JPH0658660A - Defrosting device of refrigerator - Google Patents

Abstract

PURPOSE:To provide a defrosting device for a refrigerator of cold air circulation type in which a re-energization of a compressor is facilitated upon completion of defrosting operation. CONSTITUTION:The device is provided with an operation calculation timer 2 for calculating an operation time of a compressor 1 and defrosting of an evaporator for every specified time, a defrosting temperature sensor 3 for detecting a completion of defrosting operation, a circulation fan reverse rotating circuit 9 for reversely a circulation fan 10 and a control timer 11 for controlling a circulation fan reverse rotating circuit 9. Upon detection of a completion of the defrosting operation with the defrosting temperature sensor 3, a defrosting heater 7 is turned off and concurrently the circulation fan 10 is reversely rotated for a specified period of time with the control timer 11, a temperature of the evaporator is decreased and a refrigerant pressure is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defrosting device for a refrigerator, and more particularly to a defrosting device for a refrigerator that facilitates starting of a compressor at the end of defrosting.

[0002]

2. Description of the Related Art In a cold air circulation refrigerator, cold air generated by an evaporator provided in a freezing compartment is sent to a freezing compartment and each refrigerating compartment by a circulation fan, and an inflow amount is adjusted by a damper provided in each compartment. , So that the temperature is controlled to a predetermined temperature. If operated for a long time in this state, frost will form on the evaporator or the inner wall of the refrigerator, depending on the amount of food stored and the frequency of food intake and removal, but it will cover the surface of the evaporator and prevent heat conduction. In order to prevent cold air circulation in the refrigerator, the frosted state is detected by the defrosting temperature sensor attached to the evaporator, or the operation integration timer is used to forcibly stop the operation of the compressor every fixed operating time. A method of defrosting by energizing a dedicated defrost heater is used. In this case, as shown in FIG. 2B, the compressor and the circulation fan are stopped until the defrosting is completed, the evaporator is warmed by the defrost heater, and the defrosting completion is confirmed by the temperature sensor. When the frost heater is turned off, the temperature of the evaporator becomes high, and therefore the refrigerant pressure is also high, and it is difficult to start the compressor as it is. Therefore, it was necessary to pause for a certain period of time until the refrigerant pressure approaches equilibrium and delay the startup. For this reason, when the amount of frost is large and it takes a long time to defrost, the temperature inside the refrigerating room also rises, causing a problem such as impairing the quality of the stored food.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art. When the defrosting is completed, the temperature of the evaporator is rapidly lowered to lower the refrigerant pressure and start the compressor. It is an object of the present invention to provide a defrosting device for a refrigerator that suppresses an increase in the temperature inside the refrigerator by accelerating it and does not impair the quality of stored food.

[0004]

In order to achieve the above object, at the end of defrosting of the evaporator, the circulation fan is reversely rotated for a certain period of time to send cold air in the freezing chamber to the evaporator, and the temperature of the evaporator is controlled. To lower the refrigerant pressure.

[0005]

According to the above construction, when the completion of defrosting of the evaporator is confirmed by the temperature sensor, the operation integration timer is started and at the same time, the control microcomputer reversely rotates the circulation fan for a certain time to cool the inside of the freezing chamber. To cool the evaporator, reduce the refrigerant pressure, so that the compressor can be started immediately after stopping the circulation fan,
It is possible to suppress an increase in the internal temperature.

[0006]

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing the configuration of the present invention. An operation integration timer 2 that drives only when the compressor 1 is in operation and integrates the operation time, and a defrost temperature sensor that is attached to the evaporator and detects the temperature of the evaporator. 3, a control microcomputer 4 for controlling the defrosting operation by signals from the operation integration timer 2 and the defrosting temperature sensor 3, a compressor drive circuit 5 controlled by the control microcomputer 4, a compressor 1, and a defrosting heater. It is composed of a drive circuit 6, a defrost heater 7, a circulation fan forward rotation circuit 8, a circulation fan reverse rotation circuit 9, and a circulation fan 10. The operation integration timer 2 turns on and off following the temperature control of the compressor 1, integrates the operation time of the compressor 1, and when the predetermined integration operation time is reached, the operation of the compressor 1 is started by a built-in cam mechanism. And the defrost heater 7 is energized. When the compressor 1 starts the cooling operation, the operation integration timer 2 is simultaneously driven to integrate the operation time of the compressor 1, and when the integration time reaches a predetermined defrost start time, the operation integration timer 2 starts defrosting. A signal is sent to the control microcomputer 4 and simultaneously stopped. The control microcomputer 4 judges the defrosting start by the defrosting start signal, stops the compressor 1 by the compressor drive circuit 5, stops the circulation fan 10 by the circulation fan forward rotation circuit 8, and makes the defrost heater drive circuit 6 The defrost heater 7 is energized to start defrosting the evaporator. During this time, the defrosting temperature sensor 3 detects the temperature of the evaporator and sends it to the control microcomputer 4. When the temperature of the evaporator reaches a predetermined defrosting ending temperature, it is judged that defrosting has ended and the defrosting heater 7 is turned off. At the same time, the control timer 11 built in the control microcomputer 4 is driven, and when the control timer 11 has timed out after a predetermined time has elapsed, the operation integration timer 2 is driven, and after a certain time has elapsed, the cam mechanism sends a defrosting completion signal to the control microcomputer. 4, the operation of the compressor 1 is started upon determining that the defrosting is completed, and the circulation fan normal rotation circuit 8 rotates the circulation fan 10 in the normal rotation direction to return to the cooling operation.

FIG. 2A is a defrosting time chart of the present invention, in which the compressor 1 is in a stopped state during the defrosting time,
The defrost heater 7 is energized at the same time as the start of defrost and is energized until the temperature of the evaporator reaches a predetermined defrost end temperature, and at the same time, the control fan 11 reversely rotates the circulation fan 10 and the control timer 11 times up. At the same time, the operation integration timer 2 is started, and after the deactivation time signal has passed by the cam mechanism of the operation integration timer 2, the operation of the compressor 1 and the circulation fan 10 start the normal rotation operation to start the cooling operation. I am trying to return.

FIG. 3 is a flow chart showing the details of the present invention. When the operation integration timer 2 reaches the defrosting start time (2
1), the operation integration timer 2 is stopped, the operation of the compressor 1 and the operation of the circulation fan 10 are stopped at the same time, and the defrost heater 7 is energized to start defrosting (22). When the defrosting temperature sensor 3 determines that the temperature of the evaporator has risen to a predetermined temperature and has reached the defrosting completion temperature (23), the control timer 11 is activated, and at the same time, the circulation fan reverse rotation circuit 9 circulates the air. Fan 10
Start to reverse rotation (24). When a predetermined time (about 2 minutes) has elapsed and the control timer 11 times out (25), the reverse rotation of the circulation fan 10 is stopped and the operation integration timer 2 is started at the same time (26), and a predetermined rest time elapses before operation. Integration timer 2
Reaches the start-up time of the compressor 1 (27), the compressor 1
Then, the circulation fan 10 is rotated forward at the same time to return to the normal cooling operation (28).

[0009]

As described above, in the present invention, after the defrosting is completed, the circulation fan is rotated in the reverse direction to blow cool air in the refrigerating chamber to the evaporator to lower the temperature of the evaporator and reduce the refrigerant pressure. It is possible to provide a defrosting device for a refrigerator that does not impair the quality of stored foods by accelerating the start-up of the compressor and suppressing an increase in the internal temperature.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a defrosting time chart of the present invention and a conventional example.

FIG. 3 is a flow chart showing details of the present invention.

[Explanation of symbols]

 1 Compressor 2 Operation integration timer 3 Defrost temperature sensor 4 Control microcomputer 5 Compressor drive circuit 6 Defrost heater drive circuit 7 Defrost heater 8 Circulation fan forward rotation circuit 9 Circulation fan reverse rotation circuit 10 Circulation fan 11 Control timer

Claims (1)

[Claims] 1. Cooling air generated by an evaporator provided in a freezer compartment is sent to a freezer compartment and each refrigerating compartment by a circulation fan to cool the interior of the compartment, and frost adhered to the evaporator is fixed every predetermined time by an operation integration timer. In the cold air circulation refrigerator configured to defrost, the circulation fan is reversely rotated for a certain time at the end of defrosting of the evaporator, the cool air in the freezing chamber is sent to the evaporator, and the temperature of the evaporator is lowered. A defrosting device for a refrigerator, characterized in that the pressure of the refrigerant is reduced.