 provided in which second header pipe 2 is integrally formed divides the entire core of condenser 1 into refrigerant condensing core 9 and subcool core 10. In subcool-type condenser 1, there is a single refrigerant flow path formed of heat exchanger tubes 4 extending in parallel with each other in refrigerant condensing core 9. Therefore, the refrigerant introduced through inlet pipe 6 into second header pipe 2 passes through heat exchanger tubes 4 of refrigerant condensing core 9 constituting one path route, and flows into first header pipe 3. Subsequently, after the refrigerant flows downwardly within first header pipe 3, the refrigerant is directly introduced into an inlet of subcool core 10. Moreover, the refrigerant passes through each heat exchange tube 4 of subcool core 10, and flows out though outlet pipe 7. Alternatively, refrigerant condensing core 9 may consist of two or more path routes.
Specifically, in this embodiment, an occupation rate of subcool core 9 to an entire subcool-type condenser 1 is set about 10%. According to an experiment implemented by the applicant, it is desirable that a range of this occupation rate is between about 5% and about 12%. By setting the occupation rate within this range, reducing the installation space for subcool-type condenser 1 in the engine room of the vehicle may be achieved. Moreover, an optimum supercool is achieved as well as an increase of the pressure at a high pressure side due to subcooling the refrigerant in a limited size of condensing area is suppressed and a deterioration of a fuel consumption of the vehicle is suppressed.
In this embodiment, a portion at first header pipe 3 corresponding to the inlet of subcool core 10 is a liquid-refrigerant temporary retention portion 11. The refrigerant from refrigerant condensing core 9, i.e., the refrigerant from an upper portion of first header pipe 3, is retained in retention portion 11. Subsequently, the refrigerant flows into each heat exchange tube 4 of subcool core 10 from retention portion 11.
As shown in Fig. 2, the dimension of first header pipe 3 in a thickness direction (the dimension of first header pipe 2 in a longitudinal direction in Fig. 2) is set larger than that of second header pipe 2. A desiccant unit 13 filling a desiccant member 12 is inserted into first header pipe 3. Desiccant unit 13 has a substantially C-shape in its cross section (not shown). As shown in Fig. 1, a lower portion of desiccant unit 13 is inserted into a strainer 14, which has a function capturing foreign materials. In this embodiment, desiccant unit 13 is accommodated within an entire length of first header pipe 3. Desiccant unit 13 is supported by support members 15 and 16, which are disposed within first header pipe 3.
As shown in Fig. 2, first header pipe 3 is disposed at a position downward of a thickness of subcool-type condenser 1 (downward in Fig. 2). Specifically, a centre of cross-sectional area of first header pipe 3 is offset toward an anti-radiator side. Moreover, a clearance is provided between an end portion of each heat exchange tube 4 inserted into first header pipe 3 and desiccant unit 13, so that interference between the end portion of each heat exchanger tube 4 and desiccant unit 13 is avoided. A surface 18 substantially parallel with a heat exchanger surface 17 comprising the plurality heat exchange tubes 4 is formed at a circumferential surface of first header pipe 3.
In this embodiment, surface 18 is formed at the circumferential surface of first header pipe 3, and surface 13 faces a radiator 19. Moreover, first header pipe 3 is disposed at the position downward of a thickness of subcool-type condenser 1, i.e., toward an upstream of an air flow direction as shown in an arrow A. Specifically, the centre of cross-sectional area of first header pipe 3 is offset toward an anti-radiator side. Therefore, a protruding portion of first header pipe 3 toward radiator 19 may be considerably decreased, and the length of an air flow route between subcool-type condenser 1 and radiator 19 may be considerably shortened. In addition, desiccant unit 13 is inserted within the entire length of first header pipe 3, so that the clearance is created between the end portion of each heat exchange tube 4 and desiccant unit 13. Therefore, interference between the end portion of each heat exchange tube 4 and desiccant unit 13 may be avoided.
Referring to Fig. 3, a heat exchanger 20 (a subcool-type condenser 20) according to a second embodiment is described. In the following explanation, the same reference numbers are used to represent the same parts of heat exchanger 1 (subcool-type condenser 1) as shown in Figs. 1 and 2, and the explanation of the same parts is omitted. As shown in Fig. 3, a cross-sectional area of a first header pipe 21 of subcool-type condenser 20 has a substantially elliptical shape, which swells from an insert side of each heat exchanger tube 4 toward its axial end. A centre of the cross-sectional area of first header pipe 21 is offset toward an anti-radiator side. First header pipe 21 is disposed with an inclination to the anti-radiator side, so that a surface 22 of first header pipe 21 formed at its circumferential surface is substantially parallelled with a heat exchanger surface 17. Moreover, an entire width of an end portion of each heat exchange tube 4 is inserted within header pipe 21, such that the clearance is created between the end portion of each heat exchange tube 4 and a desiccant unit 13.
In the second embodiment, because the centre of the cross-sectional area of first header pipe 21 is offset toward an anti-radiator side, a protruding portion of first header pipe 21 toward a radiator 19 may be considerably decreased, and the length of an air flow route between subcool-type condenser 20 and radiator 19 may be considerably shortened. Moreover, because the clearance is created between the end portion of each heat exchanger tube 4 and a desiccant unit 13, interference between the end portion of each heat exchanger tube 4 and desiccant unit 13 may be avoided.
As described above, according to the embodiments of the present invention, because a length of an air flow route between a heat exchanger and a radiator is considerably shortened, a decrease of the amount of an air passing through the radiator may be avoided. Moreover, the space of the installation of the heat exchanger may be substantially reduced.

Claims

A heat exchanger (1) comprising:

a first header pipe (3) and a second header pipe (2) provided in a row arrangement, wherein said first header pipe (3) has a desiccant member (12);

a plurality of tubes (4) provided in communication with said first header pipe (3) and said second header pipe (2), wherein both end of said each tube (4) is inserted into said first header pipe (3) and said second header pipe (2), respectively; and

a plurality of fins(5), each of which is disposed between said tubes (4);

wherein a centre of cross-sectional area of said first header pipe (3) is offset toward one side of said heat exchanger (1) in an air flow direction (A), and an entire width of said end of said each tube (4) is inserted into said first header pipe (3), such that a clearance is created between said end of said each tube and said desiccant member (12).
A heat exchanger (1) according to claim 1, wherein a surface (18, 22) is formed at a circumferential surface of said first header pipe (3), and said surface (18,22) is substantially parallel with a heat exchanger surface (17) comprising said plurality of tubes (4).
A heat exchanger (1) according to any one of claims 1 and 2, wherein a dimension of said first header pipe (3) in a cross section is set larger than that of said second header pipe (2).
A heat exchanger (1) according to any one of claims 1 to 3, further comprising:

a refrigerant condensing core (9) for condensing refrigerant; and

a subcool core (10) for supercooling the refrigerant condensed from said refrigerant condensing core (9).
A heat exchanger (1) according to any one of claims 1 to 4, wherein said heat exchanger (1) is a refrigerant condenser used for an automotive air conditioning apparatus that is installed in an engine compartment of a vehicle.