JPS5984055A - Refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is composed of a compressor, a condenser, a pressure reducing device, an evaporator, etc., and the compressor is controlled to start and stop using an internal temperature detection device, etc. The present invention relates to improvements in refrigeration equipment, such as refrigerators, that perform predetermined cooling.

Conventional configuration and its problems Conventionally, in this type of refrigeration system, a large amount of refrigerant compressed to high temperature and pressure exists in the condenser when the compressor is operating, and when the compressor is stopped, the decompression device is It acts as a pressure equalizing pipe that balances the pressure in the low pressure circuit, and the evaporator is heated because the high temperature and high pressure refrigerant flows into the evaporator. Therefore, after restarting the subsequent compressor, it becomes necessary to cool the evaporator again, including the heating of the evaporator due to the inflow of the high-temperature refrigerant, and as a result, it is known that excessive power consumption is required for cooling. ing. As an improvement measure for the above drawback, a refrigerant control valve such as a solenoid valve is installed between the condenser outlet and the evaporator inlet, and the flow path is opened when the compressor is operating, and closed when the compressor is stopped, thereby controlling the evaporator. There are known devices that prevent high-temperature, high-pressure refrigerant from flowing into the refrigerant. However, in this type of improved refrigeration system, the solenoid valve closes at the same time as the compressor stops, and even during the stop, the solenoid valve maintains the entire high-pressure circuit at high pressure and the entire low-pressure circuit at low pressure. The pressure between the front and rear of the compression element is uneven. Therefore, in order to start the compressor upon restart, the electric motor of the compressor requires excessive torque, and depending on the conditions, it may become impossible to start the compressor. Generally, when the outside temperature is high or the installation conditions of the refrigerator are severe (especially the installation conditions around the condenser), the high pressure increases and the conditions for restarting the refrigerator become severe.

OBJECTS OF THE INVENTION The present invention improves the restartability of a compressor by minimizing the influence on cooling efficiency and reducing the pressure difference between high and low levels at the time of restart.

Structure of the Invention The present invention delays the start of operation of the compressor until the high pressure within the cooling system falls below a predetermined pressure after a refrigerant control valve such as a solenoid valve starts opening.

DESCRIPTION OF EMBODIMENTS An embodiment in which the present invention is applied to a household refrigerator will be described below with reference to the drawings.

In the diagram, 1 is a compressor, 2 is a condenser, and 3 is a pressure reducing device!
(Here, a capillary tube), 4 is an evaporator, and 5 is a refrigerant control valve (hereinafter referred to as a solenoid valve). A solenoid valve 6 is connected between the outlet of the condenser 2 and the capillary tube 3. Furthermore, the solenoid valve 6 is connected in series with a relay 7 that opens and closes its contacts based on a signal from a temperature detection device 6 that detects the internal temperature of the refrigerator, and the compressor 1 is connected in series with the relay 7 via a relay 8. has been done. Relay 8 controls the contact opening operation to relay 7.
The control circuit is configured such that the closing operation is delayed by the time from when the relay 7 is closed until the high pressure of the cooling system becomes lower than a predetermined pressure, and then closes the contact.

Next, a control circuit for controlling the opening and closing of the relays 7 and 8 will be explained in detail.

As mentioned above, reference numeral 6 denotes a temperature detection device inside the refrigerator, which is composed of a comparator 9, resistors R1, R2, R3, and a thermistor 10 provided in a part of the inside of the refrigerator.

In this temperature detection device 6, when the potential at the point A determined by the resistor R1 and the resistance RTH which changes depending on the temperature of the thermistor 10 is higher than the potential at the point B determined by the resistor R21R3, the output of the comparator 9 becomes "1". If it is low, it operates to be '0'.The output of the comparator 9 is connected to send a signal to open/close the relay 7 via a driving means such as a transistor (not shown), and is also connected to one side of the AND circuit 11. connected to the input and via the inverter 12
- It is also connected to the reset manual power of the S flip 70 knob 13. Reference numeral 14 is a pressure detection device that detects the high pressure of the cooling system and converts it into an electrical signal.If the high pressure is higher than a predetermined pressure, the output cover 1'' is output, and if it is lower, the output is "o". The output of this pressure detection device 14 is connected to the other input of the AND circuit 11 via the input terminal 15.
The output of R-S flip-flop 13 is connected to the 130 cent input of R-S flip-flop 13, and the Q output of R-S flip-flop 13 is configured to send a signal to open and close relay 8 via driving means (not shown) such as a transistor. ing.

Next, the operational status of this configuration will be explained.

When the internal temperature of the refrigerator is lower than a predetermined value, the internal temperature detection device 6 detects the resistance value R of the thermistor 10.
As TH increases and the A potential becomes lower than the B potential, the output of the comparator 9 becomes 0'', and the relay 7 is open.At the same time, the signal inverted by the inverter 12
1'' sends a reset signal to the R-S flip-flop 13, so the Q output becomes II Oll and the relay 8 is also opened.

That is, the solenoid valve 6 is closed to close the refrigerant flow path, and at the same time, the compressor 1 is also stopped. After that, when the temperature inside the refrigerator rises to a certain level, the resistance value RTH of the thermistor 10 becomes smaller and the A potential becomes higher than the B potential, so the output of the comparator 9 becomes II I II, and the relay 7 is activated through a driving means such as a transistor. The solenoid valve 5 is closed and the solenoid valve 5 is energized to open the refrigerant flow path, and the high pressure starts to gradually decrease and the low pressure starts to increase. On the other hand, since the high pressure at this time is still higher than the predetermined pressure of the pressure detection device 14, the output of the pressure detection device 14 is ``1'' and is reversed to ``O'' through the output 16. Therefore, the output of the AND circuit 11 is It O#, that is, the set input of the R-S flip-flop is also "0", so the Q output also remains "0",
Relay 8 also remains open.

That is, the compressor 1 continues to be in a stopped state. After that, when the high pressure in the mold decreases to below the predetermined pressure of the pressure detection device 14, the output of the pressure detection device 14 becomes 'o'P, and the input to the AND circuit 11 via the inverter 15 becomes u1n. Therefore, for the first time at this point, AND circuit 1
1 becomes “1” and R-S flip-flop 1
3, the output Q of the R-S flip-flop 13 becomes "1", the relay 8 is closed via a driving means such as a transistor, and the compressor 11 starts operating. That is, in the above procedure, the start of operation of the compressor 1 is delayed for a period of time from when the electromagnetic valve 5 starts opening until the high pressure reaches a predetermined pressure or less. Furthermore, after the compressor 1 starts operating, the high pressure increases immediately and exceeds the set pressure of the pressure detection device 14, and the output is reversed to "1".
The input to D circuit 11 becomes °“o” and AND circuit 1
The output of 1 becomes °'0'', but the R-S flip 70 tube 1
Since the Q output of No. 3 continues to be "1" unless the signal "1" is input to the reset terminal (R terminal), the compressor 1 continues to operate with the relay 8 closed. When the compressor 1 is sufficiently cooled and the temperature detection device 6 detects a predetermined temperature, the solenoid valve 5 closes and the compressor 1 stops as described above, and the above-described operation is repeated thereafter.

Next, the pressure transition within the cooling system will be explained with reference to FIG. 3 while comparing it with the conventional example. The solid line shows the high-pressure and low-pressure system pressure changes of the conventional example, and the broken line shows the high-pressure and low-pressure system pressure changes of the embodiment of the present invention. As is clear from Fig. 3, after the temperature detection device outputs "1" and the solenoid valve 5 opens, the high pressure reaches the predetermined pressure (Plo).
Since the compressor 1 is kept on standby until the following i is reached, the refrigerant in the condenser 2 flows into the evaporator 4 on the low pressure side and the pressure on the high pressure side is increased to a predetermined pressure (P1') - t. In order to reduce the pressure on the low pressure side and conversely increase the pressure on the low pressure side to a certain extent (up to P2'), the high and low pressure difference when restarting the compressor 1 after the delay is the same as the high and low pressure difference (Pl - P2) of the conventional example. (pl-p2'), and the restart pressure condition of the compressor 1 is relaxed.

Effects of the Invention As is clear from the above explanation, the present invention provides a refrigerant control valve between the condenser and the evaporator, and while the refrigerant control valve is open, the compressor is also stopped and the refrigerant control valve starts opening. It has a delay device such as a pressure detection device that starts the compressor after a short delay until the pressure drops to a higher pressure or a preset value. In the meantime, the high pressure in the cooling system is lowered to a desired value that can be restarted, and the low pressure is increased, ultimately reducing the difference in high and low pressure when the compressor is restarted compared to the conventional one. This allows the compressor to be easily restarted.

In general, the high pressure of the cooling system varies depending on the outside temperature conditions and the installation conditions of the refrigerator, etc. (especially the installation conditions around the condenser). In this case, the high pressure increases and the conditions for restarting the compressor become stricter, but in this case, the compressor is automatically stopped and maintained until the pressure drops to a high level that does not pose a problem for restarting, ensuring a reliable restart. On the other hand, when the outside air temperature is low or when the installation conditions are such that the heat dissipation conditions around the condenser are good, the high pressure is also low, so the time it takes to reach the preset high pressure is shortened. Therefore, the delay time of the compressor can be shortened, and depending on the conditions, the delay time can be made unnecessary, and the restart can be performed under certain pressure conditions without causing unnecessary flow of high-pressure refrigerant into the evaporator and reducing cooling efficiency. It is possible to automatically select the minimum delay time necessary to give This has the effect of providing restartability.

[Brief explanation of the drawing]

Fig. 1 is a refrigeration cycle diagram showing one embodiment of the present invention;
The figure is an electric circuit diagram thereof, and FIG. 3 is a diagram showing pressure changes within the cooling system in a conventional example and an embodiment of the present invention. 1... Compressor, 2... Condenser, 3...
... pressure reducing device, 4 ... evaporator, 5 ...
...refrigerant control valve, 6...interior temperature detection device, 1
4...High pressure detection device (delay device). Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Figure 3 Un41 Yesterday's investigation

Claims (1)

[Claims] The refrigerant control valve is equipped with a compressor, a condenser, a pressure reducing device, an evaporator, and a refrigerant control valve interposed between the outlet of the condenser and the inlet of the evaporator. In addition to controlling opening and closing, the compressor is stopped while the refrigerant control valve is closed, and after the refrigerant control valve starts opening, the compressor is kept stopped until the high pressure side pressure of the cooling system becomes equal to or less than a predetermined pressure. Refrigeration equipment with a delay device that starts operation after