JPH05312443A - Defrosting controller of freezer - Google Patents

Abstract

PURPOSE:To provide a defrosting controller wherein wasteful operation such as defrosting even with a reduced amount of frosting is eliminated to prevent in-freezer temperature from being raised for energy saving and for ensurance of stored article quality. CONSTITUTION:A freezer/refrigerator apparatus, in which a freezing cycle is switched to a defrosting cycle for defrosting operation, includes a defrosting timer 33. The timer accumulates the time a compressor 1 is actuated for freezing operation, and issues a defrosting operation signal as the accumulated time reaches a predetermined value. A defrosting starting relay 53 is actuated as the defrosting operation signal is issued, and switches the freezing cycle to the defrosting cycle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defrost control device in a refrigeration system for cooling a cooling target such as a freezer to a low temperature by a refrigeration cycle.

[0002]

2. Description of the Related Art In this type of freezing / refrigerating apparatus, frost adheres to and grows on the evaporator during continuous cooling operation, which lowers the refrigerating capacity. Therefore, defrosting (defrosting) is appropriately performed during the cooling operation. ) You must drive. Conventionally, as disclosed in, for example, Japanese Patent Laid-Open No. 62-5053, there are many cases where a timer is used to periodically perform defrosting at every set time. The reason for periodically performing the defrosting is based on the following reasons. That is, in the case of a cooling operation of a freezer and a refrigerator, the defrost control method in which the temperature inside the refrigerator is detected by a temperature sensor and defrosted according to the temperature, or defrosted according to the discharge pressure value of the compressor, Since the set temperature condition inside changes depending on the type and amount of the items to be cooled, the set temperature and pressure must be adjusted each time, but set the optimum temperature and pressure conditions. This is because it is difficult and causes various problems in practical use. Therefore, instead, an empirically appropriate defrost cycle is determined, and for example, a timer is used to cause the freezer to perform defrost every 1 to 3 hours.

[0003]

In the method of periodically defrosting based on a predetermined time as described above, frost does not adhere to the evaporator provided in the refrigerator and the temperature fluctuations occur when the load is low. Although the temperature is small and the temperature detection thermostat is off for a long time, it is forcibly switched to the defrost operation. Therefore, the temperature inside the refrigerator rises because the high-temperature refrigerant flows to the evaporator, which adversely affects the quality of the stored products, and the defrost operation is ended immediately by the defrost end command signal because there is little frost, There is a problem that the defrost time is wasted and the running cost is increased.

The object of the present invention is to perform defrosting by the necessity of matching the amount of frost adhered with the passage of time while taking advantage of the simple and practical advantage of performing defrosting by a time measuring means such as a timer. Provided is a defrosting device capable of ensuring the quality of stored goods by reducing energy consumption by reducing running cost and preventing internal temperature rise by configuring defrosting under appropriate time management. Especially.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a refrigerating apparatus which includes a compressor 1, a condenser 3, a pressure reducer 4 and an evaporator 5, and which is a refrigerating apparatus in which the refrigerating cycle is switched to a defrost cycle to perform defrosting. 1 operates to integrate the time during which the refrigerating operation is performed, and when the integrated time reaches a constant value, the time measuring means 33 that outputs a defrost operation signal, and the defrost operation signal are output to operate, A defrost control device for a refrigeration system, comprising: a defrost control means 53 for switching the refrigeration cycle to a defrost cycle.

Further, according to the present invention, the time measuring means 33 is provided in the drive section 3.
The drive unit 33M is connected in series to an output contact 32A that is closed when the temperature is high in a temperature controller 32 for adjusting the temperature in the freezer by integrating the time by energizing 3M. ..

The present invention also includes a compressor 1, a condenser 3, a pressure reducer 4, and an evaporator 5, and the compressor 1 is operated in a refrigeration system in which the refrigeration cycle is switched to a defrost cycle to perform defrost. A time counting means 33 that integrates the time during which the refrigerating operation is performed and outputs a defrost operation signal when the integrated time becomes a constant value, and operates by outputting the defrost operation signal, thereby performing a refrigeration cycle. And a defrost control means 53 for switching the defrost control means 53 to a cold state, and the clock means 33 is further clocked after the defrost operation signal is output, and is reset when the maximum time allowed for the defrost operation elapses to freeze the defrost control means 53. It is a defrost control device for a refrigeration system, which is characterized by switching to a cycle.

[0008]

According to the present invention, the time counting means 33 integrates only the cooling operation time, and when this integration time reaches a fixed time, a defrost operation signal is output to operate the defrost control means 2 to switch to the defrost operation. .. As described above, the defrost operation is not performed unless the cooling operation is performed for a certain time. Since the amount of frost formation is considered to be substantially proportional to the cooling operation time, useless defrosting operation that is performed even when no frosting occurs is eliminated, the number of defrosting operations can be reduced, and energy saving operation can be achieved.

In this case, the time measuring means 33 is constructed so that the driving portion 33M operates in a timed manner by energization, and a series circuit with the output contact 32A of the temperature controller 32 for controlling the temperature inside the freezer is closed at high temperature. If formed, it is possible to reliably integrate the operating time of the compressor 1 with a simple circuit structure.

Further, according to the present invention, when the time measuring means 33 outputs the defrost operation signal and further time is measured, and the maximum time allowed for the defrost, for example, a set time of about 1 hour, elapses, the time measuring means is provided. By resetting 33, the defrost control means 2 also has a guard timer function for switching to the refrigeration cycle, so that the operation of the time counting means 33 that is repeatedly output is ensured and the set time of the guard timer is set. As described above, since the defrost operation is not performed, it is possible to suppress the internal temperature change and establish the reliability of the defrost operation control.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an electric circuit diagram showing an electrical configuration of an embodiment of the present invention, and FIG. 2 is a refrigeration circuit diagram of a refrigerating apparatus in which the embodiment of the present invention is used. The refrigeration system shown in FIG.
A compressor 1, a four-way switching valve 2, a condenser 3, a temperature-sensitive automatic expansion valve (hereinafter abbreviated as “expansion valve”) 4, an evaporator 5 and an accumulator 6 are provided as component devices. In the compressor 1, the discharge port is connected to the high pressure inflow port A of the four-way switching valve 2 by the high pressure gas pipe line 22, and the suction port is through the compressor accumulator 7 and the outlet of the accumulator 6 by the low pressure gas pipe line 23. Connected to.

In the four-way switching valve 2, the low-pressure outflow port B is connected to the inlet of the accumulator 6 by the low-pressure gas pipe 24 via the check valve 18, and the first switching port C is condensed by the high-pressure gas pipe 25. The second switching port D is connected to the coil inlet of the container 3, and is connected to one end of the pipe functioning as the fan guard heater 17 by the pipe 26.

The condenser 3 is connected to the inlet of the expansion valve 4 by a liquid pipe 27 having a coil outlet through the dryer 15, and the outlet of the expansion valve 4 is connected by a liquid pipe 28 to the evaporator 5
Connected to the coil inlet of. The evaporator 5 has a coil outlet connected to the inlet of the accumulator 6 by a gas line 29.

The fan guard heater 17 has the other end connected to one end of a pipe line functioning as the drain pan heater 16.
The drain pan heater 16 has the other end connected to the liquid conduit 28 by a conduit 30 having a check valve 19 interposed therebetween.

On the other hand, a balance bypass pipe line formed by connecting the solenoid valve 9 and the capillary tube 8 in series is connected across the high pressure gas pipe line 22 and the gas pipe line 29, and A liquid injection pipe formed by connecting the filter 14, the solenoid valve 13 and the capillary tube 12 in series across the condenser 3 coil outlet connection side of the liquid pipe 27 and the suction chamber inlet of the compressor 1. The road is connected.

The condenser 3 is provided with outside fans 20A and 20B for guiding and cooling the outside air, and the evaporator 5 is provided with inside fans 21A and 20A for circulating and circulating the inside air.
21B is attached.

In the refrigerating apparatus having the above-mentioned structure, the temperature controller 32 is provided as a temperature control element, the high pressure pressure switch (abbreviated as "HPS") 11 is a detection element for protection, and the high pressure switch is a defrost control element. 10 and a defrost completion thermostat 31 are provided, and the temperature controller 32 detects the air temperature on the air inflow side of the evaporator 5 and outputs a signal to start the cooling operation when the temperature rises above a certain value. To do. The high-pressure switch 11 detects the pressure in the high-pressure gas line 22 and outputs a signal to stop the compressor 1 when the pressure rises above a certain value. The high pressure switch 10 detects the high pressure in the pipe line 26 and outputs a signal to terminate the defrost operation when the pressure rises above a certain value. The defrost completion thermostat 31 detects the refrigerant temperature of the gas pipe 29 and outputs a signal for ending the defrost operation when the temperature rises above a certain value.

The freezing operation of the above refrigerating apparatus is performed as follows. The four-way switching valve 2 is set to the valve switching position shown by the solid line in FIG. 2, and the compressor 1 and the fans 20A, 20B and 21 are set.
When A and 21B are operated, the refrigerant circuit has a compressor 1 → high pressure gas pipeline 22 → four-way switching valve 2 → high pressure gas pipeline 25 → condenser 3 → liquid pipeline 27 → expansion valve 4 → liquid pipeline 28. → evaporator 5 →
A compression refrigeration cycle is formed in the order of gas line 29 → accumulator 6 → compressor accumulator 7 → compressor 1. In the condenser 3, heat of condensation latent heat is exchanged between the high-temperature high-pressure refrigerant gas and the outside air, the condenser 3 is cooled by the outside air, and the refrigerant is condensed and liquefied, while in the evaporator 5, the low temperature passing through the expansion valve 4 is used. The latent heat of vaporization is exchanged between the low-pressure refrigerant liquid and the air in the refrigerator, so that the air in the refrigerator is cooled to a low temperature. In this way, the inside of the freezer is cooled by the compression refrigeration cycle.

On the other hand, the defrost operation is performed as follows. The compressor 1 is operated, and each fan 20A, 20B, 21
A and 21B are stopped, and the four-way switching valve 2 is set to the valve switching position shown by the broken line in FIG. The refrigerant circuit is the compressor 1 →
High-pressure gas pipe 22 → four-way switching valve 2 → pipe 26 → fan guard heater 17 → drain pan heater 16 → check valve 19 →
Pipe line 30 → liquid line 28 → evaporator 5 → gas line 29 → accumulator 6 → compressor accumulator 7 → compressor 1 forms a refrigerant cycle by a hot gas bypass system, and a high temperature from the compressor 1 The high-pressure (hot) gas flows to the fan guard heater 17 to heat the fan guard,
Then, by flowing to the drain pan heater 16 to heat the drain pan, and then flowing to the coil of the evaporator 5 to heat the coil and fins, the frost adhering to and growing on each part is melted and guided to the drain pan. Is discharged as. In this way, defrosting is performed by the latent heat of condensation of hot gas.

An electric circuit for automatically performing the cooling operation and the defrosting operation is shown in FIG. An electric circuit is formed from an electric circuit portion E provided on the unit side of the refrigeration system and an electric circuit portion F provided on the remote control box side. The electric circuit section E includes a compressor 1 as a controlled device.
Motor, the motors for the internal fans 21A and 21B, and the solenoid of the four-way switching valve 2 are provided, and as control devices, an electromagnetic switch 51 for starting and stopping the compressor 1, an auxiliary relay 52, The high pressure switch 10 is provided with a defrost completion thermostat 31, a defrost start relay 53 and a defrost end relay 54.

The electromagnetic switch 51 has a coil 51 when the auxiliary relay 52 is excited and the contact 52A is turned on.
C is excited and the switch is closed to drive the compressor 1.
The auxiliary relay 52 is excited in response to the output contact 32A of the temperature controller 32 provided in the electric circuit section F being closed due to the high internal temperature, and this excited state is the defrost control means defrost. Either the start relay 53 or the defrost end relay 54 is excited, and either the output contact 53A or the output contact 54A is closed and held.

On the other hand, the solenoid of the four-way switching valve 2 operates to switch the refrigerating circuit to the refrigerating cycle when the defrost start relay 53 is de-excited and the output contact 53B deenergizes the solenoid. Relay 5
When 3 is excited, it is excited and operates to switch the refrigeration circuit to the defrost cycle.

The motors of the internal fans 21A and 21B and the defrost start relay 53 are de-energized, and the four-way switching valve 2 is driven when switching to the refrigeration cycle, and the relay 53 is excited. In the state, the four-way switching valve 2 is stopped when switching to the defrost cycle.

In the defrost start relay 53, the coil 53C is excited by closing the output contact 33A of the time measuring means 33 which is realized by the defrost timer provided in the electric circuit section F. 33A is opened, or the defrost termination relay 54 is released by switching the output contact 54B with the excitation of the coil 54C. On the other hand, the defrost termination relay 54 operates when the high-pressure pressure switch 10 or the defrost completion thermostat 31 detects the completion of defrost and closes each output contact, thereby closing the coil 5.
4C is excited, this excited state is self-held by the switching operation of the output contact 54B, and the excitation is released as the output contact 33A of the defrost timer 33 is opened.

In the electric circuit section F on the remote control box side,
As described above, the control device includes the output contact 32A that is closed at a high temperature of the temperature controller 32, and the defrost timer 33 that has the drive unit 33M and the output contact 33A that is closed by time-up as constituent elements.

FIG. 3 is a front view showing the defrost timer 33 with the front cover 56 removed, and FIG.
FIG. 4 is a functional explanatory diagram of the defrost timer 33 shown in FIG. 3. The defrost timer 33 is provided with a timer dial 57, a seter 58 detachably attached to the timer dial 57, an on / off operation switching mechanism 59, an indicator lamp 60 and a terminal 61 on the front surface of the main body 55. Timer dial 57
Is slowly rotated by the drive unit 33M and makes one rotation in 24 hours, for example. The timer dial 57 is shown in FIG.
As shown in a part of the mounted state, the set elements 58A, 58B are arranged with an interval W1 corresponding to several hours such as 2 hours and an interval W2 corresponding to a guard time of about 1 hour which will be described later. 58C is attached. Then, the timer dial 57 rotates in the direction of arrow A to set 58.
When A reaches a predetermined position, the output contact 33A is opened, when the set element 58B reaches a predetermined position, the output contact 33A is closed, and when the set element 58C reaches the predetermined position, the output contact 33 is opened. It is adjusted so that it is opened, and this is repeated several times during one rotation of 24 hours.

Control of the defrost operation will be described below with reference to the electric circuit diagram of FIG. 1 provided with the defrost timer 33 described above, the flow chart shown in FIG. 5, and the time chart shown in FIG. .. As the cooling operation of the freezer, defrosting is performed every time the cooling operation is integrated and performed for two hours. When the operation switch is turned on and the operation is started, in step a1, the temperature inside the refrigerator is detected, and when the temperature is higher than the set temperature, the output contact 32A of the temperature controller 32 is turned on, and the defrost timer 33 drives the drive unit 33M. When the auxiliary relay 52 is excited, the electromagnetic switch 52 is excited and closed to drive the motor and the compressor 1 to operate. At this time, the four-way switching valve 2
Is not excited, the refrigeration circuit becomes a refrigeration cycle and the cooling operation starts.

When the temperature inside the refrigerator decreases, the output contact 32
A is turned off, the defrost timer 3 is de-energized and the timing is interrupted, while the compressor 1 is stopped and the cooling operation is stopped.
The defrost timer 33 does not count while the cooling operation is stopped. In this way, the start and stop of the cooling operation is repeated,
In step a2, the defrost timer 33 performs integration, and in step a3, it is checked whether or not the set time of 2 hours has been reached. The integrated time of the cooling operation is W11 to W14 shown in FIG. 6 or the intermittent operation shown in FIG.
In any case of the continuous operation indicated by 20, when the total time reaches 2 hours, the process proceeds to step a4. At step a4, the output contact 33A of the defrost timer 33 is turned on, so the defrost start relay 53 excites the coil 53C and switches the output contact 53B, so that the four-way switching valve 2 moves to the defrost cycle side. And the internal fans 21A and 21B are stopped.
On the other hand, as a result of the compressor 1 being kept in operation and the operation state being maintained as the output contact 53A is turned on, the cooling operation is switched to the defrost operation. Note that the defrost timer 33 keeps timing during the defrost operation.

The end of the defrost operation is checked in step a5, and the output contact of the defrost completion thermostat 31 for detecting the refrigerant outlet temperature of the evaporator 5 is turned on by increasing the temperature to 25 ° C., for example. The high pressure switch 10 has a pressure on the high pressure side of the refrigerant of 23.5 kg.
When the defrost start relay 54 is turned on by increasing the temperature to more than / cm ² or more, the defrost end relay 54 is excited because the defrost end is completed, and the defrost start relay 53 is deenergized by the switching operation of the output contact 54B. The four-way switching valve 2 is switched to the refrigeration cycle side, the internal fans 21A and 21B are operated, the defrost operation is completed, and the cooling operation is switched to.

When the defrost operation time is less than one hour, the defrost completion thermostat 31 and the high pressure switch 1 are still operating even if the defrost operation time is one hour.
Regardless of whether 0 remains in the off state, the guard timer functions to force the output contact 33A of the defrost timer 33 to be turned off when the predetermined time of 1 hour has elapsed from the start of the defrost operation. As a result, at this time, the cooling operation is always ensured, and at the same time, the defrost timer 33 is reset and the time counting by the integration is started again. The guard timer is also used as a monitoring device for exceeding the defrost operation time.

In this embodiment, the defrost timer 33, which is a clocking means, has a contact type structure, and the defrost control means for switching the refrigeration cycle to the defrost cycle is a contact circuit having the defrost start relay 53 as a constituent element. However, the present invention is not limited to such a contact type, and naturally, the one formed by an electronic circuit such as a microcomputer exhibiting the same function is also included in the scope of the present invention. Further, the guard timer is not limited to the configuration of the embodiment integrally assembled with the above-mentioned clocking means, and may be configured as a separate and independent timer circuit associated with the clocking means.

[0032]

As described above, according to the present invention, the defrosting period is set based on the actual operating time obtained by integrating only the cooling operating time, so that the defrosting operation is performed unless the cooling operation is performed for a certain period of time. Since it does not enter, the wasteful defrost operation is eliminated, the number of defrost operations can be reduced, and energy saving operation can be achieved. Further, by switching to the defrost operation even if the amount of frost is small, it is possible to maintain the quality of stored products by suppressing the rise in the internal temperature as well as reducing the operating cost.

[Brief description of drawings]

FIG. 1 is an electrical circuit diagram showing an electrical configuration of an embodiment of the present invention.

FIG. 2 is a refrigeration circuit diagram of a refrigeration apparatus in which an embodiment of the present invention is used.

FIG. 3 is a front view showing the defrost timer 33 in FIG. 1 with a front cover 56 removed.

4 is a functional explanatory diagram of a defrost timer 33 shown in FIG. 3. FIG.

FIG. 5 is a flowchart illustrating an operation of a defrosting operation according to the embodiment of this invention.

FIG. 6 is a time chart explaining an operating state of a refrigerating apparatus in which an embodiment of the present invention is used.

[Explanation of symbols]

 1 Compressor 2 Four-way switching valve 3 Condenser 4 Pressure reducer 5 Evaporator 10 High pressure switch 31 Defrost complete thermostat 32 Temperature controller 33 Defrost timer 33M Drive section 53 Defrost start relay 54 Defrost end relay

Claims (3)

[Claims] 1. A refrigerating apparatus comprising a compressor 1, a condenser 3, a pressure reducer 4, and an evaporator 5, wherein the refrigerating cycle is switched to a defrost cycle to perform defrosting.
Is operated to integrate the time during which the freezing operation is performed, and when the integrated time reaches a certain value, the time measuring means 33 that outputs a defrost operation signal, and the defrost operation signal that is output to operate A defrost control device for a refrigerating apparatus, comprising defrost control means 53 for switching a cycle to a defrost cycle. 2. The drive unit is connected to an output contact 32A which is closed at a high temperature of a temperature controller 32 for adjusting the temperature inside the freezer by integrating the clocking means 33 by energizing the drive unit 33M. 33. The defrost control device for a refrigerating apparatus according to claim 1, wherein 33M are connected in series. 3. A refrigerating apparatus comprising a compressor 1, a condenser 3, a pressure reducer 4, and an evaporator 5, wherein the refrigerating cycle is switched to a defrost cycle to perform defrosting.
Is operated to integrate the time during which the freezing operation is performed, and the integrated time becomes a constant value to output a defrosting operation signal, and the defrosting operation signal is operated to operate, A defrost control means 53 for switching the cycle to a defrost cycle, and the timing means 33 is further clocked after the defrost operation signal is output, and is reset when the maximum time allowed for the defrost operation elapses, and the defrost control is performed. Means 53
A defrost control device for a refrigeration system, characterized in that the refrigeration cycle is switched to a refrigeration cycle.