JPH0347188Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) This invention relates to a defrosting device for a refrigeration system.

(Prior art) Conventionally, as this type of device, for example,
As shown in Publication No. 14089, the temperature of the piping at the evaporator outlet is detected, and when the detected temperature falls below a predetermined value, the solenoid valve installed in the middle of the piping on the evaporator inlet side is closed. There is a known method in which the operation of the evaporator is stopped and the evaporator is defrosted. Defrosting in this case relies solely on the temperature rise that occurs when the evaporator stops operating, which has the disadvantage of prolonging the defrosting time. There is an example (Japanese Utility Model Publication No. 50-6042) in which the blower is kept rotating even in the event of a problem.

(Problem to be solved by the invention) However, the defrosted water droplets remained attached and had a drawback that they were difficult to remove.

Therefore, the object of this invention is to provide a cooling/refrigeration device that can not only defrost the evaporator but also wipe away attached water droplets.

(Means for Solving the Problems) Therefore, the gist of this invention is to remove a refrigeration system that includes a refrigeration cycle including a compressor and an evaporator, and a blower that blows air to the evaporator. The frosting device includes a frost detection means for detecting frost formation on the evaporator, a temperature detection means for detecting the temperature of the evaporator, and a frost detection means for detecting frost formation on the evaporator; A control means for controlling the operation of a compressor and an air blower is provided, and the control means operates the air blower while operating the air blower when frost formation on the evaporator is detected by the frost formation detection means. If a first predetermined temperature is detected by the temperature detection means, the operation of the blower is stopped, and then the temperature detection means detects a second predetermined temperature higher than the first predetermined temperature. The defrosting device of the refrigeration system operates the compressor and the blower again when a predetermined temperature is detected.

(Function) Therefore, even after the compressor stops operating for defrosting, the blower continues to operate, further speeding up defrosting, while the blower is temporarily stopped immediately before restarting the compressor after defrosting. Since it is operated simultaneously with the post-compressor to wipe out water droplets adhering to the evaporator, the above-mentioned problem can be achieved.

(Example) Hereinafter, an example of this invention will be described with reference to the drawings.

In FIG. 3, reference numeral 1 denotes a refrigeration cycle, which includes a compressor 2, an evaporator 3, and other condensers (not shown) connected through piping. Reference numeral 4 denotes a blower for blowing air to the evaporator 3, and the blower 4 and the evaporator 3 are installed inside the duct case 5. Reference numeral 6 denotes a differential pressure switch, which is constructed by, for example, a diaphragm type. The inside of the casing 7 is divided into first and second chambers 7a and 7 by a diaphragm 8.
The inside of the first chamber 7a is set to the standard pressure, while the inside of the second chamber 7b is between the blower 4 and the evaporator 3 in the duct case 5. It's communicating. Further, in the first chamber 7a, the first and second contacts 9a and 9b are opposed to each other, and the casing 7 and the diaphragm 8 are connected to each other.
, and forms a normally closed contact 9.
When the pressure in the second chamber 7b, that is, the air pressure on the windward side of the evaporator 3, exceeds the reference level in the first chamber 7a, the first and second contacts 9a, 9b
is becoming more developed.

A thermostat 10 detects the temperature of an evaporation fin (not shown) of the evaporator 3 and outputs an opening/closing signal at two predetermined temperatures. Said 2
In this embodiment, the two predetermined temperatures are set to 0° C. (first predetermined temperature) and +5° C. (second predetermined temperature).

A control circuit 11 controls the operation of the compressor 2 and the blower 4 in accordance with the output signals of the differential pressure switch 6 and thermostat 10. A specific example of this control circuit 11 is shown in FIG.

In FIG. 1, reference numeral 12a denotes an excitation coil for the electromagnetic clutch 12 that connects and disconnects the drive of the compressor 2, and is parallel to an upper power source (not shown) connected in series to the first normally open contact 13a of the first relay 13. It is connected.

The blower 4 has a second normally open contact 13b of the first relay 13 and a normally open contact 14 of the second relay 14.
The parallel circuit with a is connected in series and connected in parallel to the power supply.

The normally closed contact 9 of the differential pressure switch 6 is connected in parallel to a power source in which the normally open contact 15a of the third relay 15 and the first relay 13 are connected in series. The second relay 14 is connected to the second relay 14 of the thermostat 10.
The contacts 10b are connected in parallel to the upper power supply connected in series. This second contact 10b is in an open state at room temperature and is in a closed state at 0° C. or lower.

The third relay 15 includes a thermostat 1
0's first contact 10a and the third of the first relay 13
The normally open contacts 13c are connected in parallel to the upper power supply connected in series. Said first
Contact 10a is closed at room temperature +5℃
It will be in the open state as follows.

In the above configuration, the operation will be explained based on FIG. 2. It is assumed that power is applied to the device at time _t0 . When the device is started, the normally closed contact 9 of the differential pressure switch 6 is in a closed state. Also, thermostat 1
The first contact 10a of 0 is in the closed state due to room temperature, and the second
The contact 10b is in an open state. Therefore, the first and second normally open contacts 13 of the first relay 13
a and 13b are in a closed state. As a result, the excitation coil 12a of the electromagnetic clutch 12 is excited, the compressor 2 is operated, and the blower 4 also starts operating, so that the refrigeration cycle 1 is put into operation.

As the refrigeration cycle 1 operates, the temperature of the evaporator 3 gradually decreases (see FIG. 2a). Evaporator 3
As the temperature of the evaporator 3 decreases, frost gradually forms on the evaporator 3, creating resistance to the blown air.
The air pressure on the windward side gradually increases. When this air pressure exceeds a predetermined value, the normally closed contact 9 of the differential pressure switch 6 becomes open (see Figure 2).
(see _t1 ). At this time, the differential pressure switch 6 is adjusted so that the evaporator temperature is around -2 to -3°C. As a result, the first relay 13 becomes de-energized and the first normally open contact 13a and the second normally open contact 1
3b is opened, the compressor 3 is in a stopped state. However, since power is applied to the blower 4 via the normally open contact 14a of the second relay 14, the blower 4 still continues to operate.

Here, the normally open contact 14a is closed when the second contact 10b of the thermostat 10 is closed when the evaporator temperature reaches 0° C., and the second relay 14 is energized. It is something. The compressor 2
As the operation of the thermostat 10 is stopped, the evaporator temperature gradually rises and when it reaches 0 DEG C. again, the second relay 14 is de-energized by opening the second contact 10b of the thermostat 10. For this reason, the blower 4
The power is cut off and the operation stops (Fig. 2 Time
_t2 ). Thereafter, the evaporator temperature further increases, and when it reaches 5°C (time _t3 in Figure 2), the first contact 10a of the thermostat 10 closes, and the differential pressure switch 6 becomes reset and becomes normally closed again. Since the contact 9 is closed and the first relay 13 and the third relay 15 are operated, the compressor 2 and the blower 4 start operating again, and the above-described operation is repeated. Further, during this period from time ₂ to _t3 , no air is blown, and the frost completely melts and grows into relatively large water droplets attached to the evaporator 3, which are wiped away by restarting the blower 4.

In this example, the temperature at which the blower stops is 0°C, and the temperature at which the device is restarted is 5°C.
By changing the set temperature of the thermostat 10, it is easy to set the temperature to another value.

(Effects of the invention) As described above, according to this invention, it is possible to ensure the operation of the blower after the compressor is stopped by detecting frost on the evaporator, shorten the defrosting time, and In addition to preventing a drop in refrigeration capacity immediately after a shutdown, the blower operation is stopped before restarting the compressor, and when the compressor is restarted, water droplets that adhere to the evaporator due to ice melting can be wiped out. Therefore, frost formation is not accelerated due to adhesion of water droplets, and efficient refrigeration operation is possible.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the control circuit of the refrigeration system according to the invention, Fig. 2a is a characteristic diagram showing the temperature characteristics of the evaporator of the refrigeration system above, and Fig. 2b is a diagram showing the temperature characteristics of the evaporator of the refrigeration system above. FIG. 3 is a time chart showing the operation of the device, and is a schematic diagram of the control device of the above-mentioned refrigeration device. 2...Compressor, 3...Evaporator, 4...Blower,
6... Differential pressure switch, 10... Thermostat,
12...Electromagnetic clutch.

Claims (1)

[Claims for Utility Model Registration] 1. A defrosting device for a refrigeration system comprising a refrigeration cycle including a compressor and an evaporator, and a blower for blowing air to the evaporator, A frost detection means for detecting the temperature of the evaporator, a temperature detection means for detecting the temperature of the evaporator, and a control means for controlling the operation of the compressor and the blower according to output signals of the frost detection means and the temperature detection means. The control means operates the blower and stops the operation of the compressor when frost formation on the evaporator is detected by the frost detection means, and then stops the operation of the compressor by the temperature detection means. If a first predetermined temperature is detected, the operation of the blower is stopped, and if a second predetermined temperature higher than the first predetermined temperature is subsequently detected by the temperature detection means, the compressor and the blower are stopped. A defrosting device for a refrigeration system, characterized in that it operates again. 2 Utility model registration claim 1 characterized in that the frost detection means is comprised of a differential pressure switch
A defrosting device for the refrigeration equipment described in Section 1. 3. A defrosting device for a refrigeration system as set forth in claims 1 and 2 of the utility model registration claim, wherein the temperature detection means is comprised of a thermostat.