JPH0250059A - Evaporator - Google Patents

Abstract

PURPOSE:To reduce the loss of pressure caused by refrigerant gas so as to improve the cooling capacity without structural improvement or use of special equipment by forming in a part of an evaporator passageway for refrigerant a shunt permitting refrigerant gas flowing in from the inlet port to flow directly to the outlet port. CONSTITUTION:In the upper part of a partition 7 in a tank 4 as a means of separation between an inlet port 2 and an outlet port 3 positioned adjacently, a shunt 8 is formed which permits refrigerant gas flowing in from an inlet port 2 to flow directly to an outlet port 3. The refrigerant taken in in two phases of gas and liquid through the inlet port 2 separates, as it flows through the tank 4, into liquid and gas due to a difference in specific gravity, the former flowing in the lower part of the tank 4 and the latter in the upper part of the tank 4. The liquid refrigerant which flows through flat tubes 5 is vaporized by heat exchange by means of corrugated fins 6 and the gasified refrigerant is discharged immediately through the outlet port 3. The loss of pressure caused by refrigerant gas can therefore be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an evaporator used in a refrigeration cycle of a vehicle air conditioner or the like.

[Prior Art] Conventionally, this type of evaporator is generally an evaporator that is provided with a refrigerant evaporation path that is disposed with a predetermined extended distance from an inlet port to an outlet port and that has heat transfer fins around the evaporator. is known for.

For example, in a stacked evaporator 31 as shown in FIG. 14, its inlet port 32 is connected to an expansion valve that constitutes a refrigeration cycle, and its outlet port 33 is connected to a compressor that also constitutes a refrigeration cycle. And Section 15.1
As shown in FIG. 6, after the gas-liquid two-phase refrigerant flowing from the expansion valve is introduced into the inlet port 32, the refrigerant enters the tank section 34.
While passing through the refrigerant evaporation path such as the flat tube 35, the liquid refrigerant is vaporized based on the heat exchange action by the heat transfer fins 36,
It is led out from the outlet port 33.

[Problems to be Solved by the Invention] However, in the conventional evaporator 31, among the gas-liquid two-phase refrigerant introduced from the inlet port 32, the liquid refrigerant contributes to heat exchange and is vaporized, but the gas refrigerant did not contribute to heat exchange in any way. Moreover, the gas refrigerant increases the volumetric flow rate within the evaporator 31, increasing the pressure loss. Therefore, due to this pressure loss, the evaporation temperature of the liquid refrigerant increases, the temperature difference with the surroundings becomes smaller, and the cooling capacity of the evaporator 31 is reduced.

Therefore, in order to reduce pressure loss due to gas refrigerant,
It is conceivable to increase the area of the refrigerant evaporation path. However, in this case, there is a problem that not only is heat conduction from the refrigerant to the heat transfer fins 36 disadvantageous, but also that the evaporator 31 itself becomes large.

In addition, in order to reduce the pressure loss, for example,
It is also conceivable to provide a gas-liquid separator for removing the gas refrigerant, as disclosed in Japanese Patent No. 7-36580. However, in this case, there were problems in terms of rising costs for the gas-liquid separator and securing space.

This invention was made in view of the above-mentioned circumstances, and its purpose is to reduce pressure loss due to gas refrigerant and improve cooling capacity without increasing the size and without providing special components. Our goal is to provide an evaporator that can

[Means for Solving the Problem] In order to achieve the above object, the present invention provides a refrigerant evaporator which is disposed with a predetermined extended distance from an inlet port to an outlet port and has heat transfer fins around the refrigerant evaporator. In an evaporator equipped with a refrigerant evaporation path, a short-circuit path is provided in a part of the refrigerant evaporation path to short-circuit the gas refrigerant flowing from the inlet port side to the outlet port side.

[Operation] Therefore, among the gas-liquid two-phase refrigerant introduced from the inlet port, the gas refrigerant with a light specific gravity is guided to the outlet port via the short circuit. As a result, the pressure loss in the refrigerant evaporation path is reduced, the liquid refrigerant is efficiently vaporized, and the cooling capacity is improved.

[First Embodiment] Hereinafter, a first embodiment in which the present invention is embodied in a stacked evaporator will be described in detail with reference to FIGS. 1 and 2.

FIG. 1 is a partially cutaway plan view of a stacked evaporator 1 in this embodiment, and its overall external shape is approximately the same as the conventional evaporator 31 shown in FIG. 14. Further, the evaporator 1 is one of the components of a well-known refrigeration cycle, and is connected to a well-known expansion valve and a compressor (not shown).

As shown in Figures 1 and 2, the evaporator 1 has an inlet port 2 that projects laterally and is connected to an expansion valve, and an outlet port 1 that also projects laterally and is connected to a compressor. 3, a tank portion 4 and a flat tube 5 as a refrigerant evaporation path which is disposed with a predetermined extension distance between the inlet port 2 and the outlet port 3 and allows the refrigerant to flow, and a flat tube 5 formed around the flat tube 5. It is provided with corrugated fins 6 as heat transfer fins for promoting heat exchange with air. And tank part 4
A gas-liquid two-phase refrigerant flows through the refrigerant.

The above configuration is approximately the same as the evaporator 31 of the conventional example. The refrigerant introduced from the inlet port 2 follows the path shown by solid lines and broken lines in FIG.
It is derived from

As shown in FIGS. 1 and 2, in this embodiment, from the inlet port 2 side, a A short-circuit path 8 is formed to short-circuit the inflowing gas refrigerant to the outlet port 3 side. The configuration of this short-circuit path 8 differs from that of the conventional evaporator 31.

Therefore, when the gas-liquid two-phase refrigerant introduced from the inlet port 2 passes through the tank section 4 as shown in FIG.
Due to the difference in specific gravity, the liquid refrigerant flows below the tank section 4, and the gas refrigerant flows above the tank section 4. Of the refrigerant in the gas-liquid two-phase state, the liquid refrigerant is vaporized by the corrugated fins 6 based on the heat exchange action when flowing through the flat tube 5. On the other hand, among the gas-liquid two-phase refrigerants, the gas refrigerant is immediately guided to the outlet port 3 via the short circuit path 8 as shown by arrow A, and is then led out from the port 3.

As a result, the gas refrigerant that does not directly contribute to the heat exchange action is immediately removed from the outlet port 3, the pressure loss due to the gas refrigerant can be reduced, and the liquid refrigerant can be vaporized efficiently. Therefore, the cooling capacity of the evaporator can be improved.

[Second Embodiment] Next, a second embodiment in which a short circuit path is provided at a different position will be described with reference to FIG.

FIG. 3 is a perspective view illustrating the schematic structure of the stacked evaporator 11 in this embodiment. Further, this evaporator 11 is one of the components of a well-known refrigeration cycle, and is connected to a well-known expansion valve and a compressor (not shown).

The evaporator 11, which is generally box-shaped as a whole, has an upper tank 12 at its upper part and a lower tank 13 at its lower part. A pipe section 14 is provided between the upper tank 12 and the lower tank 13 with a predetermined extension distance, and a conductor is provided around the pipe section 14 to promote heat exchange with the air. Heat fins (paths shown) are provided. Each of the members 12 to 14 constitutes a refrigerant evaporation path through which the refrigerant flows.

The upper tank 12 and the pipe section 14 are each divided into two chambers 12A, 12B, 14A, and 14B by a partition wall 15. Further, on the side of the first chamber 12A of the upper tank 12, two further small chambers 12a are formed by a partition wall 16.

It is divided into 12b. Furthermore, one of the small chambers 12a
has an inlet port 1 which projects laterally and is connected to the expansion valve.
7 is provided, and the other small chamber 12b is provided with an outlet port 18 that projects laterally and is connected to the compressor.

That is, in this embodiment, unlike the first embodiment in which the inlet port 2 and the outlet port 3 are arranged adjacent to each other, the inlet port 17 and the outlet port 1 are spaced apart on both sides. It is arranged.

The above configuration is substantially the same as that of the conventional stacked evaporator 31. Then, the gas and liquid 2 introduced from the inlet port 17
The refrigerant in phase is led out from the outlet port 18 after following the path shown by the solid line and the two-dot chain line.

In this embodiment, a short-circuit path 1 is provided in the partition wall 15 on the small chamber 12a side of the upper tank 12 for short-circuiting the gas refrigerant flowing from the inlet port 17 side to the outlet port 18 side.
9 is formed.

Therefore, among the gas-liquid two-phase refrigerant introduced from the inlet port 17, the liquid refrigerant flows through the upper tank 12, the pipe section 14, and the lower tank 13 by following the path shown by the solid line and the two-dot chain line in FIG. As it flows through the pipe section 14, it is vaporized by the heat exchange action at the heat transfer fins. On the other hand, among the gas-liquid two-phase refrigerants, the gas refrigerant is in the small chamber 1 as shown by arrow B.
2a to the other chamber 12B via the short circuit 19,
from the outlet port 18 at an early stage.

As a result, the gas refrigerant that does not directly contribute to the heat exchange action is quickly removed from the outlet port 18, the pressure loss due to the gas refrigerant can be reduced, and the liquid refrigerant can be vaporized efficiently.

Therefore, the cooling capacity of the evaporator can be improved.

Here, FIG. 4 shows a Mollier diagram based on the results of experiments conducted using the evaporators 11 of the first and second embodiments. In this figure, the broken line shows the results obtained using the evaporator 31 of the conventional example, and the solid line shows the results obtained using the evaporator 11 of the present embodiment.

The heat exchange amount Δ11 per unit weight of the evaporator 11 of this embodiment is greater than that of the conventional evaporator 31 by the amount that the pressure loss is reduced.
It can be seen that the heat exchange amount Δill increases, and correspondingly, the power consumption Δ12 of the compressor decreases compared to the power consumption Δi21 when the conventional evaporator 31 is used.

That is, Δil/Δ12>Δ111/Δt21, and in the refrigeration cycle using the evaporator 11 of this embodiment,
It can be seen that the coefficient of performance has improved.

[Third Embodiment] Next, a third embodiment in which a plurality of short circuit paths are provided will be described with reference to FIGS. 5 to 10.

FIG. 5 is a partially cutaway plan view of the stacked evaporator 21 in this embodiment, and its overall external shape is approximately the same as the conventional evaporator 31 shown in FIG. 14.

However, in the evaporator 21 of this embodiment, its inlet port 22
The position of the outlet port 23 is opposite to the position of the evaporator 31 in the conventional example. Further, this evaporator 21 is one of the components of a well-known refrigeration cycle, and is connected to a well-known expansion valve and a compressor (not shown).

As shown in Figure 5.6, the evaporator 21 has an inlet port 22 that protrudes laterally and is connected to an expansion valve, and an outlet port 23 that also protrudes laterally and is connected to the compressor. , a tank portion 24 and a flat tube 25, which are arranged with a predetermined extension distance between the inlet port 22 and the outlet port 23 and serve as a refrigerant evaporation path through which the refrigerant flows, and a flat tube 25 formed around the flat tube 25 to communicate with air. The corrugated fins 26 are provided as heat transfer fins for promoting heat exchange.

A gas-liquid two-phase refrigerant flows through the tank portion 24 .

The above configuration is approximately the same as the evaporator 31 of the conventional example. The refrigerant introduced from the inlet port 22 is then
After following the path shown by solid and broken lines in the figure, it is led out from the outlet port 23.

In this embodiment, as shown in FIG. 5, gas refrigerant flowing from the inlet port 22 side is transferred between adjacent tank parts 24 on the right half side of the boundary between the inlet port 22 and the outlet port 23. A plurality of short-circuit paths 27 are formed for short-circuiting to the 23 side. That is, between the adjacent tank parts 24 on the right half side, short circuit paths 27 are formed corresponding to all the flat tubes 5. The structure differs from the conventional evaporator 31 in terms of the plurality of short-circuit paths 27.

As shown in FIGS. 6 to 8, each short circuit path 27 is formed in the upper part between adjacent tank parts 24, and allows only gas refrigerant with a small specific gravity to pass among refrigerants in a two-phase gas-liquid state. There is.

Therefore, when the gas-liquid two-phase refrigerant introduced from the inlet port 22 passes through the tank section 24 as shown in FIG. The gas refrigerant will flow above the tank section 24. Of the refrigerant in the gas-liquid two-phase state, the liquid refrigerant is vaporized by the corrugated fins 26 based on the heat exchange effect when flowing through the flat tube 25. On the other hand, among refrigerants in a gas-liquid two-phase state, gas refrigerants have a plurality of short circuits 2 as shown by arrow C.
7, it flows from the upstream tank section 24 to the downstream tank section 24, is guided to the outlet port 23, and the port 23
It is derived from

As a result, the gas refrigerant that does not directly contribute to the heat exchange action is quickly removed from the outlet port 23, the pressure loss due to the gas refrigerant can be reduced, and the liquid refrigerant can be vaporized efficiently.

Therefore, the cooling capacity of the evaporator can be improved.

FIG. 9 is a diagram showing the difference in heat radiation performance between the evaporator 21 of this embodiment and the evaporator 31 of the conventional example. As is clear from this figure, in the conventional evaporator 31, in the length of the refrigerant passage from the inlet side to the outlet side, the heat dissipation performance gradually decreases from the inlet side, and is about 2/3 from the inlet side. It drops sharply to a minimum at the path length position of . On the other hand, in the evaporator 21 of this embodiment, the heat dissipation performance is maintained at the maximum over the entire refrigerant path length from the inlet side to the outlet side. That is, it can be seen that in the evaporator 21 of this example, the pressure loss due to the gas refrigerant is reliably suppressed.

Further, Fig. 1θ shows the heat dissipation between the evaporator 21 provided with a plurality of short circuit paths 27 in this embodiment and the evaporator 1.11 provided with one short circuit path 8, 19 in the first or second embodiment. It is a figure showing the difference in performance.

As is clear from this figure, the evaporator 21 of this embodiment,
In the evaporators 1 and 11 of the first and second embodiments, the heat dissipation performance increases with a certain peak as the refrigerant flow rate in the short circuit paths 8 and 19.27 is increased, respectively. and,
These heat dissipation performance peaks are large in the evaporator 21 of this embodiment, and the refrigerant flow rate is also large.

This is because a plurality of short circuit paths 27 are provided in the evaporator 21 of this embodiment.

That is, even if the refrigerant flow rate is increased, the refrigerant flow rate is shared by each short circuit path 27, so that it is possible to prevent liquid refrigerant from entering each short circuit path 27.

The effect of such high heat dissipation performance in the evaporator 21 of this embodiment is the same as in the case where a gas-liquid separator is provided in the evaporator 31 of the conventional example and between the paths.

As described above, in each embodiment, the pressure loss due to the gas refrigerant can be reduced in the evaporators 1, 11, 21, which have substantially the same configuration as the evaporator 31, etc. of the conventional example, and the cooling capacity can be improved. Can be done.

Moreover, for this purpose, a tank section 4 that constitutes a refrigerant evaporation path,
This method does not require any increase in the flow area of the flat tube 5, upper tank 12, lower tank 13, and pipe section 14, and does not require the provision of special members such as a gas-liquid separator for removing the gas refrigerant. can do. Therefore, heat transfer to the heat transfer fins such as the corrugated fins 6 can be made effective, and the evaporator 111.21 itself can be prevented from increasing in size, and the cost of special components such as the gas-liquid separator can be reduced. Price hikes and space expansion can be suppressed.

The present invention is not limited to the above-mentioned embodiments, and may be implemented as follows by appropriately changing a part of the structure without departing from the spirit of the invention.

(1) In the first embodiment, as shown in FIGS. 1 and 2, the gas refrigerant flowing from the inlet port 2 side is placed on the upper part of the partition wall 7 that partitions the adjacent inlet port 2 and outlet port 3. Although the short-circuit path 8 for short-circuiting to the outlet port 3 side is formed, it may be provided at other positions. For example, as shown in FIG. 5.6, a short circuit path 8 may be provided between adjacent tank sections 4 at a position remote from the inlet port 2.

(2) In the second embodiment, as shown in FIG. 3, the short circuit path 19 is provided in the partition wall 15, but it may be provided in another position. For example, it may be provided on the upper part of the partition wall 16.

(3) In each of the above embodiments, the evaporator 1.11 is a stacked type, but other types of evaporators may be used.

(4) In the third embodiment, as shown in FIG. 5, all the flat pipes 5 are supported between the adjacent tank parts 24 on the right half side with the boundary between the inlet port 22 and the outlet port 23. Although the short-circuit paths 27 are formed in this embodiment, the short-circuit paths 27 may be formed in every other flat tube 5.

(5) In the third embodiment, the short circuit path 27 was provided between the adjacent tank sections 24 provided on the upper side of the evaporator 21, but as shown in FIG. tube 2
5, when the tank portion 24 is provided on the lower side, the short circuit path 27 may be provided at an upper position within the tank portion 24 (a position close to the flat tube 25).

[Effects of the Invention] As detailed above, according to the present invention, it is possible to reduce the pressure loss due to the gas refrigerant, and improve the cooling capacity without increasing the size and without providing special members. It has the excellent effect of being able to

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway plan view of a stacked evaporator showing a first embodiment embodying the present invention, and FIG. 2 is an x-x diagram of FIG.
'fa sectional view. FIG. 3 is a perspective view illustrating the schematic structure of a stacked evaporator according to a second embodiment of the present invention. FIG. 4 is a Mollier diagram based on the results of experiments conducted using the evaporators of the first and second embodiments. Fifth
The figure is a partially cutaway plan view of a stacked evaporator showing a third embodiment of the present invention, FIG. 6 is a sectional view taken along line D-D in FIG. 5, and FIG. 7 is a cross-sectional view taken along line E-E in FIG. 8 is a cross-sectional view along F-F wA in FIG. 6, FIG. 9 is a diagram showing the difference in heat dissipation performance between the evaporator of the third embodiment and the conventional evaporator, and FIG. It is a figure which shows the difference in the heat radiation performance of the evaporator in 3rd Example, and the evaporator in 1st or 2nd Example. FIG. 11 is a partially cutaway plan view of a stacked evaporator showing another embodiment embodying the present invention, FIG. 12 is a sectional view taken along the Y-Y line in FIG. 5, and FIG. 13 is another embodiment. FIG. 2 is a partially cutaway view of a stacked evaporator. FIG. 14 is a perspective view of an evaporator showing a conventional example, and FIG. 15 is a perspective view illustrating its schematic configuration.
FIG. 16 is a longitudinal sectional view of the evaporator. In the figure, 2, 17, 22 are inlet ports, 3, 18°, 23 are outlet ports, 4, 24 are tank parts, 5, 25 are flat pipes,
12 is an upper tank, 13 is a lower tank, 14 is a pipe section (
4, 5, 12 to 14, 24°25 constitute a refrigerant evaporation path), 6.26 is a corrugated fin as a heat transfer fin, and 8, 19°27 is a short circuit path. Fig. 8 12 (upper tank) Refrigerant flow rate in short circuit 7 Fig. jI 8 Fig. 9 (inlet). Refrigerant passage length (1 outlet)

Claims (1)

[Scope of Claims] 1. In an evaporator equipped with a refrigerant evaporation path disposed with a predetermined extended distance from an inlet port to an outlet port and having heat transfer fins around the evaporator, a part of the refrigerant evaporation path An evaporator characterized in that a short-circuit path is provided for short-circuiting gas refrigerant flowing from the inlet port side to the outlet port side.