JP5899013B2 - Double tube heat exchanger - Google Patents

Description

  The present invention relates to a double-pipe heat exchanger, and more particularly to a double-pipe heat exchanger that includes an outer tube and an inner tube that is spaced from the outer tube.

  In this specification, the term “capacitor” includes a subcool condenser having a condensing part and a supercooling part in addition to a normal condenser.

  Conventionally, as a refrigeration cycle used in a car air conditioner, a compressor, a condenser having a condensing part and a supercooling part, an evaporator, an expansion valve as a decompressor, a gas-liquid separator, and a condenser and an evaporator, and An apparatus including an intermediate heat exchanger for exchanging heat between a high-temperature refrigerant coming out of a condenser supercooling section and a low-temperature refrigerant coming out of an evaporator has been proposed (see Patent Document 1). According to the refrigeration cycle described in Patent Document 1, the refrigerant that has been supercooled in the supercooling section of the condenser is further cooled by the low-temperature refrigerant that has come out of the evaporator in the intermediate heat exchanger, thereby improving the cooling performance of the evaporator. It can be improved.

  The intermediate heat exchanger used in the refrigeration cycle described in Patent Document 1 includes an outer tube and an inner tube arranged at intervals in the outer tube, and a gap between the outer tube and the inner tube is a condenser. The first refrigerant flow path through which the high-temperature refrigerant coming out of the refrigerant flows, the second refrigerant flow path through which the low-temperature refrigerant coming out of the evaporator flows through the inner pipe, and the refrigerant communicating with the first refrigerant flow path in the outer pipe An inlet and a refrigerant outlet are formed at intervals in the length direction of the outer pipe, and a refrigerant inflow pipe leading to the refrigerant inlet of the outer pipe and a refrigerant outflow pipe also leading to the refrigerant outlet are joined to the outer pipe, respectively. The inflow pipe and the refrigerant outflow pipe are composed of a double-tube heat exchanger located at the same position in the circumferential direction of the outer tube.

  However, in the case of the double-tube heat exchanger described in Patent Document 1, the refrigerant that has flowed into the first refrigerant flow path between the outer pipe and the inner pipe from the refrigerant flow-in pipe is the refrigerant flow into the first refrigerant flow path. A large amount of the pipe-side portion flows, resulting in refrigerant drift, and the refrigerant flow in the first refrigerant flow path becomes uneven in the circumferential direction. As a result, the heat exchange efficiency between the high-temperature refrigerant flowing through the first refrigerant flow path and the low-temperature refrigerant flowing through the second refrigerant flow path may be reduced.

  In view of this, the present applicant has previously found that the basic configuration is the same as that of the double pipe heat exchanger described in Patent Document 1, and the refrigerant outflow pipe is displaced in the circumferential direction of the outer pipe with respect to the refrigerant inflow pipe. Proposed a double-pipe heat exchanger (see Patent Document 2).

  However, compared with the double-pipe heat exchanger described in Patent Document 2, there is a double-pipe heat exchanger that can more effectively equalize the refrigerant flow in the first refrigerant flow path in the circumferential direction. It has been demanded.

JP 2009-204165 A JP 2012-21734 A

  The object of the present invention is to meet the above requirements and to make the refrigerant flow in the first refrigerant flow path uniform in the circumferential direction as compared with the double pipe heat exchanger described in Patent Document 2. It is to provide a heat exchanger.

  In order to achieve the above object, the present invention comprises the following aspects.

1) An outer pipe and an inner pipe arranged at intervals in the outer pipe, and a gap between the outer pipe and the inner pipe becomes the first refrigerant flow path, and the inner pipe has the second refrigerant flow path. A refrigerant inlet that leads to the first refrigerant flow path is formed in the outer pipe, and a refrigerant inflow pipe that feeds the refrigerant into the first refrigerant flow path is joined to the outer pipe so as to lead to the refrigerant inlet. A double-tube heat exchanger in which a constant length from the refrigerant inlet side end of the refrigerant inflow pipe is linear,
The center line of the straight portion on the refrigerant inlet side of the refrigerant inlet pipe and the center line of the portion of the inner pipe facing the refrigerant inlet of the outer pipe form a fixed angle when viewed from the outside in the radial direction of the outer pipe. The extension line to the inner pipe side in the center line of the linear portion of the refrigerant inflow pipe is shifted radially outward from the inner pipe ,
One end portion of the outer tube is provided with an enlarged portion that extends outward as compared with other portions and has a cylindrical portion of the peripheral wall, and exists in the enlarged portion of the inner tube on the peripheral wall of the enlarged portion The flat pipe joint parallel to one imaginary plane where the center line of the part is located is radially inward of the enlarged part from the cylindrical surface on which most of the peripheral wall of the enlarged part of the outer pipe is located A double-pipe heat exchanger that is provided so as to protrude .

2) The center line of the straight portion of the refrigerant inflow pipe and the center line of the portion of the inner pipe facing the refrigerant inlet of the outer pipe form a right angle when viewed from the outside in the radial direction of the outer pipe. A double-pipe heat exchanger as described in 1) above.

According to the double-tube heat exchangers of 1) and 2) above, the center line of the straight portion on the refrigerant inlet side of the refrigerant inflow pipe and the center line of the portion of the inner pipe facing the refrigerant inlet of the outer tube However, when viewed from the outside in the radial direction of the outer pipe, it forms a certain angle and does not intersect, and the extension line to the inner pipe side at the center line of the linear portion of the refrigerant inflow pipe extends from the inner pipe. Since it is displaced radially outward, the refrigerant that has flowed into the first refrigerant flow path through the refrigerant inflow pipe flows in the circumferential direction along the outer peripheral surface of the inner tube. Therefore, the refrigerant spreads over the entire circumferential direction in the first refrigerant flow path, and the flow of the refrigerant in the first refrigerant flow path as compared with the double pipe heat exchanger described in Patent Document 2. Is made uniform in the circumferential direction of the outer tube. As a result, the heat exchange efficiency between the high-temperature refrigerant flowing through the first refrigerant flow path and the low-temperature refrigerant flowing through the second refrigerant flow path is improved.

According to the double pipe heat exchanger of 1) above, the center line of the refrigerant inflow pipe intersects with the center line of the portion of the inner pipe facing the refrigerant inlet of the outer pipe with a relatively simple configuration. And when viewed from the outside of the outer pipe, make a certain angle, and the extension line to the inner pipe side of the center line of the refrigerant inflow pipe should be shifted radially outward from the inner pipe Can do .

According to the double-pipe heat exchanger of the two), the flow of the refrigerant in the first refrigerant passage is effectively uniform by the circumferential direction of the outer tube.

It is the vertical longitudinal cross-sectional view which abbreviate | omitted the intermediate part of the length direction which shows the whole structure of the double tube | pipe type heat exchanger by this invention. It is the sectional view on the AA line of FIG. It is a BB line expanded sectional view of Drawing 1. It is a figure equivalent to FIG. 2 which shows the modification of the expansion part of an outer tube | pipe.

  Embodiments of the present invention will be described below with reference to the drawings.

  In the following description, the term “aluminum” includes aluminum alloys in addition to pure aluminum.

  In the following description, the top and bottom and the left and right in FIG.

  FIG. 1 shows the overall configuration of a double-pipe heat exchanger according to the present invention, and FIGS. 2 and 3 show the configuration of the main part thereof.

  1 and 2, the double-tube heat exchanger (1) is inserted into the outer tube (2) made of extruded aluminum having a circular cross section and concentrically with a space in the outer tube (2). The inner pipe (3) made of extruded aluminum with a circular cross section is provided, and the gap between the outer pipe (2) and the inner pipe (3) becomes the first refrigerant channel (4), and the inner pipe (3) The inside is the second refrigerant flow path (5). Both end portions of the inner pipe (3) protrude outward from both end portions of the outer pipe (2), and pipe joint members (6) are joined to both protruding end portions, respectively.

  The right end of the outer tube (2) is provided with an enlarged portion (7) that spreads outward compared to the other portions. Here, the enlarged portion (7) is provided by joining the outer pipe (2) separately from the outer pipe (2). (2) may be provided integrally with the outer tube by expanding the tube. One virtual plane (P) where the center line (O1) of the portion (3a) existing in the enlarged portion (7) of the inner pipe (3) is located on the peripheral wall (7a) of the enlarged portion (7) A parallel flat pipe joint (8) is provided. The peripheral wall (7a) of the enlarged portion (7) is mostly cylindrical, and the pipe joint (8) is larger than the cylindrical surface on which the majority of the peripheral wall (7a) of the enlarged portion (7) is located. It is provided so as to protrude outward in the radial direction of the portion (7). A refrigerant inlet (9) that leads to the first refrigerant flow path (4) is formed in the pipe joint (8), and a refrigerant inflow pipe that feeds the refrigerant into the first refrigerant flow path (4) leads to the refrigerant inlet. The aluminum refrigerant inflow pipe (11) is brazed to the pipe joint (8) so as to communicate with the refrigerant inlet (9) of the outer pipe (2). Here, the end of the refrigerant inflow pipe (11) is brazed to the pipe joint (8) while being inserted into the refrigerant inlet (9). A constant length portion from the refrigerant inlet (9) side end portion of the refrigerant inflow pipe (11), here, the whole is linear.

  Therefore, the center line (O2) of the refrigerant inflow pipe (11) and the part of the inner pipe (3) facing the refrigerant inlet (9) of the outer pipe (2), that is, the enlarged part (7) of the outer pipe (2) The center line (O1) of the portion (3a) existing inside is perpendicular to the outer pipe (2) when viewed from the outside (right side in FIG. 2). In FIG. ) Is parallel to the tangent line of the inner tube (3) at the point where the virtual plane (P) and the outer surface of the inner tube (3) intersect. FIG. 2 shows a cross section in one plane in which the center line (O2) of the refrigerant inflow pipe (11) includes the center line (O2) and is orthogonal to the center line (O1) of the inner pipe (3). The line (O2) is parallel to the tangent of the inner tube (3) on the plane. That is, the center line (O2) of the refrigerant inflow pipe (11) and the center line (O1) of the portion (3a) existing in the enlarged portion (7) of the outer pipe (2) in the inner pipe (3) When viewed from the outside of the outer pipe (2) (right side in FIG. 2), the inner pipe (3) at a center angle (O2) of the refrigerant inflow pipe (11) forms a certain angle and does not intersect. The extension line to the side is displaced radially outward from the inner tube (3).

  A part of the outer tube (2) is expanded at a portion closer to the left end of the outer tube (2), that is, a slightly inner portion in the length direction from the left end, thereby forming the expanded portion (12). A refrigerant outlet (13) communicating with the first refrigerant flow path (4) is formed in the peripheral wall (12a) of the expanded pipe (12), and the aluminum refrigerant outlet pipe (14) is connected to the refrigerant outlet of the outer pipe (2). The peripheral wall (12a) is brazed so as to lead to (13). Here, the end of the refrigerant outflow pipe (14) is brazed to the peripheral wall (12a) in a state of being inserted into the refrigerant outlet (13).

  As shown in FIGS. 2 and 3, a plurality of ridges (15) projecting inward in the radial direction and extending in the length direction are integrally formed on the inner peripheral surface of the outer tube (2) at equal intervals in the circumferential direction. Is provided. A gap between adjacent ridges (15) in the first refrigerant channel (4) is a channel portion (4A). Then, the inside of the enlarged portion (7) of the outer pipe (2) passes through the entire flow path portion (4A) of the first refrigerant flow path (4) and flows into the outer pipe (2) from the refrigerant inflow pipe (11). The refrigerant distribution part which divides the refrigerant that has flown into the whole flow path part (4A), and the inside of the expanded pipe part (12) is allowed to pass through the whole flow path part (4A) of the first refrigerant flow path (4) and the whole flow path part. It is a refrigerant junction part that joins the refrigerant that has flowed through (4A).

  The double pipe heat exchanger (1) described above includes, for example, a compressor, a condenser, a condenser having a liquid receiver as a gas-liquid separator and a supercooling part, an evaporator, and an expansion valve as a pressure reducer. In the refrigeration cycle, the refrigerant is used as an intermediate heat exchanger for exchanging heat between the refrigerant coming out of the condenser and the refrigerant coming out of the evaporator. The refrigeration cycle is mounted on a vehicle such as an automobile as a car air conditioner.

  In this refrigeration cycle, a pipe extending from the supercooling section of the condenser is connected to the refrigerant inflow pipe (11) connected to the outer pipe (2) of the double pipe heat exchanger (1), and the outer pipe ( A pipe extending to the expansion valve is connected to the refrigerant outflow pipe (14) connected to 2). In addition, a pipe extending from the evaporator is connected to the end of the inner pipe (3) of the double pipe heat exchanger (1) on the side of the refrigerant outflow pipe (14), and the refrigerant inflow pipe ( 13) A pipe extending to the compressor is connected to the end on the side.

  During operation of the refrigeration cycle, the high-temperature and high-pressure gas-liquid mixed phase refrigerant compressed by the compressor is cooled and condensed by the condenser section of the condenser, and then flows into the receiver and is separated into two phases. Then, it flows into the supercooling section and is supercooled. The supercooled liquid-phase refrigerant flows into the enlarged portion (7) of the outer pipe (2) of the double-pipe heat exchanger (1) through the refrigerant inflow pipe (11), and the enlarged portion (7). It enters into the 1st refrigerant channel (4) via. At this time, the center line (O2) of the refrigerant inflow pipe (11) and the center line (O1) of the portion (3a) existing in the enlarged portion (7) of the outer pipe (2) in the inner pipe (3) When viewed from the outside of the outer pipe (2) (right side of Fig. 2), it is perpendicular, and the center line (O2) of the refrigerant inflow pipe (11) is parallel to the tangent of the inner pipe (3). Therefore, the refrigerant flowing into the enlarged portion (7) through the refrigerant inflow pipe (11) flows in the circumferential direction along the outer peripheral surface of the inner pipe (3) (see arrow X in FIG. 2), Occurrence of the drift of the liquid phase refrigerant is prevented. Accordingly, the refrigerant spreads over the entire circumferential direction in the first refrigerant flow path (4) and flows into all the flow path portions (4A), and the flow of the refrigerant in the first refrigerant flow path (4). Is made uniform in the circumferential direction. As a result, the efficiency of heat exchange between the high-temperature liquid-phase refrigerant flowing through the first refrigerant flow path (4) and the low-temperature gas-phase refrigerant described later flowing through the second refrigerant flow path (5) is improved.

  On the other hand, the gas-phase refrigerant that has come out of the evaporator flows into the second refrigerant flow path (5) of the double-pipe heat exchanger (1). Then, while the liquid-phase refrigerant flows in the first refrigerant channel (4), it is further cooled by the relatively low temperature gas-phase refrigerant flowing in the second refrigerant channel (5). The liquid-phase refrigerant that has passed through all the flow passage portions (4A) between adjacent ridges (15) in the first refrigerant flow passage (4) of the double tube heat exchanger (1) They are merged and sent to the expansion valve through the refrigerant outlet (13) and the refrigerant outflow pipe (14). The liquid-phase refrigerant sent to the expansion valve is adiabatically expanded and decompressed in the expansion valve, flows into the evaporator, and is vaporized in the evaporator. On the other hand, the gas-phase refrigerant that has passed through the second refrigerant flow path (5) of the double-pipe heat exchanger (1) is sent to the compressor.

  FIG. 4 shows a modification of the enlarged portion of the outer tube (2).

  In FIG. 4, one virtual plane in which the center line (O1) of the portion (3a) existing in the enlarged portion (20) of the inner pipe (3) is located on the peripheral wall (20a) of the enlarged portion (20). A flat pipe joint (21) parallel to (P) is provided. The peripheral wall (20a) of the enlarged portion (20) is mostly cylindrical, and the pipe joint (21) is larger than the cylindrical surface on which the majority of the peripheral wall (20a) of the enlarged portion (20) is located. It is provided so as to protrude radially inward of the portion (20). A refrigerant inlet (9) leading to the first refrigerant flow path (4) is formed in the pipe joint (21), and an aluminum refrigerant inflow pipe (11) is connected to the refrigerant inlet (9) of the outer pipe (2). The pipe joint (21) is brazed so as to communicate. Here, the end of the refrigerant inflow pipe (11) is brazed to the pipe joint (21) while being inserted into the refrigerant inlet (9).

  Therefore, the center line (O2) of the refrigerant inflow pipe (11) and the center line (O1) of the portion (3a) existing in the enlarged portion (7) of the outer pipe (2) in the inner pipe (3) When viewed from the outside (right side of FIG. 2) of the outer pipe (2), it is at a right angle. In FIG. 4, the center line (O2) of the refrigerant inflow pipe (11) is the virtual plane (P) and the inner pipe. (3) It is parallel to the tangent of the inner tube (3) at the point where the outer peripheral surface intersects. That is, the center line (O2) of the refrigerant inflow pipe (11) and the center line (O1) of the portion (3a) existing in the enlarged portion (7) of the outer pipe (2) in the inner pipe (3) When viewed from the outside of the outer pipe (2) (right side in FIG. 2), the inner pipe (3) at a center angle (O2) of the refrigerant inflow pipe (11) forms a certain angle and does not intersect. The extension line to the side is displaced radially outward from the inner tube (3).

  Even when the enlarged portion (20) shown in FIG. 4 is provided, the refrigerant flowing into the enlarged portion (20) through the refrigerant inflow pipe (11) flows along the outer peripheral surface of the inner pipe (3). Flowing in the circumferential direction (see arrow X in FIG. 4) prevents the occurrence of liquid refrigerant flow. Accordingly, the refrigerant spreads over the entire circumferential direction in the first refrigerant flow path (4) and flows into all the flow path portions (4A), and the flow of the refrigerant in the first refrigerant flow path (4). Is made uniform in the circumferential direction. As a result, the efficiency of heat exchange between the high-temperature liquid-phase refrigerant flowing through the first refrigerant flow path (4) and the low-temperature gas-phase refrigerant described later flowing through the second refrigerant flow path (5) is improved.

  The double pipe heat exchanger according to the present invention is disposed between a compressor, a condenser having a condensing part and a supercooling part, an evaporator, an expansion valve as a decompressor, a gas-liquid separator, and the condenser and the evaporator, In a refrigeration cycle that constitutes a car air conditioner having an intermediate heat exchanger that exchanges heat between the high-temperature refrigerant that has come out of the condenser supercooling section and the low-temperature refrigerant that has come out of the evaporator, it is suitable as an intermediate heat exchanger Used.

(1): Double tube heat exchanger
(2): Outer pipe
(3): Inner pipe
(4): First refrigerant flow path
(5): Second refrigerant flow path
(7) (20): Enlarged part
(7a) (20a): Perimeter wall
(8) (21): Pipe joint
(9): Refrigerant inlet
(11): Refrigerant inlet pipe
(O1): Center line of the inner pipe facing the refrigerant inlet of the outer pipe
(O2): Center line of refrigerant inflow pipe
(P): One virtual plane in which the center line of the portion existing in the enlarged portion of the inner pipe is located

Claims (2)

An outer pipe and an inner pipe arranged at intervals in the outer pipe are provided, and a gap between the outer pipe and the inner pipe serves as a first refrigerant flow path, and the inner pipe serves as a second refrigerant flow path. In addition, a refrigerant inlet that leads to the first refrigerant flow path is formed in the outer pipe, and a refrigerant inflow pipe that sends the refrigerant into the first refrigerant flow path is joined to the outer pipe so as to lead to the refrigerant inlet, A double-tube heat exchanger in which a certain length from the refrigerant inlet side end of the inflow pipe is straight,
The center line of the straight portion on the refrigerant inlet side of the refrigerant inlet pipe and the center line of the portion of the inner pipe facing the refrigerant inlet of the outer pipe form a fixed angle when viewed from the outside in the radial direction of the outer pipe. The extension line to the inner pipe side in the center line of the linear portion of the refrigerant inflow pipe is shifted radially outward from the inner pipe ,
One end portion of the outer tube is provided with an enlarged portion that extends outward as compared with other portions and has a cylindrical portion of the peripheral wall, and exists in the enlarged portion of the inner tube on the peripheral wall of the enlarged portion. The flat pipe joint parallel to one imaginary plane where the center line of the part is located is radially inward of the enlarged part from the cylindrical surface on which most of the peripheral wall of the enlarged part of the outer pipe is located A double-pipe heat exchanger that is provided so as to protrude . The center line of the straight portion of the refrigerant inflow pipe and the center line of the portion of the inner pipe facing the refrigerant inlet of the outer pipe form a right angle when viewed from the outside in the radial direction of the outer pipe. 2. The double-pipe heat exchanger according to 1.

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