JP3158722B2 - Gas-liquid separation type heat exchanger - Google Patents

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 using a large-capacity heat exchanger or a plurality of small-diameter tubes (for example, a diameter of 9.5 mm or less) as a heat transfer tube is used for a heat pump refrigeration cycle, the heat exchanger is used. From the viewpoint of preventing a decrease in the refrigerant temperature due to the pressure loss of the refrigerant flowing through the inside of the pipe, a multi-pass type using a plurality of heat transfer tubes, particularly in an evaporator, is used to reduce the refrigerant circulation amount per pass to reduce the pressure loss. Attempts have been made to reduce the increase. 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 uniformly distributed to each path of the evaporator. difficult.

[0003] For this reason, there is a problem in that the inherent capacity of the heat exchanger cannot be fully utilized due to the non-uniformity of the refrigerant circulation amount in each pass.

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

[0005]

However, in the above configuration, as is apparent from FIG. 3, an independent gas-liquid separation is provided on the refrigerant circulation line 14 from the expansion valve 5 to the indoor heat exchanger (evaporator) 4. In addition to the presence of the vessel 20, the bypass pipe 18 must be separately provided in parallel with the evaporator 4, resulting in a drawback that it is difficult to achieve compactness by utilizing the inherent characteristics of the mesh fin.

[0006]

Means for Solving the Problems Claims 1 and 2 of the present application
The gas-liquid separation type heat exchanger of the invention described above has been made for the purpose of solving the above-mentioned problems and enabling the system to be compact, and has the following structures.

(1) Structure of the gas-liquid separation type heat exchanger according to the first aspect of the invention The gas-liquid separation type heat exchanger according to the first aspect of the present invention has a structure as shown in FIGS. The plurality of heat transfer tubes 54, 54... Are connected between the inlet header 52 and the outlet header 53 which are vertically separated from each other, and the mesh fins 56 are connected to the plurality of heat transfer tubes 54, 54. , 56 ...
In the multi-pass heat exchanger provided with the above, 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 having 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.
Are connected.

(2) Configuration of the gas-liquid separation type heat exchanger according to the second aspect of the invention The gas-liquid separation type heat exchanger according to the second aspect of the invention is the multi-pass type heat exchanger according to the first aspect of the invention. The heat exchanger is configured as a heat exchanger 4 of a heat pump type air conditioner.

[0009]

The gas-liquid separation type heat exchanger according to the first and second aspects of the present invention has the following functions as a result of being configured as described above.

(1) Operation of the gas-liquid separation type heat exchanger according to the first aspect of the present invention:
Inlet header 52 and outlet header 5 which are vertically separated
3 are connected by a plurality of heat transfer thin tubes 54, 54,..., While a mesh fin 56, 56,. In the heat exchanger, the opening of the lower-side inlet header 52 and the opening of the upper-side outlet header 53 are connected by a gas-liquid separation tube 42 having a predetermined length. A liquid-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 moved up and down between the gas refrigerant and the liquid refrigerant in the gas-liquid separation tube 42. Are 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 tubes 54, 54... Via the inlet header 52. ing.

Therefore, each of the heat transfer tubes 54, 54.
The refrigerant to be distributed to and supplied to the liquid refrigerant is only the liquid refrigerant which does not have to make the ratio of the refrigerant to the gas refrigerant, and can be uniformly distributed with little pressure loss.

As a result, the heat exchange capacity of the heat exchange section can be sufficiently exhibited, and the heat exchange performance is also improved.

(2) Operation of the gas-liquid separation type heat exchanger according to the second aspect of the invention In the configuration of the gas-liquid separation type heat exchanger according to the second aspect,
The multi-pass type heat exchanger according to the first aspect of the present invention is configured as a heat exchanger 4 of a 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, where it is condensed into a liquid refrigerant. Then, the liquid refrigerant is decompressed and expanded by the expansion valve to become a gas-liquid two-phase refrigerant, and the gas-liquid separation cylinder 4 of the evaporator 4 is used.
2 flows into.

In the gas-liquid separation cylinder 42, the gas-liquid two-phase refrigerant flows in a diffusion state under the flow pressure of the refrigerant. For this reason, the gas-liquid two-phase refrigerant is smoothly gas-liquid separated due to a decrease in flow velocity due to a sudden increase in the flow path area. Then, the separated refrigerant temporarily accumulates in the lower part of the gas-liquid separation cylinder 42 and flows out from the refrigerant to the inlet header 53 side, which is the distributor of the evaporator 4. On the other hand, the separated gas refrigerant bypasses the heat transfer tube portion of the evaporator 4 via one end of the outlet header portion 52 as a bypass pipe line, and quickly flows out downstream thereof.

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

[0017]

Therefore, according to the gas-liquid separation type heat exchanger of the present invention, the effect of improving the heat exchange performance by supplying a uniform liquid refrigerant can be realized, and the gas-liquid separation cylinder is integrated with the evaporator itself. The system itself can be reduced in size because it becomes incorporated and the bypass pipe is not required.

[0018]

【Example】

(1) First Embodiment First, FIG. 1 shows a configuration 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 of the present embodiment comprises a liquid refrigerant and a gas refrigerant, for example, between an inlet header side and an outlet header side of a multi-pass type mesh fin heat exchanger (evaporator). And a gas-liquid separation cylinder (vessel) for separating oil from each other.

That is, in FIG. 1, reference numeral 52 denotes a gas refrigerant outlet header of the mesh fin type indoor heat exchanger (evaporator), and 53 denotes a liquid refrigerant inlet header.
One end of the outlet header 52 and one end of the inlet header 53 are connected to and integrated with the upper and lower sides of a gas-liquid separation tube 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 at a predetermined interval in the longitudinal direction thereof. A plurality of mesh fins 56, 56,... Further, a gas refrigerant circulation pipe 12 to the compressor 1 side is connected to a longitudinally intermediate portion of the outlet header 52. Further, a throttle 43 for preventing backflow is provided near a connection portion of the outlet header 52 with the gas-liquid separation tube 42.

A distal end portion 14a of the refrigerant circulation pipe 14 is inserted into the gas-liquid separation cylinder 42 from above through the expansion valve 5, and the refrigerant flow in the gas-liquid two-phase state is shown in the direction of the arrow. Is being introduced.

Therefore, the gas-liquid two-phase refrigerant introduced into the gas-liquid separation tube 42 is separated by the weight difference between the two-phase refrigerant.
As shown in the figure, the upper-layer gas refrigerant is separated into two upper and lower layers as shown in the drawing, passes through the outlet header 52 via the throttle 43, is short-circuited, and is 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 liquid refrigerant is supplied to the inlet header 53.
Are uniformly distributed to a plurality of heat transfer tubes 54, 54... Through a mesh fin 56, 56. ,
The refrigerant is supplied to the refrigerant circulation pipe 12 through an outlet header 52.

As described above, in the configuration of this embodiment, when the above-mentioned mesh fin type indoor heat exchanger capable of being made thinner is used as, for example, an evaporator, the gas-liquid separation cylinder 42 upstream of the inlet header 53 is provided. A gas-liquid separator is provided, and the gas refrigerant separated at this portion is bypassed using the outlet header 52 as the bypass line 18 in FIG. Since the heat is distributed to the heat transfer tubes 54, 54, the pressure loss is small and only the liquid refrigerant can be uniformly distributed to the heat transfer tubes 54, 54,. Also improve. In addition, the bypass pipe 18 as shown in FIG. 3 is not required, and the structure of the header section 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 a cooling operation and a gas refrigerant backflow prevention during a heating operation. For example, a multi-pass mesh fin type heat exchanger (evaporator) between the inlet header side and the outlet header side, with a float mechanism inside, the liquid refrigerant and the gas refrigerant And a gas-liquid separation cylinder (vessel) for separating oil from each other.

That is, in FIG. 2, reference numeral 52 denotes a gas refrigerant outlet header of the mesh fin type indoor heat exchanger (evaporator), and 53 denotes a liquid refrigerant inlet header.
One end of the outlet header 52 and one end of the inlet header 53 are connected to and integrated with the upper and lower sides of a gas-liquid separation tube 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 at a predetermined interval in their longitudinal direction. A plurality of mesh fins 56, 56,... Further, a gas refrigerant circulation pipe 12 to the compressor 1 side is connected to a longitudinally intermediate portion of the outlet header 52.

The refrigerant circulation pipe line 14 is connected to the gas-liquid separation cylinder 42 from above through the expansion valve 5 so that a gas-liquid two-phase refrigerant flow is introduced in the direction of the arrow. It has become.

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

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

The float pipe 51 communicates a base end 52a of a bypass conduit 52BP for bypassing the gas refrigerant of the outlet header 52 with a base end 53a of the inlet header 53 in a U-shape. The upper and lower ends are formed in small-diameter portions 46a and 46b. Inside thereof, a column-shaped float 47 having a predetermined length with upper and lower ends formed as conical valve bodies 47b and 47a is provided in accordance with a change in the liquid level of the liquid refrigerant in the gas-liquid separation chamber. It is inserted movably up and down. Further, a plurality of openings 49, 49,..., 50, 50,... Are respectively formed at the upper and lower ends of the float pipe 51, and the float chamber in the float pipe 51 and the gas-liquid outside the float pipe 51 are formed. The separation chamber communicates with the float position, in other words, in accordance with 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 positioned above a predetermined position. The ascending position is regulated by the ascending position regulating projection 45. The specific gravity of the ball 48 is set to be slightly higher than the specific gravity of the gas refrigerant. Also,
The specific gravity of the float 47 is set to an intermediate specific gravity between the gas refrigerant and the liquid refrigerant.

Therefore, when the cooling operation of, for example, a heat pump cycle is started, first, as shown in the drawing, the refrigerant flow in the gas-liquid two-phase state is sequentially passed through the fourth refrigerant circulation line 14 in the direction of the arrow. As a result, the liquid refrigerant accumulates in the lower layer due to the weight difference (specific gravity difference), while the gas refrigerant comes to stay in the upper layer, and the gas refrigerant and the liquid refrigerant are surely in the upper and lower two layers. Separated.

However, since the liquid level of the liquid refrigerant is still low until a predetermined time has elapsed since the start of the cooling operation, the float 47 in the float pipe 51 has descended to the lower end of the float chamber. The main body closes the openings 50, 50,... On the lower end side of the float pipe 51. Therefore, no liquid refrigerant is supplied to the inlet header 53 yet. 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 passes through the openings 49, 49. It flows to the pipeline 52BP side and is bypassed.

Next, after a predetermined time has elapsed from the start of the above operation, for example, in a steady state as shown in the figure, the liquid level of the liquid refrigerant is substantially at the intermediate position of the gas-liquid separation chamber as shown in the figure. , And the float 47 is located in the middle of the upper end side openings 49, 49 ... and the lower end side openings 50, 50 ... of the float pipe 51. .. Flows through the lower end side openings 50, 50... To the inlet header 53 side according to the pressure difference, while the upper side gas refrigerant flows toward the upper end side of the float pipe 51. The ball 48 is sufficiently floated by a sufficient pressure difference into the float chamber through the openings 49, 49,... To efficiently flow out to the bypass pipe line 18 side. In this manner, continuous gas-liquid separation is performed, and uniform distribution of the liquid refrigerant is performed to each of the heat transfer thin tubes 54, 54,... (Path), and the original good heat exchange performance is exhibited. You.

On the other hand, if the liquid level rises too much during a cooling operation in which the flow rate of the refrigerant is further increased due to a load change or the like, the float 47 also rises to the upper end of the float chamber in the float pipe 51, and Closes the openings 49, 49... On the upper end side of the float pipe 51. As a result, the gas refrigerant in the upper layer side of the gas-liquid separation chamber is stopped from flowing out to the bypass pipe section 52BP side, the internal pressure in the gas-liquid separation chamber increases, the outflow speed of the liquid refrigerant increases, and the liquid level quickly rises. And the outflow of the gas refrigerant starts again. In this manner, in the present embodiment, even when the refrigerant flow rate or the dryness changes due to the load fluctuation, the fluctuation in the liquid level can always be suppressed within a certain range, and the good heat exchange performance can always be obtained. Can be maintained.

On the other hand, when the operation is switched to the heating operation, the liquid refrigerant flows in the opposite direction to the above, while the gas refrigerant on the side of the bypass pipe section 52BP is supplied to the float pipe 51.
In this embodiment, the ball 48 which performs a check valve function at the base end of the bypass pipe 52BP is used.
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 through the heat transfer thin tubes 54, 54.
..Distributed into inlet header 53, float pipe 5
The first refrigerant flows to the fourth refrigerant circulation pipe 14 side.

As described above, even in the configuration of this embodiment, the first
Similarly to the embodiment, when the above-mentioned mesh fin type indoor heat exchanger capable of being thinned is used as, for example, an evaporator, the gas-liquid separation cylinder 42 upstream of the inlet header 53 has a function as a gas-liquid separator. The gas refrigerant separated in this portion is bypassed by using the outlet header 52 as the bypass pipe 18 in FIG. 2, and only the liquid refrigerant flows from the lower inlet header 53 to each of the heat transfer thin tubes 54, 54. Pressure loss is small and each heat transfer thin tube 5
Only the liquid refrigerant can be uniformly distributed to the 4,54... Portions, and the heat exchange capacity is also improved. In addition, the bypass pipe 18 as shown in FIG. 3 is not required, and the structure of the header section 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 performed efficiently and stably while having a compact structure as described above, and particularly under the condition of low pressure loss. In this case, an accurate check valve action can be obtained, for example, during heating, and can be sufficiently applied to a heat pump refrigeration cycle.

[Brief description of the 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 conventional general heat pump refrigeration system for an air conditioner.

[Explanation of symbols]

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

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-89902 (JP, A) JP-A-3-91663 (JP, A) JP-A-63-189794 (JP, A) JP-A-62-1987 56782 (JP, A) JP-A-1-121688 (JP, A) JP-A-4-84097 (JP, A) JP-A-1-121689 (JP, A) Japanese Utility Model Application No. Sho 56-45750 (JP, U) Japanese Utility Model Showa 57-196957 (JP, U) Japanese Utility Model Showa 51-20917 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 39/00 F25B 43/00 F28D 15/02

Claims (2)

(57) [Claims] An inlet header (52) which is vertically separated from each other.
And a plurality of heat transfer tubes (54), (5)
4), while the plurality of heat transfer thin tubes (5
4), (54) ... mesh fins (56), (56)
In the multi-pass heat exchanger provided with the above, 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 a gas-liquid two-phase refrigerant supply pipe (14) connected to the upper part 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.