JPS6243253Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a refrigeration system, and particularly to a refrigeration system that reliably defrosts an evaporator.

[Conventional technology]

Generally, in this type of refrigeration system, when the evaporator is frosted, high-temperature, high-pressure discharge gas from the compressor is directly supplied to the evaporator to perform a defrosting operation to defrost the evaporator. This device operation is stopped when the pressure of the refrigerant on the discharge side of the evaporator exceeds a predetermined value.

[Problem that the invention attempts to solve]

However, in such conventional refrigeration equipment, when the defrosting operation ends, the discharge refrigerant pressure, that is, the suction refrigerant pressure of the compressor, is high, so if the cooling operation is started immediately, the compressor may become overloaded. There was a drawback that shortened the life of the compressor. In addition, when the ambient temperature of the air-cooled condenser is low, a large amount of refrigerant liquid accumulates inside the air-cooled condenser, so if cooling operation is started immediately after defrosting in this condition, the pressure of the refrigerant gas discharged from the compressor will increase. At that point, the air-cooled condenser did not function sufficiently and the pressure of the refrigerant gas increased abnormally, causing the compressor to abnormally stop due to the high-pressure switch.

This invention was made in order to eliminate the above-mentioned conventional drawbacks.

[Means for solving problems]

The refrigeration system according to this invention is a refrigeration system that performs defrosting operations periodically by timer operation, and includes a pressure or temperature detection device for detecting the discharge refrigerant pressure or discharge refrigerant temperature of the evaporator, and the pressure or temperature detection device. The compressor is equipped with a relay control circuit that stops the cooling operation of the compressor until it is detected that the pressure or temperature drops below a predetermined value after the end of the defrosting operation.

[Effect]

This device detects the pressure or temperature of the refrigerant discharged from the evaporator using a pressure or temperature detection device after the defrosting operation is completed, and the control circuit operates the compressor for cooling until the discharged refrigerant pressure or temperature drops to a predetermined value. be stopped.

〔Example〕

FIG. 1 is a refrigerant system diagram of the refrigeration system according to this invention. In FIG. 1, refrigerant compressed by a compressor 1 is condensed by a condenser 2, and is supplied to an expansion valve 4 via a main path electromagnetic valve 3. The expansion valve 4 expands the supplied refrigerant and sends it to the evaporator 5. The evaporator 5 evaporates the sent refrigerant and exchanges heat with the load, and then is temporarily stored in the accumulator 6 and returned to the compressor 1. This refrigerant circulation path constitutes a freezing refrigerant path A. The defrosting solenoid valve 7 supplies the refrigerant discharged from the compressor 1 directly to the evaporator 5 when the evaporator 5 is frosted, and constitutes a defrosting refrigerant line B. The pressure detection device 8 detects the refrigerant pressure discharged from the evaporator 5. Next, the control circuit of the refrigeration cooling system shown in FIG. 1 and its operation will be explained using FIG. 2.

Cooling Operation FIG. 2 is a control circuit diagram of FIG. 1. In Fig. 2, input terminal 9a → compressor drive relay R
1 → Break contact 12 of second auxiliary relay R12
b→The relay R1 is energized by the closed circuit of the input terminal 9b, and the compressor 1 is driven. At this time again,
A closed circuit is formed from input terminal 9a → break contact 11b of first auxiliary relay R11 → relay R3 of main system path solenoid valve 3 → input terminal 9b, and main system path solenoid valve 3 opens to form refrigeration refrigerant path A. cooling operation is performed.

Defrosting Operation The timer 10 measures time by applying voltage to the input terminals 9a and 9b. Therefore, when the timer 10 is energized and a predetermined period of time has elapsed, the timer 10 is energized and instantaneously closes the make contact 10a. Therefore, a closed circuit is formed: input terminal 9a→make contact 10a→first switching contact 8A of pressure detection device 8; relay R7 of defrosting solenoid valve 7; first auxiliary relay R11 of input terminal 9b; Then, relay R7 is energized and opens defrosting solenoid valve 7. Further, the first auxiliary relay R11 is energized, and its make contact 11a is closed to self-hold the first auxiliary relay R11, and its break contact 11b is opened to switch the relay R3.
deactivate. Therefore, the freezing refrigerant system A is closed, and the defrosting refrigerant system B is configured to perform a defrosting operation to defrost the frost on the evaporator 5.

In this case, the switching contact 8A of the pressure detection device 8 is the first contact side 8a when the discharge refrigerant pressure of the evaporator 5 is low and below the low temperature side set value, that is, when the evaporator 5 is frosted. When the refrigerant pressure discharged from the evaporator 5 is high and exceeds the set value on the high temperature side, that is, when the defrosting operation is completed, it switches to the position indicated by the dotted line, which is the second contact side 8b.

Pressure reduction operation after defrosting When the defrosting operation is completed, the refrigerant pressure discharged from the evaporator 5 is higher than the high temperature side set value, so the switching contact 8A of the pressure detection device 8 is switched to the position indicated by the dotted line. Therefore, a closed circuit of input terminal 9a→switching contact 8A→second auxiliary relay R12→input terminal 9b is formed, and the break contact 12b is opened. Therefore, the relay R1 is deenergized and the operation of the compressor 1 is stopped. When the operation of the compressor 1 is stopped, the ambient temperature of the evaporator 5 is cooled by the air inside the refrigerator, so that the refrigerant pressure discharged from the evaporator 5 gradually decreases. When the discharge refrigerant pressure eventually reaches the low-temperature set value due to this decrease, the switching contact 8A of the pressure detection device 8 changes from the position indicated by the dotted line, which is the second contact side 8b.
It switches to the position indicated by the solid line, which is the first contact side 8a.
Accordingly, the second auxiliary relay R12 is deenergized and the aforementioned cooling operation is restarted again.

In addition, in the discharge refrigerant passage of the evaporator 5 to which the pressure detection device 8 is attached, the pressure level of the refrigerant uniquely corresponds to the temperature level, so it can be used instead of the pressure detection device 8 in the above embodiment. Exactly the same action and effect can be obtained even if a temperature detection device is used.

[Effect of idea]

This device is configured as described above, and the operation of the compressor 1 is stopped until the discharge pressure of the evaporator 5 decreases to the low-temperature set value after the defrosting operation is completed. A large force is prevented from being applied, the life of the compressor is not shortened, and the pressure of the refrigerant discharged from the compressor 1 does not become abnormally high and the compressor 1 does not stop abnormally.

[Brief explanation of the drawing]

FIG. 1 is a refrigerant system diagram of the refrigeration system according to this invention. FIG. 2 is a control circuit diagram of FIG. 1. In the figure, 1 is a compressor, R1 is a relay for driving the compressor, 2 is a condenser, 3 is a main line solenoid valve, R3
is the relay for the main line solenoid valve, 4 is the expansion valve, 5 is the evaporator, 7 is the defrosting solenoid valve, R7 is the relay for the defrosting solenoid valve, 8 is the pressure detection device, 8A is the switching contact, 8a
is the first contact side, 8b is the second contact side, 10 is the timer, 10a is the make contact, R11 is the first auxiliary relay, 11a is its make contact, 11b is its break contact, R12 is the second auxiliary relay Relay, 12
b is the break contact, A is the freezing refrigerant line, and B is the defrosting refrigerant line.

Claims (1)

[Claims for Utility Model Registration] A compressor 1 that compresses refrigerant, a condenser 2 that condenses the refrigerant compressed by the compressor 1, and an expansion valve 4 that expands the refrigerant condensed by the condenser 2. , a frozen refrigerant system A comprising an evaporator 5 that evaporates the refrigerant expanded in step 4 with the expansion valve and returns it to the compressor 1; installed on the suction side of the evaporator 5 of the frozen refrigerant system A; a main path solenoid valve 3 that opens and closes to control the flow of refrigerant;
a defrosting refrigerant line B consisting of a defrosting solenoid valve 7 that directly supplies discharged refrigerant to the evaporator 5; and a compressor drive relay R1 that drives the compressor 1 when activated; The main line solenoid valve 3
a relay R3 of the main line solenoid valve that opens the main line solenoid valve; a timer 10 that instantaneously closes its make contact 10a every predetermined time period; and a timer 10 that momentarily closes the make contact 10a when the discharge refrigerant pressure or temperature of the evaporator 5 is below a low pressure side or low temperature side set value. , the switching contact 8A is connected to the first contact side 8a, and when the discharge refrigerant pressure of the evaporator 5 is higher than the high temperature side set value, the switching contact 8A is connected to the second contact side 8b for pressure or temperature detection. a defrosting solenoid valve that is connected in series with the device 8, the make contact 10a of the timer 10, and the first contact side 8a of the pressure or temperature detection device 8, and opens the defrosting solenoid valve 7 when energized. The relay R7 is connected in parallel to the relay R7 of the defrosting solenoid valve, its make contact 11a is connected in parallel to the make contact 10a of the timer 10, and its break contact 11b is connected in parallel to the relay R7 of the main path solenoid valve.
a first auxiliary relay R11 connected in series to 3 and a second contact side 8 of said pressure or temperature detection device 8;
1. A refrigeration system characterized by comprising: a second auxiliary relay R12 connected in series to a relay R1 for driving a compressor;