JPH0712862Y2 - Refrigeration showcase controller - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a refrigerating showcase control device capable of varying the defrosting end temperature depending on day and night.

[Prior art]

FIG. 2 is a sectional view showing a general structure of an open showcase. In FIG. 2, a refrigerating room 1 whose front surface is open
Two layers of inner and outer air circulation passages 2 and 3 are formed on the outside of the, and by operating the fans 4 and 5 incorporated therein respectively, air is circulated in the direction of the arrow, and an air curtain is provided on the open surface of the refrigerating compartment 1. To form. A cooler 6 connected to a refrigerator (not shown) is arranged in the inner layer passage 2, and the electromagnetic valve 7 is normally opened to cool the inside of the refrigerator. Further, a temperature sensor 8 is provided in front of the air outlet of the inner layer passage 2 to adjust the temperature inside the refrigerator during the cooling operation and detect the defrosting end timing during the defrosting operation described later. Defrosting heater 9 is for melting and removing the frost adhering to cooler 6 during cooling operation. This defrosting is performed as follows. First, the electromagnetic valve 7 is turned off to stop the flow of refrigerant. Then, the outer layer fan 5 is rotated in the reverse direction so that the air flow in the outer layer passage 3 is in the direction opposite to the arrow shown in the drawing, and warm outside air is taken in, and the defrost heater 9 is energized to heat the cooler 6. When the air temperature detected by the temperature sensor 8 eventually reaches a preset defrosting end temperature, the defrosting heater 9 is de-energized,
The outer layer fan 5 is returned to the normal rotation state, the electromagnetic valve 7 is opened, and the operation of the cooler 6 is restarted. This defrosting is performed at regular time intervals about 4 to 6 times a day. Further, the defrosting end temperature is set to a temperature at which the frost of the cooler 6 is sufficiently melted.

[Problems to be solved by the device]

Conventionally, in the above defrosting operation, for example, in the case of a refrigerated showcase that keeps the temperature of goods in the refrigerator at about 0 to 2 ° C, the defrosting end temperature is set to about 12 ° C. But according to this,
There is a risk that the product temperature during defrosting will rise to about 8 to 10 ° C and deteriorate the product. Then, this invention aims at providing the control apparatus of the refrigerating showcase which suppressed the rise of the product temperature during defrosting to the minimum, and prevented the product deterioration.

[Means for Solving the Problems]

To achieve the above object, the present invention provides a refrigerating showcase having means for defrosting a cooler, and means for setting two kinds of defrosting end temperatures of a daytime temperature and a higher nighttime temperature. , Means for determining whether it is daytime or nighttime, a means for selecting one of the two types of defrosting end temperatures according to a signal from the determining means, and a detection temperature reaching the selected defrosting end temperature. And means for ending the defrosting operation.

[Action]

Whether it is daytime or nighttime is determined by whether or not the lighting is turned on or by a clock, etc., and during the daytime when the store is open, the defrosting end temperature is set low to suppress the rise in product temperature and prevent product deterioration. However, if the defrosting end temperature is low, defrosting cannot be completed, and unmelted frost may remain, resulting in an ice bank. Therefore, at night, the defrosting end temperature is set higher than in the daytime to completely melt the frost at night. Since the outside air temperature is low and it is easy to keep cold at night, even if the defrosting end temperature is raised, the product temperature does not rise much.

【Example】

FIG. 1 shows the circuit configuration of an embodiment of the present invention. First, consider the daytime case. In the daytime, in order to turn on the interior lighting (fluorescent lamp) 10 of the refrigerated showcase, the interior lighting switch 11 is turned on. Then, the photocoupler PC1 is turned on, which turns on the transistor TR1. As a result, the voltage at point A becomes approximately 0V. On the other hand, the variable resistance RV sets the daytime defrosting end temperature (hereinafter referred to as the daytime temperature) as the voltage at point B. Next, in the adder 12, the voltage at the point A and the voltage at the point B are added and output to the point C. In this case, the voltage at point A is
Since it is 0V, the voltage at the point C becomes substantially equal to the voltage at the point B. That is, the voltage corresponding to the daytime temperature is output to the point C. Further, in the comparator 13 at the next stage, the voltage at the point D corresponding to the temperature detected by the temperature sensor 8 is compared with the voltage at the point C, and the voltage at the point D, that is, the detected temperature is the voltage at the point C, that is, the daytime temperature. When the voltage reaches, the voltage at point E becomes "H" level. As a result, the transistor TR2 is turned on, the relay 14 is turned on, and the defrosting operation is stopped. Next, consider the case at night. At night, the store is closed and the interior lighting switch 11 is turned off by turning off the interior lighting 10. Then,
The photocoupler PC1 turns off and the transistor TR1 also turns off. As a result, a voltage corresponding to the resistance R2 is generated at the point A. For example, if you want to increase the defrosting end temperature at night (hereinafter referred to as nighttime temperature) by 3 ° C above the daytime temperature, set the resistance values of resistors R1 and R2 so that the voltage at point A becomes 3 ° C. Make a decision. As a result, a voltage corresponding to the defrosting end temperature, which is higher than the daytime temperature by 3 ° C., that is, the nighttime temperature appears at point C. Therefore, the temperature detected by the temperature sensor 8 at which the relay 14 is turned on via the comparator 13 and the defrosting operation is stopped also rises by 3 ° C. That is, the defrosting end temperature rises at night. When it is desired to change the increase range of the defrosting end temperature at night, the resistance value of the resistor R1 or R2 may be changed.

[Effect of device]

According to this invention, since the defrosting end temperature in the daytime is suppressed to be lower than that in the nighttime, the defrosting operation time in the daytime can be shortened and the deterioration of the product due to the increase in the product temperature can be prevented. Further, since the defrosting end temperature is raised at 3 to 5 ° C. at night, for example, the defrosting residue that is considered to occur during the daytime is completely eliminated at night, and there is no possibility of an ice bank.

[Brief description of drawings]

FIG. 1 is a rotation diagram of an embodiment of the present invention, and FIG. 2 is a sectional view showing a general structure of a refrigerating showcase. 6: Cooler, 8: Temperature sensor, 9: Defrost heater.

Claims (1)

[Scope of utility model registration request] 1. A refrigerating showcase having means for defrosting a cooler, means for setting two kinds of defrosting end temperatures of a daytime temperature and a nighttime temperature higher than this temperature, and discrimination between daytime and nighttime. Means, a means for selecting one of the two types of defrosting end temperatures in accordance with a signal from the determining means, and a means for ending the defrosting operation when the detected temperature reaches the selected defrosting end temperature. A control device for a refrigerated showcase, which is provided with.