JPS5919267B2 - Operation control device for refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an operation control device for a refrigeration system, and more particularly to a defrosting operation control device for a refrigeration system for a showcase or the like.

FIG. 1 shows a control device for a conventional showcase refrigeration system, in which when a power switch 1 is turned on, a defrost controller 2, an internal temperature control switch 3, a high pressure switch 4, an overload relay 5, etc. The electromagnetic switch coil 6 for the compressor is energized, the compressor is driven, and the refrigeration system is cooled, and the inside fan motor 7 is also energized to drive the inside fan and circulate cold air inside the refrigerator. The inside of the refrigerator will be cooled down.

Therefore, when defrosting the refrigeration equipment, the defrost heater electromagnetic switch coil 10 is energized via the overheat prevention limiter 8 and overload relay 9 in order to switch the contacts of the defrost controller 2 to the defrosting operation side. , the defrosting heater is heated to defrost the frost that has adhered to the cooler and the like.

Note that this mass-produced inner fan continues to operate.

When the defrosting is finished, the contacts of the defrost controller 2 are switched again to normal cooling operation, the compressor is restarted, and normal cooling operation is restarted.

In this way, in conventional devices of this kind, the internal fan rotates to circulate the air inside the refrigerator even during defrosting, so the air heated by the defrost heater circulates inside the refrigerator. As a result, warm air that is hotter and more humid than the products on display in the warehouse comes into contact with the products, causing a lot of frost to form on the products, and especially in the case of ice cream, some of it melts due to the warm air, causing loss of color. In addition, the defrosting heater itself is cooled by the circulating air, which causes disadvantages such as requiring a long time for defrosting.

In view of these points, it is an object of the present invention to provide an operation IIJffll device in a refrigeration system that does not have the above-mentioned disadvantages.

An embodiment of the present invention will be described below with reference to FIG.

In FIG. 2, the power switch 1 includes a high voltage switch 4,
A series circuit of an overload relay 5, a compressor electromagnetic switch coil 6, and an internal temperature control switch 3 are connected, and when the power switch 1 is turned on, the compressor electromagnetic switch coil 6 is energized. The compressor in the refrigeration system is driven.

Further, a defrost controller 11 is connected in parallel to the series circuit.

The defrost controller 11 has a timer 11a that is activated by the energization, a first contact a that is activated by the timer 11, and is a contact for cooling operation, and a second contact that is a contact for continuous defrost operation. The first contact a is connected to a refrigerator side fan motor I, and the other pole of the refrigerator side fan motor 7 is connected to a thermal on-off delay 12. 1st of
is connected to contact C.

The thermal on-off delay 12 has a heater 12a connected between the second contact of the defrost controller 11 and the power supply circuit, and further has a heater 12a connected between the second contact point of the defrost controller 11 and the power supply circuit.
2 is provided with a switching contact piece 12b that controls switching between the first contact C and the second contact d by energizing or de-energizing the heater 12a.

That is, when the heater 12a is energized, the switching contact piece 12b switches to the first switch after a predetermined period of time, for example, 50 to 90 seconds has passed.
The contact C is switched to the second contact d, and when the energization is stopped, the second contact d is switched to the first contact C after a predetermined period of time, for example, 80 to 120 seconds has elapsed.

Further, when the switching contact piece 12b is turned on at the second contact d, a bypass circuit for the internal temperature adjustment switch 3 is configured.

On the other hand, a refrigerant switching four-way valve coil 13 is connected to the second contact side of the defrost controller 11 in parallel with the on-off delay 12.

As mentioned above, when the power switch 1 is turned on, the compressor is driven and refrigerant is circulated to the refrigeration cycle, and during normal cooling operation, the refrigerant discharged from the compressor passes through the condenser. It will be supplied to the cooler to cool the inside of the refrigerator.

By the way, during this normal cooling operation, the switching contact piece 11b of the defrost controller 11 is at the first contact aKONL, and the switching contact piece 12b of the on-off delay 12 is also turned on at the first contact C, so that the inside fan motor 7 is energized, the refrigerator inside fan is driven, and cold air is circulated within the refrigerator.

Therefore, when the set time of the timer 11a has elapsed, the switching contact piece 11b of the defrost controller 11 is switched to the second contact side by the timer 11a.

Therefore, the drive of the inside fan motor 7 is stopped, the refrigerant switching four-way valve coil 13 is energized, the refrigerant switching four-way valve is switched, and the discharged gas from the compressor is directly supplied to the cooler, and its heat is Defrosting is carried out by
That is, a defrosting operation is performed.

On the other hand, by switching the switching contact piece 11b to the second contact side of the defrost controller 11 (7), the heater 12a of the on-off delay 12 is also energized, and the switching contact piece 12b is set to a predetermined position by the action of the heater 12a. After a period of time e.g. 50 to 90 seconds has elapsed, the switch from the first contact C to the second contact d
can be switched to the side.

When the defrosting time set in the timer 11a has elapsed in this way, the switching contact 11 of the defrost controller 11
b is switched from the second contact to the first contact a, thereby demagnetizing the refrigerant switching four-way valve coil 13, returning the four-way valve to normal cooling operation, and supplying liquid refrigerant to the cooler. is restarted, and the cooling action by the cooler resumes.

However, in this case, the heater 12 with the on-off delay 12
The energization to a is also stopped at the same time, but the switching contact piece 125 is not switched from the second contact d to the first contact C until a predetermined period of time, for example, 80 to 120 seconds has elapsed after the energization to the heater 12a is stopped. Therefore, the internal fan motor 7 is not driven and the air inside the refrigerator is not circulated.

After the predetermined time, the first contact C of the switching contact piece 12b
Only after switching to
is activated, and the fan inside the refrigerator resumes operation.

Therefore, within the time it takes for the inside fan to resume operation, the cooler is sufficiently cooled and the surrounding hot and humid air is cooled and dehumidified, and the hot and humid air is circulated into the refrigerator by the operation of the inside fan. It will not be done.

During this time, the defrosting water is also sufficiently drained.

In addition, the energization to the electromagnetic switch coil 6 for the compressor is also turned off by opening and closing the internal temperature control switch 3, and the drive of the compressor is turned off. Immediately after the machine stops, even if switching to defrosting operation is performed, that is, switching the switching contact 11b of the defrost controller 11 to the second contact, the switching contact 12b of the on-off delay 12 will not work as described above. Since the switching to the second contact point d is delayed for 50 to 90 seconds, the drive of the compressor is not restarted suddenly, and no unreasonable operation is applied to the compressor.

Fig. 3 is a block diagram of the above operation during normal cooling operation, and Fig. 4 is a diagram of the OF of the chamber temperature control switch.
FIG. 5 is a block diagram of the operation when the defrosting operation is started at time F, and FIG. 5 is a diagram showing temperature changes in various parts in the conventional device and the device of the present invention.

Since the present invention is configured as described above, the fan inside the refrigerator is stopped during the defrosting operation and for a predetermined period thereafter, so that the hot and humid air caused by defrosting is not circulated inside the refrigerator, and the exhibited products The temperature rise is very small, and it is possible to reliably prevent products such as ice cream from fading, and it is also possible to sufficiently prevent frost formation on displayed products.

Furthermore, since the air blowing to the cooler is interrupted during defrosting, defrosting can be carried out effectively and defrosting can be carried out in a relatively short time.

What's more, even if the internal temperature control switch is turned OFF and the compressor is stopped, the start-up of the compressor is delayed even if the defrosting operation is started immediately after the compressor stops, so there is no stress on the compressor. play.

[Brief explanation of drawings]

FIG. 1 is a control circuit diagram of an operation control device in a conventional refrigeration system, FIG. 2 is a control circuit diagram of an operation control device in a refrigeration system of the present invention, and FIGS. 3 and 4 are operational block diagrams of the device of the present invention. , FIG. 5 is a diagram showing temperature changes in the refrigerator and the cooler. DESCRIPTION OF SYMBOLS 1... Power switch, 3-... Inside temperature control switch, 6... Compressor electromagnetic switch coil, 7... Inside fan motor, 11... Defrost controller, 1
2 On-off delay, 13... Coil for refrigerant switching four-way valve.

Claims (1)

[Claims] 1 A series circuit that has an electromagnetic switch coil for the compressor and a switch for controlling temperature inside the refrigerator, and the first contact is ON during normal operation.
a defrost controller that is selectively operated so that the fan motor inside the refrigerator is energized and the second contact is switched to energize the refrigerant switching four-way valve coil during defrosting operation; When it is switched to the contact side, it is energized, and after a predetermined period of time has elapsed after the switching, the compressor electromagnetic switch coil circuit is closed regardless of whether the internal temperature adjustment switch is opened or closed, and the first contact side of the defrost controller is turned on. 1. An operation control device for a refrigeration system, characterized by having an on-off delay that is switched so that an internal fan motor circuit is closed after a predetermined period of time has elapsed after switching to the internal fan motor circuit.