JPH03225166A - Freezing cycle - Google Patents

Abstract

PURPOSE:To prevent lubricant oil from staying within an accumulated refrigerant evaporator and restrict a reduction of an amount of lubricant oil circulating in a freezing cycle by a method wherein a communication pipe for communicating a corner part of a substantial U-shaped flow passage in an accumulated refrigerant evaporator with a part having a lower pressure than that of the corner part of the passage in a refrigerant compressor is provided. CONSTITUTION:An opening is formed at a corner part 23 of a bent-back part 21 of the outermost forming plate 8 of a refrigerant flow passage pipe attanged at the outermost outlet port of an accumulated refrigerant evaporator. A connector 27 is fixed within the opening and then an inlet port side end of a return pipe 25 is assembled to it. Thus, corner parts 22 and 23 of the bent-back part 21 or a bottom part 24 is communicated with an interior of a refrigerant compressor, thereby the oil of the freezer stayed at the corner portions 22, 23 of the bent-back part 21 and the bottom part 24 is sucked into the return pipe 25 through a connection means 27. The oil of the freezer sucked into the return pipe 25 passes from the return pipe 25 through a lower pressure side service valve and then sucked into a refrigerant compressor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a refrigeration cycle incorporating a stacked refrigerant evaporator in which a plurality of refrigerant flow pipes each having a pair of molded plates are stacked together.

[Prior Art] Conventionally, a refrigeration cycle has been proposed that incorporates a stacked refrigerant evaporator in which a plurality of refrigerant flow pipes each having a pair of molded plates are stacked together. FIG. 9 shows one molded plate used in the refrigerant flow pipe of this stacked refrigerant evaporator.

This refrigerant flow pipe has a first tank part 102 and a second tank part 103 formed at the upper end by joining a pair of molded plates 101, and a first tank part 103 at the lower end.
02 and the second tank section 103 are formed.

In addition, when the liquid refrigerant that has flowed into the flow path section 104 passes through the inside, it exchanges heat with the air passing through the outside of the refrigerant flow path pipe, evaporates, and becomes refrigerant gas. It gets sucked in.

Furthermore, inside the refrigerant compressor, the refrigerant compressor is lubricated by mixing refrigerant oil into the refrigerant circulating in the refrigeration cycle and compressing the mixture.

[Problems to be Solved by the Invention] However, in the conventional stacked refrigerant evaporator, as shown in FIG.
The corner portion 105 at the lower end of the flow path portion 104
A region with a slow flow rate (stagnation) occurs. If the refrigerating machine oil separated from the refrigerant due to gasification of the refrigerant flows into the corner portion 105 due to gravity or the like, there is a problem in that the refrigerant is not sucked into the refrigerant compressor and stagnates.

In this way, when refrigerating machine oil stagnates in the stacked refrigerant evaporator, the amount of refrigerating machine oil circulating in the refrigeration cycle decreases, resulting in an insufficient amount of refrigerating machine oil being supplied to the refrigerant compressor. Resulting in.

For this reason, there was a possibility that sufficient lubrication inside the refrigerant compressor could not be performed.

An object of the present invention is to provide a refrigeration cycle that prevents an insufficient amount of lubricating oil supplied into a refrigerant compressor.

[Means for Solving the Problems] In the refrigeration cycle of the present invention, a pair of molded plates are joined to form a plurality of tank sections at the upper end, and the plurality of tank sections are communicated at the lower end, so that a refrigerant is supplied to the refrigeration cycle. A stacked refrigerant evaporator is formed by stacking a plurality of refrigerant flow pipes each having a substantially U-shaped flow path for heat exchange, and a stacked refrigerant evaporator is connected to the downstream side of the refrigerant evaporator, and the inside thereof is mixed with the refrigerant. a refrigerant compressor lubricated by lubricating oil; a corner portion of the flow path portion and a portion of the refrigerant compressor having a lower pressure than a corner portion of the flow path portion; or the refrigerant evaporator and the refrigerant compressor; and a communication pipe that communicates with the refrigerant pipe that connects between the two.

[Operation] When the refrigerant that has flowed into the stacked refrigerant evaporator flows through the substantially U-shaped flow path section, heat is exchanged and gasified, and the refrigerant and lubricating oil are separated. When the gasified refrigerant flows through the approximately U-shaped flow path, it mainly flows in a U-shape, and due to gravity, the lubricating oil has a slow flow rate, and the approximately U-shaped flow path However, the lubricating oil stagnated in this corner is transferred from the corner of the flow path by the communication pipe to the corner of the flow path in the refrigerant compressor. is attracted to the lower part of the body.

Alternatively, the refrigerant is sucked into the refrigerant pipe connecting the refrigerant evaporator and the refrigerant compressor from the corner portion of the flow path through the communication pipe.

Therefore, it is possible to prevent the lubricating oil from stagnating at the corner portions of the substantially U-shaped flow path portion.

[Effects of the Invention] Since it is possible to prevent lubricating oil from stagnation within the stacked refrigerant evaporator, it is possible to suppress a decrease in the amount of lubricating oil circulating within the refrigeration cycle. Therefore, a sufficient amount of lubricating oil can be supplied to the inside of the refrigerant compressor, so that deterioration in the lubricity of the refrigerant compressor can be reduced.

[Example] The refrigeration cycle of the present invention will be explained based on the example shown in FIGS. 1 to 8.

1 to 6 show a first embodiment of the present invention.
Figures 2 and 2 show the outermost molded plate adopted for the refrigerant flow pipe installed on the outermost side of the stacked refrigerant evaporator and on the outlet side, and Figure 3 shows the refrigeration cycle of an automobile cooling system. show.

The refrigeration cycle 1 includes a refrigerant compressor 2, a refrigerant condenser 3, a receiver 4, an expansion valve 5, a stacked refrigerant evaporator 6, and a refrigerant pipe 7 connecting these so that refrigerant circulates therebetween.

The refrigerant compressor 2 is driven by an internal combustion engine, compresses refrigerant gas drawn into the interior from the stacked refrigerant evaporator 6 , and discharges high-temperature and high-pressure refrigerant gas toward the refrigerant condenser 3 . Furthermore, the inside of the refrigerant compressor 2 is lubricated by refrigerating machine oil (lubricating oil) mixed in the refrigerant.

The refrigerant condenser 3 condenses the refrigerant gas that has flowed into the inside by exchanging heat with air passing outside.

The receiver 4 temporarily stores the liquefied refrigerant that has flowed into the receiver 4 and supplies only the necessary amount of liquefied refrigerant to the stacked refrigerant evaporator 6 .

The expansion valve 5 adiabatically expands the refrigerant passing therethrough and supplies the refrigerant mist to the stacked refrigerant evaporator 6 .

FIG. 4 shows a stacked refrigerant evaporator 6 adopted in this embodiment.

This stacked refrigerant evaporator 6 converts the atomized refrigerant that has flowed into the inside into refrigerant gas by exchanging heat with air passing outside. The stacked refrigerant evaporator 6 also includes a plurality of stacked refrigerant flow pipes 9 formed by joining a pair of molded plates 8 and corrugated fins 10 disposed between adjacent refrigerant flow pipes 9. It is then assembled and brazed together.

The molded plate 8 is formed into a shallow dish shape by pressing a thin plate-shaped aluminum alloy. This molded plate 8 has a joint wall 11 formed on its outer periphery to be joined to the outer periphery of the other opposing molded plate. Further, the molded plate 8 has a partition wall 12 obliquely formed in the center portion thereof, which joins the center portion of the other molded plate that faces the molded plate 8 . On both sides of the partition wall 12 of the molded plate 8, a large number of ribs 13 are formed on the flow path surface through which the refrigerant flows.

The refrigerant flow pipe 9 has a first tank part 14 and a second tank part 15 formed at one end thereof, and communicates with the first tank part 14 and second tank part 15 at the other end, so that the refrigerant passing through the inside is air-filled. A flow path section 16 is formed that exchanges heat with.

Each first tank section 14 has a mist-like shape, and disperses the refrigerant flowing thereinto into the flow path section 16 of each refrigerant flow path pipe 9 . Further, the first tank section 14 has a communication window (not shown) that communicates with the first tank section 14 of another adjacent refrigerant flow pipe 9 .

Each of the second tank sections 15 has a mist-like shape, and collects the refrigerant gas that has flowed in from each of the refrigerant flow path pipes 9 . Further, the second tank section 15 has a communication window (not shown) that communicates with the second tank section 15 of another adjacent refrigerant flow pipe 9 .

Note that the first tank portion 14 and the second tank portion 15 of the outermost molded plate 8 of the refrigerant flow pipe 9 disposed on the outermost side of the laminated refrigerant evaporator 6 are reinforced with the laminated refrigerant evaporator 6. Side plates 17, 18 are joined for this purpose.

The flow path portion 16 has a U-shaped flat plate shape, and is a portion that evaporates the refrigerant by exchanging heat between the refrigerant passing inside and the air passing outside. The flow path portion 16 is formed with an outgoing flow path portion 19 and a return flow path portion 20 partitioned by the partition wall 12, and a folded portion 21 that communicates these.

The outbound flow path section 19 guides the atomized refrigerant that has flowed in from the first tank section 14 above to the folded part 21 below. As the amount increases, it gradually separates from the refrigerating machine oil.

The return passage section 20 guides the gas-liquid mixed refrigerant that has flowed in from the lower folded section 21 to the upper second tank section 15 . The refrigerant passing through the return passage section 20 is transferred to the second tank section 15.
As the gas content increases, it completely separates from the refrigerating machine oil.

The folding section 21 converts the refrigerant that has flowed in from the forward flow path section 19 into a U
It turns and flows out into the return flow path section 20. The refrigerating machine oil that has flowed into the folded part 21 is transferred to the refrigerant compressor 2.
There are those that make a U-turn together with the refrigerant gas and head toward the return passage section 20, and those that are sucked by gravity and the lower corner portion 22.
Corner portion 22.23 due to stagnation of refrigerant gas generated at
It is divided into those that stagnate at 23 and the bottom part 24.

5 and 6 show the outermost molded plate 8 and the return pipe 25. FIG.

In this embodiment, one corner portion 23 of the folded portion 21 formed on the outermost molded plate 8 of the refrigerant flow pipe 9 disposed on the outermost side of the stacked refrigerant evaporator 6 and on the outlet side.
An opening 26 for connecting the return pipe 25 is formed in the opening 26 .

The return pipe 25 is a communication pipe of the present invention. This return piping 25 is a visible cylindrical tube made of resin or metal such as aluminum, and connects the corner portion 23 and the inside of the refrigerant compressor 2 (a portion with lower pressure than the corner portions 22, 23 and the bottom portion 24). By connecting the corner part 2
2. The refrigerating machine oil stagnant in 23 and the bottom part 24 is returned to the inside of the refrigerant compressor 2 by the suction force of the refrigerant compressor 2, and
The inlet end of the return pipe 25 is joined to the outer periphery of the connector 21 by torch brazing. Furthermore, the outlet side end of the return pipe 25 is connected to a low-pressure side service valve (not shown) of the refrigerant compressor 2.

The connector 27 is made of resin or metal such as aluminum, and has an annular flange portion 28 and a cylindrical portion 29 . The flange portion 28 is disposed within the folded portion 21, and the cylindrical portion 29, which is joined to the outermost molded plate 8 by brazing or the like, is inserted into the opening 26 of the outermost molded plate 8 to allow the refrigerant to flow. It protrudes to the outside of the pipe 9 and is connected to the inlet end of the return pipe 25 .

The operation of the refrigeration cycle 1 of this embodiment will be explained based on FIGS. 1 to 8.

Atomized refrigerant flows into the first tank portion 14 of the stacked refrigerant evaporator 6 from the expansion valve 5 . The atomized refrigerant that has flowed into the first tank section 14 flows into the downstream flow path section 19 of the flow path section 16 . Then, when the mist refrigerant that has flowed into the forward flow path section 19 passes through the forward flow path section 19, it exchanges heat with the air passing outside the refrigerant flow path pipe 9 and evaporates.

Therefore, the refrigerant is transferred from the first tank section 14 to the folded section 21.
The amount of gas component (refrigerant gas) gradually increases as the temperature increases. In addition, since the refrigerating machine oil dissolved in the atomized refrigerant has a relatively heavy specific gravity, as it flows along the ribs 13 formed on the flow path surface of the molded plate 8, the refrigerant oil with a relatively light specific gravity is It gradually separates from the molding plate 8 and falls downward along the joint wall 11, partition wall 12, and rib 13 of the molded plate 8.

Then, the refrigerant that has flowed into the folded portion 21 makes a U-turn at the folded portion 21 due to the suction force of the refrigerant compressor 2 and flows into the return passage portion 20 . The amount of refrigerant gas in the refrigerant that has flowed into the return passage section 20 gradually increases as it moves from the turning section 21 toward the second tank section 15, and eventually all of the atomized refrigerant becomes refrigerant gas.

By the way, since the flow path portion 16 is formed in a U-shape, the refrigerant flowing into the folded portion 21 mainly flows in a U-shape as described above, so that the flow rate is relatively low in the corner portions 22 and 23. A slow part (stagnation) occurs, and the refrigerant gas tends to stagnate. Note that, since the refrigerant gas has a relatively light specific gravity, it passes into the refrigerant compressor 2 by the suction force of the refrigerant compressor 2 through the return passage section 20 and the second tank section 15 arranged above the folded section 21. It gets sucked in. However, since the refrigerating machine oil dissolved in the atomized refrigerant has a relatively heavy specific gravity, it tends to stagnate in the corner parts 22, 23 and bottom part 24 of the folded part 21, especially in the laminated refrigerant evaporator 8. Since the refrigerant does not flow much in the refrigerant flow pipe 9 disposed on the outermost side and on the outlet side, the corner portion 22.2 of the folded portion 21
3 or the bottom part 24.

For this purpose, an opening 12 is formed in the corner part 23 of the folded part 21 of the outermost molded plate 8 of the refrigerant flow pipe 9 disposed on the outermost side of the stacked refrigerant evaporator 8 and on the outlet side. Attach the connector 27 inside the opening 12 and connect the return piping 2.
The inlet side end of No. 5 is assembled.

Therefore, the corner portions 22 and 23 of the folded portion 21 and the bottom portion 24
communicates with the inside of the refrigerant compressor 2 via the return pipe 25, so that the refrigerating machine oil stagnant in the corner portions 22, 23 and bottom portion 24 of the folded portion 21 is removed by the suction force of the refrigerant compressor 2 from the connector. 27 and is sucked into the return pipe 25. The refrigerating machine oil drawn into the return pipe 25 is drawn into the refrigerant compressor 2 from the return pipe 25 through the low-pressure side service valve.

Therefore, the refrigerating machine oil does not stagnate within the laminated refrigerant evaporator 6, and the amount of refrigerating machine oil circulating within the refrigeration cycle 1 does not decrease. Therefore, a sufficient amount of refrigerating machine oil can be supplied to the inside of the refrigerant compressor 2, so that the refrigerant compressor 2 can be sufficiently lubricated.

Therefore, the lubricated portions of the refrigerant compressor 2 are well lubricated, and the durability of the refrigerant compressor 2 can be improved.

Also, as a matter of course, the corner portions 22 and 23 of the folded portion 21
The refrigerant gas that stagnates in the area where stagnation occurs is also returned to the return pipe 2.
5 and is sucked into the refrigerant compressor 2 through the low-pressure side service valve. Therefore, a reduction in the amount of refrigerant circulation can be prevented, so that the heat exchange performance of the refrigerant condenser 3 and the stacked cold coke evaporator 6 is improved.

7 and 8 show a second embodiment of the invention. 7th
This figure shows a molded plate adopted in a refrigerant flow pipe disposed on the outlet side, and FIG. 8 shows a stacked refrigerant evaporator.

This stacked refrigerant evaporator 30 is incorporated into the refrigeration cycle 1, and is arranged between a refrigerant flow pipe 32 formed by joining a pair of molded plates 31 and adjacent refrigerant flow pipes 32. It is made by laminating a plurality of corrugated fins 33.

The molded plate 31 has a partition wall 34 and a number of ribs 35.
has been established.

The refrigerant flow path pipe 32 includes an outflow path portion 36 and a return flow path portion 37 that are partitioned by the partition wall 34 of the molded plate 31.
and a V-shaped folded portion 38 that communicates these.

Note that the molded plate 31 of the refrigerant flow pipe 32 disposed on the outlet side forms an oil reserve tank 40 at a corner portion 39 of the folded portion 38 . Refrigerating machine oil stagnant at the corner portion 39 of the folded portion 38 flows into the oil reserve tank 40 along an inclined wall 41 formed at the corner portion 39, and the oil reserve tank 40 has a circular tubular shape, It is provided to protrude in the direction of the refrigerant flow pipe 32 on the adjacent outlet side, and is connected to a circular tubular oil reserve tank 40 formed on the molded plate 31 of the refrigerant flow pipe 32 on the adjacent outlet side. .

A plurality of oil reserve tanks 40 formed in all the molded plates 31 of the refrigerant flow pipe 32 disposed on the outlet side are connected to a venturi pipe 42 protruding from the center of the stacked refrigerant evaporator 30. They are connected via a capillary tube 43.

The venturi pipe 42 increases the pressure difference between the pressure inside the oil reserve tank 40 and the pressure inside the oil reserve tank 40.
The function is to return the refrigerating machine oil inside to the outlet pipe 44 through the capillary tube 43.

The capillary tube 43 has a higher passage resistance than the refrigerant flow pipe 32, and prevents the refrigerant from entering and causing a short circuit. Note that the oil reserve tank 40 and the capillary tube 43 constitute a communication pipe of the present invention.

The outlet piping 44 has one end connected to the refrigerant flow path pipe 32 and the capillary tube 43 disposed on the exit side via the Venturi pipe 42, and the other end connected to the refrigerant compressor via a refrigerant pipe (not shown). Connected to the low pressure side of the machine.

This embodiment also has the same effects as the first embodiment.

(Modified example) In this example, one corner of the flow path of the outermost molded plate was communicated with a corner of the refrigerant compressor and a part of the refrigerant compressor whose pressure was lower than the bottom part by means of the return piping. Both corner portions of the flow path portion of the outermost molded plate may be communicated with a portion within the refrigerant compressor that has a lower pressure than the corner portion.

In addition to the corner parts, the bottom part of the flow path may be communicated with a part of the refrigerant compressor that has lower pressure than the corner part and the bottom part, and not only the outermost molded plate but also other molded plates A communicating pipe may be connected to the.

In this example, the other end of the return pipe was connected to the low-pressure side service valve of the refrigerant compressor, but the other end of the return pipe was connected to the refrigerant pipe that connects the stacked refrigerant evaporator and the refrigerant compressor. It's okay.

The shape of the ribs in the flow path portion is not limited to this embodiment, and ribs in the shape of a cane may also be used.

In this embodiment, the folded part of the refrigerant flow path is shaped like a U-shape or a
Although it was formed into a U-shape, the design can be freely changed as long as it is approximately U-shaped.

In the second embodiment, the refrigerating machine oil in the oil reserve tank is returned to the refrigerant compressor by the action of the venturi pipe, but it may be returned to the refrigerant compressor by the suction force of a pump or refrigerant compressor.

Note that as the flow rate of the refrigerant decreases, the amount of refrigerating machine oil stagnant at the corners of the refrigerant flow path increases. Therefore, the amount of refrigerating machine oil returned may be returned by a pump or the like when the flow rate of the refrigerant is low, by an amount necessary for lubricating the inside of the refrigerant compressor.

[Brief explanation of drawings]

1 to 6 show a first embodiment of the present invention.
The figure is a front view showing the outermost molded plate adopted in the refrigerant flow pipe, Figure 2 is a side view showing the outermost molded plate adopted in the refrigerant flow pipe, and Figure 3 is a schematic diagram showing the refrigeration cycle. , Fig. 4 is a perspective view showing the stacked refrigerant evaporator, Fig. 5 is a front view showing the connecting part between the outermost molded plate and the return piping, and Fig. 6 is the connecting part between the outermost molded plate and the return piping. FIG. 7 and 8 show a second embodiment of the present invention.
The figure is a front view showing a molded plate employed in the refrigerant flow pipe, and FIG. 8 is a schematic diagram showing a stacked refrigerant evaporator. FIG. 9 is a front view showing a molded plate used in a refrigerant flow pipe of a conventional stacked refrigerant evaporator. In the diagram 1... Refrigeration cycle 2... Refrigerant compressor 6.30
...Laminated refrigerant evaporator 8.31...Molded plate 9.32...Refrigerant flow pipe 25...Return piping (communicating pipe) 40...Oil reserve tank (communicating pipe)
43... Capillary tube (communicating pipe) Fig. 5 Fig. 6 Fig. 1 3 6 Fig. 1 8... Molded plate Fig. 2 25 Litter and piping (communicating pipe) 2゛f8Fig. 4゜0 Laminated refrigerant Evaporator 32/refrigerant flow pipe 3 Capillary tube (communication pipe) Fig. 9

Claims (1)

[Scope of Claims] 1) (a) A pair of molded plates are joined together to form a plurality of tank sections at the upper end thereof, and the plurality of tank sections are communicated at the lower end section so that the refrigerant is heat exchanged. (b) a stacked refrigerant evaporator in which a plurality of refrigerant flow pipes each having a U-shaped flow path portion are stacked; a refrigerant compressor lubricated by lubricating oil; (c) a corner portion of the flow path portion and a portion of the refrigerant compressor having a lower pressure than a corner portion of the flow path portion; or the refrigerant evaporator and the refrigerant compressor. A refrigeration cycle comprising a refrigerant pipe that connects the refrigerant pipe and a communication pipe that communicates with the refrigerant pipe.