JPH06201235A - Cooling device for closed control panel - Google Patents

Abstract

PURPOSE:To prevent a fast cooling from occurring and save the energy by a method wherein there are provided a first judging means, a circulating means, a second judging means and a forced cooling means. CONSTITUTION:As a control panel 3 is operated to cause a temperature rise in a closed case 2 and a detected temperature exceeds a set temperature, only an evaporator fan 15 is turned ON and only an air blowing operation in the closed case 2 is started. In the case that a sufficient cooling effect can not be obtained only with the air circulation under an operation of the fan 15 even after a specific time defined by a timer elapses, a relay switch is turned ON, compressors 24 and 25 are driven so as to start a forced cooling operation. With such an arrangement as mentioned above, it is possible to prevent a fast cooling operation against the closed control panel from being carried out and further it is also possible to perform the energy saving.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device, and more particularly to a cooling device for cooling the inside of a closed control panel.

[0002]

2. Description of the Related Art In a hermetically-sealed control panel composed of a control device and a hermetically-sealed case for housing the control device, a cooling device is attached because the internal temperature rises as the control device operates. The conventional cooling device includes an evaporator that cools by passing the air inside the case, a compressor that compresses the refrigerant from the evaporator, and a condenser that dissipates the heat of the compressed refrigerant to the outside air. It mainly has and. Further, an evaporator fan that circulates the air in the closed case to contact the evaporator and a condenser fan that contacts the outside air to the condenser are provided.

When the temperature inside the control panel becomes high and the cooling operation is required, the compressor is operated and the evaporator fan and the condenser fan are operated together to start the cooling operation. . As a result, the air in the closed case of the control panel is cooled by coming into contact with the evaporator, and the heat of the condenser is dissipated to the outside.

[0004]

SUMMARY OF THE INVENTION In the above conventional configuration,
When it is determined that the control panel needs to be cooled, the compressor and both fans are operated to immediately start the forced cooling operation. As a result, there is a case in which the control device near the outlet of the evaporator fan is adversely affected by the rapid cooling.

Further, in winter, even if the temperature of the atmosphere in the sealed case is high, the temperature of the metallic sealed case itself is often low due to exposure to the outside air. In this case, it is often the case that a sufficient cooling effect can be obtained only by increasing the amount of contact between the air in the case and the closed case without performing the forced cooling operation for driving the compressor.
Even in such a case, in the above-described conventional configuration, the forced cooling operation is performed with the driving of the compressor, so that there is much waste from the viewpoint of energy consumption.

An object of the present invention is to prevent rapid cooling operation and save energy.

[0007]

A cooling device for a closed type control panel according to the present invention comprises a first judging means, a circulating means, a second judging means and a forced cooling means. The determination means measures the ambient temperature in the closed control panel to determine whether a cooling operation is necessary. The circulation means first circulates the air in the closed control panel when the first determination means determines that the cooling operation is necessary. The second judging means judges whether or not the circulation means alone has been sufficient to cool. The forced cooling means forcibly cools the air in the sealed control panel when the second determination means determines that the circulation means alone is insufficient.

[0008]

In the cooling device for a hermetically sealed control panel according to the present invention, the first determining means measures the ambient temperature in the hermetically sealed control panel to determine whether or not the cooling operation is necessary. When the first judging means judges that the cooling operation is necessary,
The circulation means first circulates the air in the closed control panel.
Then, the second determination means determines whether or not the circulation means alone has been sufficient to cool. When it is determined by the second determination means that the circulation means alone is insufficient, the forced cooling means forcibly cools the air in the closed control panel.

Here, when it is judged that the cooling operation is necessary, the circulation means is operated first, so that the rapid cooling operation is prevented. In addition, the second determination means determines whether or not the circulation means alone is sufficient for cooling, and the forced cooling means performs the forced cooling only when the circulation means alone is insufficient, so that energy saving can be achieved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a cooling device 1 as an embodiment of the present invention is attached to a side surface of a control panel 3 having a hermetically sealed case 2. In the cooling device 1, the indoor cooling unit 4 is arranged on the upper side and the outdoor heat radiation unit 5 is arranged on the lower side. The indoor cooling unit 4 has a suction opening 10 and a discharge opening 11 that open toward the inside of the closed case 2 on the side surface of the closed case 2. Then, in the cooling path 12 connecting the suction opening 10 and the discharge opening 11, the temperature sensor 1 is sequentially arranged from the suction opening side.
3, an evaporator 14 and an evaporator fan 15 are arranged respectively. The evaporator fan 15 causes the air in the closed case 2 to contact the evaporator 14 by circulating the air in the closed case 2 in the direction of the arrow.

The outdoor heat radiating portion 5 has a suction opening 20 and a discharge opening 21 that open toward the outside of the room. Suction opening 2
At 0, a filter 22 for filtering outside air is attached. A condenser 23 and a compressor 24 are arranged in the outdoor heat dissipation section 5. The condenser 23 is a filter 22
Is located adjacent to. The discharge opening 21 is provided with a condenser fan 25, which takes in outside air into the outdoor heat radiating portion 5 in the direction of the arrow and discharges it. further,
An air volume sensor 26 for detecting an air volume of the outside air passing through the filter 22 is provided adjacent to the filter 22, and adjacent to the compressor 24, the compressor 2 is provided.
A thermostat 27 for detecting the overheated state of No. 4 is provided.

As shown in FIG. 2, the evaporator 14 and the condenser 2
3 and the compressor 24 are connected by a pipe line 30, and the refrigerant is circulated by the compressor 24. Further, the cooling device 1 has a control unit 40 as shown in FIG. The control unit 40 is a CPU, R
It is composed of a microcomputer including AM, ROM, etc., and is adapted to perform various controls. The thermostat 27 is provided in the middle of the drive circuit of the relay switch 41 that turns ON / OFF the power supply circuits of the compressor 24 and the fan 25. The relay switch 41 is switched by the control unit 40. In addition to the sensors 13 and 26, an operation panel 42 and an output connector 43 are further connected to the control unit 40.

The operation panel 42 is provided with an LED 44 that blinks or lights up when an abnormality occurs, a temperature setting knob 45 for adjusting the operation set temperature, and a sensitivity adjusting section 46 for adjusting the sensitivity of the air volume sensor 26. Has been. Also,
The output connector 43 has an alarm output terminal 47 that switches from low to high when it is determined that the filter 22 is in a clogging state, and an error output terminal that switches from low to high when an abnormal stop of the compressor 24 is detected. And 48 are provided. These output terminals 47, 4
The output signal from 8 is used by, for example, a host computer.

Next, the operation of the above embodiment will be described with reference to the control flowcharts shown in FIGS. When the program starts, in step S1 of FIG.
Initialization such as setting the LED 44 to OFF is performed. Subsequently, in step S2, the evaporator fan 15 and the condenser fan 25 are set in the stopped state, and the compressor 24 is also set in the stopped state. Then, in step S3, the temperature detected by the temperature sensor 13 is
It is determined whether or not the temperature has reached a certain set temperature at which cooling must be started.

When the control panel 3 operates and the temperature in the closed case 2 rises and the detected temperature exceeds the set temperature, the program shifts from step S3 to step S4. In step S4, first, only the evaporator fan 15 is turned on, and only the blowing operation in the closed case 2 is started. At this stage, since the compressor 24 is not operated, power consumption is small and energy saving can be achieved. Also, the problem of quenching does not occur. Then, in step S5, the timer A
To start. The timer A is set with a time sufficient to determine whether or not a sufficient cooling operation can be performed only by the air circulation in the closed case 2 by the evaporator fan 15.

In step S6, it is determined whether the timer A has timed out. The process proceeds to step S7 until the time is up. In step S7, it is determined whether or not the temperature detected by the temperature sensor 13 is equal to or lower than (set temperature-α). Here, α is 5 ° C., for example.
If the determination in step S7 is No, the process returns to step S6.

If the inside of the hermetically sealed case 2 falls below (set temperature-α) only by the circulating operation by the evaporator fan 15 before the timer A times out, step S
After returning from 7 to step S2 and stopping the blowing operation, in step S3, it waits until the temperature in the closed case 2 exceeds the set temperature. If a sufficient cooling effect is not obtained by the air circulation operation by the fan 15 even after the time specified by the timer A has passed, the process proceeds from step S6 to step S8 in FIG.

In step S8, the relay switch 41 is turned on to drive the compressor 24 and the fan 25.
As a result, the forced cooling operation is started. Step S9
Then, based on the detection result of the air volume sensor 26, it is determined whether or not the air volume becomes smaller than a predetermined volume. The predetermined amount in this case is an air amount when the filter 22 is clogged to the extent that it needs to be replaced. While the sufficient air volume is obtained, the process proceeds from step S9 to step S11.

In step S11, the LED 44 for issuing a warning to the operator is set to the OFF state, and the alarm output terminal 46 and the error output terminal 47 are also OF.
Set to F state. Then, the process proceeds to step S14, and it is determined whether or not the temperature inside the closed case 2 has become equal to or lower than (set temperature-α). Until sufficient cooling is done,
If the determination in step S14 is No, the program returns to step S9.

If it is determined in step S14 that sufficient cooling has been completed, the program returns from step S14 to step S2 in FIG. 4, and the compressor 24 and the fans 15 and 25 are stopped. When it is determined in step S9 that the air volume has become smaller than the predetermined volume, the process proceeds to step S10. In step S10, it is determined whether the detected air volume has become zero. If the air volume is not 0,
It is determined that the condenser fan 25 circulates the air inside the outdoor heat dissipation portion 5 and the cooling operation is continued. Then, in this case, it is determined that the filter 22 is clogged, and the process proceeds to step S12. In step S12, the LED 44 is caused to blink so as to mean that the filter 22 is clogged. Also, the alarm output terminal 46, which means clogging of the filter 22, is turned on. Here, since the cooling operation itself has no abnormality, the output of the error output terminal 47 is kept OFF. When the determination in step S12 is completed, step S14
Move to.

If it is determined in step S10 that the air volume is 0, the process proceeds to step S13. In the state where the air volume is 0, the compressor 24 is overheated due to the reason that the outside air temperature is too high during the cooling operation, and the thermostat 27 is turned off by receiving the heat from the compressor 24.
And the relay switch 41 becomes OF based on it.
In the F state, the compressor 24 and the condenser fan 2
It is caused by the stop of No. 5.

Here, it is judged that the detected air volume has become 0 due to the stop of the cooling operation, not the clogging of the filter 22, and therefore the LED 44 is turned on in step S13 to indicate the stop of the cooling operation. Turn on the light. Further, the error output terminal 47 is turned on. Here, the alarm output terminal 46, which means detection of clogging of the filter 22, is set to OFF. Succeedingly, in a step S15, the compressor 24 and the fans 15, 25
Forcibly set each to a stop state and terminate the program.

Here, the clogging of the filter 22 and the abnormality of the cooling operation (overheating of the compressor 24) are detected on the basis of the measurement result of the air volume sensor 26, so that the cooling operation is not complicated. It is possible to accurately detect the stop due to the abnormality. [Other Embodiments] In step S14 of FIG. 5, the judgment is Y.
When it becomes es, it may be configured to perform the control of FIG. 6 and then return to step S2 of FIG.

Here, in step S16, the relay 41 is turned off to stop only the forced cooling operation. Therefore, in this state, the air circulation operation by the evaporator fan 15 is continued. In step S17, the timer B is started. The timer B is set to a time at which the evaporator 14 in the low temperature state can effectively remove heat from the air in the closed case 2 after the forced cooling operation is completed. In step S18, the timer B waits until the time is up. When the timer B times out in step S18, the process returns to step S2 in FIG.

Here, even after the forced cooling operation is completed, the low temperature state of the evaporator 14 is effectively used for cooling the air in the closed case 2, so that further energy saving can be achieved.

[0026]

According to the cooling device for a closed control panel according to the present invention, when it is judged that the cooling operation is necessary, the air in the closed control panel is first circulated, and the circulation alone is not sufficient. In some cases, forced cooling is performed, so that it is possible to prevent the rapid cooling operation for the closed control panel and save energy.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a cooling device as an embodiment of the present invention.

FIG. 2 is a schematic block diagram showing the piping configuration.

FIG. 3 is a schematic block diagram of a control unit thereof.

FIG. 4 is a control flowchart thereof.

FIG. 5 is a control flowchart thereof.

FIG. 6 is a control flowchart of another embodiment.

[Explanation of symbols]

 1 Cooling Device 3 Control Panel 13 Temperature Sensor 15 Evaporator Fan 22 Filter 24 Compressor 25 Condenser Fan 26 Air Volume Sensor 27 Thermostat 40 Control Unit

Claims (1)

[Claims] 1. A cooling device for a closed control panel for cooling the inside of the closed control panel, wherein an ambient temperature in the closed control panel is measured to determine whether or not a cooling operation is necessary. A first determining means for determining, a circulation means for circulating the air in the closed control panel first when the first determining means determines that a cooling operation is necessary, and a sufficient cooling by the circulation means. Second judging means for judging whether or not it is possible, and forced cooling for forcibly cooling the air in the closed control panel when the second judging means judges that the circulation means alone is insufficient. A cooling device for a closed control panel, which comprises: