JP2884930B2 - Showcase defrost controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a showcase defrost control device for preventing the temperature in a refrigerator from increasing during and immediately after defrost.

[0002]

2. Description of the Related Art Conventionally, in a showcase, in order to remove frost adhering to an evaporator, hot air heated by a heater or the like is sent to an evaporator to melt frost and flow out.
The evaporator surface is dried by blowing air, which is called draining. This draining time is set in advance.

If the draining time is short, drying is not completed and cooling is restarted with water remaining on the evaporator. Therefore, the attached water freezes and causes clogging. This clogging is called an ice bank, and when the ice bank occurs, the cooling capacity is significantly impaired, and the product and the showcase are greatly damaged.

[0004] Further, melting is prolonged if frost formation is excessive or if frost formation has changed like ice over time. Therefore, in the case where the draining is started before the defrosting is completed, it must be completely melted by the end of the draining. For the above reasons, the draining time is set as large as possible.

[0005]

As described above, if the draining time is set long enough, the drying is completed within the set draining time when the amount of frost is small or the outside temperature is high. The remaining time unnecessarily raises the temperature inside the showcase storage. This degrades the freshness of the product and impairs the purchase motivation of shoppers seeking fresh products.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to prevent hot air from being blown into a showcase cabinet for an unnecessarily long time during defrosting. It is an object of the present invention to provide a showcase defrosting control device capable of preventing a rise in the internal temperature of the refrigerator and preventing deterioration of product freshness.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a showcase defrosting control apparatus for removing the frost of an evaporator by heating and melting, and then drying it by blowing air to drain the water. A temperature sensor for detecting the outside air temperature, a timer for measuring the elapsed time since the previous defrosting, and a fuzzy inference unit for calculating an optimum draining time according to the outside air state and the frost formation state based on the outside air temperature and the elapsed time. And means for controlling the air blowing time based on the calculated draining time.

[0008]

In the present invention, the outside air temperature is detected by the temperature sensor, and the elapsed time from the previous defrost is measured by the timer. An optimal draining time is calculated by the fuzzy inference unit based on the detected outside air temperature and the elapsed time according to the outside air and the frost formation state. Further, the air blowing time for draining is controlled based on the calculated draining time.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment of the present invention. In the figure, reference numeral 1 denotes a defrost start device, which sends a defrost start signal a to the showcase control device 2. When the showcase control device 2 receives the defrost start signal a, the defrost control unit 3
And sends the defrosting ON signal b to the output unit 4. When the defrost control unit 3 determines the end of defrost from the temperature information of the showcase, it sends a defrost OFF signal c to the output unit 4.

A defrost elapsed time counter 5 serving as a timer measures the defrost elapsed time d from the start of the previous defrost to the start of the current defrost and sends the measured time to the fuzzy inference unit 6. The outside air temperature sensor 7 detects the outside air temperature e and outputs a fuzzy inference unit 6.
Send to The fuzzy inference unit 6 determines the membership function 8 and the rule 9 based on the defrosting elapsed time d and the outside air temperature e.
Is used to estimate the state of frost on the evaporator (not shown), calculate the optimum draining time f according to the current outside temperature, and send it to the draining controller 10.

The membership function 8 is a membership function for determining whether the input values of the defrosting elapsed time d and the outside air temperature e are "short" or "high". Rule 9 is created based on the following concept. (1) If the defrosting elapsed time is short, the amount of water adhering to the evaporator after defrosting is small, or the defrosting is incomplete, since the frost formation is small or the frost is easy to melt at most. Judge that the danger of ending is small and shorten the draining time.

(2) If the defrosting elapsed time is long, the amount of water adhering to the evaporator after the defrosting is large, Judging that there is a high risk of incomplete defrosting is completed, the draining time is extended. (3) When the outside air temperature is high, the drainage time is shortened because the air is easily dried. (4) If the outside air temperature is low, it is difficult to dry, so the draining time is lengthened. Table 1 summarizes these concepts into IF to THEN format rules.

[0013]

[Table 1]

The drain controller 10 sends a drain ON signal g to the output unit 4 at the end of the defrosting operation, and also sets the drain ON.
After the output of the signal g, the draining time f
An OFF signal h is sent to the output unit 4. The output unit 4 starts / stops signals i, j, and k at the timing when the defrosting ON signal b, the defrosting OFF signal c, the draining ON signal g, and the draining OFF signal h are input.
And the fan 11, the heater 12, the valve 1
Send to 3. The fan 11 is for sending cool air during normal operation and for sending warm air during defrosting, the heater 12 is for heating the sending air during defrosting, and the valve 13 is for turning on / off the supply of refrigerant to the evaporator. It is for turning off.

With this embodiment, the state of frost formation at the start of defrosting is estimated based on the defrosting elapsed time d, and the ease of drying the evaporator is estimated based on the outside air temperature e. As a result, an optimum draining time f without excess or deficiency is obtained, and draining can be terminated at an appropriate timing, and unnecessary rise of the internal temperature during and immediately after draining can be prevented.

FIGS. 2 to 4 show the membership function 8 of FIG.
Here is the specific content of FIG. 2 is a membership function for the defrosting elapsed time d of the antecedent part. FIG. 3 is a membership function regarding the outside air temperature e of the antecedent part. FIG.
Is a membership function for the drainage time f of the consequent.

In this embodiment, the defrosting state at the start of defrosting is estimated, and the state of the air for drying the water adhering to the evaporator, that is, the state of the outside air, is determined to determine the drainage time, thereby performing the drainage. Therefore, it is possible to perform draining without excess or shortage. As a result, it is possible to prevent an unnecessary increase in the internal temperature, and it is possible to suppress a loss of purchase motivation of the shopper and a deterioration of the freshness of the product.

In addition, a new showcase defrosting control system has been established which guarantees the safety when defrosting is not completely performed as compared with the conventional technology. In the embodiment, the state of the outside air is detected only by the temperature, but it is also possible to detect the humidity to further improve the control accuracy.

[0019]

As described above, according to the present invention, the drainage time is obtained by fuzzy inference based on the outside air temperature and the elapsed time from the previous defrosting, and the blowing time is optimized. As a result, after defrosting, no extra air is blown and unnecessary rise in the temperature of the showcase compartment is eliminated,
The freshness of the product can be extended.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram illustrating a membership function set for a defrosting elapsed time.

FIG. 3 is a diagram showing a membership function set for an outside air temperature.

FIG. 4 is a diagram showing a membership function set for a draining time.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 defrost start device 2 showcase control device 3 defrost control unit 4 output unit 5 defrost elapsed time counter 6 fuzzy inference unit 7 outdoor temperature sensor 8 membership function 9 rule 10 drain control unit 11 fan 12 heater 13 valve

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F25D 21/06-21/08 F25D 17/06 315 A47F 3/04

Claims (1)

(57) [Claims] 1. A defrosting control device for a showcase, in which frost formed on an evaporator is removed by heating and melting, followed by drying by air blowing to drain water, a temperature sensor for detecting an outside air temperature, A timer for measuring the elapsed time, a fuzzy inference unit for calculating an optimum drainage time according to the outside air condition and the frost formation state based on the outside air temperature and the elapsed time, and a means for controlling the air blowing time based on the calculated drainage time. A defrosting control device for a showcase, comprising: