AU2020248049B2

AU2020248049B2 - Liquid separator, cooling system, and gas-liquid separation method

Info

Publication number: AU2020248049B2
Application number: AU2020248049A
Authority: AU
Inventors: Masaki Chiba; Takafumi Natsumeda; Koichi Todoroki; Minoru Yoshikawa
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2019-03-22
Filing date: 2020-03-06
Publication date: 2023-06-01
Anticipated expiration: 2040-03-06
Also published as: WO2020195711A1; JPWO2020195711A1; EP3943839A1; JP7188563B2; EP3943839A4; US20220154988A1; AU2020248049A1

Abstract

The present invention provides a liquid separator, a cooling system, and a gas-liquid separation method which enable a compressor to be stably placed on a closed container.　The present invention comprises: a cylindrical closed container in which a refrigerant is stored; a refrigerant inflow pipe that allows the refrigerant to flow into the closed container; and a refrigerant outflow pipe that allows a vapor phase refrigerant in a space inside the closed container to flow out. Each of the refrigerant inflow pipe and the refrigerant outflow pipe is connected from the upper side of the closed container to the inside thereof, and the closed container is formed in a short tube shape in which the height is smaller relative to the diameter.

Description

DESCRIPTION LIQUID SEPARATOR, COOLING SYSTEM, AND GAS-LIQUID SEPARATION METHOD TECHNICAL FIELD

[0001]

The present invention relates to a liquid separator, a cooling system and a

gas-liquid separation method, which are mainly used in a cooling system and separate a

liquid flowing from an evaporator to a compressor.

BACKGROUND ART

[0002]

In a cooling system including an evaporator, a compressor, a condenser and an

expansion valve, an accumulator serving as a liquid separator may be installed in front of

the suction port of the compressor.

For example, the cooling system shown in Patent Document 1 is provided with

an evaporator, a compressor, a condenser, and a decompression expansion valve along

the refrigerant flow path. The evaporator absorbs ambient heat by evaporating the

liquid-phase refrigerant. The compressor compresses the vapor-phase refrigerant

delivered from the evaporator. The condenser releases the heat of the refrigerant whose

high pressure is increased by the compressor to condense the vapor-phase refrigerant.

The decompression expansion valve decompresses and expands the liquid-phase

refrigerant that has been cooled by the condenser.

This cooling system shown in Patent Document 1 is provided with a liquid

separator on the upstream side of the compressor that separates the refrigerant after

passing through the evaporator into gas and liquid.

[0003]

This liquid separator has a vertically elongated separation container as a whole.

A refrigerant inflow pipe and a vapor-phase refrigerant outflow pipe are installed on top

of the separation container. In addition, a liquid-phase refrigerant outflow pipe is

installed at the bottom of the separation container.

In this liquid separator, the refrigerant that has flowed into the inside through the

refrigerant inflow pipe is centrifugally separated into a liquid-phase refrigerant and

vapor-phase refrigerant while rotating in the circumferential direction along the inner

wall of the liquid separator of the separation container.

Subsequently, the vapor-phase refrigerant in the separation container is guided to

the decompression expansion valve via the upper vapor-phase refrigerant outflow pipe,

and the liquid-phase refrigerant in the separation container is guided to the evaporator via

the lower liquid-phase refrigerant outflow pipe.

[0004]

On the other hand, a similar liquid separator is also shown in Patent Document

2.

Similar to Patent Document 1, the liquid separator disclosed in Patent Document

2 has a closed container formed vertically as a whole. At the bottom of this closed

container, a first pipe that allows gas-liquid two-phase fluid to flow into the inside of the

closed container, a second pipe that discharges the gas in the closed container to the

outside, and a third pipe that discharges the liquid in the closed container to the outside

are connected.

Prior Art Documents

Patent Documents

[0005]

[Patent Document 1] Japanese Unexamined Patent Application Publication No.

2015-172469

[Patent Document 2] Japanese Unexamined Patent Application Publication No.

2013-120028

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

[0006]

In the cooling system shown in Patent Documents 1 and 2, the compressor is

located above the accumulator, and the liquid-phase refrigerant returns to the

accumulator by gravity.

Therefore, the accumulator is long in the vertical direction, and when the

compressor is placed on the accumulator, the upper part of the liquid separator becomes

heavy and the center of gravity is high. As a result, the liquid separator becomes

unstable, and so new technology has been anticipated in order to remedy this point.

[00071

This invention was made in view of the above circumstances. Accordingly, the

present invention provides a liquid separator, a cooling system and a gas-liquid

separation method that enable a compressor to be placed on a closed container.

Means for Solving the Problems

[0008]

In order to solve the above problem, the present invention proposes the

following means.

A liquid separator according to a first aspect of the present invention includes a

closed container having a cylindrical shape in which a refrigerant is stored; a refrigerant

inflow pipe that allows the refrigerant to flow into the closed container; and a refrigerant

outflow pipe that allows a vapor-phase refrigerant in a space inside the closed container

to flow out, with each of the refrigerant inflow pipe and the refrigerant outflow pipe

being connected from the upper side of the closed container to the inside thereof, and the

closed container being formed in a short cylindrical shape in which the height is smaller

relative to the diameter.

[0009]

A cooling system according to a second aspect of the present invention includes

an evaporator that absorbs ambient heat by evaporating a liquid-phase refrigerant, a

compressor that compresses a vapor-phase refrigerant, a condenser that releases the heat

of the refrigerant that has been pressurized by the compressor and condenses the

vapor-phase refrigerant, and a decompression expansion valve that depressurizes and

expands the liquid-phase refrigerant cooled by the condenser along a refrigerant path, in

which a liquid separator for gas-liquid separation of the refrigerant after passing through

the evaporator is provided on the upstream side of the compressor, the liquid separator

has a closed container having a cylindrical shape in which a refrigerant is stored; a

refrigerant inflow pipe that allows the refrigerant to flow into the closed container; and a

refrigerant outflow pipe that allows the refrigerant in a space inside the closed container

to flow out, the closed container being formed in a short cylindrical shape in which the

height is smaller relative to the diameter.

[0010]

A gas-liquid separation method according to a third aspect of the present

invention comprising connecting a closed container having a cylindrical shape in which

the refrigerant is stored, with a refrigerant inflow pipe that allows a refrigerant to flow

into and a refrigerant outflow pipe that allows the refrigerant in a space inside the closed

container to flow out, and forming the closed container in a short cylindrical shape in

which the height is smaller relative to the diameter.

Effects of the Invention

[0011]

According to the present invention, a liquid separator can be stably held even if

a heavy compressor is arranged on the liquid separator.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]

FIG. I is a configuration diagram showing a cooling system including a liquid

separator according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a cooling system including a liquid

separator according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing a liquid separator according to the first

embodiment.

FIG. 4 is a vertical cross-sectional view showing the internal configuration of the

liquid separator shown in FIG. 3.

FIG. 5A is a diagram for explaining the operation of the splash prevention plate

provided in the liquid separator shown in FIG. 3.

FIG. 5B is a perspective view showing a splash prevention plate shown in FIG.

5A.

FIG. 6 is a perspective view showing a modification 1 of a splash prevention

plate.

FIG. 7 is a perspective view showing a modification 2 of the splash prevention

plate.

FIG. 8 is a cross-sectional view showing a liquid separator according to the

second embodiment.

FIG. 9 is a perspective view showing a liquid separator according to a third

embodiment.

FIG. 10 is a configuration diagram showing a cooling system including the

liquid separator according to the third embodiment.

EXAMPLE EMBODIMENTS

[0013]

A liquid separator 10 according to the embodiment of the present invention will

be described with reference to FIG. 1.

The liquid separator 10 is located on the upstream side of a compressor 3 in a

cooling system 1, and is provided for gas-liquid separation of a refrigerant after passing

through an evaporator 2, for example.

This cooling system 1 is provided with the evaporator 2, the compressor 3, a

condenser 4, and a decompression expansion valve 5 along a refrigerant flow path 1A.

The evaporator 2 absorbs ambient heat by evaporating the liquid-phase refrigerant. The

compressor compresses the vapor-phase refrigerant. The condenser 4 releases the heat

of the refrigerant that has become high pressure by the compressor 3 to condense (or

forcibly compress) the vapor-phase refrigerant. The decompression expansion valve 5 expands the liquid-phase refrigerant supplied from the condenser 4.

[0014]

The liquid separator 10 located on the upstream side of the compressor 3 has a

cylindrical closed container I Iin which the refrigerant C is stored. Inside the closed

container 11 are provided a refrigerant inflow pipe 12 for flowing in a vapor phase

medium or a gas-liquid two-phase refrigerant and a refrigerant outflow pipe 13 that

discharges the vapor-phase refrigerant in the closed container I Ito the outside.

[0015]

The refrigerant inflow pipe 12 and the refrigerant outflow pipe 13 are each

installed from the upper surface IIA of the closed container 11 toward the inside of the

container11B. The refrigerant inflow pipe 12 and the refrigerant outflow pipe 13 are

arranged at a mutual interval as large as possible in the radial direction (R direction) of

the closed container 11.

Further, the closed container 11 of the liquid separator 10 has a height h that is

relatively small with respect to a diameter along the R direction, and is configured to

have a short cylindrical shape as a whole.

In such a liquid separator 10, since the closed container 11 is formed in a short

cylindrical shape, even if a heavy compressor 3 is arranged on the upper surface 11A of

the closed container 11, it is possible to hold the liquid separator 10 in a stable state

without the upper part of the liquid separator 10 becoming heavy, that is, becoming

so-called top heavy.

[0016]

In such a vapor compression type cooling system 1, the vapor-phase refrigerant

that has absorbed heat H Ifrom the heat source by the evaporator 2 and evaporated is

gas-liquid separated by the liquid separator 10, compressed by the compressor 3 and then sent to the condenser 4. Subsequently, the liquid-phase refrigerant, which is condensed by heat dissipation H2 to a cold source in the condenser 4, is depressurized to a predetermined pressure by the decompression expansion valve 5 and sent to the evaporator 2 again.

Here, the liquid-phase refrigerant may not be sufficiently evaporated in the

evaporator 2 due to a decrease in the load of the heat source, a failure of the

decompression expansion valve 5, and the like and may be supplied to the compressor 3

as a gas-liquid mixed flow. The phenomenon in which a liquid is supplied to the

compressor 3 in this way is called a liquid bag. When a liquid is supplied to the

compressor 3, the performance of the compressor 3 may be deteriorated or a failure may

be caused. In order to prevent this, in the liquid separator 10 according to the

embodiment of the present invention, the liquid is separated from the gas-liquid mixed

flow after passing through the evaporator 2, and only the gas is supplied to the

compressor 3.

[0017]

As described above, in the liquid separator 10 according to the embodiment of

the present invention, the closed container 11 is formed with a short cylindrical shape

whose height (h) is relatively small with respect to the radial direction (R direction).

Accordingly, the height of the entire cooling system can be lowered, and so even if the

heavy compressor 3 is arranged on the upper surface 11A of the closed container 11, the

device as a whole can be installed in a stable state without becoming top heavy.

Further, in the liquid separator 10, the closed container 11 is formed in a short

cylinder shape. Accordingly, the refrigerant inflow pipe 12 and the refrigerant outflow

pipe 13 can be arranged on the upper surface llA of the closed container 11 at a

sufficient interval in the radial direction (R direction).

As a result, in the liquid separator 10, it is possible to prevent the effect of

turbulence of the liquid level of the refrigerant caused by inflow of the refrigerant from

the refrigerant inflow pipe 12 to the closed container 11 from extending to the refrigerant

flowing out to the refrigerant outflow pipe 13. Therefore, it is possible to prevent

beforehand the situation of the liquid-phase refrigerant in the closed container 11 flowing

out from the refrigerant outflow pipe 13 as a result of being churned.

[0018]

(First Embodiment)

The liquid separator 200 according to the first embodiment of the present

invention will be described with reference to FIGS. 2 to 7.

This liquid separator 200 is installed in the cooling system F.

As shown in FIG. 2, the cooling system F is provided with an evaporator 100, a

liquid separator 200, a compressor 300, a condenser 400, and a decompression expansion

valve 500 in a refrigerant flow path (specifically, a pipeline) composed of refrigerant

flow paths 610, 620, 630, 640, and 650. The evaporator 100 absorbs the ambient heat

HI by evaporating the liquid-phase refrigerant. The liquid separator 200 separates the

refrigerant into gas and liquid. The compressor 300 compresses the vapor-phase

refrigerant discharged from the liquid separator 200. The condenser 400 releases the

heat of the refrigerant pressurized by the compressor 300 to condense the vapor-phase

refrigerant. The decompression expansion valve 500 decompresses and expands the

liquid-phase refrigerant cooled by the condenser 400.

[0019]

The refrigerant supplied from the decompression expansion valve 500 via the

refrigerant flow path 650 absorbs heat HI from the heat source by the evaporator 100 and

evaporates. The evaporated vapor-phase refrigerant passes through the refrigerant flow path 610, the liquid separator 200, and the refrigerant flow path 620 in this order, and is sent to the compressor 300.

The vapor-phase refrigerant compressed to high temperature and high pressure

by the compressor 300 is sent to the condenser 400 via the refrigerant flow path 630,

radiates H2 to a cold source, and condenses.

After that, the liquid-phase refrigerant condensed in the condenser 400 moves to

the decompression expansion valve 500 through the refrigerant flow path 640 and is

reduced to a predetermined pressure. Subsequently, the liquid-phase refrigerant is sent

to the evaporator 100 again through the refrigerant flow path 650.

[0020]

Here, the liquid separator 200 is arranged on the upstream side of the

compressor 300 and has a role of preventing the liquid-phase refrigerant from being

sucked into the compressor 300.

Since the compressor 300 is designed to compress the vapor-phase refrigerant, it

is known that if the liquid-phase refrigerant is mixed in, it will lead to a failure (called a

liquid-back phenomenon). Normally, the refrigerant completely evaporates in the

evaporator 100 and becomes only a vapor-phase refrigerant. Howeverinthe

evaporator 100, when a disturbance such as a decrease in heat load occurs, the refrigerant

may not evaporate and a part of the liquid-phase refrigerant may remain. In that case,

this liquid-phase refrigerant is sent to the refrigerant flow path 610. Therefore, the

liquid separator 200 separates the liquid-phase refrigerant contained in the refrigerant and

supplies only the vapor-phase refrigerant to the downstream compressor 300.

[0021]

Unless there are restrictions on installation, it is preferable to construct the

refrigerant flow path 620 while avoiding a structure having a reverse gradient with respect to the direction of gravity or a U-shaped structure. This is because if such a reverse gradient structure or U-shaped structure exists in the refrigerant flow path 620, the liquid-phase refrigerant condensed in the refrigerant flow path 620 will accumulate at that portion when the cooling system F is stopped. In this way, since the liquid-phase refrigerant that accumulates in the refrigerant flow path 620 is sucked into the compressor 300 together with the vapor-phase refrigerant when the cooling system F is started next time, despite the fact that the liquid separator 200 is installed, there is a risk of causing the liquid-back phenomenon in the compressor 300.

[0022]

With reference to FIGS. 3 and 4, the liquid separator 200 located on the

upstream side of the compressor 300 has a cylindrical housing 210 that serves as a closed

container in which the refrigerant is stored. Inside the housing 210 are installed a

refrigerant inflow pipe 220 for flowing in a vapor-phase refrigerant or a vapor-liquid

two-phase refrigerant and a refrigerant outflow pipe 230 for flowing out the vapor-phase

refrigerant in the housing 210 to the outside.

[0023]

The refrigerant inflow pipe 220 and the refrigerant outflow pipe 230 are

installed from the upper surface 21OA of the housing 210 toward the inside of the

container 210B. The refrigerant inflow pipe 220 and the refrigerant outflow pipe 230

are arranged at an interval in the radial direction (R direction) of the housing 210. The

refrigerant inflow pipe 220 is connected to the refrigerant flow path 610 in which the

vapor-phase refrigerant or the gas-liquid two-phase refrigerant from the evaporator 100 is

guided. The refrigerant outflow pipe 230 is connected to a refrigerant flow path 620

that guides the vapor-phase refrigerant to the compressor 300.

The vapor-phase refrigerant or the gas-liquid two-phase refrigerant after passing through the evaporator 100 flows into the housing 210 through the refrigerant inflow pipe 220, and the liquid-phase refrigerant in the gas-liquid mixed flow falls to the bottom of the housing 210 by gravity and accumulates there. On the other hand, the vapor-phase refrigerant in the gas-liquid mixed flow is sent to the compressor 300 through the refrigerant outflow pipe 230.

[0024]

The housing 210 of the liquid separator 200 has a height h relatively small with

respect to a diameter along the R direction, and is configured to have a short cylindrical

shape as a whole.

As described above, in the liquid separator 200, since the housing 210 is formed

in the shape of a short cylinder whose height h is relatively small with respect to the

diameter in the R direction, even if the compressor 300 with weight is arranged on the

upper surface 210A of the housing 210, it is possible to hold the compressor 300 in a

stable state.

[0025]

Referring to FIG. 2 again, in the vapor compression type cooling system F as

described above, the vapor-phase refrigerant which evaporated by absorbing heat HI

from the heat source by the evaporator 2 is compressed by the compressor 300 to attain a

high temperature and high pressure, and then sent to the condenser 400. Subsequently,

the liquid-phase refrigerant, which is condensed by heat dissipation H2 to a cold source

in the condenser 400, is depressurized to a predetermined pressure by the decompression

expansion valve 500 and sent to the evaporator 100 again.

[0026]

As shown in FIGS. 4 and 5A and 5B, below an inlet (opening for the liquid to

flow into the liquid separator 200) 220A of the refrigerant inflow pipe 220, a mesh-shaped splash prevention plate 240 is installed to prevent the vapor-phase refrigerant C1 that is supplied through the refrigerant inflow pipe 220 from blowing up the liquid-phase refrigerant C2 that has accumulated in the housing 210.

In the housing 210, when the flow velocity of the vapor-phase refrigerant C1

supplied through the refrigerant inflow pipe 220 is large, even if the liquid-phase

refrigerant is not mixed in the refrigerant C1, the liquid-phase refrigerant C2 staying on

the bottom surface of the housing 210 may be blown up by the momentum of the

vapor-phase refrigerant C1. In this case, there is a risk that the blown-up liquid-phase

refrigerant C2 will flow out from an outlet (opening for the liquid to flow out from the

housing 210) 230A of the refrigerant outflow pipe 230.

Therefore, as shown in FIGS. 5A and 5B, the mesh-shaped splash prevention

plate 240 is installed below the refrigerant inflow pipe 220. The mesh-shaped splash

prevention plate 240 mitigates the impact of the vapor-phase refrigerant C1 on the liquid

surface of the liquid-phase refrigerant C2, thereby preventing the liquid-phase refrigerant

C2 from being blown up.

[0027]

As described above, in the liquid separator 200 according to the first

embodiment, since the housing 210 is formed in a short cylindrical shape having a height

h relatively small in the radial direction (R direction), even if the heavy compressor 300

is arranged on the upper surface 21GA of the housing 210, the liquid separator 200 can be

held in a stable state without becoming top heavy.

In the liquid separator 200, since the housing 210 is formed in a short cylinder

shape, the refrigerant inflow pipe 220 and the refrigerant outflow pipe 230 can be

arranged in the upper surface 210A of the housing 210 at a regular interval in the radial

direction (R direction).

As a result, in the liquid separator 200, the effect of undulation (turbulence) of

the liquid level of the liquid-phase refrigerant C2 caused by the inflow of the refrigerant

from the refrigerant inflow pipe 220 into the housing 210 is prevented from extending to

the refrigerant outflow pipe 230. Therefore, it is possible to prevent the liquid-phase

refrigerant C2 in the housing 210 from being blown up and flowing out from the

refrigerant outflow pipe 230.

[0028]

Further, in the liquid separator 200, providing the mesh-shaped splash

prevention plate 240 below the inlet 220A of the refrigerant inflow pipe 220 alleviates

the momentum of the vapor-phase refrigerant Cl colliding with the liquid surface to

prevent undulation of the liquid level of the liquid-phase refrigerant C2.

This also makes it possible to prevent the liquid-phase refrigerant C2 in the housing 210

from flowing out from the outlet 230A of the refrigerant outflow pipe 230.

[0029]

Further, in the liquid separator 200, there is no complicated structure causing a

large pressure loss in the flow path of the vapor-phase refrigerant from the refrigerant

inflow pipe 220 to the refrigerant outflow pipe 230. As a result, in the liquid separator

200, it is possible to prevent the so-called liquid back phenomenon to the compressor 300

(damage to the pipeline and equipment of the cooling system due to droplets of the

refrigerant flowing through the flow path with kinetic energy) while suppressing the

pressure loss during the gas-liquid separation of the refrigerant.

[0030]

(Modification 1)

In the above embodiment, a mesh-shaped plate is used as the splash prevention

plate 240, but the present invention is not limited thereto. That is, as the splash prevention plate 240, a plate having a large number of through holes 240a as shown in

FIG. 6, for example, a plate having a plurality of holes such as punching metal may be

used.

[0031]

(Modification 2)

Further, as the splash prevention plate 240, a net-like body formed by entwining

a plurality of fibers 240b as shown in FIG. 7, for example, a metal scrubbing brush

processed into a flat shape may be used.

[0032]

(Second Embodiment)

A liquid separator 200' according to the second embodiment of the present

invention will be described with reference to FIG. 8.

The liquid separator 200' according to the second embodiment differs from the

liquid separator 200 according to the first embodiment on the point of a liquid intrusion

prevention plate 250 being provided below the outlet of the refrigerant outflow pipe 230.

[0033]

In the liquid separator 200' shown in the second embodiment, when the flow

velocity of the vapor-phase refrigerant C1is large, there is a risk of the force blowing up

the liquid-phase refrigerant C2 stored in the housing 210 being strong enough such that

splash prevention is insufficient with the splash prevention plate 240 alone. Therefore,

in the liquid separator 200', in addition to providing the splash prevention plate 240

below the inlet (outlet when heading toward the liquid separator 200') 220A of the

refrigerant inflow pipe 220, the liquid intrusion prevention plate 250 for preventing

suctioning of the liquid-phase refrigerant C2 is provided below the outlet of the

refrigerant outflow pipe (the port through which the liquid flows from the liquid separator 200') 230A.

[0034]

As a result, in the liquid separator 200' shown in the second embodiment, by

adding the liquid intrusion prevention plate 240 below the refrigerant inflow pipe 220, it

is possible to prevent droplets of the liquid-phase refrigerant C2 from being sucked into

the refrigerant outflow pipe 230, whereby the liquid separation function can be improved.

As the liquid intrusion prevention plate 240, in addition to a normal plate, it is

possible to use a mesh-shaped plate shown in FIG. 5B, a plate having a large number of

through holes shown in FIG. 6, a net-like body (or cotton-like body) formed by the

entwining of fibers shown in FIG. 7, or the like.

[0035]

(Third Embodiment)

The liquid separator 200" according to the third embodiment of the present

invention will be described with reference to FIGS. 9 and 10.

[0036]

The liquid separator 200" shown in the third embodiment differs from the liquid

separators 200 and 200' shown in the first and second embodiments on the point of being

provided with a liquid level sensor 260, a maintenance valve 270, and a control unit 700.

[0037]

In the normal operation of the cooling system, the gaseous refrigerant is

completely sent from the outlet of the evaporator 100, and the liquid-phase refrigerant is

transferred from the evaporator 100 to the liquid separator 200 only when the operation

becomes unstable due to a disturbance. At this time, due to the unstable operation the

liquid-phase refrigerant C2 in the housing 210 gradually evaporates during the

subsequent normal operation to become the vapor-phase refrigerant C1, whereby the accumulation thereof is eliminated.

[0038]

However, if the unstable operation occurs continuously, it is expected that the

amount of the liquid-phase refrigerant C2 staying in the housing 210 of the liquid

separator 200 will gradually increase.

Therefore, in the liquid separator 200" shown in the third embodiment, as shown

in FIG. 9, the liquid level sensor 260 for monitoring the amount of liquid of the

liquid-phase refrigerant C2 remaining in the housing 210 is attached to this housing 210.

If the liquid level of the liquid-phase refrigerant C2 that accumulates in the

housing 210 becomes higher than the position of the droplet prevention plate 240, the

droplet prevention plate 240 will not function and the liquid separation function may be

significantly reduced.

In this case, since the liquid-phase refrigerant C2 may flow out from the

refrigerant outflow pipe 230 and cause liquid back, it will be necessary to stop the

compressor 300.

[0039]

Therefore, in the liquid separator 200" of the third embodiment, as shown in FIG.

10, a control unit 700 is provided that monitors the value of the liquid level sensor 260 of

the liquid separator 200 and stops the entire cooling system F' including the compressor

300 when the liquid level of the liquid-phase refrigerant C2 exceeds a limit value.

Then, in the liquid separator 200" of the third embodiment, after the cooling

system F'is stopped, the maintenance valve 270 at the lower part of the housing 210 is

opened and the accumulated liquid-phase refrigerant C2 is discharged, whereby a return

to the normal state can be achieved.

The maintenance valve 270 may be opened and closed manually by an operator, or may be opened and closed by a drive means operated by a separately provided control unit 700.

[0040]

Although the embodiment of the present invention has been described in detail with

reference to the drawings, the specific configuration is not limited to this embodiment,

and includes design changes and the like within a range that does not deviate from the

gist of the present invention.

[0041]

Priority is claimed on Japanese Patent Application No. 2019-55600, filed March

22, 2019, the content of which is incorporated herein by reference.

INDUSTRIAL APPLICABILITY

[0042]

The present invention is mainly used in cooling systems and can be applied to a

liquid separator, a cooling system and a gas-liquid separation method that separates

liquid flowing from the evaporator into the compressor. Even if a heavy compressor is

arranged on top of the liquid separator, the liquid separator can be stably held.

[0043]

Throughout this specification and the claims which follow, unless the context

requires otherwise, the word "comprise", and variations such as "comprises" and

"comprising", will be understood to imply the inclusion of a stated integer or step or

group of integers or steps but not the exclusion of any other integer or step or group of

integers or steps.

[0044]

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge in Australia.

Description of Reference Symbols

[0045]

1: Cooling system

1A: Refrigerant flow path

2: Evaporator

3: Compressor

4: Condenser

5: Decompression expansion valve

10: Liquid separator

11: Closed container

12: Refrigerant inflow pipe

13: Refrigerant outflow pipe

100: Evaporator

200: Liquid separator

200': Liquid separator

200": Liquid separator

210: Housing

240: Splash prevention plate

250: Liquid intrusion prevention plate

260: Liquid level sensor

270: Maintenance valve

300: Compressor

400: Condenser

500: Decompression expansion valve

610: Refrigerant flow path

620: Refrigerant flow path

630: Refrigerant flow path

640: Liquid pipe

650: Liquid pipe

700: Control unit

C: Refrigerant

Cl: Vapor-phase refrigerant

C2: Liquid-phase refrigerant

F: Cooling cycle

F': Cooling cycle

R: Radial direction

Claims

1. A liquid separator comprising:

a closed container having a cylindrical shape in which a refrigerant is stored; a

refrigerant outflow pipe that allows the refrigerant that has flowed into a space inside the

closed container to flow out, wherein:

the refrigerant inflow pipe and the refrigerant outflow pipe are each arranged

from the upper part of the closed container toward the inside thereof; and

the closed container is formed in a short cylindrical shape in which the height is

smaller than the diameter,

wherein the closed container has an upper surface on which a compressor is

arranged.

2. The liquid separator according to claim 1, wherein a splash prevention plate for

preventing the scattering of refrigerant droplets is installed near the outlet of the

refrigerant inflow pipe located in the closed container.

3. The liquid separator according to claim 2, wherein the splash prevention plate is

composed of a mesh-shaped plate.

4. The liquid separator according to claim 2, wherein the splash prevention plate is

composed of a plate having a large number of through holes.

5. The liquid separator according to claim 2, wherein the splash prevention plate is composed of a net-like body formed by entwining a plurality of fibers.

6. The liquid separator according to any one of claims 1 to 5, wherein a liquid

intrusion prevention plate for preventing intrusion of the liquid-phase refrigerant in the

closed container is further provided near the inlet of the refrigerant outflow pipe.

7. The liquid separator according to any one of claims 1 to 6, wherein the closed

container is provided with a liquid level sensor that detects the liquid level of the

liquid-phase refrigerant and a control unit that stops the entire device when the detected

value of the liquid level sensor exceeds a predetermined limit value.

8. The liquid separator according to any one of claims 1 to 7, wherein a discharge

valve for discharging the liquid-phase refrigerant is provided at the lower part of the

closed container.

9. A cooling system comprising an evaporator that absorbs ambient heat by

evaporating a liquid-phase refrigerant, a compressor that compresses a vapor-phase

refrigerant, a condenser that releases the heat of the refrigerant that has been pressurized

by the compressor and condenses the vapor-phase refrigerant, and a decompression

expansion valve that depressurizes and expands the liquid-phase refrigerant cooled by the

condenser along a refrigerant path, wherein:

a liquid separator for gas-liquid separation of the refrigerant after passing

through the evaporator is provided on the upstream side of the compressor;

the liquid separator includes a closed container having a cylindrical shape in

which a refrigerant is stored; a refrigerant inflow pipe that allows the refrigerant to flow into the closed container; and a refrigerant outflow pipe that allows the refrigerant in a space inside the closed container to flow out, the cylindrical closed container being formed in a short cylindrical shape in which the height is smaller than the diameter; and the closed container has an upper surface on which a compressor is arranged.

10. A gas-liquid separation method comprising:

connecting a closed container having a cylindrical shape in which the refrigerant

is stored, with a refrigerant inflow pipe that allows a refrigerant to flow into and a

to flow out;

forming the closed container in a short cylindrical shape in which the height is

smaller than the diameter; and

providing an upper surface on the closed container on which a compressor is

arranged.