JPH0814445B2 - Operation control device in refrigeration system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is provided with a hot gas bypass passage for bypassing hot gas in an evaporator for capacity control, and at the time of frosting, evaporation by hot gas bypassed. The present invention relates to an operation control device in a refrigerating device configured to perform defrosting of a container and a drain pan.

(Prior Art) Conventionally, for example, in the one described in JP-A No. 61-29652, a hot gas bypass passage is provided from the discharge side of the compressor to the evaporator side, and the hot gas is bypassed to the evaporator. , The temperature inside the container or refrigerator, for example, -5 ℃ ~
It is possible to control from a frozen region of -6 ° C or lower to a chilled region of a temperature higher than -5 ° C to -6 ° C.
A drain pan heater is branched from the bypass passage through an opening / closing mechanism, and the heater is arranged on the air blow-out side of the evaporator and above the drain pan so that it is in a normal capacity control operation, that is, in a chilled area. During operation, hot gas bypassing the bypass passage by closing the opening / closing mechanism is introduced into the evaporator without passing through the drain pan heater, while hot gas bypassing the bypass passage is provided to the drain pan heater only during frost. The gas is flowed so that the drain pan can be defrosted together with the evaporator.

(Problems to be solved by the invention) However, when fresh foods such as meat and vegetables are stored in containers such as containers during operation in the chilled area, water vaporizes from these products. Generally, it is necessary to keep the inside of the storage chamber at a high humidity so that it does not end up, but on the other hand, in the case where articles such as lilies, tulips and other bulbs or coffee beans are stored in the storage chamber, the reverse is true. It is necessary to keep the humidity low.

Therefore, in the above-mentioned conventional one, during the operation in the chilled region, the hot gas bypassing the hot gas bypass passage is directly introduced into the evaporator without flowing through the drain pan heater. However, the amount of heat possessed by the hot gas introduced into this evaporator raises the evaporation temperature by heating the liquid refrigerant that has undergone condensation and expansion, and is used to reduce the capacity of the evaporator, which is the original purpose. Even though the temperature of the passing air passing through the evaporator can be controlled, it cannot contribute to reheat for the purpose of controlling the humidity of the passing air at all. When articles such as bulbs that prefer low humidity are accommodated, an appropriate dehumidifying operation cannot be performed.

Therefore, in general, it is conceivable to dispose an electric heater on the air outlet side of the evaporator to provide a reheater for humidity control, separately from the drain pan heater branched from the bypass passage. In this case, it is necessary to provide an on / off control circuit for the electric heater and a safety device therefor, which results in high cost. Moreover, since the electric heater and the compressor are simultaneously operated, it is possible to save energy. There is a new problem that goes against the requirement of.

The object of the present invention is to utilize the advantage of the prior art that capacity control operation and defrost operation of the evaporator and drain pan can be performed, without adding an electric heater or the like, and in low capacity operation, that is, in the chilled region. An object of the present invention is to provide an operation control device in a refrigerating apparatus that can selectively perform a dehumidifying operation in accordance with the characteristics of items stored in the refrigerator during the operation.

(Means for Solving Problems) Therefore, in the present invention, the hot gas bypass passage (8) for guiding the hot gas discharged from the compressor (1) to the evaporator (5) by-passing the condenser (2). And controlling the capacity of the evaporator (5) by adjusting the amount of hot gas to be partially bypassed to the bypass passage (8), and introducing all the amount of hot gas during frost to the evaporator (5). A hot gas valve (7) for performing defrost operation is provided, and a drain pan heater (80) branched via an opening / closing mechanism (9) is provided in the hot gas bypass passage (8).
0) is an operation control device in a refrigerating device in which the air blower side of the evaporator (5) is positioned, and a temperature setting device (5
0), a temperature detector (55) for detecting the temperature of air passing through the evaporator (5), and the hot gas valve (7) is operated based on the detection result of the temperature detector (55). Capacity control command means for adjusting the amount of hot gas to be partially bypassed to the hot gas bypass path (8), the humidity setting device (60), and the ability to bypass a part of the hot gas to the hot gas bypass path (8). During the control operation, the dehumidifying operation command means for operating the opening / closing mechanism (9) based on the instruction of the humidity setting device (60) to perform dehumidification control using the drain pan heater (80) as a reheater, and a hot gas bypass. A drain pan heating finger that controls the heating of the drain pan (15) by operating the opening / closing mechanism (9) and using the drain pan heater (80) as a heater during the defrost operation in which the entire amount of hot gas is bypassed to the passage (8). And it is characterized in that it comprises a means.

(Operation) When the capacity control is performed based on the detection result of the temperature detector (55), the hot gas valve (7) is actuated, and a part of the hot gas is passed through the bypass passage (8) to the evaporator (5). ), The cooling amount in the evaporator (5) is reduced to reduce the capacity, and during this capacity control operation, the dehumidifying operation is commanded based on the instruction of the humidity setting device (60). When it is turned on, the opening / closing mechanism (9) is operated to introduce the hot gas flowing in the bypass passage (8) into the drain pan heater (80), and the heater (80) passes through the evaporator (5). It is used as a reheater when dehumidifying the air, and dehumidification control is performed. Further, when the defrost operation is commanded, the opening / closing mechanism (9) is operated and the bypass passage (8) is provided. All hot gas flowing is introduced into the drain pan heater (80) Is, the heater (80) is being utilized as a heater of the drain pan (15), is the also performed defrost the drain pan (15).

(Embodiment) FIG. 1 shows a refrigerating machine equipped in, for example, a refrigerating container, and a condenser (2) attached with a fan (F2) from the discharge gas pipe (11) side of the compressor (1). ), A liquid receiver (3), a pressure equalizer (40) and a temperature sensing expansion valve (4) having a temperature sensing tube (44), an evaporator (5) with a fan (F), and an accumulator (6). A hot gas valve (7) is provided between the discharge gas pipe (11) and the flow divider (45) provided on the inlet side of the evaporator (5) while being connected via a refrigerant pipe (10). A hot gas bypass passage (8) for guiding hot gas discharged from the compressor (1) to the evaporator (5) by-passing the condenser (2) and the expansion valve (4) is provided.

The hot gas valve (7) is an electrically operated three-way valve whose valve opening degree to the bypass passage (8) can be controlled to be 0% to 100% in proportion to the voltage, and its electrically operated part (20
The amount of hot gas bypass to the evaporator (5) is adjusted by driving M).

From the middle of the bypass passage (8), the drain pan heater (80) is branched via an opening / closing mechanism (9) composed of a three-way valve, and the heater (80) is bypassed to the short-circuit passage (81). When the hot gas bypassed to the bypass passage (8) is once passed through the heater (80) and then bypassed to the evaporator (5) by switching the switching mechanism (9). It is possible to select a case of bypassing the heater (80) and bypassing the evaporator (5) directly.

Further, the heater (80) is on the air blowing side of the evaporator (5) by the fan (F), and is provided in the drain pan (15) for receiving dew condensation water or the like from the air passing through the evaporator (5). It is installed in the upper part to reheat the blown air and thaw the drain pan (15).

In FIG. 1, the pressure equalizing pipe (40) of the expansion valve (4) is replaced by a three-way valve (43) and first and second connecting pipes (4).
1) via low pressure pipe (12) on the outlet side of the evaporator (5) and the bypass passage (8) via (42), and the low pressure or hot is fed to the pressure equalizing pipe (40). The gas pressure is selectively introduced so that the valve opening of the expansion valve (4) can be adjusted.

Thus, the operation control of the refrigeration system configured as described above is
This is done using the controller (100) shown in the figure.

The controller (100) is composed of a microcomputer or the like, and on its input side, the temperature inside the container is arbitrarily set as an input of a temperature control system for controlling the temperature of the air passing through the evaporator (5). Temperature setting device (5
0) and a temperature detector (55) consisting of a return and supply sensor (RS) (SS) which are respectively provided on the suction side and the outlet side of the evaporator (5), and a humidity control system for the passing air. As an input of, a humidity setting device (60) that is a combination of a humidity input device (61) for inputting the set temperature in the chamber and a dehumidification switch (6H) for commanding reheat at the time of dehumidification by manual operation, The suction side of the evaporator (5) is connected to a humidity detector (65) provided on the suction side, and the outlet side of the evaporator (5) is used as a defrost control system input to the evaporator (5) and the drain pan (15). Air pressure switch (APS) installed in the air conditioner, defrost switch (3D) that commands defrost operation by manual operation, and thermistor (Th) that detects the temperature of gas flowing in the low pressure pipe (12) for detecting the end of defrost To And continue to.

On the other hand, on the output side of the controller (100), an electromagnetic relay (88) for starting and stopping the motor (MC) of the compressor (1) is provided.
C), an electromagnetic relay (88F) that starts and stops the motor (MF) of the evaporator side fan (F) and the air passing through the evaporator (5) by changing the rotation speed of the motor (MF) by changing the number of poles. Electromagnetic relay (88FH) that switches the air flow between high and low air volumes, an electricity relay (88F2) that starts and stops the motor (MF2) of the fan (F2) on the condenser side, and the electric section (20M) of the hot gas valve (7) , A switching relay (20RE) of the switching valve (43) and a switching relay (20RD) of the opening / closing mechanism (9) are connected.

In addition, the energizing circuit of the electromagnetic relay (88C) (88F),
A high pressure detector (HPS) arranged in the discharge gas pipe (11), an overcurrent relay (51C) and a thermoswitch (49C) of the compressor motor (MC) are interposed in series, and further,
A thermoswitch (49CF) of the fan motor (MF) is provided in series with the electromagnetic relay (88F) for the fan.

Then, the controller (100) drives and controls the electric part (20M) based on the detection result of the temperature detector (55), and activates the hot gas valve (7) to control the capacity of the evaporator (5). And the capacity control command means for performing the capacity control operation, that is, the chilled operation, the relay (20RD) is turned on and the opening / closing mechanism (9) is operated based on the instruction of the humidity setting device (60) to operate the drain pan heater (80). Dehumidification operation command means for performing dehumidification control as a reheater, and also during defrost operation, the relay (20RD) is turned on to operate the opening / closing mechanism (9), and the drain pan heater (80) is used as a heater for the drain pan (15) The drain pan heating command means for performing the heating control is incorporated, and the three types of operation modes of the chilled operation, the frozen operation, and the defrost operation are controlled as follows.

Hereinafter, each operation mode will be described based on the flowchart of FIG.

Chilled operation The chilled operation and the frozen operation are separated according to the temperature set by the temperature setting device (50).
During this chilled operation, the temperature detected by the return sensor (RS) that constitutes the temperature detector (55) and the temperature setter (50)
The drive control of the electric part (20M) is performed by comparing with the set temperature by, and the hot gas valve (7) is opened to the bypass passage (8) by the drive control of the electric part (20M).
The valve opening is subjected to so-called PID control based on the detected temperature and the set temperature, and an appropriate amount of hot gas matching the internal temperature is bypassed to the bypass passage (8).

At this time, turn on the relay (20RE) and switch the valve (4
3) is switched so that the pressure equalizing pipe (40) and the second connecting pipe (42) communicate with each other, and hot gas pressure that bypasses the bypass passage (8) is introduced into the pressure equalizing pipe (40) to expand the expansion valve (4). ), The amount of liquid refrigerant thrown into the evaporator (5) from the expansion valve (4) is optimally set according to the heating amount of the hot gas introduced into the evaporator (5). Furthermore, the electromagnetic relay (88FH) is turned on and the fan (F) is set to a high air volume.

Then, the humidity input device (6
1) Or when the dehumidification instruction is issued by the dehumidification switch (6H), that is, when the humidity set by the humidity input device (61) is lower than the humidity detected by the humidity detector (65), or the dehumidification switch (6H) When the heater is turned on, the relay (20RD) is turned on to operate the opening / closing mechanism (9), and hot gas bypassing the bypass passage (8) is passed through the drain pan heater (80) to the heater. The (80) is used as a reheater when the passing air is dehumidified in the evaporator (5), and it depends on the amount of cooling in the evaporator (5) corresponding to the temperature rise in the reheater. Then, the moisture is condensed and recovered from the passing air and a predetermined dehumidification control is performed.

The dehumidification control command from the dehumidification switch (6H) is preset in the controller (100) in addition to turning on the relay (20RD) uniformly when the switch (6H) is turned on. It is also possible to control ON / OFF of the relay (20RD) by comparing the compared set humidity with the humidity detector (65).

Frozen operation During frozen operation, for example, by turning off the electric part (20M), the valve opening degree of the hot gas valve (7) to the bypass passage (8) is set to 0%, and hot gas bypass is not performed. In addition, the entire amount of the discharge gas from the compressor (1) is circulated from the condenser (2) side so that the operation is performed in a normal refrigeration cycle.

Further, in this case, the relay (20RE) is turned off, the switching valve (43) is switched to the first connecting pipe (41) side, and a low pressure is introduced into the pressure equalizing pipe (40). Further, the electric relay (88FH) is turned off to reduce the air volume of the fan (F).

In this case, since hot gas is not bypassed in the bypass passage (8), bypass control of hot gas to the drain bypass heater (80) by ON / OFF control of the relay (20RD) is also irrelevant, and dehumidification control is performed. Is not done.

In the case of this frozen operation, the temperature detector (5
5) (In this case, there is no reheat of the passing air, so either return sensor RS or supply sensor SS is acceptable)
Comparing the detected temperature and the set temperature of the temperature setter (50), the start / stop control of the compressor (1) and each fan (F) (F2), that is, the electric relay (88C) (88F) ( 88F2) on / off control is performed.

Defrost operation During the chilled operation or frozen operation described above, the evaporator (5) is frosted and the air pressure switch (APS) is activated, or the defrost switch (3
When D) is turned on or the defrost timer built into the controller (100) is activated,
The operation shifts to the defrost operation. During this defrost operation, the valve opening of the hot gas valve (7) to the bypass passage (8) is set to 100% by driving the electric part (20M), and The entire amount is bypassed to the bypass passage (8) to remove the frost formation on the evaporator (5) in a short time.

At the same time, turn on (20RD) and open / close mechanism (9).
The hot gas that bypasses the bypass passage (8) is passed through the drain pan heater (80) to heat the drain pan (15) to which the heater (80) is attached so that the hot gas flows over the drain pan (15). The freezing water and so on can be thawed and discharged promptly.

In the case of this defrost operation, basically, when the temperature detected by the thermistor (Th) for low pressure gas reaches a predetermined value or when the defrost ends by the timer built into the controller (100), the relay (20RD ) Is turned off to stop the introduction of hot gas to the drain pan heater (80) .For example, when the operation before shifting to the defrost operation is the chilled operation and dehumidification control is performed, the relay (20RD ) Is kept on and the introduction of hot gas to the drain pan heater (80) is continued.

Thus, as described in detail about each of the above operation modes, the capacity control operation from frozen operation to chilled operation can be performed, and at the time of frosting, defrosting of the drain pan (15) in addition to the evaporator (5) can be performed quickly. While, in addition, the drain pan heater (8
0) can be used not only as a heater for defrosting but also as a reheater for dehumidifying the air passing through the evaporator (5) during chilled operation, and is stored in the refrigerator. The proper dehumidification control can be performed according to the product to be used.

When performing dehumidification during the above chilled operation, preset depending on the detection result of the humidity detector (65) against the set humidity of the humidity input device (61) or in the case of a dehumidification command from the dehumidification switch (6H). Depending on the detection result of the humidity detector (65) with respect to the set humidity, the introduction of the hot gas pressure of the bypass passage (8) into the pressure equalizing pipe (40) is shut off, and the hot gas of the expansion valve (4) is shut off. Alternatively, the adjustment of the opening degree may be canceled.

In this case, the restriction of the opening degree of the expansion valve (4) is released, the amount of liquid refrigerant supplied to the evaporator (5) side can be increased, and the cooling amount in the evaporator (5) can be increased. It is possible to increase the amount of the dehumidification, and it is possible to expect a better dehumidifying effect.

In the above embodiment, the dehumidifying switch (6H) is connected to the input side of the controller (100) to
In (0), the on / off state of this switch (6H) and defrost switch (3D) can be identified, and when this switch (6H) is turned on, the humidity detector in the controller (100) Although it is possible to set the contrast set humidity to be compared with (65), in order to simplify the configuration, the opening / closing mechanism (9) is operated as shown by the phantom line in FIG. The relay (20RD) is connected in parallel to the excitation circuit from the controller (100) side, and the excitation line (20RD) forcibly exciting the relay (20RD) is connected in parallel.
0), and a dehumidifying switch (6) on the excitation line (200).
H ') may be interposed.

Furthermore, in the above embodiment, two sensors, a return sensor and a supply sensor, are used as the temperature detector (55). However, for example, only the return sensor (RS) may be used, and the humidity input device may be used as the humidity input device (60). Although the device (61) and the dehumidifying switch (6H) were used together, it goes without saying that only one of them may be used.

(Effects of the Invention) As described above, according to the present invention, the capacity control operation ranging from the operation in the frozen region to the operation in the chilled region,
While having the advantage that not only the evaporator (5) but also the defrost operation of the drain pan (15) can be performed, there is no need to newly add an electric heater or the like, that is, there is no adverse effect such as high cost or energy saving, and low cost and Energy saving and hot gas bypass line (8) based on the instruction of humidity setting device (60) during low capacity operation in chilled area.
The hot gas flowing through the heater can be selectively introduced into the drain pan heater (80), and the heater (80) can be used as a reheater when the passing air is dehumidified by the evaporator (5). Therefore, the dehumidifying operation can be selectively performed according to the characteristics of the items stored in the container such as the container, and the range of application as the refrigerating device can be widened.

[Brief description of drawings]

FIG. 1 is a refrigerant piping system diagram of a refrigerating apparatus including a control device according to the present invention, FIG. 2 is a schematic electric circuit diagram of the control device, and FIGS. 3 to 3 are flowcharts showing the control procedure. (1) …… Compressor (2) …… Condenser (5) …… Evaporator (7) …… Hot gas valve (8) …… Hot gas bypass path (9) …… Opening / closing mechanism (15) …… Drain pan (50) …… Temperature setter (55) …… Temperature detector (60) …… Humidity setter (80) …… Drain pan heater

Claims (1)

[Claims] 1. A hot gas bypass passage (8) for guiding hot gas discharged from a compressor (1) to an evaporator (5) by-passing a condenser (2) and a hot gas bypass passage (8). A hot gas valve (7) for controlling the capacity of the evaporator (5) by adjusting the amount of hot gas to be bypassed, and for introducing the total amount of frost hot gas into the evaporator (5) for defrost operation. ) And a drain pan heater (80) branched in the middle of the hot gas bypass passage (8) via an opening / closing mechanism (9), and the drain pan heater (80) is used to blow air from the evaporator (5). A temperature controller (50), a temperature detector (55) for detecting the temperature of passing air passing through the evaporator (5), and an operation control device in a refrigerating device located on the side, and this temperature detector. The hot gas valve based on the detection result of (55) (7) is operated to adjust the amount of hot gas to be partially bypassed to the hot gas bypass passage (8), the humidity setting device (60), and the hot gas bypass passage (8). Dehumidification operation command for dehumidification control by operating the opening / closing mechanism (9) based on an instruction from the humidity setting device (60) and performing dehumidification control by using the drain pan heater (80) as a reheater during a capacity control operation for partially bypassing And the hot gas bypass passage (8) to bypass the entire amount of hot gas, the opening / closing mechanism (9) is operated to control the heating of the drain pan (15) by using the drain pan heater (80) as a heater. An operation control device for a refrigerating apparatus, comprising: a drain pan heating command means for performing the operation.