JPH06117728A - Vapor-liquid separation type heat exchanger - Google Patents

Abstract

PURPOSE:To enhance the efficiency of a multi-pass type mesh fin heat exchanger which uses a plurality of small-sized heat exchanger tubes to a satisfactory extent and compact the heat exchanger. CONSTITUTION:An inlet manifold 53 and an outlet manifold 52 are installed and vertically separated from each other and connected with a plurality of heat exchanger tubes 54 equipped with mesh fins 56, thereby forming a multi-pass type heat exchanger. In this exchanger, the openings of the both manifolds are connected with a specified length of vapor-liquid separation cylinder 42. Furthermore, a supply pipe 14 of two phase vapor-liquid refrigerant is connected to the upper part of the vapor-liquid separation cylinder 42 and the two phase vapor-liquid refrigerant introduced by way of the pipe 14 is separated from vapor to liquid, forming an upper layer (vapor) and a lower layer (liquid) in the vapor-liquid separation cylinder 42. The gas refrigerant is bypassed by way of the outlet manifold 53. This bypassed refrigerant and the vaporized refrigerant from the liquefied refrigerant are communication to a suction pipe by way of an outlet 12. Only the liquefied refrigerant is supplied to the small-sized heat exchanger tubes 54 by way of the manifold 534 where the liquid is distributed to each pass equally, which makes it possible to enhance the efficiency of the heat exchanger and reduce the size of the heat exchanger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-liquid separation type heat exchanger applicable to a heat pump type refrigeration cycle.

[0002]

2. Description of the Related Art Generally, when a heat exchanger having a large capacity heat exchanger or a plurality of small diameter tubes (for example, a diameter of 9.5 mm or less) is used as a heat transfer tube in a heat pump type refrigeration cycle, the heat exchanger is used. In order to prevent the decrease of the refrigerant temperature due to the pressure loss of the refrigerant flowing in the pipe, especially in the evaporator etc., a multi-pass type with multiple heat transfer tubes is used to reduce the refrigerant circulation amount per pass to reduce the pressure loss. It has been attempted to suppress the increase in However, since the refrigerant after expansion is in a gas-liquid two-phase state on the inlet side of the evaporator, it is impossible to control the gas-liquid ratio and the refrigerant can be evenly distributed to each path of the evaporator. difficult.

Therefore, there is a problem that the inherent capacity of the heat exchanger cannot be fully utilized due to the non-uniform refrigerant circulation amount in each pass.

As one of means for solving such a problem, for example, as shown in FIG. 3, a gas-liquid separator 20 is provided on the upstream side of the refrigerant inlet 8 of the evaporator 4 which requires multi-pass distribution. In the liquid separator 20, the refrigerant in a gas-liquid two-phase state is separated into a gas refrigerant and a liquid refrigerant, and the gas refrigerant having a small contribution to heat exchange passes from the bypass pipe 18 bypassing the evaporator 4 to the evaporator 4. By diverting to the downstream side and distributing only the liquid refrigerant to the evaporator 4 in a single-phase state,
It has been considered to realize uniform distribution of the refrigerant without considering the gas-liquid ratio.

[0005]

However, in the above structure, as is apparent from FIG. 3, independent gas-liquid separation is provided on the refrigerant circulation line 14 from the expansion valve 5 to the indoor heat exchanger (evaporator) 4. With the presence of the vessel 20, the bypass pipe 18 has to be separately provided in parallel with the evaporator 4, which causes a drawback that it is difficult to achieve compactness by taking advantage of the original characteristics of the mesh fin.

[0006]

Claims 1 and 2 of the present application
The gas-liquid separation type heat exchanger of the described invention is made for the purpose of solving the above problems and enabling the system to be compact, and is configured as follows.

(1) Structure of the gas-liquid separation type heat exchanger of the invention described in claim 1 The gas-liquid separation type heat exchanger of the invention described in claim 1 is, for example, as shown in FIG. 1 and FIG. The inlet header 52 and the outlet header 53, which are vertically separated, are connected by a plurality of heat transfer thin tubes 54, 54, ..., On the other hand, a mesh fin 56 is provided on the plurality of heat transfer thin tubes 54, 54. 56 ...
In a multi-pass heat exchanger, the opening of the lower inlet header 52 and the opening of the upper outlet header are connected by a gas-liquid separation cylinder 42 of a predetermined length, and the gas-liquid separation is performed. A gas-liquid two-phase refrigerant supply pipe 14 is provided above the cylinder 42.
It is characterized by connecting.

(2) Structure of the gas-liquid separation type heat exchanger of the invention described in claim 2 The gas-liquid separation type heat exchanger of the invention described in claim 2 is the multi-pass type of the invention described in claim 1. The heat exchanger is configured as the heat exchanger 4 of the heat pump type air conditioner.

[0009]

The gas-liquid separation type heat exchanger of the present invention according to claims 1 and 2 of the present application has the following effects as a result of being configured as described above.

(1) Operation of the gas-liquid separation type heat exchanger of the invention described in claim 1 In the structure of the gas-liquid separation type heat exchanger of the invention described in claim 1,
Vertically separated inlet header 52 and outlet header 5
A multi-pass type in which the three are connected by a plurality of heat transfer thin tubes 54, 54 ... And a mesh fin 56, 56 ... Is provided in the plurality of heat transfer thin tubes 54, 54. In the heat exchanger, the opening portion of the lower inlet header 52 and the opening portion of the upper outlet header 53 are connected by a gas-liquid separating cylinder 42 having a predetermined length, and the upper portion of the gas-liquid separating cylinder 42 is filled with air. The liquid-two-phase refrigerant supply pipe 14 is connected, and the gas-liquid two-phase refrigerant introduced through the gas-liquid two-phase refrigerant supply pipe is placed in the gas-liquid separation cylinder 42 so as to move above and below the gas refrigerant and the liquid refrigerant. Separated into two layers, the gas refrigerant is bypassed through a part of the outlet header 53, and only the liquid refrigerant is supplied and distributed to the heat transfer thin tubes 54, 54 ... Through the inlet header 52. ing.

Therefore, the heat transfer thin tubes 54, 54 ...
The only refrigerant that can be distributed and supplied to the liquid refrigerant is a liquid refrigerant that does not have a problem with the ratio of the gas refrigerant, and the refrigerant can be uniformly distributed with less pressure loss.

As a result, the heat exchanging ability of the heat exchanging portion can be fully exerted, and the heat exchanging performance is also improved.

(2) Operation of the gas-liquid separation type heat exchanger of the invention described in claim 2 In the structure of the gas-liquid separation type heat exchanger of the invention described in claim 2,
The multi-pass heat exchanger of the invention according to claim 1 is configured as the heat exchanger 4 of the heat pump type air conditioner as illustrated in FIG.

Therefore, for example, during cooling operation,
The high-temperature and high-pressure gas refrigerant discharged from the compressor first flows into the condenser and is condensed in the condenser to become a liquid refrigerant. Then, this liquid refrigerant is decompressed and expanded in the expansion valve to become a gas-liquid two-phase refrigerant, and the gas-liquid separation cylinder 4 of the evaporator 4 described above.
It flows into 2.

In the gas-liquid separation cylinder 42, the gas-liquid two-phase refrigerant receives the flow pressure of the refrigerant and flows in a diffused state. Therefore, the gas-liquid two-phase refrigerant is smoothly gas-liquid separated due to the decrease in the flow velocity due to the rapid expansion of the flow passage area. Then, the separated refrigerant temporarily accumulates in the lower portion of the gas-liquid separation cylinder 42 and is made to flow from there to the inlet header portion 53 side which is the distributor portion of the evaporator 4. On the other hand, the separated gas refrigerant bypasses the heat transfer pipe portion of the evaporator 4 through one end of the outlet header portion 52 serving as a bypass pipe passage, and quickly flows out to the downstream side thereof.

Therefore, the heat exchanger (evaporator in this case) 4
In the above, since only the liquid refrigerant is introduced in the single-phase state into the inlet header portion 53 that functions as a distributor,
For example, as compared with the case where the refrigerant is introduced in a gas-liquid two-phase state, a much more effective uniform distribution of the refrigerant in each path is realized, and the pressure loss is reduced. As a result, in the heat exchanger, higher heat exchange performance is ensured by helping that the gas refrigerant that hardly contributes to heat exchange does not flow and the pressure loss of the refrigerant in each pass portion is small.

[0017]

Therefore, according to the gas-liquid separation type heat exchanger of the present invention, the effect of improving the heat exchange performance by the uniform supply of the liquid refrigerant can be realized, and the gas-liquid separation cylinder is integrated with the evaporator itself. Since it is built in and a bypass pipe is unnecessary, the system itself can be made compact.

[0018]

【Example】

(1) First Embodiment First, FIG. 1 shows the structure of a gas-liquid separation type mesh fin heat exchanger according to a first embodiment of the present invention.

The gas-liquid separation type heat exchanger according to the present embodiment has, for example, a liquid refrigerant and a gas refrigerant between the inlet header side and the outlet header side of a multi-pass type mesh fin type heat exchanger (evaporator). It is characterized in that it incorporates a gas-liquid separating cylinder (container) for separating the two from each other.

That is, in FIG. 1, reference numeral 52 is a gas refrigerant outlet header of the mesh fin type indoor heat exchanger (evaporator), and 53 is a liquid refrigerant inlet header.
One ends of the outlet header 52 and the inlet header 53 are connected to and integrated with the upper and lower sides of a gas-liquid separation cylinder 42 which is vertically provided.

Between the outlet header 52 and the inlet header 53, a plurality of heat transfer thin tubes 54, 54, ... Are connected in parallel with each other at predetermined intervals in the longitudinal direction thereof. A plurality of mesh fins 56, 56 ... Are attached to 54, 54 ... Further, the gas refrigerant circulation pipe line 12 to the compressor 1 side is connected to an intermediate portion in the longitudinal direction of the outlet header 52. Further, a throttle 43 for preventing backflow is provided near the connecting portion of the outlet header 52 with the gas-liquid separating cylinder 42.

Then, the tip portion 14a of the refrigerant circulation line 14 via the expansion valve 5 is inserted and connected from the upper side into the gas-liquid separation cylinder 42, and the refrigerant flow in the gas-liquid two-phase state is shown in the arrow direction. Is being introduced.

Therefore, the gas-liquid two-phase refrigerant introduced into the gas-liquid separating cylinder 42 is divided into two by the weight difference.
In FIG. 2, the upper layer gas refrigerant is separated into two layers as shown in the drawing, passes through the outlet header 52 via the throttle 43, and is short-circuited to be quickly returned from the circulation line 12 to the compressor suction side. That is, the indoor heat exchanger (evaporator) 4 is bypassed.

On the other hand, the lower layer side liquid refrigerant is the inlet header 53.
After being evenly distributed to the plurality of heat transfer thin tubes 54, 54 ... through heat exchange with the air flow through the mesh fins 56, 56 ... ,
It is supplied to the refrigerant circulation line 12 through the outlet header 52.

As described above, in the structure of this embodiment, when the mesh fin type indoor heat exchanger capable of being thinned is used as, for example, an evaporator, the gas-liquid separating cylinder 42 upstream of the inlet header 53 thereof is used. A function as a gas-liquid separator is provided, and the gas refrigerant separated in the portion is bypassed by using the outlet header 52 as the bypass pipe line 18 in FIG. Since the heat transfer thin tubes 54, 54 ... Are distributed, the pressure loss is small and only the liquid refrigerant can be uniformly distributed to the heat transfer thin tubes 54, 54. Also improves. Further, the bypass conduit 18 as shown in FIG. 3 is not necessary, and the structure of the header part can be simplified. Therefore, the system can be made compact.

(2) Second Embodiment Next, FIG. 2 shows the structure and operation of a gas-liquid separation type mesh fin heat exchanger according to a second embodiment of the present invention.

The gas-liquid separation type mesh fin heat exchanger of this embodiment is particularly suitable for the heat pump cycle as shown in FIG. 3 described above, and has a liquid level control function during cooling operation and a gas refrigerant backflow prevention during heating operation. It is configured with a function, for example, between the inlet header portion side and the outlet header portion side of the mesh fin type heat exchanger (evaporator) of the multi-pass system, a liquid refrigerant and a gas refrigerant with a float mechanism inside. It is characterized in that it incorporates a gas-liquid separating cylinder (container) for separating the two from each other.

That is, in FIG. 2, reference numeral 52 is a gas refrigerant outlet header of the mesh fin type indoor heat exchanger (evaporator), and 53 is a liquid refrigerant inlet header.
One ends of the outlet header 52 and the inlet header 53 are connected to and integrated with the upper and lower sides of a gas-liquid separation cylinder 42 which is vertically provided.

Between the outlet header 52 and the inlet header 53, a plurality of heat transfer thin tubes 54, 54 ... Are connected in parallel with each other at a predetermined interval in the longitudinal direction thereof. A plurality of mesh fins 56, 56 ... Are attached to 54, 54 ... Further, the gas refrigerant circulation pipe line 12 to the compressor 1 side is connected to an intermediate portion in the longitudinal direction of the outlet header 52.

A refrigerant circulation line 14 is connected to the inside of the gas-liquid separating cylinder 42 from the upper side via the expansion valve 5 so that a refrigerant flow in a gas-liquid two-phase state is introduced in the arrow direction. It has become.

On the other hand, a float pipe 51 forming a liquid level control unit 40 is vertically penetrated in the gas-liquid separation chamber having a predetermined length in the vertical direction inside the gas-liquid separator cylinder 42. .

From the fourth refrigerant circulation line 14, the refrigerant flow in the gas-liquid two-phase state is introduced downward through the expansion valve 5 during the cooling operation, and the difference in weight is utilized. As a result, the gas refrigerant and the liquid refrigerant are separated into upper and lower two layers.

In the float pipe 51, a base end portion 52a of the bypass conduit 52BP for bypassing the gas refrigerant in the outlet header 52 and a base end portion 53a of the inlet header 53 communicate with each other in a U-shape. The structure is integrated, and the upper and lower ends thereof are formed into small diameter portions 46a and 46b. Inside the cylinder, a float 47 in the shape of a cylinder having a predetermined length with conical valve bodies 47b and 47a at the upper and lower ends is provided according to the change in the liquid level of the liquid refrigerant in the gas-liquid separation chamber. And is vertically movably inserted. Further, a plurality of openings 49, 49 ... And 50, 50 ... Are formed at both upper and lower ends of the float pipe 51, respectively. The float chamber inside the float pipe 51 and the gas liquid outside the float pipe 51 are formed. The separation chamber is made to communicate with each other according to the float position, in other words, the liquid surface position of the liquid refrigerant.

On the other hand, a ball 48, which is a spherical valve forming a check valve, is loosely fitted in the upper end side of the upper end side small diameter portion 46a of the float pipe 51, and the ball 48 is located above the predetermined position. The raised position is regulated by the raised position regulating convex portion 45. The specific gravity of the balls 48 is set to be slightly heavier than the specific gravity of the gas refrigerant. Also,
The specific gravity of the float 47 is set to an intermediate value between the specific gravities of the gas refrigerant and the liquid refrigerant.

Therefore, for example, when the cooling operation of the heat pump cycle is started, first, as shown in the figure, the refrigerant flow in the gas-liquid two-phase state is sequentially passed through the fourth refrigerant circulation conduit 14 in the arrow direction. As a result, the liquid refrigerant accumulates in the lower layer due to the weight difference (specific gravity difference), while the gas refrigerant remains in the upper layer, ensuring that the gas refrigerant and the liquid refrigerant are in the upper and lower two layers. To be separated.

However, since the liquid level of the liquid refrigerant is still low until a predetermined time elapses after the start of the cooling operation, the float 47 in the float pipe 51 descends to the lower end of the float chamber, The main body closes the openings 50, 50 ... At the lower end of the float pipe 51. Therefore, the liquid refrigerant is not yet supplied to the inlet header 53. On the other hand, since the openings 49, 49 ... On the upper end side of the float pipe 51 are open, the separated gas refrigerant is bypassed through the outlet header 52 via the openings 49, 49. It flows to the side of the pipe portion 52BP and is bypassed.

Next, after a lapse of a predetermined time from the start of the above operation, in a steady state as shown in the figure, for example, the liquid level of the liquid refrigerant is about the intermediate position of the gas-liquid separation chamber as shown in the figure. ., The float 47 is positioned in the middle of the upper openings 49, 49 ... And the lower openings 50, 50 ... Of the float pipe 51. Liquid refrigerant flows out to the inlet header 53 side through the lower end side openings 50, 50 ... In response to the pressure difference, while the upper gas refrigerant is the upper end side of the float pipe 51. By entering the float chamber through the openings 49, 49 ... With sufficient pressure difference, the balls 48 are sufficiently levitated and efficiently flow out to the bypass pipe line 18 side. In this way, continuous gas-liquid separation is performed, and the uniform liquid refrigerant is distributed to the above-mentioned heat transfer thin tubes 54, 54 ... (Pass), and the original good heat exchange performance is exhibited. It

On the other hand, if the liquid level rises too much during cooling operation in which the refrigerant flow rate increases due to load fluctuations, etc., the float 47 also rises to the upper end of the float chamber in the float pipe 51, and its main body portion. Closes the openings 49, 49 ... on the upper end side of the float pipe 51. As a result, the outflow of the gas refrigerant in the upper layer side of the gas-liquid separation chamber to the bypass conduit portion 52BP side is stopped, the internal pressure in the gas-liquid separation chamber increases, the outflow speed of the liquid refrigerant increases, and the liquid level quickly increases. Is lowered, and then the outflow of the gas refrigerant starts again. In this way, in the present embodiment, even when the refrigerant flow rate and the dryness are changed by the load change, it is possible to always suppress the fluctuation of the liquid level within a certain range, and always obtain a good heat exchange performance. Will be able to maintain.

On the other hand, when the heating operation is switched to the one-way heating mode, the liquid refrigerant flows in the opposite direction to the above, while the gas refrigerant on the side of the bypass conduit 52BP is the float pipe 51.
However, in the present embodiment, the ball 48 that fulfills the check valve function is provided at the base end of the bypass conduit 52BP.
In this case, the ball 48, which is a spherical valve, closes the base end of the bypass conduit 52BP, and only the liquid refrigerant smoothly flows into the heat transfer thin tubes 54, 54.
..Distribution into inlet header 53 and float pipe 5
It comes to flow from the 1st to the 4th refrigerant circulation pipeline 14 side.

As described above, even in the configuration of this embodiment, the first
Similarly to the embodiment, when the mesh fin type indoor heat exchanger that can be thinned is used as, for example, an evaporator, the gas-liquid separation cylinder 42 upstream of the inlet header 53 thereof has a function as a gas-liquid separator. The gas refrigerant separated in the portion is bypassed by using the outlet header 52 as the bypass conduit 18 of FIG. 2, and only the liquid refrigerant is passed from the lower inlet header 53 to the heat transfer thin tubes 54, 54 ... Since it is distributed to each heat transfer thin tube 5
It becomes possible to evenly distribute only the liquid refrigerant to the parts 4, 54, ... And the heat exchange capacity is also improved. Further, the bypass conduit 18 as shown in FIG. 3 is not necessary, and the structure of the header part can be simplified. Therefore, the system can be made compact.

Further, according to the present embodiment, the gas-liquid separation of the two-phase refrigerant can be efficiently and stably performed while having the compact structure as described above, and especially under the condition of low pressure loss. Also, it becomes possible to obtain an accurate check valve action during heating, etc., and it can be sufficiently applied to a heat pump type refrigeration cycle.

[Brief description of drawings]

FIG. 1 is a front view showing a configuration of a gas-liquid separation type mesh fin heat exchanger according to a first embodiment of the present invention.

FIG. 2 is a front view showing a configuration of a gas-liquid separation type mesh fin heat exchanger according to a second embodiment of the present invention.

FIG. 3 is a refrigeration circuit diagram showing a configuration of a heat pump refrigeration system of a conventional general air conditioner.

[Explanation of symbols]

11 is an indoor heat exchanger, 12 and 14 are refrigerant circulation lines, 42
Is a gas-liquid separation cylinder, 52 is an inlet header, 53 is an outlet header, 54 is a heat transfer thin tube, and 56 is a mesh fin.

Claims (2)

[Claims] 1. An inlet header (52) vertically spaced apart
Between the outlet header (53) and the heat transfer thin tubes (54), (5
4) While being connected by ..., the plurality of heat transfer thin tubes (5
4), (54) ... mesh fins (56), (56)
.. In a multi-pass heat exchanger provided with, the opening of the lower inlet header (52) and the opening of the upper outlet header are connected by a gas-liquid separation cylinder (42) of a predetermined length In addition, a gas-liquid separation type heat exchanger is characterized in that a gas-liquid two-phase refrigerant supply pipe (14) is connected to an upper portion of the gas-liquid separation cylinder (42). 2. The gas-liquid separation type heat exchanger according to claim 1, wherein the multi-pass type heat exchanger is a heat exchanger of a heat pump type air conditioner.