JP2639975B2 - Refrigeration, refrigerator cooling operation method - Google Patents

Description

The present invention relates to a cooling operation system for a freezer, a refrigerator or a freezer or a refrigerated showcase.

(B) Conventional technology Generally, in this type of freezing, refrigerator, or refrigerated showcase, cooling air is forcibly circulated in a refrigerator to cool the refrigerator.

In order to keep the inside of the refrigerator within a predetermined temperature range, operation control of the cooling device is performed by various methods. Often used in these operation methods is the so-called thermocycle operation method, in which the temperature inside the refrigerator is detected by a temperature detector, and based on the result, a temperature controller such as a thermostat is operated to drive the compressor, This system controls ON / OFF of the cooling device by controlling the start and interruption of the supply of the liquid refrigerant to the cooling device by stopping or opening and closing the liquid solenoid valve.

Further, the control is normally performed by the thermocycle operation, and if a failure occurs in the control and the function is lost, the operation of the cooling device for a predetermined period of time (supply and interruption of the liquid refrigerant) is periodically performed. , That is, the system is continuously switched to a duty cycle operation using a duty timer, so that cooling is thoroughly performed.

As described above, the operation system in which the normal thermocycle operation is performed and the operation is switched to the duty cycle operation when a failure occurs is common. For example, a similar system is described in Japanese Utility Model Publication No. Sho 62-16601. That is, according to the publication, if the control system S ₁ checks the temperature inside the refrigerator, to control the operation of the cooling device according to the circumstances, abnormality occurs if the control system section S _1, the safety operating the control unit S _2, operation of the cooling device is adapted to form a constant holding of the inside temperature by intermittently performing time controlled stop.

Here, during both the thermocycle and duty cycle operations, a defrost operation control for periodically stopping the operation of the cooling device and performing defrost for a certain period of time is added, and this control is performed by a separately provided defrost timer. Is done.

(C) Problems to be Solved by the Invention However, when the thermocycle operation has failed and is switched to the duty cycle operation, the duty cycle operation does not always start from the beginning of the cooling period.
This is because the duty timer that controls the duty cycle operation operates independently during the thermocycle operation,
Therefore, when the switching time is when the operation of the cooling device is stopped, or when the operation is performed as shown in FIG. There are cases such as entering a section. In such a situation, the internal temperature of the refrigerator increases during that time. In addition, defrosting is performed periodically, but the shutdown of the cooling device during that time causes an increase in the internal temperature of the refrigerator, which has an effect such as delaying cooling after the completion of defrosting. In particular, at the end of the defrosting operation when the control is shifted to the duty cycle operation due to the failure of the thermocycle operation, the cooling delay greatly differs depending on the situation where the duty cycle operation starts. Come to. That is, since the defrosting timer for performing the defrosting operation and the duty cycle operating timer for performing the duty cycle operation are operated independently of each other, the end point of the defrosting is the OFF of the duty cycle operation, so-called. In some cases, the supply of the liquid refrigerant is interrupted, or the operation is ON, but near the end of the period, the supply of the liquid refrigerant is started, or the supply of the liquid refrigerant is interrupted in a short time. In such a case, the defrosting period is substantially extended, or the defrosting is performed again after a short period of time, and the temperature inside the refrigerator is further increased, which leads to the deterioration of the quality of refrigerated items.

In particular, in recent years, in order to keep fish, meat products, and the like fresh for a long period of time, the temperature range is near 0 ° C., which is called the ice temperature range, and has a narrow temperature range (for example, −2 ° C.). A refrigeration system in which the temperature is controlled and stored at a width of ± 0.5 ° C.) has been proposed, but in this ice temperature refrigeration, an over phenomenon of the temperature range immediately leads to deterioration of the quality of the product, which is a serious problem.

Incidentally, the investigation of the rise in the internal temperature is shown in more detail in the time charts of FIGS. 6 (a) and 7 (b). FIG. 6 shows a case where the defrosting time is 25 minutes, the operation ON time of the duty cycle operation is 15 minutes, and the OFF time is 3 minutes. After the defrosting is completed, the operation is performed for 1 minute and 30 seconds and the operation is turned off. FIG. 7 (a) shows the operation at the end of defrosting.
FIG. 2B shows a case in which the operation is in the middle of the OFF state, and FIG. In the figure, Ts and Ts' are defrosting times, T and T 'are operation ON times, and t and t' are operation OFF times.

Although such a problem exists, the above-mentioned J.
In the control device described in the 16601 publication, when switching from the thermocycle operation to the duty cycle operation due to a failure, the duty cycle operation does not start from the beginning of the cooling operation, and even after the end of the defrosting during the duty cycle operation. Similarly, the cooling operation does not start from the beginning and has the above-mentioned problems.

The present invention has been made in view of the above problems, and when switching to the duty cycle operation, or after the end of defrosting during the duty cycle operation, the cooling device always starts from ON to perform cooling. An object of the present invention is to provide an operation system of a refrigerator and a refrigerator which can ensure the cooling, suppress the rise in the internal temperature after defrosting, and perform stable cooling.

(D) Means for Solving the Problem The cooling method of the refrigerator and the refrigerator of the present invention usually operates and stops the cooling device in the thermocycle operation, and when the thermocycle becomes impossible, the duty cycle operation by the duty timer. The operation of the cooling device is started and stopped for a time set in accordance with the above.When switching to the duty cycle operation, or during the operation, the duty cycle operation that starts after the end of the defrost operation is always performed. This is performed from the beginning of operation.

(E) Operation When there is no failure of the thermostat or the like and the thermocycle operation control is normally performed, the duty timer is reset based on the normal control. Therefore, if the failure of the thermostat is detected and the operation is switched from the thermocycle operation to the duty cycle operation based on the failure, the duty timer is started for the first time, the operation of the cooling device is timed from the beginning, and the operation of the regular set time is performed. A cooling operation will be performed. Therefore, cooling is ensured even at the time of switching, and the temperature inside the refrigerator is sufficiently maintained. In addition, during the duty cycle operation, when the defrost is completed by the periodically performed defrost operation, a defrost end signal is output in accordance therewith, and the duty cycle operation is performed using the defrost end signal. A reset signal is input to reset the cycle operation timer. Then, since the duty cycle operation that starts after the end of the defrost always starts from the beginning of the period of the cooling device operation, the internal temperature that has risen due to the defrost tends to immediately decrease, and quickly reaches the target internal temperature. And prevent deterioration of the quality of the stored goods.

(F) Example Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the structure of an open-type freezing and refrigerated showcase. Reference numeral 1 denotes a showcase main body, and two internal and external cold air circulation paths 2.3 are provided in the main body 1. Are provided with a circulation fan 4.5, and a cooler 6 which forms a refrigerant circuit together with a compressor and a simulator (not shown) is arranged in the inner circulation path 2, and heat is exchanged in the cooler 6. Cool air is circulated in the refrigerator to form a double-inside / outside cold air curtain 8.9 at the front opening 7 of the showcase body 1 to block the outside air and the interior to cool the interior. Reference numeral 10 denotes a temperature detecting section which is disposed in the inner circulation path 2 and in the vicinity of the cool air discharge port 11 and detects the temperature of the inner layer circulating cool air. The detection signal is a signal transmission line 12, which controls the cooling operation as a whole. Control unit 13
It is connected to the. Therefore, in order to keep the inside of the refrigerator at a predetermined temperature substantially constant, a thermocycle operation control is performed in which the operation of the cooler 6 is operated at an upper limit value of a preset reference temperature and stopped at the following value. However, this control is determined and executed by the control unit 13 including the microcomputer based on the signal from the temperature detection unit 10. That is, the temperature detection unit 10 detects the temperature of the discharge air, and when the temperature exceeds the upper limit of the set temperature, the compressor is driven by the control unit 13 to perform cooling, and when the temperature reaches the lower limit, the compressor is cooled. Is stopped. When a plurality of refrigeration units, refrigerators, and the like are controlled, the liquid solenoid valve 16 and the like are controlled by a command from the control unit 13 to start or stop supplying the liquid refrigerant to the evaporator (cooler) 6 in the refrigerant circuit. Thus, the thermocycle operation is performed similarly.
Here, the control of the cooling operation described above will be described in more detail.
The control unit 13 including the microcomputer 17 includes a display unit 17 for displaying the temperature inside the refrigerator, an electromagnetic valve 16 for supplying a liquid refrigerant, and the like.
A command is issued to a control output unit 19 that opens and closes and controls the energization of the defrost heater 18. The temperature input section 20 has a temperature sensor
The detection signal from 10 and the signal from the defrost recovery temperature sensor 21 for determining the recovery of the defrosting operation are input, and further input to the control unit 13. Therefore, during the thermocycle operation, according to the execution program stored in the RAM 24, first, the detection output of the temperature detection unit is input to the input / output unit 23 of the control unit 13 via the temperature input unit 20 and stored in the ROM 22. The microcomputer 17 performs comparison processing with the upper and lower limit temperature of the internal temperature, and based on the result, the solenoid valve 16 is opened and closed to control the cooling operation. Further, during the thermocycle operation, the timer 25 is operated, and after a predetermined period (2.5 to 3 hours), defrosting is started. The timer 25 performs both functions of the defrost timer 15 that determines the above-described defrost period and the duty cycle operation timer 14 that repeats the cooling operation for a set time and the stop thereof. Therefore, in the defrost period, the control unit 13 outputs a defrost command and turns on the defrost heater 18 via the control output unit 19. When defrosting is about to end, defrost recovery is performed by the detection output of the defrost recovery temperature sensor 21 arranged near the evaporator 6, and the operation returns to the thermocycle operation again.

By the way, when the signal from the temperature detection unit 10 is not input to the control unit 13 due to the disconnection of the signal transmission line 12 and the control function of the thermocycle operation is lost, the duty for performing the ON / OFF control of the cooler 6 with time is used. The system is switched to cycle operation and can continue cooling. As means for that purpose, a duty cycle operation timer 14 that operates in that case is provided in the control unit 13. FIG. 4 shows a time chart of control based on temperature, that is, thermocycle operation, and control based on time to perform an alternative function when the failure occurs, that is, duty cycle operation. As can be seen from this figure, when the thermocycle operation control fails, it is detected, and the duty cycle operation timer 14 having a cycle time of 15 minutes for the operation ON time and 3 minutes for the stop time is reset, that is, Starting from the initial state, the operation control function for the cooler 6 is executed. Therefore, after that, specifically, the operation of the compressor is repeated for 15 minutes and the stop is repeated at a cycle of 3 minutes, or the liquid refrigerant supply control is performed such as opening the liquid solenoid valve 16 for 15 minutes and interrupting for 3 minutes. Control the internal temperature.

On the other hand, the defrosting operation is performed at a separately determined cycle independently of the thermocycle operation and the duty cycle operation. Reference numeral 15 denotes a defrost timer, which operates after a cooling operation for a certain period of time (2.5 to 3 hours) and periodically performs defrosting of the cooler 6 for a certain period (25 minutes). Therefore, when the thermocycle operation is in failure and the duty cycle operation is being performed, and the defrosting operations are temporally overlapped, the time chart is as shown in FIG. When the defrosting is started in the figure, the control by the duty cycle is also stopped during the period. Then, a 25-minute defrosting operation is performed. When defrosting ends, the duty cycle timer 14 starts from that point.
Is restarted, but conventionally, the counting of the timer 14 is simply continued.
In some cases, as shown in the dotted line, the operation is almost completed. In such a case, the operation of the compressor is performed for only a short time and immediately stops, and
The compressor stopped for as long as 28 minutes, 25 minutes and a 3 minute stop after a short time, causing the temperature inside the refrigerator to rise during this time.
It becomes a problem. However, in the present invention, when the defrosting operation is completed in such a case, the timer 14 for the duty cycle operation is reset to return to the initial state by using the defrosting end signal P. As a result, the time chart of the timer 14 which restarts after the completion of the defrosting is started from the operation ON time of 15 minutes as shown by the diagonal line, and thereafter, this timer 14 is started.
Based on 14, duty cycle operation control is performed.
Therefore, when defrosting is over, the cooling operation is always performed, so that the inside of the refrigerator, whose temperature has risen due to defrosting, is quickly returned to a low-temperature condition, and stable cooling of the stored items is performed. Can be avoided.

Now, the cooling operation method of the present invention will be further described with reference to the overall control flow diagram of FIG. 3. The cooling operation method is started by turning on the power, and first, it is determined whether or not it is time to perform the defrosting operation. ), The temperature detection unit 10 performs a determination 31 as to whether there is an abnormality such as a disconnection, and if there is no abnormality (NO),
That is, the thermocycle operation 40 is executed. Then, based on the temperature control control 40, a 15-minute timer reset for the duty is performed.
Perform 41. That is, the 15-minute timer that turns on (opens) the refrigerant supply solenoid valve 16 for 15 minutes, which is the operating state of the cooling device, is always in a reset state, and when the thermocycle operation is switched to the duty cycle operation due to a failure, the 15-minute timer is always reset. The minute timer is prepared to start from the beginning. Next, the process returns to the determination 30 again, and this is repeated, and the thermocycle operation is being performed. Thermocycle operation for a certain period (2.5
３3 hours), the defrosting operation is started, and the
At 30 is YES, the defrosting operation control 46 is executed, there is a detection output from the temperature sensor 21 for defrosting return, the determination 34 of the end of the defrosting operation control is performed, and the defrosting operation control 46 is continued until it is completed, When the defrosting is completed in the determination 34 (YES), a 15-minute time reset 47 for duty is performed. That is, the duty cycle operation timer 14 is always reset at the end of the defrosting operation. If an abnormality of the temperature detecting section is detected by the determination 31 (YES), the operation is switched to the duty cycle operation by the duty cycle timer 15. That is, the duty 15-minute timer starts from 0 and makes the determination 32 of the elapsed time. Then, the ON (open) operation 42 of the solenoid valve 16 is performed, and together with this,
A 3-minute timer reset 43 for duty to turn off (close) the solenoid valve for 3 minutes is executed. Therefore, when the duty cycle operation is switched, the duty 15-minute timer performs the operation for 15 minutes completely. If 15 minutes have elapsed in the determination 32 (YES), the duty 3 minute timer is started and the elapsed time determination 33 is performed. The three-minute timer executes OFF (close) 44 of the solenoid valve 16. If 3 minutes have elapsed according to the judgment 33 (YES), a 15-minute timer reset 45 for duty is performed. In this way,
During duty cycle operation, operation of the cooling device for 15 minutes,
Stop for 3 minutes.

By the way, the above duty cycle operation continues,
After a certain period (2.5 to 3 hours), it is time to perform the defrosting operation, and the determination 30 determines that the defrosting operation control 46 is performed in the same manner as in the thermocycle operation. And the end judgment
34 is performed until the temperature sensor 21 for defrost recovery detects the defrost, and the defrost time is usually regarded as about 25 minutes. Therefore, when the defrosting ends after approximately 25 minutes (YES), the duty 15-minute timer reset 47 is executed, and the operation of the cooling device that is performed again after the end of the defrosting must be performed for the duty.
Starting from 0 (initial) of the 15-minute timer, the solenoid valve 16 is always turned ON (open) for 15 minutes. Thereafter, the solenoid valve is turned off (closed) for 3 minutes in the same manner, and this is repeated.

(G) Effect of the Invention As described above, the operation of the cooling device is controlled in the normal thermocycle operation, and when the thermocycle operation fails, the operation according to the time set by the duty timer is performed.
In the cooling operation mode switched to the duty cycle operation control for stopping the operation, the duty cycle timer is always reset during the thermocycle operation, and the defrosting is periodically performed when the operation state is the duty cycle operation. After the operation was completed, the duty timer was reset to return to the initial state by the defrost end signal,
At all times, the duty cycle operation starts from the beginning of the operation period of the cooling device, and the rise in the internal temperature during defrosting is suppressed as much as possible. Therefore, as in the conventional case, the start of the duty cycle is a section in which the operation is stopped, or even if the cooling operation is performed, the operation is interrupted in a short time, which substantially extends the defrost period, and the internal temperature of the refrigerator is reduced. Can be further increased to prevent the product quality from being adversely affected.

In particular, in the ice temperature refrigeration control near 0 ° C. and a narrow temperature limit band, more complete ice temperature storage can be expected by adopting this method. More specifically, the present invention can be implemented by a simple method in which the operation signal during the thermocycle operation and the end signal based on the end of the defrost operation are input to the duty cycle operation timer as a reset signal.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a front open open showcase which is a type of freezing and refrigerator, FIG. 2 is a control circuit block diagram of a cooling operation system of the present invention, FIG. FIG. 4 is a time chart diagram before and after switching between a thermocycle operation and a duty cycle operation that operates after a failure, and FIG. 5 is a time chart showing a relationship between a duty cycle operation before and after a defrost operation according to the operation method of the present invention. FIG. 6 and FIG. 6 are time charts showing the problems caused by the duty cycle operation and the defrosting operation according to the conventional method, and FIGS. 7 (a) and 7 (b) both show the same time chart as FIG. (A) is a time chart in which the duty cycle operation is started from the middle of the OFF after defrosting is completed. (B) is a time chart in which the duty cycle operation is started from the OFF after the defrosting is completed. When is a time chart of. 1 ... showcase body, 10 ... temperature detector 12 ... signal transmission line, 13 ... controller 14 ... timer for duty cycle operation 15 ... timer for defrost, P ... defrost end signal

Claims (1)

(57) [Claims] 1. A thermo-cycle operation for detecting and controlling the temperature of the inside of a refrigerator to control the operation and the stop of the normal cooling device. When the thermo-cycle operation control becomes impossible, the operation and the operation of the cooling device for a set time are performed. In the refrigerating and refrigerator cooling operation modes switched to the duty cycle operation for stopping the operation, the respective duty cycles starting at the time of the switching to the duty cycle operation and after the end of the period of the periodically defrosting operation during the operation. The operation of cooling a refrigerator or a refrigerator, wherein the operation is always performed from the beginning of the operation of the cooling device.