JPH09303889A - Freezer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent hot gas from flowing into an evaporator due to residual pressure at the time of stopping in operation of a reciprocating type compressor in a freezing cycle using this type of compressor, eliminate a loss of energy and facilitate a re-energization of the compressor. SOLUTION: A first control valve 19 which is opened when a compressor 1 is being operated and closed when the compressor 1 is stopped is arranged between the compressor 1 and a condenser 3, and a second control valve 21 which is opened when the compressor 1 is operated and closed when the compressor 1 is stopped is arranged between the condenser 3 and the throttle device 5. In addition, there is provided a bypassing circuit 25 for preventing a flow of refrigerant from the compressor 1 to the throttle device 5 when the compressor 1 is operated, and for allowing a flow of refrigerant from the compressor 1 to the throttle device 5 when the compressor 1 is stopped in its operation. When operation of the compressor 1 is stopped, the flowing-in of the hot gas into the evaporator 7 is prohibited by the first and second control valves 19, 21 and in turn a discharging side area of the compressor 1 and a sucking side area of the compressor 1 are kept at the same pressure balanced condition with the bypassing circuit 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a refrigerating device including a refrigerating cycle that repeats operation to secure a constant set temperature.

[0002]

2. Description of the Related Art Generally, for example, in a refrigerator,
The refrigerant discharged from the compressor passes through the condenser, the throttle valve, and the evaporator in this order to form a refrigeration cycle that returns to the compressor. The refrigerant flowing through the refrigeration cycle is heat-exchanged in the evaporator through the fins through which air passes. The air cooled by this heat exchange is sent into the refrigerator, and the operation is continued until the temperature inside the refrigerator reaches the lower set temperature. When the lower set temperature is reached, the compressor is stopped, and when the internal cold storage temperature reaches the upper set temperature, the operation is restarted. Hereinafter, this operation / stop will be repeated.

[0003]

During the intermittent operation in which the compressor is repeatedly stopped and operated, immediately after the operation is stopped, the refrigeration cycle basically includes the compressor and the condenser on the discharge side of the compressor. The region is a high pressure region, and the region including the evaporator on the suction side is a low pressure region. At this time, since the throttle valve is lowered, the residual pressure causes high-pressure hot gas from the condenser having a large volume to flow into the evaporator. The evaporator performs its original work by sending low-temperature, low-pressure gas due to the throttle action of the throttle valve, but a large amount of hot hot gas is sent, so the refrigerant temperature inside the evaporator rises. However, there was a problem that led to energy loss.

Therefore, a means for preventing hot gas from flowing into the evaporator is taken by a differential pressure valve when the operation is stopped. This means is only a rotary type compressor and a compressor, and a reciprocating type compressor does not. It was not realized.

To explain this point, as shown in FIG. 5, the refrigeration cycle comprises a compressor 101, a condenser 103, a throttle valve 105 using a capillary tube, and an evaporator 107. The condenser 103 and the throttle valve 105. And a check valve 111 between the compressor 101 and the evaporator 107.

In the compressor 101, as shown in FIG. 6, a roller 117, which is eccentrically rotated by an eccentric shaft 115, and a blade capable of projecting and retracting, which comes into contact with the outer peripheral surface corresponding to the eccentric rotation of the roller 117, in a cylinder 113. The compression chamber 121 is formed by the roller 117 and the compression chamber 121.
The 0 ° eccentric rotation causes the volume to gradually decrease, and has a rotary structure in which the refrigerant taken in from the suction port 123 is compressed and discharged from the discharge port 125 into the closed case 127.

The closed case 127 becomes a high pressure case from the place where high pressure gas is discharged, and the closed case 12
The high-pressure, high-temperature gas in 7 is sent out to the condenser 103 which constitutes the refrigeration cycle via a discharge pipe (not shown).

The cylinder 113 is provided with a thin pressure balance groove 129 so as not to affect the compression, and when the compressor 101 is stopped, the inside of the hermetically sealed case 127 and the cylinder 1 are closed.
The inside of 13 is configured such that the discharge side A and the suction side B are pressure balanced via the pressure balance groove 129.

The pressure balance groove 129 is difficult to start when the pressure on the discharge side A is higher than the pressure on the suction side B when the compressor is restarted. Therefore, the pressure on the discharge side A and the pressure on the suction side B are almost the same. The pressure balance groove 129 can be structurally provided.

On the other hand, the check valve 111 flows in the direction of the arrow only when E on the downstream side and F on the upstream side have a relation of E ≧ F.

The differential pressure valve 109 is controlled to be openable / closeable by a differential pressure with a pressure tap circuit 131 connected to the suction side of the compressor 101. When the differential pressure relationship is B> G, it is open and B <G. G
At that time, it will be controlled to be closed.

Therefore, during operation of the compressor 101, A to C in the drawing are high pressure regions, and D to G are low pressure regions. Therefore, the differential pressure valve 109 is maintained in the open state, and the refrigeration cycle is performed.

Next, when the operation of the compressor 101 is stopped,
A pressure balancer groove 129 provided in the cylinder 113 of the compressor 101 works to balance the pressure with the inside of the high-pressure sealed case 1217, and the pressure of the suction side poit F gradually rises.

As a result, the check valve 111 is closed by the relationship of F> E and the differential pressure valve 109 is closed by the relationship of G> F, so that the hot gas flowing into the evaporator 107 is blocked.

Next, at the time of restart, the pressure balance groove 129
As a result, the points A and F are balanced at almost the same pressure, so that the load on the compressor 111 can be small and no bearing is required for starting. On the other hand, in the reciprocating compressor, as shown in FIG. 7, it is composed of a cylinder 131 and a piston 133 that reciprocates in the 131, and a suction port and a discharge port of the cylinder 131 are provided with suction and discharge. Since the on-off valves 135 and 136 that open and close in accordance with each timing are provided, even if a balance groove connecting the cylinder and the high-pressure case is provided in the high-pressure case, the on-off valve 135 causes the intake port to have a high pressure. Can not lead to. For this reason, in the reciprocating compressor, it is difficult to provide a pressure balance mechanism, and it is not possible to adopt a means using a differential pressure valve unlike the rotary compressor.

In this case, by providing a solenoid valve which opens and closes in response to the stop and operation of the compressor instead of the differential pressure valve, hot gas can be prevented from flowing into the evaporator, but there is no pressure balance mechanism. Therefore, when the compressor is stopped, the discharge side and suction side of the compressor remain separated into high pressure and low pressure. As a result, at the time of restarting, the pressure on the discharge side is high, so that the load is too large, and in some cases, it becomes impossible to start.

[0017] Therefore, an object of the present invention is to provide a refrigeration system which can prevent the inflow of hot gas even if it is a reciprocating compressor, and can surely restart.

[0018]

In order to achieve the above object, the present invention is a refrigeration system in which refrigerant discharged from a reciprocating compressor passes through a condenser, a throttle device, and an evaporator in this order, and then returns to the compressor. Between the compressor and the condenser of the device, a first control valve, which is open when the compressor is in operation and closed when the compressor is stopped, is provided between the condenser and the expansion device. A second control valve is provided which is opened during operation and closed when the compressor is stopped, while blocking the flow of the refrigerant from the compressor to the expansion device during operation of the compressor, and when the compressor is stopped, A bypass circuit for allowing the flow of the refrigerant from the compressor to the expansion device is provided between the first control valve and the compressor, and the second circuit.
It is provided between the control valve and the throttle device.

In a preferred embodiment, the first control valve is opened when the compressor is started after the start of the compressor.

Alternatively, the first control valve causes the refrigerant to flow from the compressor side to the condenser side and to condense only when the pressures on the compressor side and the condenser side are the same or when the pressure on the compressor side is high. When the pressure on the machine side is high, it is a check valve that shuts off the flow of refrigerant from the compressor to the condenser.

Alternatively, the bypass circuit has a circuit configuration using a capillary tube.

In such a refrigeration system, when the compressor is operating, the first and second control valves are kept open and the bypass circuit is kept shut off. Therefore, the refrigerant discharged from the compressor constitutes a refrigeration cycle which passes through the condenser, the expansion device, and the evaporator and returns to the compressor again. In this case, the refrigerant flowing through the evaporator undergoes heat exchange with the air passing through the fins and is gasified, while the air is cooled and sent into the refrigerator,
The operation is continued until the inside temperature reaches the lower set temperature.
When the lower set temperature is reached, the compressor is stopped, and when the internal cold storage temperature reaches the upper set temperature, the operation is restarted. Hereinafter, this operation / stop will be repeated.

On the other hand, when the compressor is stopped, the first and second on-off valves are closed and the bypass circuit is in the cutoff release state.
For this reason, a large amount of hot gas from the condenser with a large volume is blocked, and the hot gas flowing into the evaporator due to the residual pressure is only the volume of the bypass circuit. Will not affect the energy loss.

On the other hand, the bypass circuit functions as a balancer for keeping the discharge side and the suction side of the compressor at the same pressure, and
Since the first on-off valve opens with a slight delay with respect to the restart operation of the compressor, the low-pressure gas is sucked in at the moment of startup and sent out to the same pressure region, and the startup load becomes extremely small. . Further, a simple circuit configuration can be obtained by using the check valve as the second control valve and using the capillary tube as the bypass circuit.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawing of FIG.

In FIG. 1, 1 is a compressor which constitutes a refrigeration cycle, 3 is a condenser, 5 is a throttle device, and 7 is an evaporator.

The compressor 1 is composed of a cylinder having opening and closing valves at the suction port and a discharge port, and a piston that reciprocates in the cylinder. The reciprocating compressor (FIG. See). Compressor 1
Is controlled to be started / stopped by a control unit 9 to be described later during operation, and a high temperature / high pressure gas obtained by taking in and compressing the refrigerant sent into the closed case 11 from the suction port is discharged from the discharge pipe 13. It functions so as to send it directly to the condenser 3 via.

The condenser 3 is provided with a large number of cooling fins (none of which are shown) on a pipe through which the refrigerant flows, and also has a condensing fan 15 for passing cooling air between the fins. There is. When the condensing fan 15 is rotated, air flows between the fins, so that heat is exchanged with the high-temperature and high-pressure gas flowing in the pipe.
It functions to liquefy high pressure refrigerant gas.

The expansion device 5 is a capillary tube and functions so that the refrigerant becomes a low-temperature low-pressure gas by the expansion action when passing.

The evaporator 7 is provided with a large number of cooling fins (none of which are shown) on a pipe through which the refrigerant flows, and also has an evaporation fan 17 for passing air between the fins. . The evaporation fan 17 functions to gasify the refrigerant by flowing air between the fins by rotation.

On the other hand, between the compressor 1 and the condenser 3, a first control valve 19 for securing or blocking the flow of the refrigerant from the compressor 1 is provided between the condenser 3 and the expansion device 5. Is the condenser 3
To secure or block the flow of the refrigerant from the expansion device 5 to the expansion device 5
The respective control valves 21 are provided. Further, between the discharge side of the compressor 1 and the first control valve 19, and between the second control valve 2
1 and the expansion device 5 are connected and communicated with each other by a bypass circuit 25 having a third control valve 23, and the first, second and third control valves 19, 21, 23 are controlled by the control unit 9 to be openable and closable. It is a solenoid valve.

The control unit 9 receives the detection signal from the temperature detection sensor 29 provided in the inside 27, so that, for example, if the inside temperature does not reach the set temperature, the first and second The control valves 19 and 21 are opened, the third control valve 23 is closed,
Further, while outputting a signal for continuing the operation of the compressor 1, when the set temperature is reached, the compressor 1 is stopped, the first and second control valves 19 and 21 are closed, and the third control is performed. A signal for opening the valve 23 is output. Further, when the temperature of the interior 27 rises and the compressor 1 is restarted, it functions to output a signal that opens the first control valve 19 with a delay due to the startup of the compressor 1.

According to the refrigerating apparatus thus constructed,
During the operation of the compressor 1, the first and second control valves 19 and 21 are kept open and the third control valve 23 is kept closed. Therefore, the refrigerant discharged from the compressor 1 is
A refrigeration cycle that passes through the expansion device 5 and the evaporator 7 and returns to the compressor 1 again is configured. During this operation, heat is exchanged by passing air between the fins by the evaporation fan 17 in the evaporator 7. With this heat exchange,
The air is cooled. The cooled air is sent to the inside 37, and the operation of the compressor 1 is continued until the inside 27 reaches the lower set temperature.

When the temperature detection sensor 29 detects that the internal temperature has reached the lower set temperature, the detection signal is input to the control unit 9.

The control unit 9 controls the compressor 1 based on the detection signal.
Is stopped, the first and second control valves 19 and 21 are closed, and the third control valve 23 is opened. As a result, a large amount of hot gas from the condenser 3 is blocked by the second control valve 21, and the high temperature hot gas flowing into the evaporator 7 due to the residual pressure becomes a small volume of the bypass circuit 25. Energy loss can be suppressed without greatly affecting the temperature of the refrigerant in the evaporator 7. At this time, the compressor 1
On the discharge side and the suction side, a circuit that is balanced to the same pressure via the bypass circuit 25 is configured as shown by the dotted arrow.

Next, when the compressor 1 is restarted, the first control valve 19 is opened with a delay, so at the moment of starting, low-pressure gas is sucked and sent out to the same pressure region, and the starting load is small. Will be completed. After startup, the first control valve 1
9 opens with a delay, and gas is fed into the high pressure region including the condenser 3, but at this time, since the rotating portion of the compressor 1 has already obtained inertial force, there is no hindrance to the operation. .

FIG. 2 shows another embodiment of the bypass circuit 25 and the first control valve 19.

That is, the bypass circuit 25 has a circuit structure using the capillary tube 31, while the first control valve 19 is a check valve 33. The check valve 33 has the same pressure P1 and P2 on the compressor 1 side and the condenser 3 side (P1 = P2), or
Alternatively, only when the pressure on the compressor 1 side is high (P1> P2), the flow of the refrigerant is secured from the compressor 1 side to the condenser 3 side, and when the pressure on the condenser 3 side is high (P2> P1). Is designed to block the flow of the refrigerant from the compressor 1 to the condenser 3.

Since the other components are the same as those in FIG. 1,
The same reference numerals are given and the detailed description is omitted.

Therefore, according to the refrigerating apparatus thus constructed, when the compressor 1 is in operation, the second control valve 21 is open, and the check valve 33 has a pressure relationship of P1> P2 so that the refrigerant flows in the arrow direction. The refrigerant discharged from the compressor 1 flows through the condenser 3, the expansion device 5, and the evaporator 7 and then returns to the compressor 1 in the refrigeration cycle. In this case, since the bypass circuit 25 has a large resistance due to the capillary tube 31, the amount of the refrigerant flowing is smaller than that on the cycle side and does not affect the refrigeration cycle.

On the other hand, during operation, in the evaporator 7, heat is exchanged by passing air between the fins by the evaporation fan 17. By this heat exchange, the air is cooled, and the cooled air is sent to the inside 27 of the refrigerator,
The operation of the compressor 1 is continued until the inside 27 reaches the lower set temperature.

When the temperature detection sensor 29 detects that the internal temperature has reached the lower set temperature, the detection signal is input to the control unit 9.

The control unit 9 controls the compressor 1 based on the detection signal.
Is stopped and the second control valve 21 is closed. At the same time, the flow of the check valve 33 is shut off due to the discharge pressure relationship (P2> P1). As a result, a large amount of hot gas from the condenser 3 is blocked by the second control valve 21, and the high temperature hot gas flowing into the evaporator 7 due to the residual pressure becomes a small volume of the bypass circuit 25. Energy loss can be suppressed without greatly affecting the temperature of the refrigerant in the evaporator 7. At this time, the discharge side and the suction side of the compressor 1 are configured to have a circuit in which the pressure is balanced via the bypass circuit 25 as shown by the dotted arrow.

Next, when the compressor 1 is restarted, the low-pressure gas is sucked in and sent out to the same pressure region at the moment of starting, so that the starting load can be reduced. After the start-up operation, the check valve 33 ensures a flow in the direction of the arrow due to the relation of the discharge pressure of P1> P2, and sends the gas into the high pressure region including the condenser 3, but at this time, the check valve 33 is already in the compressor 1. Since the rotating part has an inertial force, there is no bearing for driving.
Further, since the first control valve is a check valve and the capillary tube is used in the bypass circuit, the circuit configuration is simplified.

[0045]

As described above, according to the refrigerating apparatus of the present invention, in the reciprocating compressor, the hot gas can be prevented from flowing into the evaporator, so that energy loss can be suppressed. Further, the bypass circuit allows the compressor to be restarted without any trouble.

Further, the bypass circuit using the check valve and the capillary tube has an advantage that the circuit structure can be simplified.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a refrigeration cycle according to the present invention.

FIG. 2 is an explanatory view showing a refrigeration cycle of another embodiment.

FIG. 3 is an explanatory diagram of a refrigeration cycle using a conventional rotary compressor.

FIG. 4 is an explanatory diagram of a conventional rotary compressor.

FIG. 5 is an explanatory diagram of a conventional reciprocating compressor.

[Explanation of symbols]

 1 Compressor 3 Condenser 5 Throttling device 7 Evaporator 19 First control valve 21 Second control valve 25 Bypass circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Atsushi Kusunoki 8 Shinshinsita-cho, Isogo-ku, Yokohama-shi, Kanagawa Kanagawa Prefectural Housing and Space Systems Engineering Laboratory (72) Inventor Keiaki Asakura 3-3 Shinbashi, Minato-ku, Tokyo No. 9 In Toshiba A & V Co., Ltd. (72) Inventor Koji Tsukuni 3-3-9 Shimbashi, Minato-ku, Tokyo Within Toshiba A & V E. Co., Ltd.

Claims (4)

[Claims] 1. A refrigerant discharged from a reciprocating compressor passes through a condenser, a throttling device, and an evaporator in this order, and then returns to the compressor. A first control valve, which is open during operation and closed when the compressor is stopped, is provided between the condenser and the expansion device, and a second control valve which is open during operation of the compressor and closed when the compressor is stopped. While each control valve is provided, the bypass circuit that blocks the flow of the refrigerant from the compressor to the expansion device during operation of the compressor and allows the flow of the refrigerant from the compressor to the expansion device when the compressor is stopped is described above. Between the first control valve and the compressor, and the second
A refrigerating apparatus provided between the control valve and the expansion device. 2. The refrigerating apparatus according to claim 1, wherein the first control valve opens when the compressor is started, after the start of the compressor. 3. The first control valve allows the refrigerant to flow from the compressor side to the condenser side and to condense only when the pressures on the compressor side and the condenser side are the same or when the pressure on the compressor side is high. The refrigeration system according to claim 1, wherein the refrigeration apparatus is a check valve that blocks the flow of the refrigerant from the compressor to the condenser when the pressure on the machine side is high. 4. The refrigerating apparatus according to claim 1, wherein the bypass circuit has a circuit configuration using a capillary tube.