JP2010139196A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the heat exchanging efficiency of an evaporator by making only liquid refrigerants flow to flat tubes to suppress a drift. <P>SOLUTION: This heat exchanger 1 includes two header pipes 2, 3 disposed in parallel with each other at an interval, and the plurality of flat tubes 4 disposed between the header pies 2, 3 in a state that a plurality of refrigerant passages 5 which are disposed therein communicate with the inside of the header pipes 2, 3. A gas-liquid separator 10 is disposed in the lower header pipe 3 at an inflow side of a gas-liquid two-phase refrigerant. The gas-liquid separator 10 separates the gas-liquid two phase refrigerant into the liquid refrigerant and a gas refrigerant, and mainly distributes the liquid refrigerant to the flat tubes 4. The gas refrigerant is introduced to a suction side of a compressor 102 compressing the refrigerant. The gas-liquid separator 10 includes a liquid refrigerant collecting cylinder 11 provided with a number of pleats 12 on a peripheral wall, and an exhaust pipe 18 projecting to an internal space of the liquid refrigerant collecting cylinder 11 and discharging the gas refrigerant to the outside. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a parallel flow type heat exchanger.

  A parallel flow type heat in which a plurality of flat tubes are arranged between a plurality of header pipes so that a plurality of refrigerant passages in the flat tubes communicate with the inside of the header pipe, and fins such as corrugated fins are arranged between the flat tubes. Exchangers are widely used in outdoor units of car air conditioners and building air conditioners.

  An example of a conventional parallel flow heat exchanger is shown in FIG. In FIG. 8, the upper side of the paper is the upper side in the vertical direction, and the lower side of the paper is the lower side in the vertical direction. In the heat exchanger 1, two horizontal header pipes 2 and 3 are arranged in parallel at a vertical interval, and a plurality of vertical flat tubes 4 are arranged at a predetermined pitch in the horizontal direction between the header pipes 2 and 3. Place with. The flat tube 4 is an elongated molded product obtained by extruding a metal, and a refrigerant passage 5 through which a refrigerant flows is formed. Since the flat tube 4 is arranged so that the extrusion molding direction which is the longitudinal direction is vertical, the refrigerant flow direction of the refrigerant passage 5 is also vertical. A plurality of refrigerant passages 5 having the same cross-sectional shape and cross-sectional area are arranged in the depth direction of FIG. 4, and therefore the horizontal cross section of the flat tube 4 has a harmonica shape. Each refrigerant passage 5 communicates with the inside of the header pipes 2 and 3. Corrugated fins 6 are arranged between the adjacent flat tubes 4.

  The header pipes 2 and 3, the flat tube 4 and the corrugated fin 6 are all made of a metal having good heat conduction such as aluminum, the flat tube 4 is for the header pipes 2 and 3, and the corrugated fin 6 is for the flat tube 4. It is fixed by brazing or welding.

  The heat exchanger 1 shown in FIG. 8 is a so-called downflow type parallel flow type heat exchanger. A large number of flat tubes 4 having a longitudinal direction in the vertical direction are provided between the upper and lower header pipes 2 and 3, and corrugated fins 6 are provided between the flat tubes 4. The area is large and heat can be exchanged efficiently. The lower header pipe 3 that is the lower header pipe is provided with a refrigerant inlet / outlet 7 at one end, and the upper header pipe 2 that is the upper header pipe is provided with a refrigerant inlet / outlet 8 at one end that forms a diagonal with the refrigerant inlet / outlet 7. ing. The positional relationship between the refrigerant inlet / outlet 7 and the refrigerant inlet / outlet 8 shown here is merely an example, and the present invention is not limited to this. For example, a configuration in which the upper header pipe 2 includes the refrigerant inlet / outlet 8 at two locations on both ends is also possible.

  The heat exchanger 1 can be mounted on a separate type air conditioner. The separate type air conditioner is composed of an outdoor unit and an indoor unit. The outdoor unit includes a compressor, a four-way valve, an expansion valve, an outdoor heat exchanger, an outdoor fan, and the like. The indoor unit is an indoor heat exchanger, a room Includes an internal blower. The outdoor heat exchanger functions as an evaporator during heating operation and functions as a condenser during cooling operation. The indoor heat exchanger functions as a condenser during heating operation and functions as an evaporator during cooling operation.

  FIG. 9 shows a basic configuration of a separate type air conditioner that uses a heat pump cycle as a refrigeration cycle. The heat pump cycle 101 includes a compressor 102, a four-way valve 103, an outdoor heat exchanger 104, a decompression / expansion device 105, and an indoor heat exchanger 106 connected in a loop. The compressor 102, the four-way valve 103, the heat exchanger 104, and the decompression / expansion device 105 are accommodated in the casing of the outdoor unit, and the heat exchanger 106 is accommodated in the casing of the indoor unit. An outdoor fan 107 is combined with the heat exchanger 104, and an indoor fan 108 is combined with the heat exchanger 106. The blower 107 is often composed of a propeller fan, and the blower 108 is often composed of a cross flow fan. As the heat exchanger 104 or the heat exchanger 106, the parallel flow heat exchanger 1 described above can be used.

  FIG. 9 shows a state during heating operation. At this time, the high-temperature and high-pressure refrigerant discharged from the compressor 102 enters the indoor heat exchanger 106 where it dissipates heat and condenses. The refrigerant exiting the heat exchanger 106 enters the outdoor heat exchanger 104 from the decompression / expansion device 105 and expands there, takes heat from the outdoor air, and returns to the compressor 102. The airflow generated by the indoor fan 108 promotes heat dissipation from the heat exchanger 106, and the airflow generated by the outdoor fan 107 accelerates heat absorption of the heat exchanger 104.

  FIG. 10 shows a state during cooling operation or defrosting operation. At this time, the four-way valve 103 is switched so that the refrigerant flow is reversed from that during the heating operation. That is, the high-temperature and high-pressure refrigerant discharged from the compressor 102 enters the outdoor heat exchanger 104, where it dissipates heat and condenses. The refrigerant exiting the heat exchanger 104 enters the heat exchanger 106 on the indoor side from the decompression / expansion device 105 and expands there, takes heat from the indoor air, and returns to the compressor 102. The airflow generated by the outdoor fan 107 promotes heat dissipation from the heat exchanger 104, and the airflow generated by the indoor fan 108 promotes heat absorption of the heat exchanger 106.

  About a parallel flow type heat exchanger, in order to improve the performance, various devices have been made so far.

  For example, in the parallel flow type heat exchanger described in Patent Document 1, a gas-liquid diffuser that mixes and diffuses an inflowing gas refrigerant and a liquid refrigerant is disposed in a refrigerant inflow portion of a refrigerant inflow side header pipe, The gas refrigerant and liquid refrigerant until reaching the heat transfer tube are almost evenly distributed to improve the heat exchange efficiency.

In the parallel flow heat exchanger described in Patent Document 2, a gas-liquid separator is provided on the upstream side of the header, and the refrigerant is a gas-liquid two-phase flow having a high liquid or liquid ratio and a gas-liquid two-phase having a high gas or gas ratio. By separating one gas-liquid two-phase flow from one end of the header and the other gas-liquid two-phase flow from the other end of the header and mixing them in the header, dryness / void A homogeneous gas-liquid two-phase flow with a relatively uniform rate is formed, and the heat exchanger heat transfer area is effectively utilized to obtain a stable heat exchange capability.
JP 2008-39304 A JP-A-2-282670

In many cases, a gas-liquid two-phase refrigerant flows through the flat tube of the parallel flow type heat exchanger. However, a refrigerant mixed with gas and liquid tends to cause a so-called drift, which causes a deviation in the refrigerant flow rate between the flat tubes. In addition, a flow mixed with gas has a large pressure loss, which becomes an obstacle to refrigerant circulation.

  The present invention has been made in view of the above points, and an object of the present invention is to suppress only the flow of liquid refrigerant through the flat tube as much as possible, thereby improving the heat exchange efficiency when used as an evaporator.

  In order to achieve the above object, the present invention provides a plurality of header pipes arranged in parallel at intervals, and a plurality of refrigerant pipes arranged between the plurality of header pipes and provided in the header pipe. In the heat exchanger having a flat tube communicated with the inside of the plurality of header pipes, a gas-liquid separator is arranged inside the header pipe which is the inflow side of the gas-liquid two-phase refrigerant in the plurality of header pipes, It is characterized in that mainly liquid refrigerant of gas-liquid two-phase refrigerant is sent to the flat tube.

  According to this configuration, since it is mainly liquid refrigerant that flows through the flat tube, the flow is less likely to occur than when the gas-liquid two-phase refrigerant flowing into the header pipe flows directly into the flat tube. In addition, since the pressure loss in the flat tube is small compared to the refrigerant mixed with gas, the circulation amount of the refrigerant is increased, and the heat exchange performance is improved.

  In the heat exchanger configured as described above, the gas refrigerant of the gas-liquid two-phase refrigerant separated from the liquid refrigerant by the gas-liquid separator is preferably introduced into a suction side pipe of a compressor that compresses the refrigerant.

  With such a configuration, the gaseous refrigerant is compressed by the compressor and liquefied again by the condenser, so that the refrigerant can be circulated in the closed loop without waste.

  In the heat exchanger having the above-described configuration, the gas-liquid separator is a cylindrical member in which a large number of pleats are formed on a peripheral wall, and the liquid refrigerant of the gas-liquid two-phase refrigerant introduced into the inside by the surface tension of the liquid. It is preferable to include a liquid refrigerant collecting cylinder that collects inside the pleats and an exhaust pipe that protrudes into the internal space of the liquid refrigerant collecting cylinder and discharges the gas refrigerant of the gas-liquid two-phase refrigerant to the outside.

  With this configuration, gas-liquid separation is performed using the simple physical phenomenon of surface tension of the liquid, so the structure of the gas-liquid separator is simplified, operation is reliable, and there are few failures. Can do.

  In the heat exchanger configured as described above, through holes for communicating the inside of the liquid refrigerant collecting cylinder and the inside of the header pipe in which the gas-liquid separator is disposed are dispersedly formed in the pleats. preferable.

  With such a configuration, the liquid refrigerant can be appropriately distributed to various places in the header pipe.

  In the heat exchanger having the above-described configuration, an end in which a through hole that connects the inside of the liquid refrigerant collecting cylinder and the inside of the header pipe in which the gas-liquid separator is disposed is fixed to the liquid refrigerant collecting cylinder It is preferable that it is formed on the bracket.

  With such a configuration, the through hole can be easily formed.

  In the heat exchanger configured as described above, it is preferable that the plurality of header pipes extend in a substantially horizontal direction and the plurality of flat tubes extend in a substantially vertical direction.

  With such a configuration, it is possible to solve the drift problem of the parallel flow heat exchanger that is a down flow type.

  In the heat exchanger configured as described above, it is preferable that the gas-liquid separator is disposed inside a header pipe located at a lower portion of the plurality of header pipes.

  With such a configuration, when this heat exchanger is used as an evaporator, the liquid refrigerant flowing from the lower end of the flat tube increases the gas ratio as it rises in the flat tube. The increase is promoted and the amount of refrigerant circulation increases.

  According to the present invention, by separating the liquid from the gas-liquid two-phase refrigerant and flowing it through the flat tube, it is possible to suppress the drift and increase the refrigerant circulation amount, thereby improving the heat exchange performance.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 is a partial cross-sectional view of a parallel flow type heat exchanger, FIG. 2 is a partially enlarged cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a gas view taken along line BB in FIG. 4 is an enlarged cross-sectional view of the liquid separator, FIG. 4 is a perspective view of a rectifying cone, and FIG. 5 is a basic configuration diagram of a separate type air conditioner equipped with a parallel flow type heat exchanger according to the first embodiment. Since many of the configurations of the first embodiment are common to the conventional structure shown in FIGS. 8 to 10, such common components are denoted by the same reference numerals as those used in FIGS. The description is omitted.

  The heat exchanger 1 is a downflow parallel flow heat exchanger similar to that shown in FIG. 8, wherein the plurality of header pipes extend in a substantially horizontal direction, and the plurality of flat tubes extend in a substantially vertical direction. . A gas-liquid separator 10 is disposed inside the lower header pipe 3. The gas-liquid separator 10 has an elongated cylindrical shape that reaches almost from end to end inside the lower header pipe 3, and is arranged such that the central axis coincides with the central axis of the lower header pipe 3.

  The main component of the gas-liquid separator 10 is the liquid refrigerant collecting cylinder 11. The liquid refrigerant collecting cylinder 11 is a cylindrical member in which a large number of pleats 12 are formed on a peripheral wall, and is formed from an aluminum thin plate or the like. The liquid refrigerant collecting cylinder 11 is formed with through holes 13 in communication with the inside of the lower header pipe 3 in a distributed manner. The through holes 13 are formed for each pleat 12 at a predetermined interval in the axial direction of the liquid refrigerant collecting cylinder 11.

  Synthetic resin or metal end brackets 14 and 15 formed in a cap shape are fixed to both ends of the liquid refrigerant collecting cylinder 11. FIG. 2 shows a fixed portion of the end bracket 14 and the liquid refrigerant collecting cylinder 11. At this location, the end bracket 14 is formed with a radial opening that matches the shape of the pleat 12. The liquid refrigerant collecting cylinder 11 and the end bracket 14 are fixed in an airtight (liquid-tight) manner by a conventional fixing method such as adhesion or welding in a state where the pleat 12 is fitted in the opening. The fixing positions of the end bracket 15 and the liquid refrigerant collecting cylinder 11 have the same structure.

  A pipe-like refrigerant inlet 16 that protrudes outward is formed on the end surface of the end bracket 14. The refrigerant inlet 16 is inserted into the refrigerant inlet / outlet 7 of the lower end bracket 3 in an airtight (liquid tight) manner from the inside.

  A sleeve 17 projecting inward is formed on the end face of the end bracket 15. An exhaust pipe 18 that penetrates the end face of the lower header pipe 3 is inserted into the sleeve 17 from the outside. The exhaust pipe 18 protrudes into the internal space of the liquid refrigerant collecting cylinder 11 by a predetermined length. Appropriate air-tight (liquid-tight) treatment is applied to the place where the exhaust pipe 18 penetrates the lower header pipe 3 and the place where the exhaust pipe 18 is inserted into the end bracket 15.

  On the end bracket 14 side, the refrigerant inlet 16 of the end bracket 14 is inserted into the refrigerant inlet / outlet 7 of the lower header pipe 3, and on the end bracket 15 side, the exhaust pipe 18 penetrating the lower header pipe 3 is inserted into the end bracket 15. As a result, the gas-liquid separator 10 is held and fixed at the center of the lower header pipe 3.

  A rectifying cone 20 is fixed inside the end bracket 14 so as to face the refrigerant flow flowing from the refrigerant inlet 16. The rectifying cone 20 includes a cone body 21 having a combination of a cylinder and a cone, a mounting ring 22 surrounding the cone body 21 at a predetermined interval, and a radial spoke 23 connecting the cone body 21 and the mounting ring 22. Prepare.

  The description continues with the setting that the heat exchanger 1 is used as an evaporator and the gas-liquid two-phase refrigerant flows from the lower header pipe 3. In FIG. 1, the block arrow represents the flow of the gas-liquid two-phase medium, the solid line arrow represents the liquid refrigerant flow, and the dotted line arrow represents the gaseous refrigerant flow. The gas-liquid two-phase refrigerant that has flowed into the gas-liquid separator 10 from the inlet 16 is guided toward the inner periphery of the liquid refrigerant collecting cylinder 11 by the rectifying cone 20, and flows inside the pleat 12 toward the end bracket 15. .

  In the process of flowing inside the pleat 12, the liquid refrigerant of the gas-liquid two-phase refrigerant is concentrated on the tip portion of the pleat 12 by surface tension. Paradoxically speaking, the apex angle of the pleat 12 is set to an acute angle such that the liquid refrigerant is concentrated due to surface tension, and the pleats 12 having such a shape are arranged in a dense state. As the liquid refrigerant collects in the pleats 12, the gas refrigerant collects in the central portion of the liquid refrigerant collecting cylinder 11.

  The liquid refrigerant collected at the tip portion of the pleat 12 flows out into the space between the outer cotton of the gas-liquid separator 10 and the inner surface of the lower header pipe 3 through the through hole 13 and flows into the flat tube 4. The gaseous refrigerant remaining inside the gas-liquid separator 10 is discharged out of the lower header pipe 3 through the exhaust pipe 18.

  By passing the gas-liquid two-phase refrigerant through the gas-liquid separator 10, the flow through the flat tube 4 is mainly liquid refrigerant, and the gas-liquid two-phase refrigerant flowing into the lower header pipe 3 flows into the flat tube 4 as it is. In comparison, drift is less likely to occur. Moreover, since the pressure loss in the flat tube 4 is small compared with the refrigerant mixed with gas, the circulation amount of the refrigerant is increased, and the heat exchange performance is improved.

  The gas-liquid separator 10 plays a role of gas-liquid separation, which is a liquid refrigerant collecting cylinder 11 in which a large number of pleats 12 are formed on a peripheral wall. The gas-liquid separator utilizes a simple physical phenomenon called liquid surface tension. Since the separation is performed, the structure of the gas-liquid separator 10 is simplified, and the operation can be reliably performed and the failure is reduced.

  Further, the through holes 13 that allow the inside of the liquid refrigerant collecting cylinder 11 and the inside of the lower header pipe 3 to communicate with each other are distributed and formed for each pleat 12 at predetermined intervals in the axial direction of the liquid refrigerant collecting cylinder 11. The liquid refrigerant can be appropriately distributed to various places in the lower header pipe 3.

  When the heat exchanger 1 is mounted as the heat exchanger 104 in the outdoor unit of the separate type air conditioner shown in FIG. 5, the gaseous refrigerant discharged through the exhaust pipe 18 during the heating operation is passed through the pipe 109. It can be introduced into the suction side piping of the compressor 102. In this way, the refrigerant gas refrigerant can be compressed by the compressor 102 and liquefied again by the indoor heat exchanger 106, so that the refrigerant can be circulated in the closed loop without waste. In addition, it is preferable to provide the solenoid valve 110 in the piping 109. During the cooling operation, the outdoor heat exchanger 104 serves as a condenser, and the state of the refrigerant changes from gas to liquid, so there is no need to perform gas-liquid separation. Therefore, the electromagnetic valve 110 is controlled to be closed during the cooling operation and to be opened during the heating operation.

  A second embodiment of the present invention is shown in FIGS. FIG. 6 is a partial cross-sectional view of the parallel flow heat exchanger, and FIG. 7 is a partial enlarged cross-sectional view taken along line CC in FIG.

  The difference between the first embodiment and the second embodiment resides in the position of a through hole that communicates the inside of the liquid refrigerant collecting cylinder 11 and the inside of the lower header pipe 3. That is, in the second embodiment, a plurality of through holes 25 are formed in the end bracket 15. This configuration has a feature that the formation of the through hole is easy.

  The formation of the through hole 13 in the pleat 12 and the formation of the through hole 25 in the end bracket 15 are not in an exclusive relationship. If necessary, both can be performed simultaneously.

  As mentioned above, although each embodiment of the present invention was described, the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention.

  The present invention is widely applicable to parallel flow heat exchangers.

The fragmentary sectional view of the parallel flow type heat exchanger concerning a 1st embodiment Partial expanded sectional view which makes the AA line of FIG. 1 a cross-sectional location FIG. 1 is an enlarged cross-sectional view of a gas-liquid separator having a cross-section taken along line BB in FIG. Perspective view of rectifying cone 1 is a basic configuration diagram of a separate air conditioner equipped with a parallel flow heat exchanger according to an embodiment. Partial sectional view of a parallel flow heat exchanger according to the second embodiment Partial expanded sectional view which makes the CC line of FIG. 6 a cross-sectional location Vertical sectional view showing the schematic structure of a conventional parallel flow heat exchanger Basic configuration diagram of separate air conditioner FIG. 9 is a basic configuration diagram of a separate type air conditioner, showing a state different from FIG. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Upper header pipe 3 Lower header pipe 4 Flat tube 5 Refrigerant passage 6 Corrugated fin 7, 8 Refrigerant inlet / outlet 10 Gas-liquid separator 11 Liquid refrigerant collection cylinder 12 Pleated 13 Through hole 14, 15 End bracket 16 Refrigerant flow Inlet 18 Exhaust pipe 20 Rectification cone 25 Through hole

Claims (7)

A plurality of header pipes arranged in parallel at intervals, and a flat tube arranged between the plurality of header pipes and having a plurality of refrigerant passages provided therein communicated with the inside of the header pipe. In the heat exchanger
A gas-liquid separator is disposed inside the header pipe which is the inflow side of the gas-liquid two-phase refrigerant among the plurality of header pipes, and the liquid refrigerant mainly flowing in the gas-liquid two-phase refrigerant is sent to the flat tube. Features heat exchanger.   The heat exchanger according to claim 1, wherein the gas refrigerant of the gas-liquid two-phase refrigerant separated from the liquid refrigerant by the gas-liquid separator is introduced into a suction side pipe of a compressor that compresses the refrigerant. .   The gas-liquid separator is a cylindrical member in which a large number of pleats are formed on the peripheral wall, and collects the liquid refrigerant of the gas-liquid two-phase refrigerant introduced into the inside of the pleat by the surface tension of the liquid. The heat exchange according to claim 1 or 2, further comprising: a collecting tube; and an exhaust pipe that protrudes into the internal space of the liquid refrigerant collecting tube and discharges the gas refrigerant of the gas-liquid two-phase refrigerant to the outside. vessel.   The through-hole which connects the inside of the said liquid refrigerant | coolant collection cylinder and the inside of the said header pipe in which the said gas-liquid separator is arrange | positioned is distributedly formed in the said pleat. Heat exchanger.   A through hole for communicating the inside of the liquid refrigerant collecting cylinder and the inside of the header pipe where the gas-liquid separator is disposed is formed in an end bracket fixed to the liquid refrigerant collecting cylinder. The heat exchanger according to claim 3, wherein   6. The heat exchanger according to claim 1, wherein the plurality of header pipes extend in a substantially horizontal direction, and the plurality of flat tubes extend in a substantially vertical direction.   The heat exchanger according to claim 6, wherein the gas-liquid separator is disposed inside a header pipe located at a lower portion of the plurality of header pipes.

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