JPS5986869A - 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 Field of Industrial Application The present invention is formed by 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. In particular, the present invention relates to improvements in refrigeration equipment for, for example, refrigerated rhinoceroses, which perform predetermined cooling.

Conventional configuration and its problems Conventionally, in this type of refrigeration system, a large amount of high-temperature, high-pressure compressed refrigerant exists in the condenser when the compressor is in operation1, and when the compressor is stopped, a decompression device is used. acts as a pressure equalizing pipe that balances the pressure of the high and low pressure circuit, and the high temperature and high pressure refrigerant flows into the evaporator, thereby heating 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 a solution to the above drawbacks, a refrigerant control valve such as a solenoid valve is installed between the condenser outlet and the evaporator inlet to open the flow path when the compressor is running, and close the flow path when the compressor is stopped to prevent evaporation. There are known devices that block high-temperature, high-pressure refrigerant from flowing into the container. 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 when restarting, the compressor motor requires excessive torque, and depending on the conditions, for example, if the supply voltage is bad and the desired motor torque cannot be obtained, it may become impossible to start the compressor. There is also.

OBJECTS OF THE INVENTION The present invention reduces the pressure difference between high and low pressures at the time of restart while minimizing the influence on cooling efficiency, thereby making it easier to restart the compressor.

Structure of the Invention The present invention is equipped with a delay device that varies the delay time at which the compressor is started depending on the level of the supply power voltage after opening and starting of a refrigerant control valve such as a solenoid valve.

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 figure, 1 is a compressor, 2 is a condenser, 3 is a pressure reducing device (capillary tube here), 4 is an evaporator, and 6 is a refrigerant control valve (
(hereinafter referred to as a solenoid valve). A solenoid valve 5 is connected between the outlet of the condenser 2 and the inlet of the capillary tube 3. Also, the solenoid valve 5
is connected in series with a relay 7 that opens and closes its contacts in response to 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. . The relay 8 synchronizes the opening operation of the contact with the relay 7, and the closing operation is controlled so that the contact is closed with a delay from the time when the relay 7 closes by a time corresponding to the voltage of the power supply E at that time. It consists of a circuit.

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, Rs, and a thermistor 1o provided in a part of the inside of the refrigerator.

This temperature detection device 6 detects that when the potential at point A, which is determined by the resistor R1 and the resistance value RTH that changes depending on the temperature of the thermistor 10, is higher than the potential at eight points determined by the resistors R2 and R3, the output of the comparator 9 is 1. The output of the comparator 9 is connected to send a signal to open and close the relay 7 via a driving means (not shown) such as a transistor, and is connected to an AND gate. It is connected to one input of the circuit 11. 12 is a pulse source configured to periodically generate pulses, and its output is A.
It is connected to one input of the ND circuit 13, and the output of the comparator 9 of the temperature detection device 6 is connected to the other input of the AND circuit 13. Further, the output of the AND circuit 13 is disconnected from the delay timers 14 and 15. Here, the set time T1 of the delay timer 14 and the delay timer 15
The set time T2 is set so that TI<T2. The output of the delay timer 14 is connected to one input of an AND circuit 16, and the AND circuit 16 performs AND with the output signal of the power supply voltage detection device 17 supplied to the compressor 1, and outputs the output from the R-S flip-flop 18. connected to send a set signal. This power supply voltage detection device 17 generates an output "1" when the power supply voltage is above a set value V1 (V), and generates an output "0" when it is below. On the other hand, the output of the delay timer 15 is connected to the R-3 flip 70 knob 19 to send a set signal. The Q outputs of the R-S flip-flops 18 and 19 are both connected to the other input terminal of the AND circuit 11, and the output of the AND circuit 11 controls the operation of the compressor 1. It is configured to send a signal to open and close the controlled relay 8.

Further, the output terminals of the comparator 9 of the temperature detection device 6 are connected to the reset terminals of the delay timers 14 and 15 and the R-S flip-flops 18 and 19 via an inverter 20, respectively.

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 RT of the thermistor 1Q.
Since H increases and the input potential becomes lower than the B potential, the output of the comparator 9 becomes Q I+, and the relay 7 is open. At the same time, one input of the AND circuit 11 becomes 0'.
'', the output of the AND circuit 11 becomes "○" and the relay 8 is also opened. That is, the solenoid valve 5 is closed and the refrigerant flow path is closed, and at the same time, the compressor 1 is also stopped. At the same time, each timer 14°15
, and send reset signals to the R-S flip-flops 18 and 1.9 to clear their internal states. After that, when the temperature inside the refrigerator rises to a certain level, the resistance value RTH of the thermistor 1° becomes smaller and the A potential becomes higher than the B potential, so the output of the comparator 9 becomes "1" and the relay 7 is activated through a driving means such as a transistor. After closing, the solenoid valve 5 is energized to open the refrigerant flow path, and the high pressure starts to gradually decrease, and conversely, the low pressure starts to increase. At the same time, the input to the AND circuit 13 is also
1", the pulse signal from the pulse source 12 is simultaneously counted by the delay timers 14 and 15. Here, the set time T1 of the delay timer 14 and the delay timer 1
Since the set time T2 of 5 is in the relationship TI<T2, the count of the delay timer 14 ends early, and the output "1" is
It is sent to the ND circuit 16, but at this time the voltage of the supply power E is vl.
(v) If PJ is above, the output of the power supply voltage detection device 17 is 1", and the AND circuit 16 generates an output "1" and sends a set signal to the R-S flip-flop 18.

On the other hand, if the supplied power supply voltage is below Vl (V) Ju, the output of the power supply voltage detection device 17 is 0", and the output of the AND circuit 16 is "0", so the set time T1 of the timer 14 is
No set signal is sent to the R-S flip-flop 18 even if . In this case, when further time passes and the set time T2 of the delay timer 15 is reached, the timer 15
directly sends a set signal to the R-S flip-flop 19. In this way, the set signal sent to either 18 or 19 R-S flip-flops depending on the supply voltage generates a Q output of 1'', the input to the AND circuit 11 becomes 1'', and temperature detection is performed. Since the other input of the AND circuit sent from the comparator 9 of the device 6 is also "1", the output of the AND circuit 11 is "1", and the relay 8 is closed via a driving means such as a transistor, and the compressor 1 is closed. In other words, according to the above procedure, the start of operation of the compressor 1 is delayed for a predetermined period of time depending on the level of the power supply voltage from the start of opening of the solenoid valve 5. After that, the inside of the refrigerator is sufficiently cooled and the temperature drops. When the detection device 6 detects a predetermined temperature, the solenoid valve 6 closes and the compressor 1 also stops as described above, and the above-described operation is repeated thereafter.

Next, the pressure transition of the cooling system will be explained with reference to FIG. 3 while comparing it with a conventional example. The solid line shows the pressure transition in the high-pressure and low-pressure systems of the conventional example, and the broken line shows the pressure transition in the high-pressure and low-pressure systems of the conventional example, and the broken line shows the pressure change in the example of the present invention when the supply voltage is higher than the preset voltage V1 (V), that is, when V')>Vl. The pressure profile in the high-pressure and low-pressure systems is shown.

Furthermore, the dashed line indicates the case where the supply voltage is lower than the preset voltage V1 (V) in the embodiment of the present invention, that is, V<vl
The pressure profile in the high-pressure and low-pressure systems is shown in the case of .

As is clear from the figure, when the temperature detection device 6 becomes the output "1" and the solenoid valve 5 starts to open, the supply voltage is maintained at a voltage higher than the set value v1 (v>vl)
is for a relatively short time T1 to wait for the startup of the bamboo compressor 1, and on the other hand, if the supply voltage is lower than the set value v1 (V(
Vl) waits for the start of the compressor 1 for a longer time T2 (TI<T2) than T1, so if v>vl, the refrigerant in the condenser 2 flows to the low pressure side during the waiting time T1. As it flows into the evaporator 4, the pressure on the high pressure side drops to P1', and conversely, the pressure on the low pressure side rises to P2/.
The pressure difference between high and low pressures when restarting compressor 1 after the delay is P
It is reduced to 1'-P2'. On the other hand, if v<vl, the pressure on the high pressure side further decreases to P1'' during the waiting time T2, and the pressure on the low pressure side further increases to P2〃, so the high-low pressure difference further decreases to pI II p2N. As a result, the restart pressure condition of the compressor 1 is relaxed depending on the power supply voltage compared to the high-low pressure difference P1-P2 of the conventional example.

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 closed, the compressor is also stopped and the refrigerant control valve starts opening. After that, depending on the level of the supply voltage, i.e. if the supply voltage is relatively high, the compressor is started with a relatively short delay, and if the supply voltage is relatively low, the compressor is started for a relatively long time. It has a delay device consisting of a delay timer that starts with a delay, a power supply voltage detection device, etc., and reduces the high pressure in the cooling system after the refrigerant control valve is opened and before the compressor is operated. Conversely, the compressor is restarted after the low pressure is increased and reduced to a pressure difference between high and low pressures that can be restarted according to the supply voltage, ensuring reliable compression even under low voltage conditions. In addition to being able to prove the restart of the machine, depending on the conditions, such as when the supply voltage is stable near the rated voltage, the delay time can be set to "none", which prevents unnecessary high-pressure refrigerant from being used. It will not flow into the evaporator and impair the cooling effect.In short, it is possible to automatically select the minimum delay time necessary to provide a reliable restart pressure condition according to the supply voltage at that time. This has the effect of minimizing the influence on cooling efficiency and providing reliable restartability of the compressor.

[Brief explanation of drawings]

Fig. 1 is a refrigeration cycle diagram showing one embodiment of the present invention;
FIG. 3 is an electrical 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, 6 ...
・・Refrigerant control valve, 6・・・・・Interior temperature detection device, 1
4.15...Delay timer, 17...
・Power supply voltage detection device.

Claims (1)

[Claims] The refrigerant control valve includes 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. The compressor is stopped while the refrigerant control valve is closed, and after the refrigerant control valve starts to open, the compressor is stopped and maintained for a period of time corresponding to the power supply voltage at that time, and then operation is started. Refrigeration equipment with a delay device.