WO1999058908A1

WO1999058908A1 - Heat exchanger

Info

Publication number: WO1999058908A1
Application number: PCT/JP1999/002456
Authority: WO
Inventors: Takanobu Tamada
Original assignee: Zexel Corporation
Priority date: 1998-05-13
Filing date: 1999-05-12
Publication date: 1999-11-18

Abstract

A heat exchanger (1), wherein both end parts of tubes (4), which are overlapped one upon another with fins (5) provided therebetween, are connected communicably to a pair of header pipes (6 and 7), a heat exchange medium flows through the tubes between the header pipes while meandering a plurality of times, and a receiver tank (2) for reserving and circulating liquid refrigerant inside it is installed, a supercooling part (B) through which a gas-liquid separated liquid medium is passed is provided in the lower area of the heat exchanger, and also a flow path outlet (17) for re-circulating the liquid medium passed through the overcooling part into a refrigerating cycle is provided at the longitudinal lower part of the header pipe which is positioned lower than the tubes forming the supercooling part.

Description

Description Heat exchanger Technical field

TECHNICAL FIELD The present invention relates to a heat exchanger used for a refrigeration cycle, the heat exchanger including a receiver tank for storing and circulating a liquid refrigerant therein. Background art

2. Description of the Related Art In a refrigeration cycle of an automobile, for example, a stacked heat exchanger is known as a heat exchange medium condensing device. In this type of heat exchanger, a plurality of tubes and fins are alternately stacked, and both ends of the stacked tubes are inserted into and joined to insertion holes formed in a header pipe. A partition plate for partitioning the header pipe in the longitudinal direction is provided at required positions of the header pipe, and the heat exchange medium flowing from an inlet joint provided in the header pipe meanders between the header pipes several times. It is equipped with a configuration for passing through.

The heat exchanger may be connected to a receiver tank in order to prevent a decrease in cooling capacity. The receiver tank separates the heat exchange medium, which has undergone heat exchange with the external air into a gas-liquid two-phase state in the heat exchanger, by means of a dryer and a filter inside the receiver tank. This is a device that is used as an exchange medium and flows into the heat exchanger again to circulate the cooling cycle. As described above, when the receiver tank is connected to the heat exchanger, the refrigerant in the gas-liquid two-phase state is separated into the liquid single-phase liquid refrigerant that does not contain the gas medium, and circulates again in the refrigeration cycle. In addition, it is possible to prevent the cooling capacity from lowering without lowering the circulation amount of the refrigerant. In addition, since the heat exchange medium flows through the inside of the receiver tank, foreign matter in the medium is removed by a filter or the like, and the heat exchange medium can flow in a clean state.

Traditionally, this type of receiver tank is generally A receiver tank is provided in the vicinity of the header pipe to which the portion is joined. For example, as described in Japanese Patent Application Laid-Open No. 8-219590, a portion of the outer periphery of the header pipe is provided. A structure in which a part of the outer periphery of the receiver tank is physically connected, or a connection between the header pipe of the heat exchanger and the receiver tank, as disclosed in Japanese Patent Application Laid-Open No. Hei 9-191468. The structure is such that the heat exchange medium can flow through the members.Otherwise, for example, the invention of Japanese Patent Application Laid-Open No. Hei 9-166713 discloses that the receiver tank and the header pipe are integrated. It solves the problem that the heat exchanger has a header pipe and a receiver tank that are separately provided, which hinders the degree of freedom of arrangement when the heat exchanger is mounted inside the vehicle.

FIG. 3 is a sectional view showing a structure of a heat exchanger to which a receiver tank described in Japanese Patent Application Laid-Open No. 9-166713 is connected. The heat exchanger 31 described in Japanese Patent Application Laid-Open No. Hei 9-1666371 introduces a gas-liquid refrigerant from below and discharges the refrigerant from above. One end of the laminated tube 34 is connected to the header pipe 36, and the other end is connected to the inside of the cylinder 32 constituting the receiver tank. Inside the tubular body 32, a first return chamber 33, which is a small tubular body, to which the tube ends in the middle and lower regions of the heat exchanger 31 are connected is arranged and partitioned. The lower part of the cylinder 32 is a storage chamber 37 for storing a gas-liquid separated heat exchange medium. In addition, a supercooling inflow chamber 38 that leads to a supercooling tube 39 located at the uppermost part of the stacked tubes 34 is defined above the cylindrical body 32. At the top of the header pipe 36, an inflow chamber 40 provided with an outflow pipe 41 for guiding the liquid refrigerant flowing through the subcooling tube 39 to another circulation cycle is defined. The subcooling inflow chamber 38, the subcooling tube 39, and the inflow chamber 40 constitute a supercooling section 42.

The supercooled inflow chamber 38 communicates with the storage chamber 37 via the delivery pipe 43. are doing.

The heat exchange medium flowing into the heat exchanger 31 from the inflow pipe 44 provided at the lower end of the header pipe 36 flows between the tube 34, the header pipe 36, and the small cylinder 33, The gas flows into the cylinder 32 in a gas-liquid two-phase mixed state, and is separated into gas and liquid inside the cylinder 32, and only the liquid medium is stored in the storage chamber 37. Then, the refrigerant flows into the subcooling chamber 38 via the delivery pipe 43, and further flows through the subcooling tube 39 to circulate the refrigeration cycle from the outflow pipe 41 of the inflow chamber 40.

The heat exchange medium is provided with a degree of supercooling by flowing through the subcooling tube 39, so that the cooling capacity of the refrigeration cycle is improved.

However, for example, in a structure in which a receiver tank and a header pipe are integrally formed as described in Japanese Patent Application Laid-Open No. 9-166713, the liquid level S2 of the stored liquid medium is reduced by a delivery pipe. It is necessary to always reach the lower end of 43.If the liquid surface of the liquid medium separated by gas and liquid does not reach the lower end of the delivery pipe 43, the flow of the liquid medium is performed. However, there is a problem that the flow rate of the medium flowing through the entire refrigeration cycle changes, which causes the gas-liquid separation function to deteriorate.

Therefore, the present invention can maintain a constant flow rate of the liquid medium circulating in the refrigeration cycle by utilizing the natural flow of the liquid medium cooled and separated into gas and liquid in the heat exchanger and the receiver tank. It is an object of the present invention to provide a heat exchanger capable of improving separation performance. Disclosure of the invention

The invention described in claim 1 of the present application is characterized in that both ends of the tubes laminated with fins interposed therebetween are connected to a pair of header pipes, and the heat exchange medium passes between the header pipes a plurality of times. In a heat exchanger equipped with a receiver tank for meandering and flowing and storing and circulating liquid refrigerant inside, a subcooling section through which gas-liquid separated liquid medium flows is provided in the lower area of the heat exchanger. And a flow path for recirculating the liquid medium flowing through the subcooling section to the refrigeration cycle. A heat exchanger having a configuration in which an opening is provided in a lower region in a longitudinal direction of a header pipe than a tube constituting the supercooling section.

As described above, the subcooling section through which the liquid medium separated into gas and liquid flows is provided in the lower region of the heat exchanger inside the receiver tank, and further, at a position below the subcooling section in the longitudinal direction of the header pipe, By providing a flow path outlet for circulating the liquid medium to the refrigeration cycle, the liquid medium separated from gas and liquid can be circulated to the refrigeration cycle using the natural flow of liquid without complicating the structure. it can. Therefore, even if the amount of liquid to be gas-liquid separated is small, a fixed amount of liquid medium is circulated to the refrigeration cycle without deteriorating the gas-liquid separation function of the receiver tank to stabilize the refrigeration cycle. And the reliability of the heat exchange performance is improved.

In addition, since the flow rate of the liquid medium circulating in the refrigeration cycle is kept constant, the amount of the liquid medium added can be reduced, and the cost can be reduced.

The invention described in claim 2 of the present application is the heat exchanger according to claim 1, wherein the flow path outlet is provided at a longitudinal lower end of the header pipe.

In this way, when the flow path outlet is provided at the lower end in the longitudinal direction of the header pipe, a certain amount of the liquid medium circulates through the refrigeration cycle by using the natural flow of the liquid even when the medium flow rate is small. As a result, the gas-liquid separation function of the heat exchanger can be improved.

According to the invention described in claim 3 of the present application, in the invention described in claim 1 or 2, the base of the receiver tank is communicated with an outlet communication hole of a header pipe, and the tip protrudes upward. The heat exchanger is provided with piping, and the heat exchange medium flows into the receiver tank from the piping projecting upward.

As described above, when the heat exchange medium is allowed to flow into the receiver tank through the pipe projecting upward, the heat-exchange medium in the gas-liquid two-phase mixed state flowing into the receiver tank from the heat exchanger is not reciprocated. Gas-liquid inside one tank Since the mixing with the separated liquid refrigerant is prevented, the liquid refrigerant can be efficiently stored and circulated in the receiver tank. BRIEF DESCRIPTION OF THE FIGURES

【Figure 1】

FIG. 2 is a front view of a heat exchanger according to a specific example of the present invention.

【Figure 2】

FIG. 3 is a cross-sectional view showing an internal structure of a heat exchanger and a receiver tank according to a specific example of the present invention.

[Figure 3]

FIG. 4 is a cross-sectional view showing an internal structure of a heat exchanger and a receiver tank according to a conventional example. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, specific examples of the present invention will be described with reference to the drawings.

FIG. 1 shows a front view of a heat exchanger 1 and a receiver link 2 according to this example. FIG. 2 is a cross-sectional view showing the internal structure of the heat exchanger 1 and the receiver tank 2 of FIG.

As shown in FIGS. 1 and 2, the heat exchanger 1 has a plurality of tubes 4 and fins 5 alternately stacked, and both ends of the stacked tubes 4, 4 are respectively connected to header pipes 6, 4. The tube insertion holes 8, 8 of 7 are inserted and connected. Side plates 9 having a U-shaped cross section are provided on the upper end side and the lower end side of the stacked tubes 4. The header pipes 6 and 7 are formed by rolling a plate of a predetermined size on which a brazing material is clad by press molding or the like. The openings at the upper and lower ends of the header pipes 6 and 7 are closed by caps 10. In addition, partition plates 11 are provided at required locations of the header pipes 6 and 7. The header pipe 6 connected to the receiver tank 2 has an inlet joint member 12, and the header pipe not connected to the receiver tank 2 7 is provided with an outlet joint member 13. As shown in FIG. 2, the header pipe 6 connected to the receiver tank 2 is formed with an outlet communication hole 14 and an inlet communication hole 15 for flowing a heat exchange medium. The header pipe 7 is formed so as to protrude below the tube 4 located at the lowermost layer in the longitudinal direction. Further, the header pipe 7 has a flow path outlet for circulating the gas-liquid separated liquid medium to the refrigeration cycle below the tube insertion hole 8b to which the tube 4b located at the lowermost layer is connected. 17 is formed, and the outlet joint 13 is connected to the flow path outlet 17.

The receiver tank 2 is a vertically-long closed container, and an inlet through-hole 24 corresponding to the outlet communication hole 14 of the header pipe 6 is formed. An outlet through hole 25 communicating with the inlet communication hole 15 is formed.

A pipe 21 projecting upward from the outlet communication hole 14 of the header pipe 6 is provided inside the receiver tank 2. Further, the inlet communication hole 15 of the header pipe 6 and the outlet through hole 25 of the receiver tank 2 are connected by a pipe 22. The lower part of the receiver tank 2 is a storage part 23 for storing the liquid refrigerant S1 separated by gas and liquid.

Next, the flow state of the heat exchange medium in the heat exchanger 1 and the receiver tank 2 will be described with reference to FIG. The arrows in FIG. 2 indicate the flow direction in which the heat exchange medium flows.

As shown in FIG. 2, the heat exchange medium circulated through the refrigeration cycle flows into the heat exchanger 1 from the flow path inlet 16 to which the inlet joint 12 is connected. Then, the gas flows between the stacked tubes 4 and the header pipes 6 and 7, and is radiated from the fins 5 interposed between the tubes 4 to be cooled. The gas-liquid two-phase heat exchange medium flows into the receiver tank 2 from the pipe 21 projecting upward. Here, the heat exchange medium is gas-liquid separated, and only the liquid refrigerant is stored in the storage part 23 below the receiver tank 2. The liquid refrigerant stored in the storage part 23 flows into the tube 4 in the lower area of the heat exchanger 1 again from the outlet through hole 25 provided in the lower area of the receiver tank 2.

The lower region of the heat exchanger 1 into which the liquid refrigerant separated in the receiver tank 2 flows forms a subcooling section. The upper region of the subcooling section の of the heat exchanger 1 constitutes a cooling section Α.

The liquid refrigerant which has been separated into gas and liquid inside the receiver tank 2 and becomes a single liquid flows through the supercooling section B, whereby it is sufficiently cooled, and the cooling capacity of the refrigeration cycle is improved.

The liquid refrigerant flowing through the supercooling section B again flows into the header pipe 7, and is provided below the insertion hole 8 into which the tube 4b located at the lowest layer is inserted, in the longitudinal direction of the header pipe 7. The refrigeration cycle is circulated again from the circulation channel 17.

In the heat exchanger 1 of this example, a subcooling section B is provided in a lower area of the heat exchanger 1, and the tube 4b of the lowermost layer constituting the supercooling section B is connected to the tube 揷 8b. Since the flow path outlet 17 is provided in the lower part of the header pipe in the longitudinal direction, even if the amount of the gaseous and liquid separated liquid medium is small inside the receiver tank 2, the liquid refrigerant The liquid refrigerant can circulate through the refrigeration cycle using the natural flow.

Therefore, it is possible to stabilize the refrigeration cycle by passing a certain amount of heat exchange medium through the refrigeration cycle without deteriorating the gas-liquid separation performance of the heat exchanger caused by a decrease in the medium flow rate. Performance can be improved.

Further, according to the configuration of the present example, the heat-exchange medium in the gas-liquid two-phase mixed state flowing into the receiver tank from the heat exchanger flows into the receiver tank 2 from the pipe 21 projecting upward. The liquid refrigerant separated in gas and liquid inside the receiver tank 2 is prevented from being mixed with the heat exchange medium in a gas-liquid two-phase state flowing from the heat exchanger, and the liquid refrigerant is efficiently stored in the receiver tank. Can be circulated. g Also, in this example, the structure of the heat exchanger in which the receiver tank is separated from the header pipe is shown, but the present invention is not limited to this. Also, a subcooling zone through which the heat exchange medium flowing into the heat exchanger flows is provided below the heat exchanger, and a flow path outlet through which the subcooling zone flows and the refrigeration cycle is again circulated is provided. By providing the heat exchanger in a lower area than the supercooling area, it is possible to provide a heat exchanger having an improved gas-liquid separation function without changing the flow rate of the liquid coolant circulating in the refrigeration cycle. Industrial applicability

The present invention is a heat exchanger having a simple structure and capable of improving a gas-liquid separation function, and is particularly used for a refrigeration cycle having a limited installation space, for example, an air conditioner of an automobile.

Claims

The scope of the claims

1. Both ends of the tubes stacked with fins interposed are connected and connected to a pair of header pipes, and the heat exchange medium flows meandering between the header pipes several times, and the liquid refrigerant is stored inside. , In a heat exchanger with a circulating receiver tank,

A subcooling section through which the liquid medium separated by gas and liquid flows is provided in the lower area of the heat exchanger,

Further, a flow outlet for recirculating the liquid medium flowing through the subcooling section to the refrigeration cycle is provided in a longitudinally lower region of the header pipe than a tube constituting the subcooling section. vessel.

2. The heat exchanger according to claim 1, wherein the flow path outlet is provided at a lower end in a longitudinal direction of the header pipe.

3. The receiver tank is provided with a pipe whose base is communicated with the outlet communication hole of the header pipe and whose tip projects upward, from which the heat exchange medium flows. 3. The heat exchanger as claimed in claim 1, wherein the heat exchange flows into the receiver tank.