JPH06347143A - Freezing apparatus - Google Patents

Abstract

PURPOSE:To properly keep the amount of a refrigerant in defrosting operation in a freezing apparatus which performs hot gas defrosting. CONSTITUTION:A main refrigerant circuit A is constructed by connecting a compressor 1, a condenser 2, an expansion valve 4, and an evaporator 5 through a refrigerant piping. A hot gas bypass passage 10 for connecting a discharge pipe and an inlet piping of the evaporator 5 is provided, and a three-way proportional valve MV is provided at a branch point. A liquid line and a suction line are connected through an injection bypass passage 15 via an injection solenoid valve ISV. When a refrigerant pressure value detected by a high pressure sensor HPT is lower than a downward set value in defrost operation, the injection solenoid valve ISV is opened to replenish the suction line with the refrigerant, while as the refrigerant pressure becomes higher than an upward set value, the degree of opening of the three-way proportional valve MV is adjusted to free a discharge gas refrigerant to the side of the condenser 2 of the main refrigerant circuit A. Hereby, a proper refrigerant amount in response to the advancement of the defrosting is secured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus for performing defrosting by bypassing a discharge gas refrigerant,
In particular, it relates to measures for reducing the defrost time.

[0002]

2. Description of the Related Art Conventionally, for example, JP-A-59-1776.
As disclosed in Japanese Patent No. 4, the refrigerating apparatus having the following configuration is a known technique. That is, as shown in FIG. 9, the refrigeration system is mainly composed of a compressor (1), a condenser (2), a pressure reducing mechanism (4), an evaporator (5), etc., which are sequentially connected by a refrigerant pipe. The refrigerant circuit (A), a discharge gas bypass passage (10) that bypass-connects the discharge line of this main refrigerant circuit and the inlet side of the evaporator, and the flow of discharge refrigerant to the condenser (2) of the main refrigerant circuit (A). ) Side and discharge gas bypass passage (10)
And a three-way switching valve (MV) for switching to and.
Further, the liquid line of the main refrigerant circuit (A) is provided with a liquid reservoir (LST) which is sandwiched between two on-off valves (SV1, SV2) and stores a fixed amount of liquid refrigerant. When there is a defrost command, the on-off valve (SV2) on the upstream side of the liquid reservoir (LST) is opened and the on-off valve (SV1) on the downstream side is closed to store the liquid refrigerant in advance in this liquid reservoir (LST). After the pump down operation is performed, the on-off valve (SV2) on the upstream side of the liquid reservoir (LST) is closed and the on-off valve on the downstream side (SV1).
And the connection of the three-way switching valve (MV) is switched, and this fixed capacity of the refrigerant is discharged into the gas bypass passage (10).
Then, the so-called metering pump down type defrosting is performed. With this metering pump down type defrosting, efficient defrosting operation is performed without wasteful heating of the evaporator.

Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. 4-24478, as shown in FIG. 10, a compressor (1), a condenser (2), an electric expansion valve (EV) and an evaporator (5). A main refrigerant circuit (A) configured by sequentially connecting the refrigerant pipes, a discharge gas bypass passage (10) and a three-way switching valve (MV) are provided, while the discharge gas bypass passage (10) and the three-way switching valve (MV) are provided. There is a refrigerating apparatus having a configuration in which a high pressure gas line on the downstream side of (1) is connected by a bypass pipe via a relief valve (RV). In this case, if there is a defrost command, the metering pump down operation before the defrost operation is not performed, only the electric expansion valve (EV) is closed, and only the defrost that causes the discharge gas bypass passage (10) to bypass the discharge gas refrigerant is performed. When the high pressure becomes higher than a predetermined value during defrosting, the relief valve (RV) is opened to return a part of the discharged gas refrigerant to the condenser (2) side. Furthermore, when the high pressure drops during defrost, the electric expansion valve (EV) of the main refrigerant circuit (A) is opened to replenish the evaporator (5) with the refrigerant in the liquid line so as to compensate for the lack of defrost capacity. I have to.

[0004]

However, the above-mentioned conventional devices have the following problems.

In the case of the refrigerating apparatus described in the former publication among the technologies of the two publications, since only the refrigerant in the liquid reservoir is used for defrosting, the defrosting ability is low under conditions where the outside air temperature is low. There was a shortage of time, which sometimes increased the time required for defrosting.

On the other hand, in the refrigeration system described in the latter publication, a relief valve is provided in the bypass pipe between the discharge gas bypass passage and the condenser upstream side of the main refrigerant circuit. Since a valve having a considerably large capacity is required, the cost is increased. Furthermore, when the evaporator is replenished with refrigerant in response to a decrease in the low-pressure side pressure, it is effective under conditions where the outside air temperature is high, but under conditions where the outside air temperature is low, the internal pressure of the high-pressure liquid line such as the receiver during defrosting is effective. There is a problem that a means for detecting whether or not the pressure is higher than the internal pressure of the evaporator (for example, a low pressure switch (LPS) in the figure) and a control for judging are necessary.

The present invention has been made in view of the above points, and an object thereof is to perform the defrost operation in progress.
Focusing on the fact that the required amount of refrigerant differs depending on the melting state of frost on the evaporator, by grasping the required amount of refrigerant from the high-pressure or low-pressure state, and taking measures to adjust the amount of refrigerant with a simple configuration The purpose is to reduce defrost operation time and improve reliability while suppressing an increase in cost.

[0008]

Means for Solving the Problems To achieve the above object, the means taken by the invention of claim 1 is, as shown in FIG. 1, a compressor (1), a condenser (2), a pressure reducing mechanism (4). ) And an evaporator (5) are sequentially connected by a refrigerant pipe, and a refrigerating apparatus provided with a closed main refrigerant circuit (A).

A liquid line opening / closing mechanism (LSV) which is provided at a portion of the main refrigerant circuit (A) between the condenser (2) and the evaporator (5) and opens and closes the liquid line pipeline. By connecting a part of the main refrigerant circuit (A) between the compressor (1) and the condenser (2) and a part of the pressure reducing mechanism (4) and the evaporator (5) by a refrigerant pipe. The discharge gas bypass passage (10) and the flow of the discharge gas refrigerant are changed to the main refrigerant circuit (A).
A three-way proportional valve (MV) configured to divide the flow into the condenser (2) side and the discharge gas bypass passage (10) side and change the flow rate ratio in each direction by adjusting the opening. The refrigerant pressure detecting means (HPT) for detecting the pressure of the gas refrigerant in the main refrigerant circuit (A) and the liquid line opening / closing mechanism (LSV) are closed when a defrost command is received during the operation of the refrigeration system. Adjust the opening of the three-way proportional valve (MV),
Discharge all of the discharge gas refrigerant into the discharge gas bypass passage (10).
And a defrost operation control means (51) for controlling so as to melt the frost of the evaporator (5), and the refrigerant pressure detection means (HPT) during the defrost operation by the defrost operation control means (51). When the pressure of the gas refrigerant becomes higher than the upper set value, the three-way proportional valve (MV)
And a relief control means (52) for controlling the discharge gas refrigerant to escape to the condenser (2) side of the main refrigerant circuit (A).

According to the invention of claim 2, in the invention of claim 1, the output of the refrigerant pressure detecting means (HPT) is received and the pressure of the gas refrigerant is changed as shown in the broken line portion of FIG. Relief end detecting means (53) which outputs a relief end signal for stopping the control of the relief control means (52) when the upper set value falls by a certain value or more.
Is provided.

A third aspect of the present invention is based on the first or second aspect of the invention, in which a refrigerant replenishing bypass passage (15) for connecting the high pressure liquid line and the suction line of the main refrigerant circuit (A). And an opening / closing mechanism (55) having at least an opening / closing function of the passage of the refrigerant replenishing bypass passage (15),
At the initial stage of starting the defrost operation by the defrost operation control means (51), there is provided a refrigerant replenishment control means (54A) for opening the opening / closing mechanism (55) to replenish the suction line with refrigerant.

According to a fourth aspect of the present invention, in the first or second aspect of the invention, the liquid line of the main refrigerant circuit (A) is provided at the beginning of the start of the defrost operation by the defrost operation control means (51). Refrigerant replenishing control means (54B) is provided for controlling the opening and closing mechanism (LSV) to open the evaporator (5) to replenish the liquid refrigerant.

As shown in FIG. 2, the means taken by the invention of claim 5 is that a compressor (1), a condenser (2), a pressure reducing mechanism (4) and an evaporator (5) are sequentially connected by a refrigerant pipe. The object is a refrigerating apparatus including a closed-circuit main refrigerant circuit (A).

A liquid line opening / closing mechanism (LSV) which is provided at a portion of the main refrigerant circuit (A) between the condenser (2) and the evaporator (5) and opens and closes the liquid line pipeline. By connecting a part of the main refrigerant circuit (A) between the compressor (1) and the condenser (2) and a part of the pressure reducing mechanism (4) and the evaporator (5) by a refrigerant pipe. The discharge gas bypass passage (10) and the flow of the discharge gas refrigerant are changed to the main refrigerant circuit (A).
Connection switching mechanism (MV) for switching between the condenser (2) side and the discharge gas bypass path (10) side of the main refrigerant circuit and the bypass path for refrigerant replenishment that connects the high pressure liquid line and the suction line of the main refrigerant circuit (A). (15), an opening / closing mechanism (55) having at least an opening / closing function of the passage of the refrigerant replenishing bypass passage (15), and a refrigerant pressure detecting means (HPT) for detecting the pressure of the gas refrigerant in the main refrigerant circuit (A). ) And a defrost command is received during operation of the refrigeration system, the liquid line opening / closing mechanism (LSV) is closed and the connection switching mechanism (M
V) to switch the discharge gas refrigerant to the discharge gas bypass passage (10) to control the defrost operation control means (51) to melt the frost on the evaporator (5), and the defrost operation control. During the defrosting operation by the means (51), when the output of the refrigerant pressure detecting means (HPT) is received and the pressure of the gas refrigerant becomes lower than the lower set value, the opening / closing mechanism (55) is opened to direct the refrigerant to the suction line. A refrigerant replenishment control means (54) for controlling replenishment is provided.

According to the means of the invention of claim 6, in the invention of claim 5, the output of the refrigerant pressure detecting means (HPT) is received as shown by the broken line portion in FIG. When it becomes higher than the lower set value by a constant value, a refrigerant replenishment end detection means (5) that outputs a refrigerant replenishment end signal for ending the control of the refrigerant replenishment control means (54).
6) is provided.

According to a seventh aspect of the present invention, in the third, fifth or sixth aspect of the present invention, the refrigerant replenishing bypass passage (15) is connected to the discharge pipe temperature of the compressor (1) of the refrigeration system. Injection bypass path for control (15)
It is configured so as to be used also as.

The means taken by the invention of claim 8 is the opening / closing mechanism (5) according to the invention of claim 3, 5, 6 or 7.
5) is provided so that the opening can be changed. The refrigerant replenishment control means (54) is configured to control the opening degree of the opening / closing mechanism (55) to increase as the pressure value of the gas refrigerant decreases.

According to a ninth aspect of the invention, in the invention of the fifth, sixth, seventh or eighth aspect, when the output of the refrigerant pressure detecting means (HPT) is received and the pressure of the gas refrigerant reaches an upper set value. A relief control means (52) is provided to control a part of the discharged gas refrigerant discharged from the compressor (1) to the condenser (2) side of the main refrigerant circuit (A).

The means taken by the invention of claim 10 is, in the invention of claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, the condenser (2) -the pressure reducing mechanism (5). The liquid refrigerant storage section (3) interposed between the liquid refrigerant and the defrost operation control means (5) when receiving a defrost command.
Before performing the control of 1), the liquid line opening / closing mechanism (LSV) of the main refrigerant circuit (A) is closed, and all the discharged gas refrigerant is supplied to the liquid refrigerant reservoir (3) side of the main refrigerant circuit (A). A pump-down operation control means (57) is provided which controls the liquid refrigerant storage section (3) to be circulated to store the refrigerant therein.

According to the invention of claim 11, in the invention of claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, the defrost operation control means (51) is vaporized. A heating operation for performing defrosting while operating an electric fan (EF) is possible.

[0021]

With the above construction, in the invention of claim 1, during the defrost operation by the defrost operation control means (51),
When the pressure of the gas refrigerant becomes higher than the upper set value, the relief control means (52) causes the discharge gas bypass passage (1
0) A part of the discharge gas refrigerant flowing through the main refrigerant circuit (A)
It is controlled to escape to the condenser (2) side. Therefore,
With a simple configuration, the excessive increase in the refrigerant pressure is eliminated, and abnormal stoppage of the refrigeration system is avoided. Further, non-uniformity of defrosting and overheating of the evaporator (5) due to excess refrigerant in the latter stage of defrosting operation and the like will be eliminated.

In the second aspect of the invention, while the relief control of the refrigerant is being performed by the relief control means (52),
When the amount of refrigerant becomes insufficient for some reason and the pressure value of the gas refrigerant becomes lower than the upper set value by a fixed value, the relief end detection means (53) outputs a relief control end signal. The control is smoothly returned to the normal defrost control, and the defrost operation time is prevented from increasing due to the shortage of the refrigerant amount.

In the invention of claim 3, the above-mentioned claim 1 or 2
In addition to the function of the invention described above, in the initial stage of the defrost operation in which the amount of frost on the evaporator (5) is large and heating capacity is required, the refrigerant replenishment control means (54) causes the refrigerant replenishment bypass passage (1).
Since the opening / closing mechanism (55) of 5) is opened and the suction line is replenished with an appropriate amount of refrigerant in advance, the defrost ability is increased,
The defrost operation time will be shortened.

In the invention of claim 4, the above-mentioned claim 1 or 2
In addition to the function of the invention described above, in the initial stage of the defrost operation in which the frost amount of the evaporator (5) is large and the heating capacity is required, the refrigerant replenishment control means (54) causes the evaporator (5) to have an appropriate amount of refrigerant. Are replenished, the defrost capacity is increased and the defrost operation time is shortened.

According to the fifth aspect of the present invention, during the defrosting operation by the defrosting operation control means (51), when the detected value of the refrigerant pressure detection means (HPT) becomes lower than the lower set value, the refrigerant replenishment control means (54) causes Since the opening / closing mechanism (55) of the refrigerant replenishing bypass passage (15) is opened and the refrigerant is replenished to the suction line, the frost formation of the evaporator (5) is quickly melted and the defrost operation time is shortened. become.

In the invention of claim 6, in the operation of the invention of claim 5, when the detected value of the refrigerant pressure detecting means (HPT) rises from the lower set value and becomes higher by a certain value, the refrigerant replenishment completion detecting means. As a result of (56), the refrigerant replenishment end signal is output, so that the amount of refrigerant is prevented from becoming excessive.

In the invention of claim 7, the refrigerant replenishing bypass passage (15) also serves as an injection bypass passage for controlling the discharge pipe temperature. Therefore, the existing equipment is used to make a shortage of the refrigerant amount during the defrost operation. Will be eliminated, and the increase in cost will be suppressed.

In the eighth aspect of the present invention, the refrigerant replenishment control means (54) controls the opening degree of the opening / closing mechanism (55) of the refrigerant replenishment bypass passage (15) to increase as the pressure of the gas refrigerant decreases. Therefore, the appropriate amount of the refrigerant is replenished according to the insufficient amount of the refrigerant, and the defrost ability is appropriately maintained.

In the invention of claim 9, the above-mentioned claims 5, 6,
In addition to the action of the invention of 7 or 8, relief control means (5
When the refrigerant pressure value becomes the upper set value by the control of 2),
Part of the discharged gas refrigerant is the condenser (2) of the main refrigerant circuit (A)
Since it is escaped to the side, the excessive rise state of the refrigerant pressure is resolved,
An abnormal stop or the like due to the rise of the refrigerant pressure is avoided.

According to the tenth aspect of the present invention, when the defrost command is given, the pump down operation control means (57) performs the pump down operation before the defrost operation, and the refrigerant is stored in the liquid refrigerant reservoir (3). Is stored, the amount of refrigerant used for performing the defrost operation is substantially constant for each defrost operation, and uniform defrost is performed.

According to the eleventh aspect of the present invention, the evaporator fan (EF) is operated and the inside of the refrigerator is heated during the defrosting operation by the defrosting operation control means (51) depending on the conditions such as the temperature inside the refrigerator. The internal temperature control function will be improved.

[0032]

Embodiments of the present invention will be described below with reference to the drawings starting from FIG.

FIG. 3 shows a refrigerant piping system of a container refrigerating apparatus according to an embodiment of the present invention. The main refrigerant circuit (A) is provided with a compressor (1) for compressing and discharging the sucked refrigerant into a high-pressure state, and a discharge gas refrigerant discharged from the compressor (1) which is arranged outside the refrigerator to condense and liquefy. An air-cooled condenser (2)
A receiver (3) that stores the liquid refrigerant condensed in the air-cooled condenser (2) and can also function as a water-cooled condenser;
Liquid solenoid valve (LSV) that opens and closes the passage of the liquid line of the main refrigerant circuit (A), temperature-sensitive expansion valve (4) in which the temperature-sensitive cylinder (4a) is arranged in the suction gas line, and the inside of the refrigerator And an evaporator (5) for evaporating the liquid refrigerant by heat exchange with the air in the refrigerator, and the devices (1) to (5) are sequentially connected by a refrigerant pipe, and the refrigerant is It constitutes a closed closed circuit main refrigerant circuit (A). The air-cooled condenser (2) and the evaporator (5) each have a pair of condenser fans (C).
F), (CF) and evaporator fans (EF), (EF) are attached. That is, the cold heat obtained by heat exchange with the outside air in the air-cooled condenser (2) is applied to the inside air in the evaporator (5) to cool the inside to a predetermined low temperature state. ing.

Further, a part of the main refrigerant circuit (A) between the compressor (1) and the condenser (2) and a part of the expansion valve (4) and the evaporator (5) (here, the evaporator). The hot gas bypass passage (10), which is a discharge gas bypass passage for bypassing the discharge gas refrigerant to the inlet side of the evaporator (5), is connected to the inlet pipe of (5) by a refrigerant pipe. It is provided. A drain pan heater (11) for heating the drain pan is provided in the hot gas bypass passage (10), and the main refrigerant circuit (A) and the hot gas bypass passage (10) are branched. A three-way proportional valve (MV) is arranged at the point. This three-way proportional valve (MV) bypasses all the discharged gas refrigerant to the condenser (2) side of the main refrigerant circuit (A) in the fully closed state, while in the fully opened state, it discharges all the discharged gas refrigerant into the hot gas bypass passage. It is configured to bypass the (10) side. And at the intermediate opening, the main refrigerant circuit (A)
The flow rate ratio between the hot gas bypass passage 10 and the hot gas bypass passage 10 is variably adjusted.

Further, a partial connection (P) between the receiver (3) of the main refrigerant circuit (A) and the liquid solenoid valve (LSV) and a part (Q) of the suction line are bypass-connected by a refrigerant pipe. An injection bypass passage (15) for injecting the refrigerant in the liquid line into the suction line is provided. This injection bypass path (15)
Is provided with an injection solenoid valve (ISV), and the injection solenoid valve (ISV) is opened and closed according to a signal from a discharge pipe temperature sensor (Thd) attached to the discharge pipe.

Many sensors are arranged in the refrigeration system. (HPT) is a high pressure sensor which is arranged in the discharge pipe of the compressor (1) and serves as a refrigerant pressure detecting means for detecting the high pressure Hp of the refrigerant circuit (A). (LPT) is arranged in the suction pipe of the compressor (1) and is a low pressure L of the refrigerant circuit (A).
It is a low-voltage sensor that detects p. (DCHS) is a discharge pipe sensor which is arranged in the discharge pipe of the compressor (1) and detects the discharge pipe temperature Td. (EOS) is an outlet evaporator outlet sensor that is arranged in the refrigerant pipe on the outlet side of the evaporator (5) and detects the evaporator outlet temperature Teo of the refrigerant. (SS) is a blowout air sensor which is arranged at the air blowout port of the evaporator (5) and detects the blown air temperature Tss into the refrigerator. (RS)
Is a suction air sensor which is arranged at the air suction port of the evaporator (5) and detects the suction air temperature. (HPS) is a high pressure switch that operates when the high pressure Hp exceeds the upper limit value to abnormally stop the compressor (1). (AMBS) is an ambient temperature sensor that is arranged on the air intake side of the air-cooled condenser (2) and detects the temperature of the surroundings where the freezer is arranged. Also,
Although not shown, a humidity sensor (H
eS) and three core temperature sensors (USDA1 to USDA3) for detecting the actual internal temperature of fruits or the like stored in the refrigerator.

Here, the control system of the refrigeration system will be described. 4 and 5 show the control system of the refrigeration system, in which the equipment operating circuit (102) is connected to the three-phase AC power supply circuit (101) via three-phase wiring, while the second transformer (Tr2 )) Is connected to the control circuit (103) via a two-phase wiring that is converted into a two-phase alternating current of 24V. In the power supply circuit (101), (P1) is a two-phase AC
A 00V power source, (P2) is a three-phase AC 400V power source, and the frequency can be switched to 50 Hz or 60 Hz. Further, (VS-1, VS-2) are voltage changeover switches for alternately changing the power supply voltage between 200V and 400V.

In the device operating circuit (102), (CM) is the motor of the compressor (1),
Two contacts (which are directly connected to the power supply circuit (101) through a contact (CC-1) of an electromagnetic relay (CC) described later and which are interlocked with the voltage changeover switches (VS-1, VS-2) ( 400V-200V via VS-3, VS-4)
The characteristics are switched according to the above. And
When the power supply voltage is 400V, it is 400V as it is, and when the power supply voltage is 200V, it is boosted to 400V by the first transformer (Tr1), and the fan motors (EFM1) of the above-mentioned two internal fans (EF1, EF2), (EF M2)
Are respectively connected via the contacts (EFH-1, EFL-1) of the air quantity switching electromagnetic relay. Further, the fan motors (CFM1, CFM2) of the two outside fans (CF1, CF2) are connected to each other via the contacts (CFC1-1, CFC2-1) of the electromagnetic relays. In addition, (PCC1-1, PCC2-1)
Is a contact of the phase correction contactor (PCC1, PCC2) for switching the connection so that the phase is correct when the phase of the three-phase AC power supply is incorrect.

Next, the control circuit (103) is provided with a first
-Fifth printed circuit boards (EC1 to EC5) are arranged.
A CPU having a control function is mounted on the first printed circuit board (EC1) (not shown), and the operation of the equipment arranged on each printed circuit board is performed in response to a command from a remote controller (RCD). Is designed to control.

The second printed circuit board (EC2) is a power source I / O.
It functions as a board, and is connected to the second printed circuit board (EC2) through the second transformer (Tr2).
Two two-phase AC power supplies of V and 48V are connected. Then, first to nineteenth relays (Ry1 to Ry19) for controlling ON / OFF of each contactor and the like mounted on a third printed circuit board (EC3) described later, and each switch (WPS) described later,
An air-water cooling detection circuit for operating (HPS) and (CTP) and two protection device detection circuits are provided. Furthermore, the second printed circuit board (EC2) has a three-way proportional valve (M
V), backup battery (BAT), recorder (R)
CRD) etc. are connected.

The third printed circuit board (EC3) functions as an output terminal board, and connects the relays (Ry1 to Ry19) to devices such as contactors. That is, from the left side of the figure, four contactors (X, ...) for options, two contactors (USV1), (USV2) for opening and closing valves for controlling the unloader of the compressor (1), and an injection solenoid valve (ISV) contactor and liquid solenoid valve (LS
V) contactor, remote monitor receptacle (RM) for connecting signals to instruments that monitor the operating status of the refrigeration equipment on the bridge of a container ship, etc., and start / stop of the compressor motor (CM) An electromagnetic relay (CC) to control, an air-water cooling changeover switch (WPS) that opens and differentially receives the output of the air-water cooling detection circuit, a high-pressure pressure switch (CPS) that opens when the high pressure exceeds a predetermined value, and a compression A thermal switch (C that opens when the internal temperature of the machine (1) exceeds a specified temperature
TP), compressor start / stop contactor (CC), high air flow side internal fan contactor (EFH), low air flow side internal fan contactor (EFL), first and second external fan Contactor (CFC1, C
FC2) and the first and second contactors (PCC1) for phase correction,
(PCC2) is provided.

In addition, the contactor (EFH,
EFL) is a normally closed contact (EFL-2,
EFH-2) are respectively connected in series so that only one of the contactors operates. Also,
The phase correction first and second contactors (PCC1), (PCC
2) is the normally closed contact (PCC2-2, PCC) of the other contactor.
1-2) are connected in series. That is, when the phases of the three-phase AC power supply are opposite, the rotation directions of the fans are prevented from being opposite.

Next, the fourth printed circuit board (EC4) functions as a sensor terminal board, and the fourth printed circuit board (EC4) has the suction air sensor (SS).
, Discharge pipe sensor (DCHS) and evaporator outlet sensor (E
OS), ambient temperature sensor (AMBS), humidity sensor (H
us), low pressure sensor (LPT) and high pressure sensor (HPT)
And an outlet air sensor (RS) and three core temperature sensors (U
SDA1-3) are connected. Among the above sensors, the intake air sensor (SS) and the blown air sensor (RS)
And two are provided for each, and the other one is connected to a recorder (RCRD) to record the change.

The fifth printed circuit board (EC5) is provided with an overcurrent detection circuit (OC) and a phase detection device (PF) for a three-phase AC power supply.

Here, the operation control method of the refrigerating apparatus will be described with reference to the timing chart of FIG.
It will be explained based on the flowchart of.

First, in step ST1, normal operation is performed to cool the inside of the refrigerator. At this time, the compressor (1) is normally operated, the three-way proportional valve (MV) is fully closed or partially opened (when heating the inside of the refrigerator), and the inside fan (EF) is turned on. When operated, the liquid solenoid valve (LSV) is opened, and the injection solenoid valve (ISV) of the injection bypass passage (15) is controlled according to the discharge pipe temperature (between time t0 and t1 in FIG. 7). ).

During the normal operation, according to the detected value of the compressor discharge pipe sensor (DCHS), it is said that the discharge pipe temperature Td is low, while the injection solenoid valve (ISV) is closed while the discharge pipe temperature Td is decreased. When the temperature rises excessively, the injection solenoid valve (ISV) is opened to maintain the discharge pipe temperature within an appropriate range. Further, the temperature inside the refrigerator is detected by the blow-out sensor (SS) or the suction sensor (RS), and the compressor (1) is switched between full load and unload according to these signals so that the refrigerant state is properly maintained. Has been done. Furthermore, in the case of the freezing mode, the three-way proportional valve (M
V) is fully closed and all of the discharged gas refrigerant circulates in the main refrigerant circuit (A), but in the refrigerating mode, the three-way proportional valve (MV) is slightly opened to control the temperature of the air blown inside the refrigerator. A part of the discharged gas refrigerant is bypassed to the hot gas bypass passage (10) so as to be constant.

Here, when the defrost command is input by the command signal from the manual defrost switch (MDS) or the CPU (time t1 in FIG. 7), step S
At T2, the pump down operation is performed. That is, while operating the compressor (1), the internal fan (EF) is stopped, the injection solenoid valve (ISV) is fully closed, the three-way proportional valve (MV) is fully closed, and the liquid solenoid valve (LSV). Is controlled so that the liquid refrigerant is stored in the receiver (3). Then, during this pump down operation, in step ST3, it is judged whether or not the low pressure side pressure Lp detected by the low pressure sensor (LPT) is lower than a predetermined value Lps (for example, -50 cmHg), and the suction is performed. When the amount of refrigerant in the line decreases and the low-pressure side pressure Lp decreases to reach a predetermined value Lps (time t in FIG. 7).
2) End the pump down operation. By this control,
Pump down operation control means (57) is configured.

Then, in step ST4, the defrost operation is started. That is, without stopping the compressor (1) from the time of pump down operation, only the three-way proportional valve (MV) is opened to allow all the discharged gas refrigerant to flow through the hot gas bypass passage (10) and the refrigerant replenishment control. Timer (CR-MT) starts counting. Then, in step ST5, it is determined whether or not the detection temperature Teo of the outlet sensor (EOS) of the evaporator (5) which is the defrost completion thermostat is 35 ° C. or higher, and the following control is performed until Teo ≧ 35 ° C. .

First, in step ST6, the high pressure Hp detected by the high pressure sensor (HPT) is set to the upper set value 13 (Kg / c).
It is determined whether it is higher than m2), and Hp> 13 (Kg / cm2)
If not, the process proceeds to step ST10 and the timer (CR-
It is determined whether or not (MT) is counting, and if it is counting, the process returns to step ST5. On the other hand, a timer (CR-
If (MT) is being counted, further step ST11
Then, it is determined whether or not the timer (CR-MT) has counted up. If the timer (CR-MT) has counted up, the timer (CR-MT) is stopped and cleared in step ST12. Then, each proceeds to step ST13. Then, in step ST13, it is determined whether or not the high pressure Hp is lower than the lower set value 9 (Kg / cm2), and if Hp <9 (Kg / cm2), the process returns to the control of step ST5 and the normal defrost operation is performed. repeat.

On the other hand, if Hp <9 (Kg / cm2), it is judged that the amount of the refrigerant is insufficient to end the defrost quickly, and the process proceeds to step ST14, where the injection bypass passage (15) is injected. Solenoid valve (ISSV)
Open to replenish the suction line with refrigerant (time t in FIG. 7).
3). Then, in step ST15, Hp ≧ 10 (Kg / c
m2) or not, and the refrigerant is replenished until Hp ≧ 10 (Kg / cm2), and when Hp ≧ 10 (Kg / cm2),
In step ST16, the injection solenoid valve (I
SV) is closed and refrigerant replenishment control timer (CR-M
T) is started and the process returns to the control of step ST5 (time t4 in FIG. 7). The control of step ST14 constitutes the refrigerant replenishment control means (54), and the control of shifting from step ST15 to ST16 constitutes the refrigerant replenishment end time detection means (56).

On the other hand, when the frost of the evaporator (5) is melted, the condensing ability of the refrigerant is reduced, and the high pressure Hp rises. Therefore, in the determination of step ST6, Hp
When it is> 13 (Kg / cm2), it is determined that the refrigerant amount is too large, and the process proceeds to the control of step ST7, and the three-way proportional valve (M
The position V) is controlled to the intermediate position (time t5 in FIG. 7).
That is, by returning a part of the discharged gas refrigerant to the condenser (2) side of the main refrigerant circuit (A), the defrosting ability is reduced, the evaporator (5) is uniformly defrosted, and the evaporator (5) is )
Don't waste energy by raising the temperature too much. This control constitutes relief control means (52).

Then, in step ST8, Hp≤12
(Kg / cm2) is determined, and relief control is performed until Hp ≤12 (Kg / cm2), then Hp ≤12 (Kg / cm2).
When it becomes 2), the process proceeds to step ST9, the three-way proportional valve (MV) is fully opened, and all the discharged gas refrigerant is circulated to the hot gas bypass passage (10) again.
The control shifts to 0 (time t6 in FIG. 7). By the control of the step ST8, the relief end detecting means (53)
Is configured.

When the above control is carried out and when the detected value Teo of the evaporator outlet sensor (EOS) becomes 35 ° C. or more in the judgment of step ST5, it is judged that the frost on the evaporator (5) has melted, and the defrosting is performed. The operation is terminated and the normal operation of step ST1 is resumed (time t7 in FIG. 7). Above step ST4
By the control of ST5 and ST5, the defrost operation control means (5
1) is configured.

Therefore, in the above embodiment, the high pressure Hp is set to the upper set value (13 in the above embodiment) during the defrosting operation.
(Kg / cm2)), a part of the refrigerant is relieved from the hot gas bypass passage (10) to the condenser (2) side by the relief control means, so the high pressure switch (H
While preventing the compressor (1) from stopping due to the operation of PS),
The melting of frost on the evaporator (5) can be made uniform, and the evaporator (5) is not overheated, and the operation efficiency can be improved.

In this case, the opening of the three-way proportional valve (MV) is controlled to appropriately adjust the ratio of the refrigerant used for defrosting and the refrigerant to be relieved to the condenser (2) side. Compared with the one in which the relief control is performed by the combination of the three-way valve, the bypass pipe from the hot gas bypass passage (10) to the inlet side of the condenser, and the opening / closing valve, the opening / closing valve does not need to be separately provided, so that the cost is reduced.

Further, during the defrosting operation, particularly immediately after the defrosting operation is started, the refrigerant flowing through the hot gas bypass passage (10) under the condition that the evaporator (5) is frosted and thus has a large condensation capacity for the discharged gas refrigerant. When the amount is small, the defrosting ability is small and the defrosting operation time may be long. Here, as in the above embodiment, the shortage of the refrigerant is eliminated by replenishing the suction side with the refrigerant immediately after the start of operation or when the high pressure value Hp is low, so that the defrost operation time can be shortened. Can be planned.

This refrigerant replenishment control is not limited to the method of the above embodiment, but the liquid solenoid valve (LSV) of the main refrigerant circuit (A) is opened to replenish the evaporator (5) with refrigerant. May be. However, when the injection bypass passage (15) for controlling the discharge pipe temperature Td is used to control the replenishment of the refrigerant to the suction line,
It is not necessary to add a control for detecting a pressure difference that compares the magnitude of the liquid line and the internal pressure of the evaporator (5), as compared with the one that opens and closes the liquid solenoid valve (LSV), so the control is simplified. There is an advantage that it can be planned.

In the above embodiment, the injection bypass passage (15) which is a refrigerant replenishing bypass passage is provided with the injection solenoid valve (ISV) which is an opening / closing valve. However, instead of the opening / closing valve, the electric expansion valve (IEV) is provided. ) (Not shown)
May be provided. In that case, as shown in FIG. 8, by detecting the high pressure value Hp immediately before performing the refrigerant replenishment control, and performing control such that the opening degree of the electric expansion valve (IEV) is increased as the high pressure value Hp is lower, The amount of refrigerant for defrosting can be adjusted to a necessary and sufficient amount, and the defrosting operation time can be shortened and the defrosting efficiency can be improved.

Further, by performing the pump down operation before the defrost operation and temporarily storing the refrigerant in the receiver (3) which is the liquid reservoir, it is possible to make the amount of the refrigerant used for the defrost uniform to some extent. It is possible to reduce the variation caused by the difference in the conditions.

Although the embodiment is omitted, when defrosting is performed, the inside fans (EF1) and (EF2) are operated, and hot air is sent to heat the inside of the refrigerator to heat the inside of the refrigerator even with low outside air. It can be heated and the control function can be improved.

In the above embodiment, the high pressure sensor (HP
The upper and lower set values are provided for the detected value of (T),
Although relief control or refrigerant replenishment control is performed, the present invention is not limited to such an embodiment,
It goes without saying that two high voltage switches that output a rush command and a return command may be provided for one control, for example, relief control.

Further, in the above embodiment, the liquid solenoid valve (LSV) as the liquid line opening / closing mechanism is provided separately from the expansion valve (4) which is the pressure reducing valve. However, a single electric expansion valve is arranged, The pressure reducing valve and the liquid line opening / closing mechanism may be operated at the same time.

In the above embodiment, the high pressure sensor (HPT) is used as the refrigerant pressure detecting means for detecting the pressure of the gas refrigerant in the refrigerant circuit (A), but as can be seen from FIG. 7, the low pressure sensor (LPT) is used. ) May be used as the refrigerant pressure detecting means.

[0065]

As described above, according to the invention of claim 1, as a configuration of the refrigerating apparatus having the main refrigerant circuit in which the compressor, the condenser, the pressure reducing mechanism and the evaporator are sequentially connected,
A liquid line opening / closing mechanism that opens and closes the pipeline of the main refrigerant circuit liquid line, a discharge gas bypass passage that bypass-connects the discharge pipe of the compressor and the evaporator inlet, and an evaporator by the heat of the refrigerant flowing through the discharge gas bypass passage. It is configured so that the heater for heating and the flow of the discharge gas refrigerant are divided into the condenser side and the discharge gas bypass passage side of the main refrigerant circuit, and the flow rate ratio in each direction can be changed by adjusting the opening degree. When a defrost command is received during operation of the refrigeration system, the liquid line opening / closing mechanism is closed, the opening of the three-way proportional valve is adjusted, and all of the discharge gas refrigerant is supplied to the discharge gas bypass path. While hot gas defrosting is carried out and the pressure of the gas refrigerant becomes higher than the upper set value during the defrosting operation, the opening of the three-way proportional valve is changed to direct the discharged gas refrigerant to the condenser side of the main refrigerant circuit. Miss So it was configured to perform-safe control,
With a simple configuration, it is possible to eliminate the excessive increase in the refrigerant pressure and avoid abnormal stoppage of the refrigeration system, thus improving reliability. In addition, in the latter half of the defrosting operation, it is possible to prevent uneven defrosting due to excessive defrosting ability and overheating of the evaporator.

According to the invention of claim 2, in the invention of claim 1, when the refrigerant pressure drops from the upper set value by a certain value or more, the relief control end signal is output. Is smoothly restored to the defrost control, and an increase in the defrost operation time due to a decrease in high pressure can be prevented.

According to the invention of claim 3, in the invention of claim 1 or 2, the refrigerant replenishing bypass passage for connecting the high pressure liquid line and the suction line of the main refrigerant circuit through the opening / closing mechanism is provided, and the defrosting is performed. In the initial stage of operation, the opening / closing mechanism is opened to perform the refrigerant replenishment control for replenishing the suction line with the refrigerant. Therefore, in addition to the effect of the invention of claim 1 or 2, the amount of frost formed on the evaporator is large. The defrosting capacity can be increased in the early stage of the defrosting operation that requires the heating capacity, so that the defrosting operation time can be shortened.

According to the invention of claim 4, in the invention of claim 1 or 2, the refrigerant for opening the liquid line opening / closing mechanism of the main refrigerant circuit to replenish the evaporator with the liquid refrigerant in the early stage of the start of the defrost operation. Since the replenishment control is performed, in addition to the effect of the invention of claim 1 or 2, it is possible to increase the defrosting ability at the initial stage of the defrosting operation in which the frost amount of the evaporator is large and the heating ability is required. Therefore, the defrost operation time can be shortened.

According to the fifth aspect of the present invention, as a constitution of a refrigerating apparatus having a main refrigerant circuit in which a compressor, a condenser, a pressure reducing mechanism, and an evaporator are sequentially connected, a main refrigerant circuit liquid line pipeline is provided. A liquid line opening / closing mechanism that opens and closes, a discharge gas bypass path that bypass-connects the discharge pipe of the compressor and the evaporator inlet, a heater that heats the evaporator by the heat of the refrigerant flowing through the discharge gas bypass path, and a discharge gas refrigerant. The connection switching mechanism that switches the flow of the main refrigerant circuit to the condenser side and the discharge gas bypass path side, and the refrigerant replenishing bypass path that connects the high-pressure liquid line and the suction line of the main refrigerant circuit via the opening / closing mechanism. When a defrost command is received during operation of the refrigeration system, the liquid line opening / closing mechanism is closed, the connection switching mechanism is switched, and all of the discharge gas refrigerant is circulated in the discharge gas bypass passage. While performing the defrost operation, when the pressure of the gas refrigerant becomes lower than the lower set value, the opening / closing mechanism is opened to perform the refrigerant replenishment control for controlling the refrigerant to be replenished to the suction line. The frost formation on the evaporator can be eliminated and the frost formation on the evaporator can be quickly melted, and thus the defrost operation time can be shortened.

According to the invention of claim 6, in the invention of claim 5, when the pressure of the gas refrigerant rises from the lower set value and rises by a fixed value, the refrigerant replenishment end signal is output. It is possible to prevent the amount of the refrigerant from becoming excessive, so that it is possible to appropriately supplement the refrigerant.

According to the invention of claim 7, the above-mentioned claim 3,
Since the refrigerant replenishing bypass passage in the invention of 5 or 6 also serves as the liquid injection bypass passage for controlling the discharge pipe temperature of the compressor of the refrigeration system, the existing equipment is used to remove the refrigerant during defrost operation. The shortage can be resolved, and thus the increase in cost can be suppressed.

According to the invention of claim 8, the above-mentioned claim 3,
In the invention of 5, 6, or 7, the opening degree of the opening / closing mechanism is changeable, and the refrigerant replenishment control is configured to increase the opening degree of the opening / closing mechanism as the pressure of the gas refrigerant decreases. It is possible to replenish an appropriate amount of the refrigerant in accordance with the insufficient amount of, and thus it is possible to appropriately maintain the defrosting ability.

According to the invention of claim 9, the above-mentioned claim 5,
In the invention of 6, 7, or 8, when the pressure of the gas refrigerant reaches the upper set value, relief control is performed so that a part of the discharge gas refrigerant is released to the condenser side of the main refrigerant circuit. By reducing the amount of the circulating refrigerant, it is possible to reduce the refrigerant pressure value and avoid an abnormal stop or the like. Therefore, in addition to the effects of the above-described inventions, the reliability can be improved.

According to the invention of claim 10, in the invention of claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, the liquid refrigerant reservoir is provided in the liquid line of the main refrigerant circuit, When there is a defrost command, before performing defrost operation,
Since the pump down operation for storing the liquid refrigerant in the liquid refrigerant reservoir is performed, the amount of the refrigerant used for the defrost operation can be made substantially constant for each defrost operation, and thus,
Defrost can be made uniform.

According to the invention of claim 11, in the invention of claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, the evaporator fan is operated during defrost operation. While it is possible to do heating operation,
When the inside of the refrigerator is heated under conditions such as low outside air, heating can be performed quickly by performing the same control as in defrosting.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing the configuration of the invention of claim 5;

FIG. 3 is a piping system diagram of the refrigerating apparatus according to the embodiment.

FIG. 4 is an electrical wiring diagram of a power supply device and a device operating circuit of the refrigerating apparatus according to the embodiment.

FIG. 5 is an electric wiring diagram of a device control circuit of the refrigerating apparatus according to the embodiment.

FIG. 6 is a flowchart showing the contents of defrost operation control of the refrigerating apparatus according to the embodiment.

FIG. 7 is a timing chart showing a temporal change in the operating state of each device during the defrost operation of the refrigerating apparatus according to the embodiment.

FIG. 8 is a characteristic diagram showing a relationship between a high pressure and an opening when the refrigerant replenishment control is performed by an opening / closing mechanism whose opening can be changed.

FIG. 9 is a refrigerant piping system diagram of a conventional refrigeration system.

FIG. 10 is a refrigerant piping system diagram of a conventional refrigeration system.

[Explanation of symbols]

 A main refrigerant circuit 1 compressor 2 condenser 3 receiver 4 temperature-sensitive expansion valve (decompression mechanism) 5 evaporator 10 hot gas bypass passage (discharge gas bypass passage) 11 drain pan heater (heater) 15 injection bypass passage 51 defrost Operation control means 52 Relief control means 53 Relief end detection means 54 Replenishment control means 55 Opening / closing mechanism 56 Refrigerant replenishment end detection means 57 Pump down operation control means AMBS Ambient temperature sensor HPT High pressure sensor (refrigerant pressure detection means) HPS High pressure switch LPT Low pressure sensor LPS Low pressure switch LSV Liquid solenoid valve MV Three-way proportional valve ISV Injection solenoid valve (Open / close mechanism) IEV Injection electric expansion valve

Claims (11)

[Claims] 1. A refrigeration system comprising a closed-circuit main refrigerant circuit (A) in which a compressor (1), a condenser (2), a pressure reducing mechanism (4) and an evaporator (5) are sequentially connected by a refrigerant pipe. In the apparatus, a liquid line opening / closing mechanism (LSV) which is provided at a part of the condenser (2) -evaporator (5) of the main refrigerant circuit (A) and opens and closes a pipe line of the liquid line, Discharge in which a part of the main refrigerant circuit (A) between the compressor (1) and the condenser (2) and a part of the pressure reducing mechanism (4) and the evaporator (5) are bypass-connected by a refrigerant pipe. The gas bypass passage (10) and the flow of the discharge gas refrigerant are divided into the condenser (2) side and the discharge gas bypass passage (10) side of the main refrigerant circuit (A),
A three-way proportional valve (MV) configured to change the flow rate ratio in each direction by adjusting the opening, and a refrigerant pressure detecting means (HPT) for detecting the pressure of the gas refrigerant in the main refrigerant circuit (A). ), And when a defrost command is received during operation of the refrigeration system, the liquid line opening / closing mechanism (LSV) is closed and the opening degree of the three-way proportional valve (MV) is adjusted so that all of the discharged gas refrigerant is During the defrost operation by the defrost operation control means (51) which is controlled to melt the frost on the evaporator (5) by flowing through the discharge gas bypass passage (10), the above-mentioned defrost operation is performed. Receives the output of the refrigerant pressure detection means (HPT),
When the pressure of the gas refrigerant becomes higher than the upper set value, the relief which controls the opening degree of the three-way proportional valve (MV) so that the discharged gas refrigerant is released to the condenser (2) side of the main refrigerant circuit (A). A refrigeration system comprising: a control means (52). 2. The refrigerating apparatus according to claim 1, wherein when the pressure of the gas refrigerant falls below the upper set value by a certain value or more in response to the output of the refrigerant pressure detecting means (HPT), the relief control means (52) operates. Relief end detection means (5 for outputting a relief end signal for stopping the control)
An operation control device for a refrigeration system, which is provided with 3). 3. The refrigerating apparatus according to claim 1, wherein the refrigerant replenishing bypass passage connects the high-pressure liquid line and the suction line of the main refrigerant circuit (A), and the refrigerant replenishing bypass passage. The opening / closing mechanism (55) having at least the opening / closing function of the passage of (15) and the opening / closing mechanism (55) is opened to replenish the suction line with the refrigerant at the beginning of the defrost operation by the defrost operation control means (51). A refrigeration apparatus comprising: a refrigerant replenishment control means (54A). 4. The refrigerating apparatus according to claim 1 or 2, wherein the liquid line opening / closing mechanism (LSV) of the main refrigerant circuit (A) is opened at an early stage of starting the defrost operation by the defrost operation control means (51). A refrigeration apparatus comprising a refrigerant replenishment control means (54B) for controlling the evaporator (5) to replenish the liquid refrigerant. 5. A refrigeration comprising a closed-circuit main refrigerant circuit (A) in which a compressor (1), a condenser (2), a pressure reducing mechanism (4) and an evaporator (5) are sequentially connected by a refrigerant pipe. In the apparatus, a liquid line opening / closing mechanism (LSV) which is provided at a part of the condenser (2) -evaporator (5) of the main refrigerant circuit (A) and opens and closes a pipe line of the liquid line, Discharge in which a part of the main refrigerant circuit (A) between the compressor (1) and the condenser (2) and a part of the pressure reducing mechanism (4) and the evaporator (5) are bypass-connected by a refrigerant pipe. A gas bypass passage (10), a connection switching mechanism (MV) for switching the flow of the discharged gas refrigerant between the condenser (2) side and the discharged gas bypass passage (10) side of the main refrigerant circuit (A), A bypass line (15) for replenishing the refrigerant, which connects the high-pressure liquid line and the suction line of the refrigerant circuit (A), An opening / closing mechanism (55) having at least an opening / closing function of the passage of the bypass passage (15), a refrigerant pressure detecting means (HPT) for detecting the pressure of the gas refrigerant in the main refrigerant circuit (A), and a When the defrost command is received, the liquid line opening / closing mechanism (LSV) is closed, and the connection switching mechanism (MV) is switched to allow the discharge gas refrigerant to flow through the discharge gas bypass passage (10) to cause the evaporator ( 5) Defrost operation control means (51) for controlling so as to melt the frost, and the output of the refrigerant pressure detection means (HPT) during the defrost operation by the defrost operation control means (51),
When the pressure of the gas refrigerant becomes lower than the lower preset value, the opening / closing mechanism (55) is opened to provide a refrigerant replenishment control means (54) for controlling the replenishment of the refrigerant to the suction line. apparatus. 6. The refrigerating apparatus according to claim 5, wherein when the pressure of the gas refrigerant becomes higher than the lower set value by a certain value in response to the output of the refrigerant pressure detecting means (HPT),
Refrigerant replenishment end detection means (5) for outputting a refrigerant replenishment end signal for ending the control of the refrigerant replenishment control means (54).
6) A refrigerating apparatus comprising: 7. The refrigerating apparatus according to claim 3, 5 or 6, wherein the refrigerant replenishing bypass passage (15) is an injection bypass passage (15) for controlling a discharge pipe temperature of a compressor (1) of the refrigerating apparatus. A refrigerating device which is also used as 15). 8. The refrigerating apparatus according to claim 3, 5, 6 or 7, wherein the opening / closing mechanism (55) is provided so that the opening can be changed, and the refrigerant replenishing control means (54) is A refrigeration system characterized in that the opening degree of the opening / closing mechanism (55) is controlled to increase as the pressure of the gas refrigerant decreases. 9. The refrigerating apparatus according to claim 5, 6, 7 or 8, wherein when the pressure of the gas refrigerant reaches an upper set value upon receiving the output of the refrigerant pressure detecting means (HPT), the gas is discharged from the compressor (1). Part of the discharged gas refrigerant to be discharged is the condenser (2) of the main refrigerant circuit (A).
A refrigeration system provided with a relief control means (52) for controlling to escape to the side. 10. Claims 1, 2, 3, 4, 5, 6, 7,
The refrigerating apparatus according to claim 8 or 9, wherein the defroster is provided between the condenser (2) and the decompression mechanism (5), and a liquid refrigerant reservoir (3) that stores a liquid refrigerant, and the defroster when receiving a defrost command. Before controlling the operation control means (51), the main refrigerant circuit (A)
The liquid line opening / closing mechanism (LSV) is closed, and all the discharged gas refrigerant is circulated to the liquid refrigerant storage section (3) side of the main refrigerant circuit (A) to store the refrigerant in the liquid refrigerant storage section (3). And a pump down operation control means (57) for controlling so that the refrigerating apparatus. 11. Claims 1, 2, 3, 4, 5, 6, 7,
In the refrigerating apparatus according to 8, 9, or 10, the defrost operation control means (51) is an evaporator fan (E).
A refrigerating apparatus characterized in that a heating operation for performing defrosting while driving F) is possible.