JPS626455Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention is mainly concerned with improving the internal temperature control of a cooling device used for cooling a refrigerator.

Conventionally, this type of cooling system consists of a refrigeration cycle in which a compressor, an air-cooled condenser, an expansion device, and a cooler are connected in sequence, and the air inside the refrigerator is circulated through the cooler to lower the temperature of the refrigerated items. The electrical circuit used for this purpose was constructed as shown in FIG. That is, in the figure, 1 is a compressor, 2 is an electromagnetic contactor for the compressor, 2a is an a contact of the electromagnetic contactor for the compressor 2, and 3 is an overcurrent relay, which is connected in series with the a contact 2a to the compressor. has been done. 3b
4 is a B contact of the overcurrent relay 3, and 4 is an air-cooled condenser blower, which is connected in series with the A contact 2a.
Reference numeral 5 denotes a cooler blower for circulating air inside the refrigerator to a cooler (not shown). 6 is an electromagnetic contactor for cooler blower 5, and the two electromagnetic contactor circuits are parallel circuit A.
is formed. 6a is a contact a of the electromagnetic contactor 6 for a cooler blower connected in series with the blower 5, 7 is an operation switch connected in series with the parallel circuit A, and 8 is a temperature control whose contacts open and close by sensing the air temperature inside the refrigerator. It is connected in series with coil 2 to form a two-coil circuit. In such a configuration, normally when the operation switch 7 is closed, the cooler blower 5 is operated via the a contact point 6a of the electromagnetic contactor 6, and the compressor 1 and condenser blower 4 are operated when the temperature inside the refrigerator is low. When the temperature rises above a predetermined value, the temperature regulator 8 closes, and the a contact 2a of the electromagnetic contactor 2 closes.
When the temperature inside the refrigerator falls below a predetermined value, the temperature regulator 8 is opened, and the operation is accordingly stopped. With such a control method, the cooling operation is continued with the temperature inside the refrigerator within a predetermined temperature range.

Figure 2 is a graph showing changes in the internal air temperature and stored product temperature over time when the conventional cooling device described above performs cooling operation with stored products stored in the refrigerator. shows the temperature, and the horizontal axis shows the elapsed time.
In the figure, 21 is a change in the air temperature in the refrigerator, 22 is a change in the stored product temperature, T ₁ is the temperature at which the temperature regulator 8 closes, T ₂ is the temperature at which the temperature regulator 8 is opened, H ₁ , H ₃
indicates the time when the refrigerator door (not shown) for loading and unloading stored items is opened, and H ₂ and H ₄ indicate the times when the door is closed. Since the compressor 1 is started and stopped in the temperature range between T ₁ and T ₂ by the aforementioned control circuit, the internal air temperature 21 is maintained within the temperature range between T ₁ and T ₂ after the pulldown. However, the refrigerator door (not shown)
When the door opens, the temperature rises and remains high until a certain period of time elapses. Furthermore, as long as the door is not opened or closed, the temperature is maintained within a certain range at all times. On the other hand, the stored product temperature 22 follows the internal air temperature 21 with a slight delay, and when the door is opened and the internal air temperature 21 rises, the stored product temperature 22 also rises as shown in the figure, but when the door is opened and closed, If the temperature is not used for a long time, the internal air temperature 21 gradually approaches the average value.

Normally, refrigerators are used by frequently opening and closing the door as stored items are frequently brought in and taken out during the day, but at night the door is left closed at all times. Therefore, at first glance, it may seem that the temperature controller 8 is controlling the air temperature in the refrigerator to keep the stored items at an appropriate temperature, but the temperature of stored items differs during the day and at night, and is higher at night. Stored at low temperatures. In addition, in order to keep the average daytime temperature of stored items at an appropriate temperature, it is necessary to lower and set the operating temperature of the temperature controller 8 so that it is lower than the internal air temperature. If the equipment is not opened or closed, excessive cooling will occur, making it difficult to store stored items at an average temperature, and at night, etc., excessive cooling will result in higher operation and maintenance costs. There were flaws.

This invention aims to provide a cooling device that eliminates the conventional drawbacks, and one embodiment of this invention will be described below.

In Fig. 3, parts with the same symbols as in Fig. 1 are the same functional parts, 80 is a two-step internal temperature controller connected in series with the electromagnetic contactor 2, and 81 is opened and closed at a low temperature. A contact point of the internal temperature controller 80,
Reference numeral 82 is a contact point of the internal temperature controller 8 that opens and closes at a high temperature, and 9 is a contact point of the refrigerator that is open while the refrigerator door (not shown) is open and closed when the refrigerator door is closed. Door switch installed, 91, 9
2 is a terminal block for guiding and connecting the electrical signal from the door switch 9 to the cooling device; 10 is a timer connected in series with the door switch 9 to ensure a predetermined time after energization; 10a is a contact point of the timer 10; The contacts 81 and 82 of the internal temperature regulator 80 are switched. The solid line indicates the contact position during the non-energization period and up to a predetermined time after energization, and the broken line indicates the contact position after the predetermined time has elapsed. Also, a magnetic contactor 6 for the cooler blower 5, a circuit for the timer coil 10 and the door switch 9, and a magnetic contactor 2 for the compressor 1 and a temperature controller 8.
0 and the contact of the timer 10 mutually constitute a parallel circuit B, which is connected in series to the operation switch 7.

In this circuit, after the door switch 9 is closed, that is, until a predetermined period of time has passed after the refrigerator door is closed, the compressor 1 is controlled by the contacts 81 of the internal temperature controller 80, which open and close at a low temperature. , after a predetermined period of time has elapsed, it is controlled by a contact 82 that opens and closes at a high temperature.

The operating characteristics of this control circuit are shown in Figure 4, where T ₁ and T ₂ are the opening/closing temperatures of the low temperature contacts 81 of the internal temperature controller 80, and T ₁₁ and T ₁₂ are the high temperature contacts. 82 shows the opening/closing temperature, t is the securing time of the timer 10 for securing a predetermined time, _H5 is the time point after the predetermined time t has passed from the time _H4 when the door of the refrigerator is closed, 31 is the change in the air temperature in the refrigerator, 32 indicates the change in stored product temperature.

In this figure, the periods H ₁ to _{H 2} and H ₃ to _{H 4} indicate the period when the refrigerator door is open, as mentioned above, and under operating conditions such as during the day when the refrigerator door is opened and closed, it is different from the conventional one. However, when the refrigerator door is not opened or closed because stored items are not brought in or taken out at night or on holidays, the compressor 1 will switch to the low temperature of the internal temperature controller 80 after a predetermined time t has passed after the door is closed. Since _{the control} is performed by switching from _the contact point ₈₁ of
The range is changed and maintained. On the other hand, the stored product temperature 32 maintains the same temperature as before because the internal air temperature 31 sometimes becomes high when the refrigerator door is opened and closed and stored products are carried in and out. When there is no loading or unloading of stored items, the stored item temperature 32 gradually reaches the average temperature of the internal air temperature 31, but as mentioned above, the internal air temperature 31 is controlled at a higher temperature, so the stored items The temperature 32 is also maintained at a relatively high temperature to prevent unnecessary overcooling. In other words, when doors are opened and closed and stored items are brought in and out, the system acts to cool the stored items to the specified temperature more quickly, and under conditions where stored items are kept refrigerated stably, it is effective in preventing overcooling. , always works to maintain the appropriate temperature. In addition, under conditions of use where there is no opening/closing of doors or loading/unloading of stored items, and there is little load on the refrigerator from outside, it prevents unnecessary overcooling of the air inside the refrigerator and reduces operation and maintenance costs.

In addition, this device has a circuit that can maintain the internal air temperature at a high temperature after a certain period of time has passed after receiving a signal from the refrigerator door switch, etc., so that it can indirectly maintain the temperature of the air inside the refrigerator regardless of the time of day or night. Since it is controlled based on the frequency of use, it is fully effective even during periods when the door is not opened or closed, such as on holidays, and the amount of heat entering from the outside is reduced. The stored product temperature can be maintained more appropriately.

As described above, the conventional drawbacks are eliminated, and the temperature of stored products can be stabilized and operation and maintenance costs can be reduced.

As an example of this invention, a temperature controller with two contacts and a door switch were used as the receiving signal. The same effect can be achieved by using a change signal of the internal air pressure that changes.

[Brief explanation of the drawing]

Figures 1 and 2 are electrical circuit diagrams and graphs of changes in temperature inside the refrigerator showing a conventional embodiment, and Figures 3 and 4 are electrical circuit diagrams and graphs of changes in temperature inside the refrigerator showing an embodiment of this invention. It is a graph. In the figure, 80 is a temperature controller, 9 is a door switch,
81 is a contact that operates at a high temperature of the temperature controller; 8
2 is a contact that operates at the same low temperature, 10 is a timer,
10a is a timer contact. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] A two-stage temperature controller that senses the air temperature inside the refrigerator and controls the start and stop of the compressor, as well as operating at different temperatures, and a constant temperature control after receiving a signal to increase the internal cooling load due to the opening and closing of the refrigerator door, etc. and a timer device that counts a predetermined period of time, and after a predetermined period of time has elapsed since receiving the signal, the timer device switches the temperature controller to a temperature higher than the operating temperature before the elapse of the predetermined period of time, and turns on/off the compressor circuit. A cooling device characterized in that the cooling device is configured to form a cooling device.