JPH04324066A - Refrigerator - Google Patents

Abstract

PURPOSE:To eliminate storage of refrigerant liquid in a compression chamber at the time of stopping a compressor in a refrigerator using the compressor having a liquid injection and to prevent compression of the liquid at the time of starting the compressor. CONSTITUTION:A bypass passage 13 branched from an injection tube 12 to a suction side 9 of a compressor 1, is provided, a first switching valve 21 is provided at a high pressure liquid tube 6 side from a branch 14 in the tube 12, a second switching valve 22 is provided in the passage 13, and control means 20 for stopping injection by both the valves 21, 22 at the time of stopping the compressor 1 and communicating a compression chamber 40 with the suction side 9 of the compressor 1, is provided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration system, and more particularly to a refrigeration system equipped with a compressor having an injection port communicating with a compression chamber during a compression process.

0002

[Prior Art] Conventionally, in order to lower the temperature of refrigerant discharged from a compressor, there has been a special method in which refrigerant liquid discharged from a condenser is injected into the compression chamber of the compressor by opening and closing a control valve as necessary. This is a known technique as described in JP-A No. 2-82056.

0003

When the compressor is stopped, the injection control valve is normally closed, but some leakage occurs and refrigerant liquid accumulates in the compression chamber of the compressor. Alternatively, the refrigerant gas in the compression chamber when the compressor is stopped condenses and refrigerant liquid accumulates. If the compressor is started in this state, it will compress the liquid, which may cause damage to the compressor. The present invention has been made in view of this problem, and its purpose is to prevent liquid compression when starting up a compressor.

0004

[Means for Solving the Problem] In order to achieve the above object, the solution means of the present invention includes a compressor (1) equipped with an injection port (10) communicating with a compression chamber (40) during a compression process, and a condenser. (2), expansion mechanism (3) and evaporator (4)
) are sequentially connected, and the high-pressure liquid pipe (6) on the outlet side of the condenser (2) and the injection port (10) are connected by an injection pipe (12) with a pressure reducing mechanism (11) interposed. Assuming that.

The first solution, as shown in FIG. 1, is a compressor (1) branched from the injection pipe (12).
A bypass path (13) leading to the suction side (9) of the injection pipe (12) is provided, and a first on-off valve ( 21), a second on-off valve (22) is provided in the bypass path (13), and the first on-off valve (21) is opened and the second on-off valve (22) is closed during injection operation of the compressor (1). , an on-off valve control means (20) is provided which closes the first on-off valve (21) and opens the second on-off valve (22) when the compressor (1) is stopped.

As shown in FIG. 2, the second solution is to branch out from the injection pipe (12) and connect the compressor (1) to the compressor (1).
A bypass passage (13) leading to the suction side (9) of the injection pipe (12) and the bypass passage (13) are provided.
13) and the injection outlet (14).
31) between the liquid inlet (32) and the bypass port (33).
During the injection operation of the compressor (1), the injection outlet (31) and the liquid inlet (32) are communicated with each other.
) is provided with a switching valve control means (30) that communicates the injection outlet (31) and the bypass port (33) when the engine is stopped.

As shown in FIGS. 5 and 6, a third solution means, in addition to the first or second solution means, includes a branch part (
A vent part (15) protruding upward is provided on the injection port (10) side of the bypass passage (14).
3) is arranged below the upper end of the vent part (15).

A fourth solution, in addition to the first, second or third solution, is that the compressor (1) is wrapped around end plates (41) and (42) as shown in FIGS. 7 and 8. (43), (4
4) is of a scroll type, comprising a fixed scroll (45) and a movable scroll (46) facing each other.

[0009]

[Operation] With the above solution, in the invention of claim 1,
By closing the first on-off valve (21) and opening the second on-off valve (22) when the compressor (1) is stopped, the refrigerant liquid leaking from the closed first on-off valve (21) is transferred to the bypass path ( 13)
and flows to the suction side (9) of the compressor (1). Further, immediately after the compressor (1) is stopped, the refrigerant in the compression chamber (40) also flows to the suction side (9) due to the pressure difference. Therefore, when the compressor (1) is stopped, the refrigerant liquid does not enter the compression chamber (40) and does not accumulate therein.

In the invention of claim 2, when the compressor (1) is stopped, the injection outlet (31) of the three-way switching valve (34) is closed.
) and the bypass port (33).
Even if refrigerant liquid leaks from the three-way switching valve (34), the bypass port (
33) and passes through the bypass path (13) to the compressor (1).
flows to the suction side (9) of the Further, immediately after the compressor (1) is stopped, the refrigerant in the compression chamber (40) also flows to the suction side (9) due to the pressure difference. Therefore, when the compressor (1) is stopped, refrigerant liquid does not enter the compression chamber (40) and does not accumulate therein.

In the invention of claim 3, in addition to the invention of claim 1 or claim 2, since the bypass passage (13) is provided below the upper end of the vent part (15), the compressor (1)
When the engine is stopped, the refrigerant liquid leaking from the closed first on-off valve (21) or from the three-way switching valve (34) in which the injection outlet (31) and the bypass port (33) are communicated is discharged to the vent part (15). Compression chamber (40) of the compressor (1)
branch (14) and bypass path (13).
and flows to the suction side (9) of the compressor (1).

[0012] In the invention of claim 4, claims 1 and 2
Or, in addition to the invention of claim 3, since the compressor (1) is of a scroll type, when the compressor (1) is stopped, the compression chamber (40) formed by the wraps (43) and (44)
Refrigerant liquid does not accumulate in the .

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. An embodiment according to the invention of claim 1 will be described based on FIG. The refrigeration system includes a compressor (1) equipped with an injection port (10) communicating with a compression chamber (40), a condenser (2), an expansion mechanism (3), and an evaporator (
4) are connected in sequence. In addition,
The compressor (1) and the condenser (2) are connected by a high-pressure gas pipe (5), and the condenser (2) and the expansion mechanism (3) are connected by a high-pressure liquid pipe (
The expansion mechanism (3) and the evaporator (4) are connected by a low pressure liquid pipe (7), and the evaporator (4) and the compressor (1) are connected by a low pressure liquid pipe (7).
is connected by a low-pressure gas pipe (8), and is further connected to a high-pressure liquid pipe (6).
) and the injection port (10) of the compressor (1) are connected by an injection pipe (12) via a pressure reducing mechanism (11) and an electromagnetic first on-off valve (21). The suction side (9) of the machine (1) is connected to the bypass passage (1) via a second electromagnetic on-off valve (22).
3), and the first on-off valve (21) is provided closer to the high-pressure liquid pipe (6) than the branch part (14) of the bypass path (13) in the injection pipe (12). Furthermore, a thermostat (23) is provided on the discharge side of the compressor (1), which closes when the temperature is higher than a predetermined temperature and opens when the temperature is lower than a predetermined temperature. Then, the first on-off valve (2
1) and the second on-off valve (22) are on-off valve control means (20).
controlled by.

The operation of the refrigeration system constructed as described above will be explained below. During operation of the compressor (1), when the discharge side temperature of the compressor (1) rises and the thermostat (23) reaches a predetermined temperature, the on-off valve control means (20)
As a result, the first on-off valve (21) opens and the second on-off valve (22
) is closed, the refrigerant liquid in the high-pressure liquid pipe (6) passes through the injection pipe (12), is depressurized by the pressure reducing mechanism (11), and enters the compression chamber (40) of the compressor (1) from the injection port (10). Since it is injected, the compression chamber (4
0) and the discharge gas are cooled. Further, when the discharge side temperature of the compressor (1) decreases and the thermostat (23) becomes lower than a predetermined temperature, the on-off valve control means (20)
Since the first on-off valve (21) and the second on-off valve (22) are closed and the injection of refrigerant liquid is stopped, the compression chamber (40)
And the cooling of the discharged gas also stops. When the compressor (1) is stopped, the first on-off valve (21) is closed by the on-off valve control means (20) and the second on-off valve (22) is opened, so that the compression chamber (40) and the suction side (9 ) are communicated. At this time, since the suction side (9) has a lower pressure than the compression chamber (40), the refrigerant that was in the compression chamber (40) moves to the suction side (9). In addition, some leakage may occur even when the solenoid valve is closed, but even if refrigerant liquid leaks from the first on-off valve (21), it will not enter the compression chamber (40) and will not enter the suction side (9).
).

Here, based on FIG. 3, the on-off valve control means (2
A control circuit as an example of 0) will be explained. The control circuit includes fuses (
FUS) and (FUR). The control circuit includes a thermostat (23) provided on the discharge side of the compressor (1) that closes when the temperature is higher than a predetermined temperature and opens when the temperature is lower than a predetermined temperature; Three normally open contacts (88C1), (88C2), (88C3) for driving the motor (MC) in (1)
The electromagnetic switch (88C) has a solenoid switch (88C), an electromagnetic coil (SV1) of the first on-off valve (21) that is energized open, and an electromagnetic coil (SV2) of the second on-off valve (22) that is energized closed, Compressor (1) operation switch (S) and electromagnetic switch (88C)
) are connected in series, and the second normally open contact (88C
2), thermostat (23) and first on-off valve (21)
An electromagnetic coil (SV1) connected in series,
The third normally open contact (88C3) and the electromagnetic coil of the second on-off valve (
SV2) are connected in series and connected in parallel.

The operation of such a control circuit will be explained below. When the operation switch (S) and thermostat (23) of the compressor (1) are closed, the first normally open contact (88C1) and the second normally open contact (88C2) of the electromagnetic switch (88C)
and the third normally open contact (88C3) are closed, both electromagnetic coils (SV1) and (SV2) are excited, and the first on-off valve (2
1) is opened and the second on-off valve (22) is closed. Compressor (
1) The operation switch (S) is closed and the thermostat (
23) is opened, the three normally open contacts (88C1), (88C2), and (88C3) of the electromagnetic switch (88C) are closed, and the electromagnetic coil (SV1) of the first on-off valve (21) is demagnetized and Electromagnetic coil (SV2) of the second on-off valve (22)
is excited, and the first on-off valve (21) and the second on-off valve (2
2) is closed. When the operation switch (S) of the compressor (1) opens, the three normally open contacts (88C) of the electromagnetic switch (88C) open.
C1), (88C2), and (88C3) are opened, and the electromagnetic coil (SV1) of the first on-off valve (21) and the second on-off valve (
The electromagnetic coil (SV2) of 22) is demagnetized, the first on-off valve (21) is closed, and the second on-off valve (22) is opened.

[0017] With this configuration, refrigerant does not accumulate in the compression chamber (40) when the compressor (1) is stopped, and damage due to liquid compression when the compressor (1) is started can be prevented. In addition, in the invention according to this claim, the compressor (1) has an injection port (
10), and any compressor (1) including reciprocating type, rotary type, screw type, scroll type, etc. is applicable. Further, the pressure reducing mechanism (11) is connected to the first on-off valve (21) and the branch part (14) through the high pressure liquid pipe (6).
) side or the injection port (10) side. Furthermore, both on-off valves (21), (22),
Branch (14), bypass path (13) and suction side (9)
may be located inside the main body of the compressor (1).

Next, an embodiment of the invention according to claim 2 will be explained based on FIG. The refrigerant circuit of the refrigeration system of this embodiment is equipped with a refrigerant circuit that is almost the same as the embodiment of the invention according to claim 1, but the first on-off valve (21) and the second on-off valve (
This is a modification of the part related to 22). The configuration of the parts related to the changes will be explained below. The high pressure liquid pipe (6) and the injection port (10) of the compressor (1) are connected by the injection pipe (12) via the pressure reducing mechanism (11), and the injection pipe (12) and the compressor (1)
It is connected to the suction side (9) of the fuel injection pipe through a bypass passage (13), and an electromagnetic three-way switching valve (34) is provided at the branch part (14) between the injection pipe (12) and the bypass passage (13). There is. The three-way switching valve (34) has an injection outlet (31) on the injection port (10) side, a bypass port (33) on the bypass path (13) side, and a liquid inlet (32) on the high pressure liquid pipe (6). ) side, the injection outlet (31) is connected to the liquid inlet (32).
and the bypass port (33). The three-way switching valve (34) is controlled by switching valve control means (30).

The operation of the refrigeration system configured as described above will be explained below. During operation of the compressor (1), the liquid inlet (32) of the three-way switching valve (34) and the injection outlet (31) communicate with each other, and the refrigerant liquid in the high-pressure liquid pipe (6) passes through the injection pipe (12). Then, the pressure is reduced by the pressure reducing mechanism (11), and the gas is injected from the injection port (10) into the compression chamber (40) of the compressor (1), thereby cooling the compression chamber (40) and the discharged gas. When the compressor (1) is stopped, the injection outlet (31) of the three-way switching valve (34) is controlled by the switching valve control means (30).
The bypass port (33) communicates with the compression chamber (40), and the suction side (9) communicates with the compression chamber (40). At this time, the pressure on the suction side (9) is lower than that in the compression chamber (40), so the pressure in the compression chamber (
The refrigerant that was at 40) moves to the suction side (9). Also,
Even if refrigerant liquid leaks from the three-way switching valve (34), the compression chamber (4
0), but flows to the suction side (9).

Here, based on FIG. 4, the switching valve control means (3
A control circuit as an example of 0) will be explained. The control circuit includes fuses (
FUS) and (FUR). The control circuit includes a drive switch (S) for the compressor (1) and a motor (MC) for the compressor (1).
An electromagnetic switch (88C) with two normally open contacts (88C1) and (88C2) communicates with the liquid inlet (32) and injection outlet (31) when energized, and communicates with the bypass port (33) and injection when not energized. It is equipped with an electromagnetic coil (SV3) of a three-way switching valve (34) that communicates with the outlet (31), and the operation switch (S) of the compressor (1) and the electromagnetic switch (88C) are connected in series. and the second normally open contact (88C2) and the electromagnetic coil (S) of the three-way switching valve (34).
V3) are connected in series and connected in parallel.

The operation of such a control circuit will be explained below. When the operation switch (S) of the compressor (1) is closed, the first normally open contact (88C1) and the second normally open contact (88C2) of the electromagnetic switch (88C) are closed, and the three-way switching valve (34) is closed. The electromagnetic coil (SV3) is energized and the three-way switching valve (34)
The liquid inlet (32) and the injection outlet (31) communicate with each other. When the operation switch (S) of the compressor (1) opens, the two normally open contacts (88C1) of the electromagnetic switch (88C) open.
, (88C2) are opened, the electromagnetic coil (SV3) of the three-way switching valve (34) is demagnetized, and the bypass port (33) of the three-way switching valve (34) and the injection outlet (31) communicate with each other.

[0022] With this configuration, refrigerant does not accumulate in the compression chamber (40) when the compressor (1) is stopped, and damage due to liquid compression when the compressor (1) is started can be prevented. In addition, in the invention according to this claim, the compressor (1) has an injection port (
10), and any compressor (1) including reciprocating type, rotary type, screw type, scroll type, etc. is applicable. Moreover, it does not matter whether the pressure reducing mechanism (11) is on the high pressure liquid pipe (6) side or the injection port (10) side with respect to the branch part (14). moreover,
Three-way switching valve (34), branch part (14), bypass path (1
3) and the suction side (9) may be located inside the main body of the compressor (1), and although the compressor (1) of this embodiment has been described as one that always requires injection during operation, injection Pipe (12) or bypass line (13)
By adding an electromagnetic on-off valve and changing the control circuit, injection may be performed when necessary during operation of the compressor (1).

Next, an embodiment according to the invention of claim 3 will be explained based on FIGS. 5 and 6. FIG. 5 shows an embodiment according to the invention of claim 3, which corresponds to the invention of claim 1, and FIG. 6 corresponds to the invention of claim 2. Injection tube (12)
The injection port (
10) has a vent part (15) protruding upward on the side;
The bypass passage (13) is provided below the upper end of the vent part (15). As a result, the refrigerant liquid leaking from the closed first on-off valve (21) or the three-way switching valve (34) in which the injection port (31) and the bypass port (33) are communicated with each other is transferred to the compressor (1) by the head. It flows to the suction side (9).

Next, an embodiment according to the invention of claim 4 will be explained based on FIGS. 7 and 8. In the invention according to this claim, the compressor (1) in each of the above claims is particularly of a scroll type, and FIGS. 7 and 8 show an embodiment of such a scroll type compressor (1). be. At the inner upper part of the sealed casing (47), wrap (43) on the end plate (41).
A fixed scroll (45) consisting of a wrap (44) erected on an end plate (42) and a movable scroll (46) consisting of a wrap (44) erected on an end plate (42) are disposed vertically opposite each other, and each scroll (45) , (46) is provided with a motor (MC) having a drive shaft (48) connected to the movable scroll (46). The suction side of the compressor (1) is connected to a low pressure gas pipe (8), the discharge side is connected to a high pressure gas pipe (5), and the compressor (1) is incorporated into a refrigerant circuit of a refrigeration system.

The movable scroll (46) is driven to revolve around the fixed scroll (45) by the rotation of the drive shaft (48) as the motor (MC) is driven, and the refrigerant is introduced from the low pressure gas pipe (8). Gas, said each wrap (
It is compressed in a compression chamber (40) formed between 43) and (44), and from this high pressure side compression chamber (40) passes through a discharge port (51) provided at the center of the fixed scroll (45).
The gas is discharged into a high pressure gas pipe (5). Further, an injection port (10) connected to the injection pipe (12) in the embodiment according to the invention of each claim and communicating with the compression chamber (40) during the compression process in the end plate (41) of the fixed scroll (45). ) to inject refrigerant liquid into the compression chamber (40) during the compression process.

When the compressor (1) is of the scroll type as described above, the wrap (40) forming the compression chamber (40) is
43) and (44) are thin and easily broken, so they are easily damaged by liquid compression, but as in the present claim, claim 1,
By applying the invention according to claim 2 or claim 3 to the scroll compressor (1), the wraps (43), (44
), the reliability of the compressor (1) is improved,
The effect is particularly remarkable.

[0027]

Effects of the Invention In the invention of claim 1, when the compressor (1) is stopped, the first on-off valve (21) is closed and the second on-off valve (22) is closed.
) is controlled by the on-off valve control means (20) to open the refrigerant liquid leaking from the first on-off valve (21) via the bypass path (13) to the suction side (9) of the compressor (1). can be passed to. Furthermore, immediately after the compressor (1) stops, the refrigerant in the compression chamber (40) also flows to the suction side (9) due to the pressure difference.
can be passed to. Therefore, the refrigerant liquid does not enter or accumulate in the compression chamber (40) when the compressor (1) is stopped, so that liquid compression when the compressor (1) is started can be prevented.

In the invention of claim 2, when the compressor (1) is stopped, the injection outlet (31) and the bypass port (3
3), the three-way switching valve (21)
The refrigerant liquid leaking from the compressor (1) can flow to the suction side (9) of the compressor (1) via the bypass path (13). moreover,
Immediately after the compressor (1) is stopped, the refrigerant in the compression chamber (40) can also flow to the suction side (9) due to the pressure difference. Therefore, when the compressor (1) is stopped, the refrigerant liquid does not enter or accumulate in the compression chamber (40), so that liquid compression when the compressor (1) is started can be prevented.

In the invention of claim 3, in addition to the effects of the invention of claim 1 or claim 2, since the bypass passage (13) is provided below the upper end of the vent part (15), the compressor (1 ), the refrigerant liquid leaking from the closed first on-off valve (21) or the three-way switching valve (34) in which the injection outlet (31) and the bypass port (33) are communicated is transferred to the vent part (15). can be prevented from entering the compression chamber (40) of the compressor (1), and the suction side (9 ). Therefore, it is possible to prevent liquid compression when starting up the compressor (1).

In the invention of claim 4, since the compressor (1) is of scroll type, the wraps (43) and (44) forming the compression chamber (40) are thin and easily damaged. Since refrigerant liquid does not accumulate in the compression chamber (40) when (1) is stopped, liquid compression does not occur during startup, and damage to the wraps (43) and (44) that formed the compression chamber (40) can be prevented. .

[Brief explanation of drawings]

FIG. 1 is a refrigerant circuit showing an embodiment of the invention according to claim 1.

FIG. 2 is a refrigerant circuit showing an embodiment of the invention according to claim 2.

FIG. 3 is a control circuit showing an embodiment of the invention according to claim 1.

FIG. 4 is a control circuit showing an embodiment of the invention according to claim 2.

FIG. 5 is a schematic diagram of main parts showing an embodiment of the invention of claim 3.

FIG. 6 is a schematic diagram of main parts showing an embodiment of the invention according to claim 3.

FIG. 7 is a partially cutaway longitudinal cross-sectional view of a scroll compressor showing an embodiment of the invention according to claim 4;

FIG. 8 is a schematic diagram of a compression chamber and its vicinity showing a compression action of a scroll compressor according to an embodiment of the invention;

[Explanation of symbols]

1 Compressor 2 Condenser 3. Expansion mechanism 4 Evaporator 6 High pressure liquid pipe 9 Suction side 10 Injection port 11　Pressure reduction mechanism 12 Injection tube 13 Bypass road 14 Branch part 15 Vent part 20 Opening/closing valve control means 21 First on-off valve 22 Second on-off valve 23 Thermostat 30 Switching valve control means 31 Injection outlet 32 Liquid inlet 33 Bypass port 34 Three-way switching valve 40 Compression chamber 41　End plate 42　End plate 43 Rap 44 Lap 45 Fixed scroll 46 Movable scroll

Claims (4)

[Claims] Claim 1: A compressor (1) equipped with an injection port (10) communicating with a compression chamber (40) during a compression process.
), a condenser (2), an expansion mechanism (3) and an evaporator (4) are connected in sequence, and a high pressure liquid pipe (6) on the outlet side of the condenser (2) is connected in sequence.
) and the injection port (10) are connected to each other by an injection pipe (12) with a pressure reducing mechanism (11) interposed therein, the injection pipe (
A bypass passage (13) is provided which branches from the injection pipe (12) and reaches the suction side (9) of the compressor (1), and a branch part (
14), a first on-off valve (21) is provided on the high-pressure liquid pipe (6) side, and a second on-off valve (22) is provided on the bypass path (13). Open the on-off valve (21), close the second on-off valve (22),
A refrigeration system comprising an on-off valve control means (20) that closes a first on-off valve (21) and opens a second on-off valve (22) when the compressor (1) is stopped. Claim 2: A compressor (1) equipped with an injection port (10) communicating with a compression chamber (40) during a compression process.
), a condenser (2), an expansion mechanism (3) and an evaporator (4) are connected in sequence, and a high pressure liquid pipe (6) on the outlet side of the condenser (2) is connected in sequence.
) and the injection port (10) are connected to each other by an injection pipe (12) with a pressure reducing mechanism (11) interposed therein, the injection pipe (
A bypass passage (13) is provided which branches from the injection pipe (12) and reaches the suction side (9) of the compressor (1), and a branch part (14) between the injection pipe (12) and the bypass passage (13) is provided.
), connect the injection outlet (31) to the liquid inlet (32)
and the bypass port (33).
4), and the injection outlet (31) and liquid inlet (32) are provided during injection operation of the compressor (1).
), and a switching valve control means (30) which communicates the injection outlet (31) and the bypass port (33) when the compressor (1) is stopped. 3. An upwardly protruding vent portion (
15), and connect the bypass passage (13) to the vent part (15).
Claim 1 characterized in that it is arranged below the upper end of the
Or the refrigeration device according to claim 2. Claim 4: The compressor (1) has end plates (41), (42
) and a fixed scroll (45) having wraps (43) and (44) erected thereon, and a movable scroll (46) facing each other. Item 3. Refrigeration device according to item 3.