JPH11304377A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger exhibiting excellent heat exchanging performance in both functions of condenser and evaporator and suitable for use as a heat pump. SOLUTION: Flat tubes 1 of specified length are arranged in parallel at a specified interval and conducted, at the opposite ends thereof, through hollow headers 3, 4 so that a heat exchanging medium conducts simultaneously in parallel through a plurality of flat tubes 1. Among a group of flat tubes conducting the heat exchanging medium simultaneously in parallel, at least one flat tube 1 is provided with a counterflow preventing mechanism 10 permitting conduction of the heat exchanging medium only in one direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called parallel flow type heat exchanger used, for example, as an outdoor heat exchanger for a heat pump type air conditioner.

[0002]

2. Description of the Related Art Conventionally, as this type of heat exchanger, a plurality of flat tubes of a predetermined length are arranged in parallel at predetermined intervals in the thickness direction with corrugated fins interposed therebetween. At the same time, it is known that hollow headers are connected to both ends of these flat tubes in a communicating state, respectively, so that a heat exchange medium flows through a plurality of tubes simultaneously and in parallel.

When this type of heat exchanger is used as an outdoor heat exchanger for a heat pump type air conditioner in a refrigeration cycle, it functions as a condenser for liquefying a gasified heat exchange medium in summer or the like where the outside air temperature is high. On the other hand, in winter or the like when the outside air temperature is low, the liquefied heat exchange medium is used as an evaporator for vaporizing the heat exchange medium.

[0004] In order to improve the function as a condenser in summer, the interval between adjacent tubes is set as small as possible, in other words, the height of the fins arranged between adjacent tubes. Is set to be low to improve the fin efficiency and to be excellent in heat dissipation performance.

[0005]

However, when such a heat exchanger having excellent heat radiation performance is used as an evaporator in winter or the like, especially when the humidity of the outside air is high, the fin efficiency is high and the heat exchange performance is high. Frost may be rapidly attached to the fin surface. The frost adhering to the fin surface in this manner acts to hinder ventilation between the fins, and the heat exchange performance is rapidly reduced, so that frequent defrosting operations are required, which in turn degrades the performance as an evaporator. There was an inconvenience of becoming.

In order to avoid such inconvenience in the evaporator, the distance between the adjacent tubes is set large, in other words, the substantial height of the fins arranged between the adjacent tubes is set high. It is conceivable to set the fin efficiency low. As a result, the frosting property is improved. As a result, the inconvenience caused by the impeded ventilation due to the frosting described above is avoided beforehand, and the performance as an evaporator can be maintained at a high level.

[0007] However, reducing the fin efficiency in this way means that the heat radiation performance when used as a capacitor is reduced. In this way, if the fin efficiency is improved to improve the performance as a capacitor, the problem of frost occurs when used as an evaporator, and conversely, if the fin efficiency is set low to solve the problem of frost formation of the evaporator, the capacitor As a result, there was a dilemma that the performance was lowered.

In view of the above problems, the present invention provides a heat exchanger which is excellent in heat exchange performance capable of exhibiting excellent performance in both functions as a condenser and an evaporator and which can be suitably used as a heat pump. The task is to provide.

[0009]

According to the present invention, flat tubes of a predetermined length are arranged in parallel at predetermined intervals in the thickness direction, and hollow tubes are provided at both ends of the flat tubes, respectively. Are connected in a communication state, in a heat exchanger in which the heat exchange medium flows through the plurality of flat tubes in parallel, at least one of the flat tube groups in which the heat exchange medium flows in parallel 1
The gist of the present invention is the heat exchanger, wherein the flat tube of the present invention includes a backflow prevention mechanism that allows only the heat exchange medium to flow in one direction.

As described above, at least one of the flat tubes in the group of flat tubes through which the heat exchange medium flows at the same time is provided with a backflow prevention mechanism that allows only the heat exchange medium to flow in one direction. Therefore, when flowing the heat exchange medium in one direction of the flat tube, the heat exchange medium flows through all tubes including the tube provided with the backflow prevention mechanism. On the other hand, when flowing the heat exchange medium in the reverse direction, the heat exchange medium flows only through the remaining tubes except for the tube provided with the backflow prevention mechanism.

Therefore, when this heat exchanger is used as a condenser, the heat exchange medium is provided with the backflow prevention mechanism so that the heat exchange medium flows through all the flat tubes and exchanges heat efficiently. The heat exchange medium flows from one of the headers so as to flow in all the flat tubes including the tubes, that is, in the one direction. As a result, the heat exchange medium flows through all the flat tubes, so that the fin efficiency is excellent, and thus it is possible to function as a capacitor exhibiting high heat exchange performance.

On the other hand, when the heat exchanger is used as an evaporator, the heat exchange medium is passed through only the flat tubes excluding the flat tubes having the backflow prevention mechanism to exchange heat. The heat exchange medium flows in a direction opposite to the above-mentioned one direction, that is, from the other header. As a result, the heat exchange medium does not flow through the flat tubes provided with the backflow prevention mechanism. As a result, the space between the adjacent flat tubes through which the heat exchange medium flows increases, that is, the fin height is substantially higher. As a result, the fin efficiency decreases. Therefore, even when the humidity of the outside air is high, the generation rate of frost on the fin surface is reduced, and the fin can function as an evaporator with reduced inconvenience caused by frost.

As the backflow prevention mechanism, for example, a check valve provided at one end opening of the flat tube is suitably used.

If the flat tubes having the backflow prevention mechanism and the flat tubes not having the backflow prevention function are alternately arranged, the heat exchange medium can be compared with the case where the flat tube is used as an evaporator and the case where the flat tube is used as a condenser. The distance between adjacent flat tubes, that is, the substantial fin height can be doubled.

[0015]

Next, an embodiment of the present invention will be described with reference to the drawings.

The heat exchanger according to the present embodiment is suitably used particularly as an outdoor heat exchanger for a heat pump type air conditioner.

As shown in FIG. 1, in this heat exchanger, a plurality of flat perforated tubes (1) having a predetermined length are arranged at predetermined intervals in parallel in the thickness direction along the left-right direction. A meandering fin (2) is interposed between adjacent tubes (1), and both ends of each tube (1) are a pair of upper and lower hollow headers (3).
This is a so-called multi-flow type having a basic structure connected in communication with (4).

The flat porous tube (1) is made of an extruded aluminum material provided with a plurality of heat exchange medium flow paths (1a) along the width direction. The fin (2) is formed by bending a thin aluminum sheet material in a meandering shape. The headers (3) and (4) are formed by molding a brazing sheet in which a brazing material layer is coated on the inner surface, outer surface, or both surfaces of an aluminum core material into a cylindrical shape. In this case, the shims are joined and integrated by electric resistance welding or the like.
The upper and lower ends of the tube (1) are inserted into tube insertion holes (3a) (4a) formed at predetermined intervals along the longitudinal direction of the upper and lower headers (3) and (4). It is integrated by brazing with brazing material.

A heat exchange medium inlet / outlet pipe (5) is connected to the left end of the upper header (3) in communication with the header (3), and is also connected to the left end of the lower header (4). Similarly, the heat exchange medium inlet / outlet pipe (6) is connected in a communicating state. The right ends of the upper and lower headers (3) and (4)
It is closed by caps (7) and (8).

Thus, in this type of multi-flow type heat exchanger, one header (3) or (4) is generally provided through one heat exchange medium inlet / outlet pipe (5) or (6). ) Flows through all the tubes (1)... At the same time and flows through the other header (4) or (3).
And are led out through the heat exchange medium inlet / outlet pipe (6) or (5).

However, in the heat exchanger according to this embodiment, the tube (1) provided with the backflow prevention mechanism (10) that allows only the heat exchange medium to flow in one direction, and such a backflow A configuration in which tubes (1) having no prevention mechanism are alternately arranged.

The backflow prevention mechanism (10) is shown in FIG.
As shown in FIG. 3 and FIG. 3, a check valve provided at the lower end of the tube (1) is used. This check valve (10)
Is made of a thin sheet material bent in an L-shape when viewed from the side, and one end side thereof is fixed to the side surface of the tube end by appropriate means such as brazing. The other end of the thin plate is a portion that functions as a valve, and is closed at a predetermined angle from the tube opening end and a closed position that closes the tube opening end, and opens the opening end. It can be switched between the opening position.

Therefore, the tube (1) provided with the check valve (10) allows the heat exchange medium to flow from the upper end of the tube to the lower end thereof, but from the lower end of the tube to the upper end. Is prevented from flowing through the heat exchange medium.

Therefore, as shown in FIG. 4, when the heat exchange medium flows into the upper header (3) through the heat exchange medium inlet / outlet pipe (5) at the upper left, the heat exchange medium is supplied to all the tubes (1). Divides into ... and descends. Meanwhile, the heat exchange medium exchanges heat with the outside air by the action of the fins (2). The heat exchange medium thus heat-exchanged merges at the lower header (4), and is then led out through the lower left heat exchange medium inlet / outlet pipe (6).

On the other hand, as shown in FIG. 5, when the heat exchange medium is caused to flow into the lower header (4) through the heat exchange medium inlet / outlet pipe (6) at the lower left, the heat exchange medium is forced into each tube by its pressure. (1) are shunted and flow upward, but are prevented from flowing into the tube (1) having the check valve (10) at the lower end thereof by the backflow prevention mechanism (10). As a result, the flow is diverted only to the tube (1) not provided with the backflow prevention mechanism (10) and rises. Since the tubes (1) having the backflow prevention mechanism (10) are arranged in a row, the heat exchange medium is used for every other tube (1).
Will rise. Meanwhile, the heat exchange medium exchanges heat with the outside air by the action of the fins (2). The heat exchange medium thus heat-exchanged merges at the upper header (3), and is then led out through the upper left heat exchange medium inlet / outlet pipe (5).

As is clear from the above description, when the heat exchange medium flows from the upper header (3), it flows through all the tubes (1), and conversely, when the heat exchange medium flows from the lower header (4), it becomes 1 Distribute every other tube (1). Therefore, when this heat exchanger is used as an outdoor heat exchanger for a heat pump type air conditioner, if the heat exchanger is to function as a condenser, the heat exchange medium is connected to the upper left heat exchange medium inlet / outlet pipe (5). Through the upper header (3). Then the heat exchange medium is
Since all tubes (1) are distributed, high performance can be exhibited as a condenser. Conversely, when the heat exchanger functions as an evaporator, the heat exchange medium flows into the lower header (4) via the lower left heat exchange medium inlet / outlet pipe (6). Then, since the heat exchange medium flows through every other tube (1), the interval between adjacent tubes through which the heat exchange medium flows increases, and the fin height is substantially increased, and the fin efficiency decreases. I do. However, due to the decrease in the fin efficiency, the generation rate of frost is slowed down, the interval between defrosting operations can be lengthened, and the performance as an evaporator can be maintained high.

By simply reversing the flow direction of the heat exchange medium into the heat exchanger, the performance of the condenser or the evaporator can be maintained at a high level.

In this embodiment, a check valve is used as a check valve. However, the present invention is not limited to the check valve. In other words, the heat exchange medium flows only in one direction. Any other means can be adopted as long as it allows the above.

In the above embodiment, the tubes having the backflow preventing mechanism and the tubes not having the backflow preventing mechanism are alternately arranged. However, a plurality of tubes having the backflow preventing mechanism may be continuously arranged depending on the application. You may make it arrange | position.

Furthermore, the present invention is also applicable to a heat exchanger of a type in which the inside of the header is partitioned by a partition plate in the longitudinal direction and a heat exchange medium flows in a meandering manner through a tube group composed of a plurality of tubes. Can be done. In this case, at least one tube having a backflow prevention mechanism may be included in each tube group including a plurality of tubes through which the heat exchange medium flows at the same time.

Naturally, the present invention can also be applied to a heat exchanger of a type in which a plurality of tubes are arranged vertically in a horizontal state, and headers are arranged at both right and left ends of the tubes and connected to each other. is there.

[0032]

As described above, according to the first aspect, in a so-called multi-flow type heat exchanger,
Since at least one flat tube in the group of flat tubes through which the heat exchange medium circulates at the same time is provided with a backflow prevention mechanism that allows only the heat exchange medium to flow in one direction, When flowing the exchange medium in one direction of the flat tube, the heat exchange medium flows through all the tubes including the tube having the backflow prevention function. On the other hand, when flowing the heat exchange medium in the reverse direction, the heat exchange medium flows only through the remaining tubes except for the tube provided with the backflow prevention mechanism.

Therefore, when this heat exchanger is used as a condenser, the heat exchange medium is transferred from one header to the other header so that the heat exchange medium flows through all the flat tubes and exchanges heat efficiently. By flowing all the flat tubes including the flat tubes provided with the backflow prevention mechanism in the flowing direction, that is, in the one direction, high heat exchange performance with excellent fin efficiency can be exhibited.

On the other hand, when the heat exchanger is used as an evaporator, the heat exchange medium is passed through only the flat tubes excluding the flat tubes provided with the backflow prevention mechanism to exchange heat. By flowing in the direction opposite to the above-mentioned one direction, that is, from the other header toward one header, as a result, the interval between the flat tubes through which the heat exchange medium flows increases, and the fin height is substantially reduced. And the fin efficiency decreases. Therefore, even when the humidity of the outside air is high, the generation speed of the frost on the fin surface is reduced, and the time of the defrosting operation can be shortened, and thus the performance as the evaporator is excellent. be able to.

As described above, even if the heat exchanger is used as a condenser or as an evaporator by changing the flow direction of the heat exchange medium, the heat exchange performance can be improved. .

As described in the second aspect, by using a check valve provided at one end opening of the flat tube as the backflow prevention mechanism, a heat pump having a simple structure and reliable operation can be suitably used. The heat exchanger used can be provided at low cost.

According to a third aspect of the present invention, if the flat tubes provided with the backflow prevention mechanism and the flat tubes not provided with the backflow prevention mechanism are alternately arranged, they can function as a condenser having excellent heat exchange performance. On the other hand, only by reversing the flow direction of the heat exchange medium, the interval between the adjacent flat tubes through which the heat exchange medium flows, in other words, the substantial fin height can be doubled, so that the frosting property Thus, it can function as an excellent evaporator.

[Brief description of the drawings]

FIG. 1 is a front view of a heat exchanger according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing the vicinity of a connection portion between a lower header and a tube of the heat exchanger.

FIG. 3 is an enlarged perspective view showing an end of a flat tube having a backflow prevention mechanism used in the heat exchanger.

FIG. 4 is a schematic diagram showing the flow of a heat exchange medium when the heat exchanger is used as a condenser.

FIG. 5 is a schematic diagram showing the flow of a heat exchange medium when the heat exchanger is used as an evaporator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Flat tube 2 ... Fin 3 ... Header 4 ... Header 10 ... Backflow prevention mechanism (check valve)

Claims (3)

[Claims] 1. A flat tube having a predetermined length is arranged in parallel with a predetermined interval in a thickness direction, and hollow headers are connected to both ends of the flat tube in a communicating state, respectively. In the heat exchanger, the flat tubes of the present invention are configured to flow in parallel at the same time. In the heat exchanger, at least one of the flat tubes in the group of flat tubes through which the heat exchange medium flows at the same time is a heat exchange medium. A heat exchanger comprising a backflow prevention mechanism that allows only one-way flow. 2. The heat exchanger according to claim 1, wherein the backflow prevention mechanism is a check valve provided at one end opening of the flat tube. 3. The heat exchanger according to claim 1, wherein the flat tubes provided with the backflow prevention mechanism and the flat tubes not provided with the backflow prevention mechanism are alternately arranged.