JPH08285414A - Refrigerator - Google Patents

Abstract

PURPOSE: To provide a refrigerator which may contribute to a reliability in operation of a compressor by a method wherein a low pressure operation of the compressor is prevented and a rapid transferring in operation to its stabled condition is carried out. CONSTITUTION: This refrigerator is comprised of a freezing cycle in which a high pressure container type compressor 1, a condenser 2, a capillary tube 3 acting as a pressure reducing means and an evaporator 4 are connected in sequence in a ring-like manner. Further, the refrigerator is comprised of a bypass circuit 13 having an adjusting device between the condenser 2 and an inlet part of the evaporator 4; a solenoid valve 15 at a connection part between the condenser 2 and the bypass circuit 13; a suction pressure sensing means 18 acting as an opening or closing timing sensor means for the solenoid valve 15; and a solenoid valve control means 16 for use in opening or closing the solenoid valve 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator, and more particularly to prevention of low pressure operation that occurs during transient operation of starting a compressor after defrosting.

[0002]

2. Description of the Related Art A conventional refrigerator is a fully open 3-83791.
It has a configuration as known from the publication. Hereinafter, the configuration of the conventional refrigerator will be described with reference to FIG. 7.

1 is a high-pressure container type compressor, 2 is a condenser, 3
Is a decompression device such as a capillary tube, 4 is an evaporator, and the compressor 1, the condenser 2, the capillary tube 3, and the evaporator 4 are sequentially connected in an annular shape to form a refrigeration cycle. Reference numeral 5 is a main body of the refrigerator, which divides the inside thereof to form two chambers, a freezing chamber 6 and a refrigerating chamber 7, respectively. A defrosting heater 8 is provided near the evaporator 4.

Reference numeral 9 is a defrost detecting means for detecting a preset time interval, the temperature of the evaporator 4 and a frosting state, and detecting the end of defrosting during a defrosting operation. Defrost detection means 9
Based on the detection output of the compressor 1,
The operation, stop, and operation stop of the defrosting heater 8 are controlled.

Reference numeral 10 is a water pipe for guiding defrosted water to the evaporation dish 11, and the evaporation dish 11 is in the machine room 12 and a part of the condenser 2 is arranged in the evaporation dish 11. A part of the condenser 2 is usually used near the discharge of the compressor 1 in order to improve the efficiency of evaporation.

Next, the operation of the above conventional configuration will be described. Due to the operation of the compressor 1, the high-temperature and high-pressure refrigerant discharged from the compressor 1 is condensed and liquefied by the condenser 2, and further,
The pressure is reduced by the capillary tube 3, evaporated and vaporized by the evaporator 4, and the freezing chamber 6 and the refrigerating chamber 7 are cooled by a heat transfer means (not shown). The refrigerant vaporized in the evaporator 4 is again sucked into the compressor 1.

By performing such a cooling operation, the moisture contained in the air in the freezing compartment 6 and the refrigerating compartment 7 adheres to the surface of the evaporator 4 as frost when heat is exchanged in the evaporator 4. . When this frost formation progresses, the heat exchange efficiency of the evaporator 4 decreases, and it becomes impossible to perform a sufficient cooling operation.

The defrost detecting means 9 detects this state and outputs a defrost start signal to the defrost control means. Upon receiving this signal, the defrost detecting means starts defrosting.

The defrost control means stops the compressor 1 and operates the defrost heater 8 to start defrost. By operating the defrosting heater 8, the frost on the surface of the evaporator 4 is melted by heat generation.

When the frost on the surface of the evaporator 4 is melted, the defrost detecting means 9 indicates that the defrosting is completed and the temperature of the evaporator 4 is usually higher than a predetermined temperature (generally 10 to 20 ° C.). And outputs a defrosting end signal to the defrosting control means. Upon receiving this signal, the defrost control means stops the defrosting heater 8 to end the defrosting operation, and then starts the compressor 1. By this operation, the refrigeration cycle starts the cooling operation again.

Defrosting water generated by defrosting is the water pipe 10.
To the evaporating dish 11. The defrost water once stored in the evaporating dish is heated by the high temperature condenser 2 when the compressor 1 starts to operate.
It gradually evaporates by exchanging heat with a part of.

[0012]

However, in the above-mentioned conventional configuration, at the time of low ambient temperature, in addition to the refrigerant held in the evaporator 4 immediately before the start of defrosting, at the same time as the compressor 1 is stopped, the condenser 2 and The refrigerant starts to move from the compressor 1 and the condenser 2 to the evaporator 4 due to the difference in the saturated pressure of the refrigerant caused by the difference between the ambient temperature of the compressor 1 and the ambient temperature of the evaporator 4.

The temperature of the evaporator 4 rises due to the progress of defrosting, and the temperature of the evaporator 4 becomes higher than the ambient temperature of the compressor 1 and the condenser 2.
And when the ambient temperature becomes higher, the saturation pressure of the refrigerant becomes higher inside the evaporator 4 contrary to the initial stage of the defrosting operation, and the refrigerant moves from the evaporator 4 to the compressor 1 and the condenser 2. .

At the end of defrosting, the refrigerant in the evaporator 4 almost disappears and stays ubiquitously in the condenser 2 having the lowest temperature during the refrigeration cycle. Especially, it is ubiquitous in a part of a condenser that is cooled by low-temperature defrost water.

Therefore, at the time of starting the compressor 1 after defrosting,
Refrigerant is distributed in the condenser 2 in a normal operation stable state, that is, in a state from the compressor 1 to the capillaries 3 in the direction from the gas phase to the liquid phase. .

Therefore, when the compressor 1 is started, the evaporator 4 is
Since there is almost no refrigerant inside, the suction gas has a small specific volume and cannot be sufficiently pressurized. At the same time, since the refrigerant is omnipresent in the condenser 2, the liquid refrigerant does not reach the inlet of the capillary tube 3 stably, and a large amount of gas is trapped in the capillary tube 3 to hinder the circulation of the refrigerant.

This vicious circle causes a low-pressure operation state in which the balance of the refrigeration cycle is lost during the operation transition period after defrosting.

In a state where the oil film on the sliding portion of the compressor 1 is cut off due to liquid return during the transition period of startup, the refrigerant and the lubricating oil circulating with the refrigerant are returned only to a small extent, and the low pressure operation continues. The sliding part of the above became dry friction and abnormal wear occurred, which was a very big problem from the aspect of reliability of the compressor 1.

Furthermore, it takes time for the refrigeration cycle after starting to stabilize, which leads to an increase in operating time and power consumption.

The refrigerator of the present invention solves the conventional problems, and an object thereof is to provide a refrigerator capable of preventing low-pressure operation at the time of starting the compressor after defrosting.

[0021]

In order to achieve this object, a refrigerator according to the present invention is a refrigeration cycle in which a high-pressure container type compressor, a condenser, a capillary tube, and an evaporator are sequentially connected in an annular shape. And a heater for defrosting in the vicinity of the evaporator,
A bypass circuit having a constriction between the condenser and the evaporator inlet section; a solenoid valve at a connection section between the condenser and the bypass circuit; an opening / closing timing detection means for the solenoid valve; And a solenoid valve control means for opening and closing the valve.

Further, the opening / closing timing detection means of the solenoid valve is suction pressure detection means provided at the connecting portion between the high-pressure container compressor and the evaporator, and the solenoid valve control means has a timer, and the suction pressure is The electromagnetic valve is opened when the suction pressure detected by the detection means becomes equal to or lower than a predetermined pressure, and the electromagnetic valve is closed when the timer next passes a predetermined time.

Further, the opening / closing timing detecting means of the electromagnetic valve is a defrost detecting means provided in the vicinity of the evaporator, the electromagnetic valve control means has a timer, and the defrost detecting means detects the end of the defrost. The electromagnetic valve is opened, and the electromagnetic valve is closed when the timer has passed a predetermined time.

Further, the opening / closing timing detecting means of the solenoid valve is a temperature detecting means provided at the connecting portion between the capillary tube and the evaporator, and the solenoid valve control means has a timer,
It is provided that the electromagnetic valve is opened when the temperature detected by the temperature detecting means becomes equal to or lower than a predetermined temperature, and the electromagnetic valve is closed when the timer elapses a predetermined time.

[0025]

With the above construction, in the refrigerator of the present invention, when low pressure operation occurs, the pressure detected by the suction pressure detecting means, which is the electromagnetic valve opening / closing timing detecting means, becomes equal to or lower than a predetermined pressure, and the electromagnetic valve controlling means outputs a signal. Sent, the solenoid valve provided at the connection between the condenser and the bypass circuit is opened, the refrigerant directly circulates from the condenser to the evaporator inlet, the evaporation pressure rises, the suction pressure also rises, Further, the high pressure rises.

The rise of the high pressure promotes the circulation of the refrigerant and corrects the unbalanced state of the refrigeration cycle.

When the timer of the solenoid valve control means has passed a predetermined time, the solenoid valve is closed, so that the low pressure operation does not occur and the transition to the stable state can be smoothly performed.

When the defrosting detecting means, which is the electromagnetic valve opening / closing timing detecting means, detects the end of defrosting, the electromagnetic valve control means sends a signal to open the electromagnetic valve. When the high-pressure container compressor is activated, the refrigerant directly circulates from the condenser to the evaporator inlet portion, and the evaporation pressure rises, so the suction pressure also rises, and further the high-pressure pressure rises.

The rise of the high pressure promotes the circulation of the refrigerant and corrects the unbalanced state of the refrigeration cycle.

When the timer of the solenoid valve control means has passed the predetermined time, the solenoid valve is closed, so that the low pressure operation does not occur and the transition to the stable state can be performed smoothly.

Further, when the low-pressure operation occurs, the evaporation temperature of the refrigerant decreases, and the piping temperature at the evaporator inlet sharply decreases.
As a result, the temperature detected by the temperature detecting means provided at the connecting portion between the capillary and the evaporator, which is the electromagnetic valve opening / closing timing detecting means, becomes equal to or lower than the predetermined temperature, the electromagnetic valve is opened, and from the condenser to the evaporator inlet portion. The refrigerant circulates directly. As a result, the evaporation pressure rises, the suction pressure also rises, and further the high pressure rises.

The rise of the high pressure promotes the circulation of the refrigerant and corrects the unbalanced state of the refrigeration cycle. When the timer of the solenoid valve control means has passed a predetermined time, the solenoid valve is closed, so that low-pressure operation does not occur and a smooth transition to a stable state can be performed.

[0033]

FIG. 1 shows an embodiment of a refrigerator according to the present invention.
~ It demonstrates with reference to FIG. However, the same components as those of the related art will be designated by the same reference numerals and detailed description thereof will be omitted.

1 is a high-pressure container type compressor, 2 is a condenser, 3
Is a capillary tube, and 4 is an evaporator, and the compressor 1, the condenser 2, the capillary tube 3, and the evaporator 4 are sequentially connected in an annular shape to form a refrigeration cycle.

Reference numeral 13 is a bypass circuit having a throttle 14, which connects the condenser 2 and the inlet of the evaporator 4.
An electromagnetic valve 15 is provided at the connecting portion between the bypass circuit 13 and the condenser 2. Reference numeral 16 is an electromagnetic valve control means having a timer 17, and 18 is suction pressure detection means which is an opening / closing timing detection means of the electromagnetic valve.

Reference numeral 5 denotes a main body of the refrigerator, which defines the inside thereof, and at least two rooms are formed by at least one freezing room 6 and at least one refrigerating room 7. A defrosting heater 8 is provided near the evaporator 4.

Reference numeral 9 is a defrosting detecting means which detects a preset time interval, the temperature of the evaporator 4 and a frosting state, and also detects the end of defrosting during the defrosting operation. Defrost detection means 9
Based on the detection output of the compressor 1,
The operation, stop, and operation stop of the defrosting heater 8 are controlled.

Next, the operation of the above conventional configuration will be described. The cooling operation is performed by the operation of the compressor 1, and the evaporator 4
And frost formation progresses. As a result, the heat exchange efficiency of the evaporator 4 decreases, and it becomes impossible to perform a sufficient cooling operation.

The defrosting detecting means 9 detects this state and outputs a defrosting start signal to the defrosting controlling means. Upon receiving this signal, the defrost detecting means starts defrosting.

The defrost control means stops the compressor 1 and operates the defrost heater 8 to start defrost. By operating the defrosting heater 8, the frost on the surface of the evaporator 4 is melted by heat generation.

When the frost on the surface of the evaporator 4 is melted, the defrost detecting means 9 indicates that the defrosting is completed, and the temperature of the evaporator 4 is usually higher than a predetermined temperature (generally 10 to 20 ° C.). And outputs a defrosting end signal to the defrosting control means. Upon receiving this signal, the defrost control means stops the defrosting heater 8 to end the defrosting operation, and then starts the compressor 1. By this operation, the refrigeration cycle starts the cooling operation again.

The evaporator 4 is operated during defrosting at low ambient temperature.
Rises and the evaporator 4 and its ambient temperature become higher than the ambient temperature of the compressor 1 and the condenser 2, the saturated pressure of the refrigerant becomes higher in the evaporator 4, and the refrigerant is compressed from the evaporator 4. Transfer to machine 1 and condenser 2.

At the end of defrosting, the refrigerant in the evaporator 4 almost disappears and stays ubiquitously in the condenser 2 having the lowest temperature during the refrigeration cycle.

Therefore, when the compressor 1 is started after defrosting,
Refrigerant is distributed in the condenser 2 in a normal operation stable state, that is, in a state from the compressor 1 to the capillaries 3 in the direction from the gas phase to the liquid phase, and the refrigerant is retained, and almost all the refrigerant is present in the evaporator 4. Since it does not do so, the specific volume of the suction gas is small and it is not possible to pressurize it sufficiently.

At the same time, since the refrigerant is ubiquitous in the condenser 2, the liquid refrigerant does not reach the inlet of the capillary tube 3 stably, and a large amount of gas is trapped in the capillary tube 3 to hinder the circulation of the refrigerant.
This reduces the suction pressure of the compressor 1.

As shown in FIG. 2, if the pressure value detected by the suction pressure detecting means 18 in step 1 is input to the solenoid valve control means 16 and the detected pressure value is below a predetermined pressure in step 2, The process proceeds to step 3 to start the timer 17, and if it is higher, the process returns to step 1.

After the timer 17 is started in step 3, the solenoid valve 15 is opened in step 4. Then, in step 5, it is checked whether the timer 17 is counting up. If it is not counting up, the process returns to step 4,
If the count is up, proceed to step 6 and solenoid valve 15
To close.

When the suction pressure of the compressor 1 is lowered in this way, the bypass circuit 13 is opened, and the refrigerant unevenly distributed in the condenser 2 is sucked into the inlet of the evaporator 4 through the throttle 14 and evaporated. Since the pressure rises in accordance with the throttle amount of the throttle 14 and the suction pressure also rises, the high pressure also rises at the same time.

When the solenoid valve 15 is closed and the bypass circuit 13 is shut off, the high pressure increases the circulation of the refrigerant to correct the unbalanced state of the refrigeration cycle.

Since there is no low-pressure operation during the start-up transition period, the lubricating oil circulating with the refrigerant returns, so the sliding part of the compressor 1 does not become dry friction, and therefore abnormal wear of the sliding part of the compressor 1 occurs. The reliability of the compressor 1 can be ensured without any occurrence.

Further, since the refrigeration cycle is quickly stabilized after the start after defrosting, the operating time is shortened and the power consumption is reduced.

Further, as shown in FIGS. 3 and 4, the defrost detecting means 9 is used in place of the suction pressure detecting means 18 which is the opening / closing timing detecting means of the solenoid valve, and in step 1, the defrost detecting means 9 The electromagnetic valve control means 16 may take in a signal for ending defrosting and proceed to step 3 if defrosting is completed in step 2 and return to step 1 if it is not completed.

As a result, the cost of the pressure detecting means can be reduced. Further, as shown in FIGS. 5 and 6, the suction pressure detection means 1 which is the opening / closing timing detection means of the solenoid valve.
In place of 8, the temperature detecting means 19 provided at the connecting portion between the capillary tube 3 and the evaporator 4 is used to take in the pipe temperature from the temperature detecting means 19 which is, for example, a thermistor in step 1, and the detected temperature value is predetermined in step 2. Below the temperature of
Alternatively, the solenoid valve control means 16 may proceed to step 3 to start the timer 17 and return to step 1 if the timer 17 is high.

Even if the temperature detecting means 19 is a bimetal, the same effect can be obtained. The solenoid valve 15 may be closed by energization and opened by a power failure, or vice versa. However, it is desirable that the solenoid valve 15 is closed during normal refrigerator operation, which consumes most of the time, so that power consumption can be reduced. Open up better. Further, it is more preferable that it can switch between an open state and a closed state by energization.

[0055]

As is apparent from the above description, the refrigerator of the present invention is provided with a refrigeration cycle in which a high-pressure container type compressor, a condenser, a capillary tube, and an evaporator are sequentially connected in an annular shape. A defrosting heater in the vicinity of the evaporator, the condenser, and a bypass circuit having a throttle between the evaporator inlet portion, the condenser, and a solenoid valve at a connection portion between the bypass circuit and the condenser. Since the solenoid valve opening / closing timing detection means and the solenoid valve control means for opening / closing the solenoid valve are provided, when the suction pressure of the high-pressure container compressor becomes equal to or lower than a predetermined pressure, the bypass is performed at a predetermined timing. After the circuit is opened and the high pressure is increased, the bypass circuit is closed, so that the refrigeration cycle can be smoothly shifted to a stable state and low pressure operation does not occur.

Further, the opening / closing timing detection means of the solenoid valve is suction pressure detection means provided at the connecting portion between the high-pressure container compressor and the evaporator, and the solenoid valve control means has a timer, and the suction pressure is Since the solenoid valve is opened when the suction pressure detected by the detection means becomes equal to or lower than a predetermined pressure, and the solenoid valve is closed when the timer has passed a predetermined time, the high pressure container is provided. When the suction pressure of the die compressor becomes equal to or lower than a predetermined pressure, the bypass circuit is opened, and the bypass circuit is closed after a lapse of a predetermined time, so that the low pressure operation is avoided.

Further, the opening / closing timing detecting means of the solenoid valve is a defrosting detecting means provided in the vicinity of the evaporator, the solenoid valve controlling means has a timer, and when the defrosting detecting means detects the defrosting completion, Since the solenoid valve is opened and the solenoid valve is closed when the timer has passed a predetermined time, the bypass circuit is opened after defrosting and the bypass circuit is closed after the predetermined time has passed. Low pressure operation does not occur.

Further, the opening / closing timing detection means of the solenoid valve is a temperature detection means provided at the connecting portion between the capillary tube and the evaporator, and the solenoid valve control means has a timer,
Since the electromagnetic valve is opened when the temperature detected by the temperature detecting means becomes equal to or lower than a predetermined temperature, and the electromagnetic valve is closed when the timer elapses a predetermined time, the refrigerant of the capillary tube is provided. It is detected that the flow rate drops and the evaporator inlet temperature drops, and when the temperature falls below a predetermined temperature, the bypass circuit is opened, and after the lapse of a predetermined time, the bypass circuit is closed, so low-pressure operation is avoided. .

As described above, since low-pressure operation does not occur during the transition period of startup, the lubricating oil circulating with the refrigerant immediately returns, and the sliding portion of the high-pressure container type compressor does not have dry friction. The reliability of the high-pressure container compressor can be ensured without abnormal wear of the sliding parts of the high-pressure container compressor.

Furthermore, since the unbalanced state of the refrigeration cycle does not continue after startup, the operating time of the high-pressure container compressor is shortened and the power consumption is reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a refrigerator according to the present invention.

FIG. 2 is a flowchart showing the operation of a solenoid valve of an embodiment of the refrigerator according to the present invention.

FIG. 3 is a sectional view of an embodiment of a refrigerator according to the present invention.

FIG. 4 is a flowchart showing the operation of the solenoid valve of the embodiment of the refrigerator according to the present invention.

FIG. 5 is a sectional view of an embodiment of the refrigerator according to the present invention.

FIG. 6 is a flowchart showing the operation of a solenoid valve of an embodiment of the refrigerator according to the present invention.

FIG. 7 is a sectional view of a conventional refrigerator.

[Explanation of symbols]

 1 Compressor 2 Condenser 3 Capillary tube 4 Evaporator 8 Defrost heater 9 Defrost detecting means 13 Bypass circuit 15 Solenoid valve 16 Solenoid valve control means 17 Timer 18 Suction pressure detecting means 19 Temperature detecting means

Claims (4)

[Claims] 1. A refrigeration cycle in which a high-pressure container type compressor, a condenser, a capillary tube, and an evaporator are sequentially connected in an annular shape is installed, and a defrosting heater and the condenser are provided near the evaporator. Circuit, a bypass circuit having a throttle between the evaporator inlet section, an electromagnetic valve disposed at a connection section between the condenser and the bypass circuit, an opening / closing timing detection means for the electromagnetic valve, and the electromagnetic valve. A refrigerator provided with a solenoid valve control means for opening and closing a valve. 2. A solenoid valve opening / closing timing detection means is suction pressure detection means provided at a connection portion between the high-pressure container compressor and the evaporator, and a solenoid valve control means has a timer, 2. The electromagnetic valve according to claim 1, further comprising: opening the solenoid valve when the suction pressure detected by the detection means becomes equal to or lower than a predetermined pressure, and then closing the solenoid valve when the timer elapses a predetermined time. refrigerator. 3. An electromagnetic valve opening / closing timing detecting means is a defrost detecting means provided in the vicinity of an evaporator, the electromagnetic valve control means has a timer, and the defrost detecting means detects the end of defrost. The refrigerator according to claim 1, further comprising: opening a solenoid valve, and closing the solenoid valve when the timer has elapsed a predetermined time. 4. An electromagnetic valve opening / closing timing detecting means is a temperature detecting means provided at a connecting portion between the capillary tube and the evaporator, and an electromagnetic valve controlling means has a timer, and a temperature detected by the temperature detecting means. The refrigerator according to claim 1, further comprising: opening the electromagnetic valve when the temperature reaches a predetermined temperature or lower, and closing the electromagnetic valve when the timer elapses a predetermined time.