JP3469832B2 - Multi-stage compression refrigeration equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-stage compression refrigerating apparatus which multi-stage compresses a refrigerant using a plurality of compression means.

[0002]

2. Description of the Related Art Conventionally, a refrigerating apparatus used in a refrigerator, an air conditioner, etc., is of a rotary type in which two compressing means composed of rollers rotating inside respective rotary cylinders are housed in the same hermetic container. Using a compressor, each compression means is used as a low-stage side compression means and a high-stage side compression means, and the refrigerant gas compressed by one stage by the low-stage side compression means is sucked into the high-stage side compression means, whereby the refrigerant is multi-stage compressed. Things are known.

According to such a multi-stage compression refrigeration system, it is possible to obtain a high compression ratio while suppressing torque fluctuation per compression.

However, in the above-mentioned multistage compression refrigeration system, when a refrigerant having a high specific heat ratio is used, the gas refrigerant temperature of the low-stage side compression means which the high-stage side compression means sucks becomes high, so that the intake efficiency is lowered, and There is a problem that the input becomes high. Further, since the discharge gas refrigerant temperature of the high-stage compression means also becomes high, when ester oil (for example, POE: polyol ester) is used as the lubricating oil, the lubricating oil undergoes hydrolysis due to heat, and the acid and alcohol are Is generated. Then, sludge is generated by this acid, which causes a problem that the capillary tube is clogged, and the lubricating characteristics are deteriorated. Further, there is also a problem that the refrigerating effect is lowered and the efficiency of the apparatus is deteriorated.

For this reason, the discharge gas refrigerant after being compressed by the low-stage compression means is cooled, the temperature of the gas refrigerant sucked by the high-stage compression means is lowered, and the discharge gas refrigerant temperature of the high-stage compression means is kept low. A configuration is proposed. As a conventional multi-stage compression refrigerating apparatus of this type, as shown in FIG. 4, for example, a multi-stage compressor 41 including low-stage side compression means and high-stage side compression means
1, condenser 412, first pressure reducing means 413, intercooler 414, second
Having a pressure reducing means 415 and an evaporator 416, the refrigerant discharged from the condenser 412 is diverted to introduce one refrigerant into the first pressure reducing means 413 and the other refrigerant to the intercooler 414 and the second pressure reducing means 415. From the first depressurizing means 413 to heat exchange with the other refrigerant in the intercooler 414, and at the same time, the refrigerant from the evaporator 416 to the low-stage side compression means. It is configured such that one refrigerant that has been sucked and has undergone heat exchange in the intercooler 414 is mixed with the refrigerant that has been discharged from the low-stage compression means, and that the refrigerant is sucked into the high-stage compression means.

The state of the refrigerant in the refrigeration cycle of this multistage compression refrigeration system changes as shown in the Ph diagram shown by the solid line in FIG. As shown in the figure, in the conventional apparatus, one refrigerant discharged from the first pressure reducing means 413 and the refrigerant flowing into the second pressure reducing means 415 are heat-exchanged by the intercooler 414 and flow into the second pressure reducing means 415. The cooling medium is cooled to reduce the enthalpy δH ₀ shown in FIG. As a result, the enthalpy difference in the evaporator 416 can be increased.

[0007]

Then, in the above-mentioned conventional apparatus, after the other refrigerant is decompressed by the third decompression means (not shown), it is discharged from the first decompression means 413 by the intercooler 414. In the case where the heat is exchanged with the one refrigerant, the refrigerant discharged from the third pressure reducing means is in a gas-liquid two-phase state. When the intercooler 414 has a double-pipe structure in which the refrigerant flowing inside the inner pipe and the refrigerant flowing inside the outer pipe surrounding the inner pipe exchange heat, they are easily affected by disturbance. There is a possibility that the gaseous refrigerant may flow into the second pressure reducing means 415. Therefore, the inflow of the gaseous refrigerant causes the second
In the decompression unit 415, there is a problem that the refrigerant is decompressed too much and the pressure loss increases, so that the desired performance and evaporation temperature cannot be obtained.

Further, at the initial stage of starting the above-mentioned conventional apparatus (FIG. 4), the intercooler 414 is operated by the second intercooler 414 due to the influence of sensible heat held by the pipes of the heat exchange part of the intercooler 414.
The refrigerant flowing into the pressure reducing means 415 is not sufficiently cooled, and the enthalpy δH ₀ in the steady state as shown by the dotted line in FIG.
It was not possible to supercool for a minute. Therefore, there is a problem that the enthalpy difference in the evaporator 416 cannot be made large in the initial stage of starting the operation.

The present invention has been made in view of the above point, and the discharge gas refrigerant after being compressed by the low-stage compression means is cooled by using an intercooler, and the discharge gas of the high-stage compression means is cooled. An object of the present invention is to provide a multi-stage compression refrigeration system capable of achieving a desired performance by suppressing the refrigerant temperature to a low level and stabilizing the refrigerant supplied to the second pressure reducing means irrespective of the influence of disturbance such as a change in the outside air temperature. And Another object of the present invention is to provide a multi-stage compression refrigeration system in which the enthalpy difference in the evaporator 416 in the initial stage of starting the refrigeration system is increased to increase the refrigeration effect and improve the efficiency.

[0010]

The present invention has low-stage side compression means and high-stage side compression means, a condenser, a first pressure reducing means, an intercooler, a second pressure reducing means, and an evaporator. The refrigerant discharged from the condenser is diverted so that one refrigerant flows to the first pressure reducing means and the other refrigerant flows to the evaporator from the intermediate cooler and the second pressure reducing means, respectively. While exchanging heat with one of the refrigerant discharged from the pressure reducing means, the refrigerant discharged from the evaporator is sucked into the low pressure side compression means,
In the multi-stage compression refrigeration device configured to suck the one refrigerant after heat exchange with the intercooler into the high-stage compression means together with the refrigerant discharged from the low-stage compression means,
The intercooler is composed of a storage container that temporarily stores the inflowing refrigerant and separates it into gas and liquid, and then supplies only the liquid refrigerant to the second depressurizing means, and the other one that flows into the intercooler. And a third pressure reducing means for reducing the pressure of the refrigerant.

By using this structure, the temperature of the gas refrigerant discharged from the high-stage compression means is kept low, and the intercooler temporarily stores the refrigerant to separate it into gas and liquid, and then supplies only the liquid refrigerant downstream. By configuring the storage container, it is possible to store the refrigerant having a low temperature on the upstream side as a liquid refrigerant, and supply only the liquid refrigerant to the second pressure reducing means irrespective of the influence of disturbance such as a change in outside air temperature. be able to.

A second heat exchanging section for exchanging heat between the other refrigerant flowing into the third pressure reducing means and the refrigerant discharged from the evaporator may be provided. By using this configuration, the enthalpy difference in the evaporator at the initial stage of starting the refrigerating apparatus can be made larger than that in the conventional apparatus.

A third heat exchange section may be provided for exchanging heat between the one refrigerant after heat exchange with the intercooler and the refrigerant discharged from the condenser.

Further, the second heat exchange portion and the third heat exchange portion have a double pipe structure in which the refrigerant flowing inside the inner pipe and the refrigerant flowing inside the outer pipe surrounding the inner pipe exchange heat. Also good. As described above, by adopting the double pipe structure which is easily affected by the disturbance but has high heat exchange efficiency, the degree of supercooling is improved in the heat exchange portion other than the intercooler that supplies the refrigerant to the second pressure reducing means. It becomes possible to take it big.

And, more specifically, the second decompression means is
It may be composed of a cupillary tube. By using this configuration, it is possible to prevent such a situation in the capillary tube in which, when the gaseous refrigerant flows in, the pressure is excessively reduced and the pressure loss tends to increase remarkably.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a multistage compression refrigeration system of the present invention will be described below with reference to the drawings shown below. FIG. 1 is a refrigerant circuit diagram of a multi-stage compression refrigerating apparatus which is an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of an essential part of a two-stage compression rotary compressor applied to the present invention.

First, referring to FIG. 2, a two-stage compression type rotary compressor 10 as a multi-stage compression means of the present invention comprises a cylindrical hermetic container 12 made of a steel plate and an electric element arranged in an upper space of the hermetic container 12. And a rotary compression mechanism 18 as a compression element which is arranged in a lower space of the electric motor 14 and is driven by a crank shaft (drive shaft) 16 connected to the electric motor 14.

The closed container 12 has an oil reservoir at the bottom,
It is composed of two members, a 12A that houses the electric motor 14 and the rotary compression mechanism 18, and a lid 12B that seals the upper opening of the container body 12A. The lid 12B has a terminal terminal that supplies external electric power to the electric motor 14 ( Power supply wiring is omitted) 20 is attached.

The electric motor 14 includes a stator 22 mounted in an annular shape along the inner circumference of the upper space of the hermetic container 12, and a rotor 24 arranged inside the stator 22 with a slight gap.
Consists of. The rotor 24 is integrally provided with a crankshaft 16 that extends vertically through the center of the rotor 24.

The stator 22 has a laminated body 26 in which ring-shaped electromagnetic steel sheets are laminated, and a plurality of coils 28 wound around the laminated body 26. Further, the rotor 24 is also composed of a laminated body 30 of electromagnetic steel plates, like the stator 24. In this embodiment, an AC motor is used as the electric motor 14, but a permanent magnet may be embedded to form a DC motor.

The rotary compression mechanism 18 includes a low-stage compression element 32 as low-stage compression means and a high-stage compression element 34 as high-stage compression means. That is, the intermediate partition plate 36, the upper and lower cylinders 38 and 40 provided above and below the intermediate partition plate 36, and the vertical eccentric portion in which the insides of the upper and lower cylinders 38 and 40 are provided on the crankshaft 16.
Upper and lower rollers 46 and 48 which are connected to 42 and 44 and rotate, and contact the upper and lower rollers 46 and 48 to divide the insides of the upper and lower cylinders 38 and 40 into a suction chamber (suction side) and a compression chamber (discharge side). The upper and lower vanes 50 and 52 are composed of an upper support member 54 and a lower support member 56 that also serve as bearings of the crankshaft 16 that close the opening surfaces of the upper and lower cylinders 38 and 40.

Also, the upper support member 54 and the lower support member 56.
The discharge muffling chambers 58, 60 are formed in the upper and lower cylinders 38, 40 via a valve device (not shown), and the openings of these discharge muffling chambers are formed by the upper plate 62 and the lower plate 64. It is blocked.

The upper and lower vanes 50 and 52 are upper and lower cylinders.
Radial guide grooves 66 formed in the cylinder walls of 38 and 40,
It is slidably arranged on 68 and is urged by springs 70 and 72 so as to always contact the upper and lower rollers 46 and 48.

The lower cylinder 40 carries out the first-stage (lower-stage side) compression action, and the upper cylinder 38 carries out the lower cylinder.
The second-stage (higher-stage side) compression action of further compressing the refrigerant gas compressed in 40 is performed.

The upper support member 54, the upper cylinder 38, the intermediate partition plate 36, the lower cylinder 40 and the lower support member 56, which constitute the rotary compression mechanism 18, are arranged in this order together with the upper plate 62 and the lower plate 64. Multiple mounting bolts
It is connected and fixed using 74.

Further, a straight oil hole 76 is formed in the crankshaft 16 at the center of the shaft, and spiral oil supply grooves 82, 84 which are continuous with the hole 76 through lateral oil supply holes 78, 80 are formed on the outer peripheral surface, Oil is supplied to the bearing and each sliding part.

In this embodiment, R134a is used as the refrigerant, and the oil as the lubricating oil is, for example, mineral oil (mineral oil), alkylbenzene oil, PAG oil (polyalkylene glycol oil), ether oil, ester. Existing oil such as oil is used.

In the low-stage compression element 32 of the rotary compression mechanism 18, the suction side refrigerant pressure is 0.08 MPa and the discharge side refrigerant pressure is 0.63 MPa. Then, in the high-stage compression element 34,
The suction side refrigerant pressure is 0.63 MPa and the discharge side refrigerant pressure is
It is 1.17 MPa.

The upper and lower cylinders 38 and 40 have upper and lower refrigerant suction passages (not shown) for introducing the refrigerant and a refrigerant discharge passage for discharging the compressed refrigerant through the discharge muffling chambers 58 and 60.
86 and are provided. Then, in each of the refrigerant suction passages and the refrigerant discharge passages 86, the connection pipe 9 fixed to the closed container 12 is formed.
Refrigerant pipes 98, 100, 102 are connected via 0, 92, 94. A suction muffler 106 that acts as a gas-liquid separator is connected between the refrigerant pipes 100 and 102.

The suction muffler 106 is provided outside the compressor 10 and joins the refrigerant discharged from a third heat exchange section (not shown) through a refrigerant pipe 201 as described later.

Further, the upper plate 62 includes an upper support member.
A discharge pipe 108 that connects the discharge muffling chamber 58 of 54 and the internal space of the closed container 12 is provided, and the compressed refrigerant gas of the second stage (high-stage compression element 34) is directly introduced into the closed container 12. After discharging and making the closed container 12 have an internal high pressure, it is delivered to an external condenser (not shown) via a connection pipe 96 and a refrigerant pipe 104 fixed to the lid 12B on the upper part of the closed container 12, which will be described later. The vapor compression refrigeration cycle is realized by returning to the low-stage compression element 32 again through the refrigerant pipe 98, the connecting pipe 90, and the upper refrigerant suction passage of the upper cylinder 38 through the refrigerant circuit in order.

The fitting clearance between the constituent parts of the low-stage compression element 32 is set smaller than the fitting clearance between the constituent parts of the high-stage compression element 34. Specifically, the fitting clearance between the constituent parts of the low-stage compression element 32 is set to 10 μm, and the fitting clearance between the constituent parts of the high-stage compression element 34 is set to 20 μm. As a result, the high-pressure gas in the closed container 12 can be prevented from leaking into the low-stage compression element 32 having a large pressure difference, and the volume efficiency and the compression efficiency can be improved.

Next, a multi-stage compression refrigeration system of the present invention using the above-mentioned two-stage compression rotary compressor 10 will be described.
Description will be made with reference to the refrigerant circuit of FIG.

In FIG. 1, reference numeral 1 is a condenser, and
The high-pressure refrigerant discharged from the stage compression rotary compressor 10 flows in through the refrigerant pipe 104. This condenser 1
After the refrigerant which has been condensed and flows through the refrigerant pipe 110 is heat-exchanged with a third heat exchange unit 2 described later, the refrigerant pipe 110 is branched into two.

Reference numeral 3 is a first expansion valve as a first pressure reducing means for reducing the pressure of the refrigerant flowing through the branched one branch pipe 112.

Reference numeral 4 is a second expansion valve as a third pressure reducing means for reducing the pressure of the refrigerant flowing through the other branched pipe 114, and in the second heat exchange section 5 described later, the branch pipe 114 is used.
After exchanging heat between the refrigerant flowing through and the refrigerant discharged from the evaporator 8,
It flows into the second expansion valve 4.

Reference numeral 6 denotes an intercooler connected to the discharge side of the second expansion valve 4, which exchanges heat with the refrigerant decompressed by the first expansion valve 3. The one refrigerant after heat exchange with the intercooler 6 flows into the third heat exchange section 2 and exchanges heat with the refrigerant discharged from the condenser 1.

The intercooler 6 is composed of a storage container for temporarily storing the refrigerant discharged from the second expansion valve 4 to separate it into gas and liquid, and then supplying only the liquid refrigerant to the capillary tube 7 as the second pressure reducing means. There is.

Therefore, the other refrigerant whose temperature has been lowered by the second heat exchange section 5, the third heat exchange section 2 and the second expansion valve 4 flows into the storage container 6 and is temporarily stored in the container to be vaporized. After liquid separation, only the liquid refrigerant is supplied to the capillary tube 7. Therefore, it is possible to supply only the liquid refrigerant to the capillary tube 7 irrespective of the influence of disturbance such as a change in the outside air temperature, and the inflowing refrigerant in the capillary tube 7 is excessively decompressed and the pressure loss increases. It is possible to prevent a situation in which desired performance and evaporation temperature cannot be obtained.

The second heat exchange section 5 and the third heat exchange section 2 are double tubes in which the refrigerant flowing inside the inner tube and the refrigerant flowing inside the outer tube surrounding the inner tube exchange heat. In order to improve heat exchange efficiency, the refrigerant on the low temperature side flows inside the inner tube and the refrigerant on the high temperature side flows inside the outer tube, so that the flow directions are opposite. Has been done.

As described above, the second heat exchange section 5 and the third heat exchange section 2 have a double tube structure which is easily affected by disturbance but has a high heat exchange efficiency, so that the capillary tube 7 is filled with the refrigerant. It is possible to obtain a large degree of supercooling in the heat exchange portion other than the storage container 6 to be supplied.

The refrigerant discharged from the third heat exchange section 2 flows into the suction muffler 106 through the refrigerant pipe 201,
It is combined with the discharge refrigerant from the low-stage compression element 32 flowing into the suction muffler 106 via the refrigerant pipe 100.

The gas refrigerant discharged from the suction muffler 106 is sucked into the high-stage compression element 34 via the refrigerant pipe 102.

The refrigerant discharged from the capillary tube 7 is supplied to the evaporator 8 to evaporate the refrigerant and exchange heat with the outside. The second heat exchange section 5 is provided on the discharge side of the evaporator 8.
Is provided, after heat exchange with the split refrigerant flowing through the refrigerant pipe 114, the refrigerant after the heat exchange is supplied to the connecting pipe 90 of the low-stage compression element 32 of the compressor 10 via the refrigerant pipe 98. .

The refrigeration cycle of the multistage compression refrigeration system of the present invention is constituted as described above.

Here, the storage container 6 and the second heat exchange section 5
The third heat exchange section 2 exerts a cooling action by removing heat from the surroundings, and each heat exchange section is hereinafter referred to as a first supercooling section, a second supercooling section, and a third supercooling section, respectively. .

In the above description, the second subcooling unit 5
The refrigerant cooled in 1st through the 2nd expansion valve 4
The structure for heat exchange in the supercooling unit 6 is
As a result of the experiment, it was confirmed that when the supercooling is dispersed and performed, the heat exchange efficiency at that time is improved by performing the subcooling after expanding the refrigerant after performing the supercooling once. Is.

Next, the state of the refrigerant in the above refrigeration cycle will be described based on the Ph diagram shown in FIG.
In the figure, the refrigerant state in the stationary state of the apparatus is shown by a solid line, and the refrigerant state in the initial stage of the apparatus is shown by a dotted line.

In FIG. 3, point A shows the state of the refrigerant discharged from the high-stage compression element 34 of the compressor 10, which is condensed in the condenser 1 and changes to the point B. Then, the refrigerant is cooled by heat exchange in the third supercooling unit 2 and reaches the point C.

Then, the refrigerant at the point C is diverted, one of the diverted refrigerant is decompressed by the first expansion valve 3 to be reduced in pressure to the point D, and then flows into the first supercooling section 6.

Further, the other refrigerant obtained by branching the refrigerant at the point C is cooled by heat exchange with the refrigerant discharged from the evaporator 8 in the second supercooling section 5 to reach the point H, and then to the second expansion valve 4. It is decompressed and the pressure drops to point I. In the first supercooling section 6, the refrigerant at the point I exchanges heat with the refrigerant at the point D decompressed by the first expansion valve 3 to change the state to the point J, and the refrigerant at the point D becomes the first supercooling section. At the exit of 6, the state changes to point E. At this time, a disturbance occurs due to a change in the outside air temperature, etc.
Even if the refrigerant at the point is in an unstable state (gas-liquid two-phase state), gas-liquid separation is performed in the first supercooling unit 6, and the capillary at a stable state in which the refrigerant at the point J is surely made into a liquid refrigerant. It will be supplied to the tube 7.

The point F is the condenser 1 in the third supercooling section 2.
The heat exchange with the refrigerant at the point B from the third subcooling unit 2
2 shows the state of the discharged refrigerant.

The refrigerant at the point J is decompressed by the capillary tube 7, drops in pressure to the point K, and then flows into the evaporator 8.

Then, the refrigerant (L
Point) changes to the point M at the outlet of the second supercooling section 5 due to heat exchange in the second supercooling section 5, and then the compressor
It flows into 10 low-stage compression elements 32.

Then, the high-temperature and high-pressure discharged refrigerant, which has been compressed in the first stage by the low-stage compression element 32 and has increased in pressure to the N point, is transferred to the third supercooling section 2 in the suction muffler 106.
The refrigerant is mixed with the discharged refrigerant (point F), the refrigerant is cooled, and the state changes to point G. The temperature-lowered refrigerant at the point G is sucked into the high-stage compression element 34 of the compressor 10, compressed at the second stage (point A), and then discharged to the condenser 1.

In this way, the refrigerant discharged from the condenser 1 is supercooled in the third supercooling section 2, and the other refrigerant flowing in the capillary tube 7 and the evaporator 8 is further cooled in the first subcooling section 6 and Supercooling can be performed in the second supercooling unit 5.

By dispersing the supercooling section,
The heat capacity of the sensible heat held by each subcooling unit can be reduced, and supercooling can be performed in the initial stage of the apparatus (dotted line in FIG. 3) as compared with the conventional case, and the enthalpy difference (δH) in the evaporator 8 Can be big.

In particular, in addition to the first subcooling section 6, the evaporator 8
By providing the second supercooling unit 5 that exchanges heat with the low-temperature refrigerant at the outlet, the other refrigerant flowing through the capillary tube 7 and the evaporator 8 can be sufficiently supercooled within a short time after the start of the apparatus. .

The above description of the embodiments is for explaining the present invention and should not be construed as limiting the invention described in the claims or reducing the scope. Further, the configuration of each part of the present invention is not limited to the above embodiment,
It goes without saying that various modifications can be made within the technical scope described in the claims.

For example, in the above embodiment, the internal high pressure type two-stage compression rotary compressor is used as the multi-stage compression means.
Although the case where 10 is used has been described, the present invention is not limited to this, and an internal low-pressure type in which the inside of the closed container 12 is approximately equal to the suction side refrigerant pressure of the low-stage compression element 32, or the inside of the closed container 12 is the low-stage compression element 32. The present invention is also applicable to an internal intermediate pressure type in which the pressure of the discharge side refrigerant is substantially the same.

Further, although the configuration having the first subcooling section, the second subcooling section and the third subcooling section has been described, the present invention is not limited to this, and the above conventional apparatus for supercooling with a single intercooler is used. The present invention is also applicable to (FIG. 4).

Furthermore, in the above-mentioned embodiment, the case where R134a is used as the refrigerant to be used has been described, but the present invention is not limited to this, and the same effect can be expected by using other refrigerant such as R404A.

[0063]

As described above, according to the present invention, the discharge gas refrigerant after being compressed by the low-stage compression means is cooled by using the intercooler, and the discharge-gas refrigerant temperature of the high-stage compression means is lowered. In addition to suppressing, the refrigerant supplied to the second pressure reducing means can be brought into a stable state to achieve desired performance regardless of the influence of disturbance due to changes in the outside air temperature.

Furthermore, by disposing the subcooling portions in a distributed manner, the enthalpy difference in the evaporator in the initial stage of starting the refrigerating apparatus can be increased, the refrigerating effect can be increased, and the efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram of a multistage compression refrigeration system according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of a two-stage compression rotary compressor applied to the present invention.

FIG. 3 is a Ph diagram of the multistage compression refrigeration apparatus of the present invention.

FIG. 4 is a refrigerant circuit diagram of a conventional multistage compression refrigeration system.

FIG. 5 is a Ph diagram of a conventional multistage compression refrigeration system.

[Explanation of symbols]

1 condenser 2 3rd intercooler 3 First expansion valve (first pressure reducing means) 4 Second expansion valve (third pressure reducing means) 5 Second intercooler 6 Intercooler 7 Capillary tube (second pressure reducing means) 8 evaporator 10 Two-stage compression rotary compressor 12 Cylindrical closed container 14 Drive motor (electric element) 16 crankshaft 18 Rotary compression mechanism (rotary compression element) 32 Low-stage compression element (low-stage compression means) 34 High-stage compression element (high-stage compression means)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Yamakawa 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd. (56) References Japanese Patent Laid-Open No. 10-288407 (JP, A) (58) ) Fields surveyed (Int.Cl. ⁷ , DB name) F25B 1/10

Claims (4)

(57) [Claims] 1. A low-stage side compression means and a high-stage side compression means, a condenser, a first pressure reducing means, an intercooler, a second pressure reducing means, and an evaporator, which divides the refrigerant discharged from the condenser. One refrigerant flowing through the first pressure reducing means and the other refrigerant flowing through the intercooler and the second pressure reducing means to the evaporator, respectively, and in the intercooler, one refrigerant discharged from the first pressure reducing means. Along with the refrigerant discharged from the low pressure side compression means, the refrigerant discharged from the evaporator is sucked into the low pressure side compression means, and the one refrigerant after heat exchange with the intercooler is absorbed. In the multi-stage compression refrigeration system configured to suck the high-stage compression means, the intercooler temporarily stores the inflowing refrigerant to separate it into gas and liquid, and then supplies only the liquid refrigerant to the second depressurizing means. It is composed of a storage container and the intermediate cooling Of the other flowing the other of the refrigerant flowing into the vessel to a third pressure reducing means and the third pressure-reducing means for pressure reduction
Heat exchange between the refrigerant and the refrigerant discharged from the evaporator
And a second heat exchange section . 2. The one after heat exchange with the intercooler
Heat exchange between the refrigerant and the refrigerant discharged from the condenser.
A third heat exchanging part for allowing the heat exchange part to be provided.
1. The multi-stage compression refrigeration system described in 1. 3. The second heat exchange section and the third heat exchange section,
Of the refrigerant flowing inside the inner pipe and the outer pipe surrounding the inner pipe
It has a double pipe structure that exchanges heat with the refrigerant flowing through the section.
The multi-stage compression refrigeration system according to claim 2, wherein 4. The second depressurizing means is a capillary tube.
4. The method according to claim 1, which is a probe.
The multi-stage compression refrigeration system described in.