JPH0820126B2 - Refrigeration equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a refrigeration system, and more particularly, to a reciprocating compressor having a motor and a compression element driven by the motor in a hermetically sealed casing and extending from a liquid region. The present invention relates to a refrigeration system in which a liquid injection pipe having an electromagnetic opening / closing valve in the middle is connected to the suction side of the compressor.

(Prior Art) Conventionally, in this type of refrigeration system, an intake gas pipe is opened in a closed casing, and the motor is cooled by the intake gas to prevent the motor temperature from becoming higher than about 100 ° C. Ratio, when used with a low circulation rate, the discharge gas temperature rises, so to suppress this temperature rise,
By connecting the liquid injection pipe extending from the liquid region of the refrigeration system and having an electromagnetic on-off valve in the middle to a suction pipe for introducing suction gas into the closed casing of the compressor, and opening the electromagnetic on-off valve. It is designed to perform liquid injection.

(Problems to be Solved by the Invention) However, since the liquid is injected into the suction pipe, the suction gas passes through the motor and is overheated by the motor, so that the temperature rise of the discharge gas is suppressed accordingly. Therefore, a large amount of liquid refrigerant is required, and there has been a problem that the capacity is deteriorated. In order to solve this problem, for example, it is conceivable to perform liquid injection on the internal suction pipe communicating with the compression element so that the liquid injected liquid refrigerant is not overheated by the motor. When the motor is stopped by the operation such as the above, even if the solenoid valve is closed, the liquid refrigerant leaks from the solenoid valve due to the pressure difference between the suction side and the discharge side, stagnate in the compression element, and liquid compression occurs when restarting. It is dangerous and cannot solve the above-mentioned problems fundamentally.

The present invention was invented to solve the above problems, the object is to suppress the temperature rise of the discharge gas by liquid injection, it is possible to reduce the liquid injection amount to suppress the capacity down, and, This is to prevent liquid refrigerant from stagnation in the compression element when the motor is stopped so that liquid compression does not occur when the motor is restarted.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a reciprocating machine in which a motor (1) and a compression element (2) driven by the motor (1) are housed in a casing (5). The suction gas provided with the compressor (6) and sucked from the suction pipe (4) provided in the casing (5) is the motor (1).
In a refrigeration system in which the refrigerant is cooled before being sucked into the suction chamber (14) of the compression element (2), a liquid that extends from a high-pressure liquid region and has an electromagnetic opening / closing valve (26, 27) interposed midway A pressure equalizing pipe (3) that connects the injection pipe (24) to the suction chamber (14) of the compression element (2) and extends from the high-pressure liquid region.
0) is connected to the suction pipe (4) on the downstream side of the accumulator (23) interposed in the suction pipe (4), while the on-off valve (31) that opens to the pressure equalizing pipe (30) when the motor (1) is stopped. ).

(Operation) By opening the electromagnetic opening / closing valve (26, 27) interposed in the middle of the liquid injection pipe (24), the suction chamber of the compression element (2) is cooled without cooling the motor (1). Since liquid injection can be performed on (14) and the rise in discharge gas temperature can be suppressed by this liquid injection, overheating by the motor (1) is prevented,
The amount of liquid injection can be reduced, and by reducing the amount of liquid injection, the ability down can be suppressed and the ability up can be increased accordingly. Further, when the motor (1) is stopped, the on-off valve (31) provided in the pressure equalizing pipe (30) is opened, and the suction side of the compressor (6) is promptly passed through the pressure equalizing pipe (30). Since the low pressure of and the high pressure of the discharge side are equalized, the pressure difference before and after the electromagnetic on-off valve (26, 27) disappears quickly, and as a result, liquid refrigerant leaks from the on-off valve (26, 27). Can be suppressed. Therefore, the liquid refrigerant when the motor (1) is stopped does not accumulate in the suction chamber (14), and it is possible to prevent the liquid compression at the time of restart.

(Embodiment) A refrigerating apparatus shown in the drawings is a hermetically sealed motor (1) and a compression element (2) driven by the motor (1) having a discharge pipe (3) and a suction pipe (4). Casing (5)
A reciprocating compressor (6) installed inside, a heat source side heat exchanger (7) that becomes a condenser or an evaporator, a utilization side heat exchanger (8) that becomes an evaporator or a condenser, and the flow direction of the refrigerant are switched. First four-way switching valve (9) and capillary tube
And a second expansion mechanism (19) (20) connected by a refrigerant pipe, and the compression element (2) includes a cylinder chamber (12) having a discharge valve (10) and an intake valve (11). , A piston (13) movably installed in the cylinder chamber (12) and a suction chamber (14) and a discharge chamber (15) formed adjacent to the cylinder chamber (12), and a closed casing ( After the piston (13) is reciprocally driven by the motor (1) installed in (5), the piston (13) is sucked into the casing (5) through the suction pipe (4) and the motor (1) is cooled. The low pressure gas refrigerant introduced into the suction chamber (4) through the internal suction pipe (35) is compressed to discharge the high pressure gas refrigerant to the discharge chamber (15).

The fixed port of the four-way switching valve (9) has a high pressure gas pipe (41) connected to the discharge pipe (3) of the casing (5) and a low pressure gas pipe (41) connected to the suction pipe (4). 42)
And heat exchange (7) (8) at the switching port.
Gas pipes (43) and (44) extending from the respective parts are connected to each other, and by switching the four-way switching valve (9), a refrigerant flows as indicated by a solid arrow, and the heat source side heat exchanger (8) serves as a condenser, A refrigeration cycle using the use side heat exchanger (7) as an evaporator and a refrigerant flow as indicated by a dotted arrow, and the use side heat exchanger (7)
Is a condenser and the heat source side heat exchanger (8) is an evaporator to form a refrigeration cycle. Incidentally, (21)
(22) is a check valve that allows the liquid refrigerant to flow only in one direction by bypassing the expansion mechanisms (19) (20), and (23) is an accumulator provided in the suction gas pipe (42). .

Therefore, in the refrigerating apparatus configured as described above, the liquid pipe that is always in the high pressure liquid region during the operation of the compressor (6) regardless of the switching of the four-way switching valve (9) is shown in the drawing. The liquid injection pipe (24) is branched from the (45), and the liquid injection pipe (24) is connected to the suction chamber (14).
The liquid injection pipe (24) is connected to the electromagnetic on-off valves (26) (27) and the capillary tube (28).
(29) is interposed between the first and second branch pipes (32) (33) in a parallel circuit, and these solenoid valves (26) (2)
By opening 7), the high pressure liquid area and the suction chamber (1
4) Due to the pressure difference from the internal pressure, the liquid injection pipe (2
4) through which liquid injection can be performed, and a capillary tube for pressure equalization (25) is interposed at a position on the primary side with respect to the insertion position of the parallel circuit in the liquid injection pipe (24), Further, at the position on the primary side of each of the on-off valves (26, 27), the suction gas pipe (4
2) A pressure equalizing pipe (30) communicating with the pressure equalizing pipe (30) is provided.
In addition, an electromagnetic opening / closing valve (31) that is opened when the motor (1) is stopped is interposed.

In addition, the suction chamber (14) of the liquid injection pipe (24)
Connection to the suction chamber (14) may be directly connected,
In the drawing, it is connected to the internal suction pipe (35) that opens into the closed casing (5). That is, the tip of the liquid injection pipe (24) is projected into the closed casing (5) and connected to the internal suction pipe (35) through a meandering portion (24a) for avoiding resonance. There is.

The pressure equalizing pipe (30) is connected to the solenoid opening / closing valve (26).
It suffices to reduce the flow resistance when the (27) is closed, and the pressure equalizing pipe (30) is the liquid pipe (45).
May be connected in parallel with the liquid injection pipe (24), but as shown in FIG. 1 and as described above, the on-off valve (26) in the liquid injection pipe (24).
(27) When connected to the primary side, the differential pressure across the on-off valves (26) and (27) can be eliminated more quickly when the operation is stopped by stopping the motor (1). (2
6) It is advantageous in that refrigerant leakage from (27) can be reduced.

Further, the pressure equalizing capillary tube (25) interposed in the liquid injection pipe (24) is provided with the on-off valve (31).
It is installed in consideration of safety at the time of failure, and is not particularly necessary for the pressure equalizing function.

The first branch pipe (3) of the electromagnetic on-off valves (26) (27) interposed in the first and second branch pipes (32) (33).
The electromagnetic on-off valve (26) installed in 2) is normally open during a cooling operation in which the use side heat exchanger (7) is an evaporator, and during this cooling operation, the first branch pipe (32) is used. Liquid injection is always performed to keep the discharge gas temperature below a certain level. Further, the discharge gas pipe (41) is provided with a high temperature thermostat (34) for outputting when the discharge gas temperature rises above a predetermined level during cooling operation, that is, when it is detected that overload operation is performed. The electromagnetic on-off valve (27) interposed in the second branch pipe (33) is opened by the output of the thermostat (34), and the amount of liquid injection from the first branch pipe (32) becomes the second branch pipe (33). ) Is added to prevent overload operation.

Further, the on-off valves (26) (27) are closed at the time of operation stop and at the time of heating operation in which the utilization side heat exchanger (7) is a condenser.

The operation of the on-off valves (26) (27) and the on-off valve (31) is shown in the table below.

Next, the operation of the refrigerating apparatus configured as described above is canceled.

First, during a normal cooling operation, the electromagnetic on-off valve (31) and the electromagnetic on-off valve (27) are closed, the electromagnetic on-off valve (26) is opened, and the liquid injection amount adjusted by the capillary (28) is in operation. The liquid is always injected into the suction chamber (14), and the liquid injection can suppress the rise of the discharge gas temperature. Next, during the cooling operation in the overload state, the on-off valve (31) remains closed, but the discharge gas temperature rises, and the high temperature thermostat (34) attached to the discharge gas pipe (41) outputs. Then, the solenoid on-off valve (27) is opened, and the solenoid on-off valves (26) (2
7) is opened, and the injection amount from the second branch pipe (33) is added to the liquid injection amount from the first branch pipe (32) to increase, and in this case as well, the discharge gas temperature The temperature rise can be suppressed.

Even during the cooling operation in which only the solenoid on-off valve (26) is open, or during the overload operation in which both the solenoid on-off valves (26) and (27) are open, Since the liquid refrigerant injected from the liquid injection pipe (24) does not pass through the motor (1) and is not overheated by the motor (1), the amount of liquid injection is smaller than that of the conventional refrigeration system. It can be used less, avoiding the ability down due to the increase of injection amount, therefore,
The capability can be increased compared to the conventional example.

Furthermore, for example, in the case of cooling the inside of a refrigerator or a refrigerator using the refrigerating apparatus of the present invention, when a thermoswitch (not shown) for keeping the inside temperature at a predetermined temperature operates, the compressor (6) The operation is stopped, but in this case, the electromagnetic on-off valves (26, 27) are closed and the on-off valve (31) is opened. Therefore, by the opening operation of the opening / closing valve (31), the primary side of the liquid injection pipe (24) with respect to the interposed position of the branch pipes (32) (33) causes the suction gas pipe (42) and the pressure equalizing pipe ( Since high pressure liquid refrigerant flows through the accumulator (23) because it communicates with each other and quickly equalizes pressure, each solenoid on-off valve (26) (27) interposed in each branch pipe (32) (33). The primary side pressure immediately drops, and therefore the differential pressure across the on-off valves (26) (27) disappears, and the liquid refrigerant does not leak from the on-off valves (26) (27). As a result, the liquid refrigerant does not accumulate in the suction chamber (14) during the stop of the operation, and the liquid refrigerant is retained even when the compressor (6) is restarted by the operation of the thermoswitch. It is possible to prevent liquid from being inhaled and causing liquid compression.

The tip of the liquid injection pipe (24) is opened in the internal suction pipe (35) communicating with the suction chamber (14). The communication pipe (35) may be provided with a communication pipe or the like for mutual communication, and the communication pipe (35) may be opened.

In addition, the liquid injection pipe (24) is provided with a first and a second.
Although the branch pipes (32) (33) are provided, it is not necessary to branch them.

Further, the refrigeration system shown in FIG. 1 has a four-way switching valve (9).
Although the reverse cycle operation is enabled by providing the above, the present invention can be similarly applied even when the four-way switching valve (9) is not provided.

(Effects of the Invention) As described above, in the refrigeration apparatus according to the present invention,
The compression element (2) is provided with the liquid injection pipe (24) extending from the liquid region and having an electromagnetic opening / closing valve (26, 27) interposed in the middle thereof.
And a pressure equalizing pipe (30) extending from the high-pressure liquid region is connected to the suction pipe (4) downstream of the accumulator (23) interposed in the suction pipe (4). On the other hand, since the on-off valve (31) that is opened when the motor (1) is stopped is provided in the pressure equalizing pipe (30), the liquid refrigerant injected from the liquid injection pipe (24) is overheated by the motor (1). Since the liquid injection can be performed into the suction chamber (14) of the compression element (2) without the need for overheating by the motor (1), the liquid injection amount can be reduced, and therefore the injection amount can be increased. It is possible to suppress the capacity decrease, and to suppress the temperature rise of the discharge gas while increasing the capacity accordingly. Further, when the motor (1) is stopped, the on-off valve (31) provided in the pressure equalizing pipe (30) is opened, and the suction side of the compressor (6) is promptly passed through the pressure equalizing pipe (30). Since the pressure is equalized between the discharge side and the discharge side, it is possible to eliminate the differential pressure across the electromagnetic on-off valve (26, 27) and prevent the liquid refrigerant from leaking from the on-off valve (26, 27). Therefore, when the motor (1) is stopped, the liquid refrigerant is sucked into the suction chamber (1) of the compressor (6).
It does not accumulate in 4), and it is possible to prevent the liquid refrigerant from being sucked and liquid compression occurring at the time of restart.

[Brief description of drawings]

The drawing is a piping system diagram of a refrigerating apparatus to which an embodiment of the present invention is applied. (1) ...... Motor (2) ...... Compression element (5) ...... Closed casing (6) ...... Reciprocating compressor (14) ...... Suction chamber (24) ...... Liquid injection pipe (30) ...... Pressure equalizing pipe (31) …… Open / close valve

Claims (1)

[Claims] 1. A reciprocating compressor (6) in which a motor (1) and a compression element (2) driven by the motor (1) are installed in a casing (5), and the casing (5) is provided. The inhaled gas inhaled from the provided inhalation pipe (4)
In a refrigeration system in which the motor (1) is cooled before being sucked into a suction chamber (14) of the compression element (2), a solenoid on-off valve (26, 27) extending from a high pressure liquid region An accumulator which communicates the liquid injection pipe (24) interposed between the suction chamber (14) of the compression element (2) and the pressure equalizing pipe (30) extending from the high-pressure liquid region with the suction pipe (4). A refrigeration system characterized in that, while being connected to the suction pipe (4) on the downstream side of (23), an on-off valve (31) that is opened in the pressure equalizing pipe (30) when the motor (1) is stopped is interposed.