JPH0481712B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat pump type cooling device in which a compressor for operating a refrigeration cycle is driven by an engine.

[Prior Art] Conventionally, this type of heat pump type cooling device has an engine 1 as a driving source, as shown in FIG. is driven, and the refrigerant compressor 3 compresses the refrigerant. The refrigerant discharged from the refrigerant compressor 3 is input into the refrigerant suction port of the four-way switching valve 4 . The four-way switching valve 4 is for switching between cooling cycle operation and defrosting cycle operation. A first connection port of the four-way switching valve 4 is connected to one refrigerant port of the external heat exchanger 5. The external heat exchanger 5 functions as a condenser during the cooling cycle operation and as an evaporator during the defrosting cycle operation. A second connection port of the four-way switching valve 4 is connected to one refrigerant port of the internal heat exchanger 6. The internal heat exchanger 6 functions as an evaporator during cooling cycle operation and as a condenser during defrosting cycle operation. The internal heat exchanger 6 is provided inside a refrigerator, a cold storage case, or the like. During the cooling cycle operation, the refrigerant condensed by the external heat exchanger 5 enters the first expansion valve 8 from the other refrigerant port via the first check valve 7, and then enters the first expansion valve 8 through the first check valve 7. After being expanded at step 8, the refrigerant is input to the other refrigerant port of the internal heat exchanger 6. On the other hand, during the defrosting cycle operation, the refrigerant condensed by the internal heat exchanger 6 is expanded from the other refrigerant port via the second check valve 9 at the second expansion valve 10. The refrigerant is input to the other refrigerant port of the external heat exchanger 5. Note that 11 is a condenser fan for the external heat exchanger 5, and 12 is a cooling fan for the internal heat exchanger 6.

In such a configuration, during cooling cycle operation, the high temperature and high pressure gaseous refrigerant discharged from the compressor 3 driven by the engine 1 passes through the four-way switching valve 4 as shown by the solid arrow in the figure. It is sent to the external heat exchanger 5. The outside heat exchanger 5 is
Condenses high-temperature, high-pressure gaseous refrigerant into high-pressure liquid refrigerant. This high pressure liquid refrigerant flows through the first check valve 7
The refrigerant is guided to the first expansion valve 8 through the refrigerant, where it is adiabatically expanded and becomes a low-pressure liquid refrigerant. This low-pressure liquid refrigerant is guided to the internal heat exchanger 6, where it evaporates and becomes a gaseous refrigerant. This gaseous refrigerant is sucked into the refrigerant compressor 3 via the four-way switching valve 4, where it is compressed to become the high-temperature, high-pressure gaseous refrigerant. Hereafter, the same action is repeated again.

On the other hand, during the defrosting cycle operation, the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 3 driven by the engine 1 passes through the four-way switching valve 4 to heat up the interior of the refrigerator, as shown by the dashed arrow in the figure. It is sent to the exchanger 6. The internal heat exchanger 6 condenses the high-temperature, high-pressure gaseous refrigerant into high-pressure liquid refrigerant. At this time,
Melt the frost on the outer periphery of the internal heat exchanger 6,
The melted frost becomes water and collects on a drain pan (not shown) provided at the bottom of the internal heat exchanger 6.
This accumulated water is led out of the refrigerator through a drain hole (not shown) made in the drain pan and a drain hose (not shown). On the other hand, the high-pressure liquid refrigerant condensed in the internal heat exchanger 6 is guided to the second expansion valve 10 via the second check valve 9, where it is adiabatically expanded and becomes a low-temperature liquid refrigerant. At this time, a defrosting device such as a defrosting pipe (not shown) for defrosting the drain pan is connected after the second check valve 9, and the air is connected to the second expansion valve 10 via this defrosting pipe. You can also guide them. The low-temperature liquid refrigerant is guided to the external heat exchanger 5, where it evaporates and becomes a gaseous refrigerant. This gaseous refrigerant is sucked into the refrigerant compressor 3 via the four-way switching valve 4, where it is compressed to become the high-temperature, high-pressure gaseous refrigerant. Hereafter, the same action is repeated again.

[Problems to be Solved by the Invention] By the way, in the conventional heat pump type cooling device having such a configuration, when the rotational speed of the engine 1 increases when the outside air temperature is high, during the cooling cycle operation and the defrosting cycle operation, At the same time, the temperature of the gaseous refrigerant discharged from the refrigerant compressor 3 increases significantly. Therefore,
There is a problem that the refrigerant compressor 3 and the refrigerant hose for connecting the refrigerant compressor 3 and the four-way switching valve 4 are damaged due to overheating operation. Here, the main causes of the increase in the temperature of the gaseous refrigerant discharged from the refrigerant compressor 3 are the increase in the rotation speed of the engine 1 (the rotation speed of the refrigerant compressor 3) and the increase in outside air temperature, as described above. In addition, there are also effects from heat exchange between the discharged gaseous refrigerant and the intake gaseous refrigerant at the four-way switching valve 4, and heat generated by the engine 1 when the refrigerant compressor 3 is attached to the engine 1 with a fitting.

In addition, the internal heat exchanger 6 due to the defrosting cycle operation
As mentioned above, the defrosting of
This is done by melting the frost on the outer periphery of the internal heat exchanger 6 by flowing . In such a hot gas defrosting method, the low temperature liquid refrigerant condensed in the internal heat exchanger 6 is used to defrost the drain pan of the internal heat exchanger 6, which is installed behind the second check valve 9. There is a problem that the defrosting performance of the drain pan decreases, and water that collects on the drain pan freezes at the bottom of the drain pan and around the drain hole drilled in the drain pan.

Therefore, an object of the present invention is to provide a heat pump type cooling device that can prevent overheating of a refrigerant compressor and prevent damage to the refrigerant compressor, refrigerant hose, etc.

Another object of the present invention is to provide a heat pump type cooling device that can significantly improve the defrosting performance of the drain pan section of the internal heat exchanger.

[Means for Solving the Problems] According to the present invention, during cooling cycle operation, the refrigerant discharged from the compressor driven by the engine is transferred to the four-way switching valve, the external heat exchanger, the expansion means, and the internal heat. The refrigerant is returned to the refrigerant inlet of the compressor via the exchanger and the four-way switching valve, and during the defrosting cycle operation, the refrigerant discharged from the compressor is transferred to the four-way switching valve, the internal heat exchanger, the expansion means, and the Temperature detection means for detecting the temperature of refrigerant discharged from the compressor in a heat pump type cooling device configured to return to the refrigerant inlet of the compressor via the external heat exchanger and the four-way switching valve. , a first bypass path that bypasses the external heat exchanger, a second bypass path that bypasses the internal heat exchanger, and a first bypass path provided in the first and second bypass paths, respectively. and a second control valve, which controls the opening and closing of the second control valve based on the detected temperature detected by the temperature detection means during the cooling cycle operation, and controls the temperature detection during the defrosting cycle operation. A heat pump type cooling device is obtained, characterized in that the temperature of the refrigerant discharged from the compressor is controlled by controlling the opening and closing of the first control valve based on the detected temperature detected by the means. .

Further, according to the present invention, during cooling cycle operation, the refrigerant discharged from the compressor driven by the engine passes through the four-way switching valve, the external heat exchanger, the expansion means, the internal heat exchanger, and the four-way switching valve. During the defrosting cycle operation, the refrigerant discharged from the compressor is returned to the refrigerant inlet of the compressor through the four-way switching valve, the internal heat exchanger, the expansion means, the external heat exchanger, and the external heat exchanger. The refrigerant is returned to the refrigerant suction port of the compressor via a four-way switching valve, and during the defrosting cycle operation, the frost attached to the outer periphery of the internal heat exchanger is melted, and the melted frost is removed from the drain pan. Receive it, guide it to the outside of the refrigerator via the drain hose from the drain hole drilled in the drain pan, and into the drain pan,
In a heat pump type cooling device that is inserted between the internal heat exchanger and the expansion means, and is provided with a defrosting means for defrosting the drain pan,
temperature detection means for detecting the temperature of the refrigerant discharged from the compressor; a first bypass path that bypasses the external heat exchanger; and a second bypass path that bypasses the internal heat exchanger; and first and second control valves provided in the first and second bypass paths, respectively, and the second control valve is configured to control the second control valve based on the detected temperature detected by the temperature detection means during the cooling cycle operation. The temperature of the refrigerant discharged from the compressor is controlled by controlling the opening and closing of the control valve and controlling the opening and closing of the first control valve based on the detected temperature detected by the temperature detection means during the defrosting cycle operation. and controlling the opening and closing of the second control valve based on the detected temperature detected by the temperature detection means during the defrosting cycle operation, thereby improving the defrosting performance of the drain pan. A heat pump type cooling device is obtained.

[Examples] Examples of the present invention will be described below with reference to the drawings.

Referring to FIG. 1, a heat pump type cooling device according to a first embodiment of the present invention is shown, and the same components as in FIG. 12 are denoted by the same reference numerals and explanations thereof will be omitted.

In this embodiment, a first sensor is provided on the refrigerant discharge port side of the refrigerant compressor 3 for detecting (sensing) the temperature of the discharged refrigerant.
and second temperature sensors 21 and 22 are provided. A first bypass path 26 that bypasses the external heat exchanger 5 is connected to the refrigerant inlet/outlet of the external heat exchanger 5, and a refrigerant inlet/outlet of the internal heat exchanger 6 is connected to the refrigerant inlet/outlet of the internal heat exchanger 5. A second bypass path 27 that bypasses 6 is connected. First and second control valves (electromagnetic valves) 31 and 32 are provided in the first and second bypass paths 26 and 27, respectively.

The first temperature sensor 21 is connected to the four-way switching valve 4 and the first electromagnetic valve 31 via a first control cord 36 . The first temperature sensor 21 is activated when the four-way switching valve 4 switches to the defrost cycle operation, and the temperature of the refrigerant discharged from the refrigerant compressor 3 exceeds a preset first temperature. When the temperature of the refrigerant discharged from the refrigerant compressor 3 becomes equal to or lower than the first set temperature, the control signal is sent to the first solenoid valve 31 as a control signal. A first closing control signal is sent to the first electromagnetic valve 31 as follows. The first solenoid valve 31 opens when receiving the first open control signal, and closes when receiving the first close control signal.

Further, the second temperature sensor 22 is connected to the cooling fan 12 by the second control cord 37.
It is connected to the solenoid valve 32 of. The second temperature sensor 22 is activated when the cooling motor 12 is turned on during cooling cycle operation, and the temperature of the refrigerant discharged from the refrigerant compressor 3 is set in advance.
When the temperature exceeds the set temperature, the second control signal is sent.
An opening control signal is sent to the second electromagnetic valve 32, and the temperature of the refrigerant discharged from the refrigerant compressor 3 is set in advance.
When the temperature drops below the set temperature, the second control signal is sent.
A closing control signal is sent to the second solenoid valve 32. The second electromagnetic valve 32 opens when it receives the second open control signal, and closes when it receives the second close control signal.

Next, the operation of the first embodiment will be explained with reference to FIG. 2 as well.

During cooling cycle operation, when the cooling fan 12 is turned on, the second temperature sensor 22 is energized and becomes operational. However, since the four-way switching valve 4 remains in the off state, the first temperature sensor 21 is not energized and is in a non-operating state. Therefore, during the cooling cycle operation, the second electromagnetic valve 32 is controlled to open and close by the second temperature sensor 22. Normally, during the cooling cycle operation, the amount of refrigerant required for cooling is adiabatically expanded by the first expansion valve 8 and then supplied to the internal heat exchanger 6 . However, when the rotational speed of the engine 1 (refrigerant compressor 3) increases or the outside air temperature increases, the temperature of the refrigerant discharged from the refrigerant compressor 3 becomes higher than the second set temperature.
At this time, the second temperature sensor 22 sends out a second opening control signal to the second solenoid valve 32 to open the second solenoid valve 3.
Open 2. As a result, low-temperature gaseous refrigerant that does not absorb heat in the internal heat exchanger 6 is supplied to the suction port of the refrigerant compressor 3 via the four-way switching valve 4, and the temperature of the refrigerant discharged from the refrigerant compressor 3 can be lowered. can. As a result, the temperature of the refrigerant discharged from the refrigerant compressor 3 gradually decreases. When the temperature of the refrigerant discharged from the refrigerant compressor 3 becomes lower than the second set temperature, the second temperature sensor 22 sends a second closing control signal to the second solenoid valve 32 to close the second solenoid valve 32. . As a result, the high temperature gaseous refrigerant that has absorbed heat in the internal heat exchanger 6 is supplied to the suction port of the refrigerant compressor 3 via the four-way switching valve 4, and the temperature of the refrigerant discharged from the refrigerant compressor 3 can be increased. can. In this way, during the cooling cycle operation, the second temperature sensor 22 senses the temperature of the refrigerant discharged from the refrigerant compressor 3, and the second solenoid valve 32 is controlled to open and close, thereby adjusting the engine 1 rotation speed and the outside air temperature. By supplying a gaseous refrigerant depending on the temperature to the suction port of the refrigerant compressor 3, the temperature of the refrigerant discharged from the refrigerant compressor 3 can be controlled so as to always be around the second set temperature.

On the other hand, when the cooling fan 12 is turned off during the defrosting cycle operation, the second temperature sensor 22
energization is stopped, and the second temperature sensor 22 becomes inactive. On the contrary, the four-way switching valve 4 is turned on, and the first temperature sensor 21 is energized and becomes operational. Therefore, during the defrost cycle operation, the first
The opening and closing of the first electromagnetic valve 31 is controlled by the temperature sensor 21 . Normally, during the defrosting cycle operation, the amount of refrigerant necessary for defrosting the internal heat exchanger 6 is adiabatically expanded by the second expansion valve 10, and the refrigerant is supplied to the external heat exchanger 5. However, when the rotational speed of the engine 1 (refrigerant compressor 3) increases or the outside temperature increases, the temperature of the refrigerant discharged from the refrigerant compressor 3 becomes
becomes higher than the set temperature. At this time, the first temperature sensor 21 sends the first open control signal to the first solenoid valve 3.
1, and the first solenoid valve 31 is opened. As a result, low-temperature gaseous refrigerant that does not absorb heat in the external heat exchanger 5 is supplied to the suction port of the refrigerant compressor 3 via the four-way switching valve 4, and the temperature of the refrigerant discharged from the refrigerant compressor 3 can be lowered. can. As a result, the temperature of the refrigerant discharged from the refrigerant compressor 3 gradually decreases. When the temperature of the refrigerant discharged from the refrigerant compressor 3 becomes lower than the first set temperature, the first temperature sensor 21 sends a first closing control signal to the first electromagnetic valve 31 .
Close. As a result, the high-temperature gaseous refrigerant that has absorbed heat in the external heat exchanger 5 is supplied to the suction port of the refrigerant compressor 3 via the four-way switching valve 4.
The temperature of the discharged refrigerant can be increased. In this way, during the defrosting cycle operation, the first temperature sensor 21 senses the temperature of the refrigerant discharged from the refrigerant compressor 3,
By controlling the opening and closing of the first electromagnetic valve 31, gaseous refrigerant is supplied to the suction port of the refrigerant compressor 3 according to the rotational speed of the engine 1 and outside temperature, and the temperature of the refrigerant discharged from the refrigerant compressor 3 is controlled. It is possible to control the temperature so that it is always near the first set temperature.

Referring to FIG. 3, a heat pump type cooling device according to a second embodiment of the present invention is shown, and the same components as in FIG.

In this embodiment, a temperature sensor 2 is provided on the refrigerant discharge port side of the refrigerant compressor 3 to sense the temperature of the discharged refrigerant.
0 is set. First bypass path 26a
is the external heat exchanger 5, the first check valve 7, and the second
The expansion valve 10 is bypassed. The second bypass path 27a bypasses the internal heat exchanger 6, the second check valve 9, and the first expansion valve 8. The first bypass path 26a is provided with a first solenoid valve 31 and a first capillary 41, and the second bypass path 27a is provided with a second solenoid valve 32 and a second capillary 42. There is. Temperature sensor 2
0 is connected to a relay 45, and the relay 45 is connected to the first and second solenoid valves 31 and 32 via first and second control cords 36 and 37, respectively.

The temperature sensor 20 is connected to a clutch (not shown) of the refrigerant compressor 3, and becomes operational when the heat pump cooling device is in operation.
When the temperature of the refrigerant discharged from the refrigerant compressor 3 exceeds a preset temperature, an open control signal is sent to the relay 45 as a control signal, and the temperature of the refrigerant discharged from the refrigerant compressor 3 is set to the preset temperature. When the temperature drops below the temperature, a close control signal is sent to the relay 45 as a control signal. Relay 45 is connected to four-way switching valve 4, and supplies control signals from temperature sensor 20 to first and second solenoid valves 31 and 32, respectively, depending on whether defrosting cycle operation or cooling cycle operation is performed. The first solenoid valve 31 opens upon receiving an opening control signal;
Closes when receiving a close control signal. Similarly, the second solenoid valve 32 opens when it receives an open control signal, and closes when it receives a close control signal.

Next, the operation of the second embodiment will be explained with reference to FIG. 4 as well.

During operation of the heat pump cooling system, when the clutch of the refrigerant compressor 3 is turned on, the temperature sensor 20 is energized and becomes operational.

During the cooling cycle operation, the four-way switching valve 4 remains in the OFF state, so no current flows through the coil of the relay 45, and its contacts are in the OFF state. Therefore, the temperature sensor 20 is connected to the second solenoid valve 32 via the relay 45, and the second solenoid valve 32 is controlled to open and close by the temperature sensor 20. Normally, during cooling cycle operation, the amount of refrigerant required for cooling is adiabatically expanded by the first expansion valve 8 and transferred to the internal heat exchanger 6.
is supplied to. However, when the rotational speed of the engine 1 increases or the outside air temperature increases, the temperature of the refrigerant discharged from the refrigerant compressor 3 becomes higher than the set temperature. At this time, the temperature sensor 20 sends an open control signal to the second electromagnetic valve 32 via the relay 45.
Open the solenoid valve 32. Thereby, the refrigerant sent through the first check valve 7 is depressurized in the second capillary 42, and then supplied to the suction port of the refrigerant compressor 3 via the four-way switching valve 4, and the refrigerant The temperature of the refrigerant discharged from the compressor 3 can be lowered. As a result, the temperature of the refrigerant discharged from the refrigerant compressor 3 gradually decreases. When the temperature of the refrigerant discharged from the refrigerant compressor 3 becomes lower than the set temperature, the temperature sensor 20 sends a close control signal to the second solenoid valve 32 via the relay 45 to close the second solenoid valve 32 . As a result, the high temperature gaseous refrigerant that has absorbed heat in the internal heat exchanger 6 is supplied to the suction port of the refrigerant compressor 3 via the four-way switching valve 4, and the temperature of the refrigerant discharged from the refrigerant compressor 3 can be raised. . In this manner, during the cooling cycle operation, the temperature of the refrigerant discharged from the refrigerant compressor 3 is sensed by the temperature sensor 20, as in the first embodiment described above.
By controlling the opening and closing of the second electromagnetic valve 32, gaseous refrigerant is supplied to the suction port of the refrigerant compressor 3 according to the rotation speed of the engine 1 and the outside temperature, and the temperature of the refrigerant discharged from the refrigerant compressor 3 is controlled. It is possible to control the temperature so that it is always around the set temperature.

On the other hand, during the defrosting cycle operation, the four-way switching valve 4 is turned on, and current flows through the coil of the relay 45, so that its contacts are turned on. Therefore,
The temperature sensor 20 is connected to the first solenoid valve 31 via a relay 45, and the first solenoid valve 31 is controlled to open and close by the temperature sensor 20. Normally, during the defrosting cycle operation, the amount of refrigerant necessary for defrosting the internal heat exchanger 6 is adiabatically expanded by the second expansion valve 10, and the refrigerant is supplied to the external heat exchanger 5. however,
When the rotational speed of the engine 1 increases or the outside air temperature increases, the temperature of the refrigerant discharged from the refrigerant compressor 3 becomes higher than the set temperature. At this time, the temperature sensor 20 sends an opening control signal to the first solenoid valve 3 via the relay 45.
1, and the first solenoid valve 31 is opened. Thereby, the refrigerant sent through the second check valve 9 is depressurized in the first capillary 41, and then supplied to the suction port of the refrigerant compressor 3 via the four-way switching valve 4, and the refrigerant is The temperature of the refrigerant discharged from the compressor 3 can be lowered. As a result, the temperature of the refrigerant discharged from the refrigerant compressor 3 gradually decreases. When the temperature of the refrigerant discharged from the refrigerant compressor 3 becomes lower than the set temperature, the temperature sensor 20 sends a close control signal to the first solenoid valve 31 via the relay 45 to close the first solenoid valve 31 .
As a result, the high temperature gaseous refrigerant that has absorbed heat in the external heat exchanger 5 is supplied to the suction port of the refrigerant compressor 3 via the four-way switching valve 4, and the temperature of the refrigerant discharged from the refrigerant compressor 3 can be raised. . In this manner, during the defrosting cycle operation, the temperature sensor 20 senses the temperature of the refrigerant discharged from the refrigerant compressor 3, and the opening/closing of the first electromagnetic valve 31 is controlled, as in the first embodiment described above. By supplying gaseous refrigerant to the suction port of the refrigerant compressor 3 according to the rotational speed of the engine 1 and the outside air temperature, the temperature of the refrigerant discharged from the refrigerant compressor 3 is controlled so as to always be around the set temperature. I can do it.

Referring to FIGS. 5 and 6, the third embodiment of the present invention
A heat pump type cooling device according to an embodiment is shown, in which the same components as in FIG.

First, referring to FIG. 5, in this embodiment, the second
The temperature sensor 22a is connected to a relay 45a, and the relay 45a is connected to the cooling fan 12.
and the clutch of the refrigerant compressor 3.
During cooling cycle operation, the second temperature sensor 22
a is under the switching control of relay 45a.
Similarly to the embodiment, when the temperature of the refrigerant discharged from the refrigerant compressor 3 exceeds the second set temperature, a second open control signal is sent to the second solenoid valve 32 as a control signal, and the refrigerant is compressed. When the temperature of the refrigerant discharged from the machine 3 becomes equal to or lower than the second set temperature, a second closing control signal is sent to the second solenoid valve 32 as a control signal. On the other hand, during the defrosting cycle operation, the second temperature sensor 22a
Under the switching control of the relay 45a, when the temperature of the refrigerant discharged from the refrigerant compressor 3 exceeds the second set temperature, a third closing control signal is sent to the second solenoid valve 32 as a control signal. However, when the temperature of the refrigerant discharged from the refrigerant compressor 3 becomes equal to or lower than the second set temperature, a third opening control signal is sent to the second electromagnetic valve 32 as a control signal. The second electromagnetic valve 32 opens when receiving the second or third open control signal, and closes when receiving the second or third close control signal.

Referring to FIG. 6, a drain pan 51 is provided at the bottom of the internal heat exchanger 6, and the frost attached to the outer periphery of the internal heat exchanger 6 melts and falls during the defrosting cycle operation. This drain pan 51
I accept it. The water collected in this drain pan 51 is
Drain hose 52 from the drain hole drilled in it.
is guided outside the warehouse via the Also, drain pan 51
A defrost pipe 53 for defrosting is disposed in the defrost pipe 53, and during the defrost cycle operation, the refrigerant that has passed through the internal heat exchanger 6 is passed through the second check valve 9 to this defrost pipe. 53 is passed through.

In this embodiment, the second bypass path 27b that bypasses the internal heat exchanger 6 is connected to the cooling fan 1.
around the fan shield 12a of No. 2 (Fig. 7),
The refrigerant is disposed so as to pass through the drain hole portion (FIG. 8) of the drain pan 51, and during the defrosting cycle operation, the high-temperature refrigerant flows through the second bypass passage 27b to prevent freezing A around the fan shield 12a. This prevents freezing B of the drain hole portion of the drain pan 51.

Next, the operation of the third embodiment will be explained with reference to FIG. 9 as well.

During cooling cycle operation, when the cooling fan 12 is turned on, the relay 45a is turned on. Therefore, the second temperature sensor 22a is in the on state, that is, the temperature of the refrigerant discharged from the refrigerant compressor 3 is the second temperature sensor.
When the temperature reaches the set temperature or higher, a second opening control signal is sent to the second solenoid valve 32. Further, the second temperature sensor 22a is in the off state, that is, the refrigerant compressor 3
When the temperature of the discharged refrigerant becomes equal to or lower than the second set temperature, a second closing control signal is sent to the second solenoid valve 32. Since the four-way switching valve 4 remains in the off state, the first temperature sensor 21 is in a non-operating state. Therefore, during the cooling cycle operation, the opening and closing of the second solenoid valve 32 is controlled by the second temperature sensor 22a. A detailed explanation of the operation during this cooling cycle operation will be omitted since it is the same as that of the first embodiment described above.

On the other hand, when the cooling fan 12 is turned off during the defrosting cycle operation, the relay 45a is turned off. Therefore, the second temperature sensor 22a is
When in the on state, a third close control signal is sent to the second solenoid valve 32, and when in the off state, a third open control signal is sent to the second solenoid valve 32. Also, since the four-way switching valve 4 is in the on state, the first temperature sensor 21
becomes operational. Therefore, during the defrosting cycle operation, the first temperature sensor 21 controls the first solenoid valve 3.
1 is controlled to open and close, and the second temperature sensor 2
The opening and closing of the second electromagnetic valve 32 is controlled by 2a.
A detailed explanation of the opening/closing control of the first electromagnetic valve 31 by the first temperature sensor 21 in this defrosting cycle operation is omitted because it is the same as that of the first embodiment described above. Next, the second solenoid valve 32 is activated by the second temperature sensor 22a during the defrosting cycle operation.
The opening/closing control operation will be explained in detail.

In the defrosting cycle operation, when the temperature of the refrigerant discharged from the refrigerant compressor 3 is equal to or higher than the second set temperature,
Since the second temperature sensor 22a is in the on state,
The second temperature sensor 22a sends a third closing control signal to the second solenoid valve 32 to close the second solenoid valve 32. Therefore, the refrigerant discharged from the refrigerant compressor 3 is passed through the four-way switching valve 4 to the internal heat exchanger 6 as hot gas.
The frost attached to the outer periphery of the internal heat exchanger 6 melts and falls onto the drain pan 51, and is led out of the refrigerator through the drain hole and the drain hose 52.
In this state, it is assumed that the temperature of the refrigerant discharged from the refrigerant compressor 3 becomes equal to or lower than the second set temperature. At this time, the second temperature sensor 22a is in the off state, so the second temperature sensor 22a sends the third opening control signal to the second solenoid valve 32, and the second temperature sensor 22a
open. Thereby, the refrigerant discharged from the refrigerant compressor 3 is supplied as hot gas to the second bypass passage 27b via the four-way switching valve 4, and then supplied to the defrosting bypass via the second check valve 9. Thereby, freezing A around the fan shield 12a and freezing B in the drain hole portion of the drain pan 51 can be prevented, and the defrosting efficiency of the drain pan 51 can be improved.

Referring to FIG. 10, a heat pump type cooling device according to a fourth embodiment of the present invention is shown,
Components that are the same as those in FIG. 5 are given the same reference numerals and their explanations will be omitted.

In this embodiment, the relay 45b is connected to the four-way switching valve 4 and the clutch of the refrigerant compressor 3.
The temperature sensor 22b is connected to a relay 45c and a clutch of the refrigerant compressor 3.
is connected to the relay 45b and the solenoid valve 32. During the cooling cycle operation, the second temperature sensor 22b detects the refrigerant compressor 3 under switching control of the relays 45b and 45c, as in the first embodiment.
When the temperature of the refrigerant discharged from the refrigerant compressor 3 becomes equal to or higher than the second set temperature, a second open control signal is sent to the second solenoid valve 32 as a control signal, and the temperature of the refrigerant discharged from the refrigerant compressor 3 reaches the second set temperature. When the temperature falls below the set temperature, a second close control signal is sent to the second solenoid valve 32 as a control signal. On the other hand, during the defrosting cycle operation, the second temperature sensor 22b detects that the temperature of the refrigerant discharged from the refrigerant compressor 3 reaches the second temperature under the switching control of the relays 45b and 45c, as in the third embodiment. When the temperature reaches the set temperature or higher, a third closing control signal is sent as a control signal to the second solenoid valve 32, and when the temperature of the refrigerant discharged from the refrigerant compressor 3 falls below the second set temperature, the control is performed. The third opening control signal is sent to the second solenoid valve 3 as a signal.
Send to 2. The second electromagnetic valve 32 opens when receiving the second or third open control signal, and closes when receiving the second or third close control signal.

Next, the operation of the fourth embodiment will be explained with reference to FIG. 11 as well.

During cooling cycle operation, when the clutch of the refrigerant compressor 3 is turned on, the second temperature sensor 22b is energized and becomes operational. Since the four-way switching valve 4 is in the OFF state, no current flows through the first temperature sensor 21 and the coil of the relay 45b, and the first temperature sensor 21 is in the non-operating state and the relay 45b is in the off state.
The contact is in the off state. When the temperature of the refrigerant discharged from the refrigerant compressor 3 is equal to or higher than the second set temperature, the second temperature sensor 22b is turned on, and the relay 45c is turned on.
Since current flows through the coil and its contact becomes on, the second temperature sensor 22b is connected to the relay 45c.
A second opening control signal is sent to the second solenoid valve 32 via the second solenoid valve 32 . On the other hand, when the temperature of the refrigerant discharged from the refrigerant compressor 3 is lower than the second set temperature, the second temperature sensor 22b is turned off, no current flows through the coil of the relay 45c, and its contacts are turned off. , the second temperature sensor 22b sends a second closing control signal to the second solenoid valve 32 via the relay 45c. Therefore, during the cooling cycle operation, the second electromagnetic valve 32 is controlled to open and close by the second temperature sensor 22b. A detailed explanation of the operation during this cooling cycle operation will be omitted since it is the same as that of the first embodiment described above.

On the other hand, when the clutch of the refrigerant compressor 3 is turned on during the defrosting cycle operation, the second temperature sensor 2
2b is energized and becomes operational. Since the four-way switching valve 4 is in the on state, current flows through the first temperature sensor 21 and the coil of the relay 45b, and the first temperature sensor 21 becomes in the operating state and the relay 45b is turned on.
The contact is in the on state. When the temperature of the refrigerant discharged from the refrigerant compressor 3 is equal to or higher than the second set temperature, the second temperature sensor 22b is turned on, and the relay 45c is turned on.
Since current flows through the coil and its contact becomes on, the second temperature sensor 22b is connected to the relay 45c.
A third closing control signal is sent to the second solenoid valve 32 via the third solenoid valve 32 . On the other hand, when the temperature of the refrigerant discharged from the refrigerant compressor 3 is lower than the second set temperature, the second temperature sensor 22b is turned off, no current flows through the coil of the relay 45c, and its contacts are turned off. , the second temperature sensor 22b sends a third opening control signal to the second solenoid valve 32 via the relay 45c. Therefore, during the defrosting cycle operation, the first temperature sensor 21 controls the opening and closing of the first solenoid valve 31, and the second temperature sensor 22b controls the opening and closing of the second solenoid valve 32. A detailed operation explanation of the opening/closing control of the first electromagnetic valve 31 by the first temperature sensor 21 in this defrosting cycle operation is as follows.
Since this is the same as the first embodiment described above, a description thereof will be omitted.
Further, a detailed explanation of the opening/closing control of the second electromagnetic valve 32 by the second temperature sensor 22b during the defrosting cycle operation is omitted because it is the same as that of the third embodiment described above.

[Effects of the Invention] As is clear from the above description, according to the present invention, the temperature of the refrigerant discharged from the compressor is detected, and the internal heat exchanger and the external heat exchanger are operated based on the detected temperature. Since the solenoid valve provided in the bypass path is controlled to open and close, damage to the compressor, refrigerant hose, etc. can be prevented. In addition, during defrost cycle operation, a solenoid valve installed in a bypass path that bypasses the internal heat exchanger is opened and closed, so that hot gas can be supplied to the drain pan defrost pipe without going through the internal heat exchanger. Therefore, it is possible to improve the defrosting performance of the internal heat exchanger.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the configuration of a heat pump type cooling device according to a first embodiment of the present invention, FIG. 2 is a diagram for explaining the operation of the circuit of FIG. 1, and FIG. A circuit diagram showing the configuration of a heat pump type cooling device according to a second embodiment, FIG. 4 is a diagram for explaining the operation of the circuit in FIG. 3, and FIG. 5 is a diagram showing a heat pump according to a third embodiment of the present invention. 6 is a perspective view showing the structure of the internal heat exchanger section in FIG. 5, and FIG. 7 is an enlarged view of the section in FIG. 6. FIG. 8 is an enlarged view of the part in FIG. 6, FIG. 9 is a diagram for explaining the operation of the circuit in FIG. 5, and FIG. 10 is a heat pump according to the fourth embodiment of the present invention. FIG. 11 is a diagram for explaining the operation of the circuit shown in FIG. 10, and FIG. 12 is a circuit diagram showing the configuration of a conventional heat pump cooling device. DESCRIPTION OF SYMBOLS 1... Engine, 2... Drive transmission device, 3... Refrigerant compressor, 4... Four-way switching valve, 5... External heat exchanger, 6...
Internal heat exchanger, 7... Check valve, 8... Expansion valve, 9... Check valve, 10... Expansion valve, 11... Condenser fan,
12... Cooling fan, 12a... Fan shield, 20, 21, 22, 22a, 22b... Temperature sensor, 26, 26a, 27, 27a, 27b... Bypass path, 31, 32... Solenoid valve, 36, 37... Control code, 41 , 42...capillary, 45, 4
5a, 45b, 45c...Relay, 51...Drain pan, 52...Drain hose, 53...Defrosting pipe.

Claims (1)

[Claims] 1. During the cooling cycle operation, the refrigerant discharged from the compressor driven by the engine passes through the four-way switching valve, the external heat exchanger, the expansion means, the internal heat exchanger, and the four-way switching valve. During the defrosting cycle operation, the refrigerant discharged from the compressor is returned to the refrigerant suction port of the compressor through the four-way switching valve, the internal heat exchanger, the expansion means, the external heat exchanger, and the four-way switching valve. The refrigerant is configured to return to the refrigerant suction port of the compressor via a switching valve, and during the defrosting cycle operation, it melts the frost attached to the outer periphery of the internal heat exchanger and receives the melted frost in a drain pan. , which is led out of the refrigerator via a drain hose from a drain hole drilled in the drain pan, and inserted into the drain pan between the internal heat exchanger and the expansion means, for defrosting the drain pan. In a heat pump type cooling device provided with a defrosting means, a temperature detection means for detecting the temperature of the refrigerant discharged from the compressor, a first bypass path that bypasses the external heat exchanger,
a second bypass path that bypasses the internal heat exchanger; and first and second control valves provided in the first and second bypass paths, respectively; The opening and closing of the second control valve is controlled based on the detected temperature detected by the temperature detecting means, and the first control valve is controlled based on the detected temperature detected by the temperature detecting means during the defrosting cycle operation.
The temperature of the refrigerant discharged from the compressor is controlled by controlling the opening and closing of the control valve, and the temperature of the refrigerant discharged from the compressor is controlled based on the detection degree detected by the temperature detection means during the defrosting cycle operation. A heat pump type cooling device characterized in that the defrosting performance of the drain pan is improved by controlling the opening and closing of the control valve No. 2. 2. The heat pump type cooling device according to claim 1, wherein the second bypass path is arranged to pass through the drain hole portion. 3. The heat pump type cooling device according to claim 1, wherein the second bypass path is arranged so as to pass around a fan shield of the internal heat exchanger fan.