JPH0684280U - Defrost control device for showcase - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to switch the defrosting operation stop mode depending on whether the store is open or closed, and perform the optimum defrosting operation at each of opening and closing. And [Structure] When the fluorescent lamp 4 is turned on, the stop time of the defrosting operation is controlled based on the temperature detected by the blowing temperature sensor 8b. Since the defrosting control based on the blowout temperature has a smaller defrosting heat radiation amount than the defrosting control based on the evaporator temperature, it does not excessively raise the internal cold storage temperature. On the other hand, when the fluorescent lamp 4 is off, the defrosting operation stop time is controlled based on the evaporator temperature. In this defrosting control based on the evaporator temperature, a large amount of defrost heat is released and a large amount of defrosting heat flows into the warehouse, but most of the products that are heat loads are sold and the products in the warehouse 2 are few, and Since the fluorescent lamp 4 is turned off, the internal temperature of the refrigerator is low, and therefore the temperature influence due to the inflow of the defrosting heat is small.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a defrost control device for a showcase, which controls a defrosting means based on the evaporator temperature and the cold air blowing temperature.

[0002]

[Prior art]

 Generally, in a showcase, for example, an open showcase, an evaporator of a cooling device is installed in a cool air duct formed around the inside of the storage, and the cool air cooled by this evaporator is blown to the front of the storage and the inside of the storage is blown out. I keep cold. Since frost adheres to and grows on the evaporator when keeping the inside of the refrigerator cold, after the cooling operation has been performed for a predetermined time, defrosting means for removing this frost, for example, a defrost heater is energized to evaporate. The frost on the vessel is removed.

In such defrosting operation, an evaporator temperature sensor that detects the temperature of the evaporator is used as a means for detecting whether or not the defrosting of the evaporator is finished, or It is known to use a blow-out temperature sensor that detects the temperature of cold air blown to the front surface. The former one that uses the evaporator temperature sensor focuses on the fact that the evaporator temperature rises with defrosting of the evaporator.When the evaporator temperature becomes higher than the defrosting end temperature, the defrosting operation is performed. Stop. On the other hand, the latter one using the blow-out temperature sensor focuses on the fact that the temperature of blow-out cold air rises with this defrosting.When the blow-out temperature becomes higher than the defrosting end temperature, the defrosting operation is performed. To stop.

[0004]

[Problems to be solved by the device]

 By the way, in the former type that uses the evaporator temperature sensor, emphasis is placed on improving the cooling efficiency by completely defrosting the frost adhering to the evaporator, while in the latter type that uses the blowout temperature sensor. The defrosting operation is controlled with an emphasis on keeping the inside temperature cold.

Therefore, in the former case, whether or not the frost adhering to the evaporator has been removed can be reliably detected, and reliable defrosting can be realized, but the defrosting time becomes longer and the defrosting heater is correspondingly longer. There was a problem that a large amount of heat flows into the refrigerator and the temperature inside the refrigerator rises significantly. On the other hand, in the latter case, since the cold storage temperature in the refrigerator is emphasized, the defrosting operation is terminated when the temperature reaches a temperature at which there is a problem in cold storage even when the defrosting of the evaporator is not completely completed. Therefore, it is possible to prevent the temperature inside the refrigerator from rising excessively, but there is a problem that the evaporator is not completely defrosted.

In view of the above-mentioned conventional problems, the object of the present invention is to switch the defrosting operation end mode depending on whether the store is open or closed, and is most suitable for each of opening and closing. An object is to provide a defrost control device for a showcase capable of defrosting operation.

[0007]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a method for keeping the commodities in a refrigerator by cold air blown through an evaporator, while defrosting frost attached to the evaporator by a defrosting means. In the showcase defrost control device, an evaporator temperature sensor that detects the temperature of the evaporator, a blowout temperature sensor that detects the temperature of the cold air blown into the refrigerator, and a store being opened or closed When the store is opened based on the detection signal of the opening / closing store detecting means for detecting whether or not the store is open, the stop time of the defrosting means is controlled based on the detection temperature of the blowing temperature sensor, When the store is closed, it comprises a control means for controlling the stop time of the defrosting means based on the temperature detected by the evaporator temperature sensor.

A second aspect of the present invention is the defrosting control device for a showcase according to the first aspect, wherein the opening / closing point detecting means is constituted by an illumination switch of an illumination device for illuminating the inside of the refrigerator, and the illumination switch is When it is on, it is detected that the store is open, and when it is off, it is closed.

According to a third aspect of the present invention, in the defrosting control device for a showcase according to the first aspect, the opening / closing detection means is composed of a timer, and the opening time set by the timer detects that the store is open, The closing time set by the timer is configured to detect that the shop is closed.

[0010]

[Action]

 According to the first aspect of the present invention, the stop time of the defrosting operation is controlled based on the temperature detected by the blow-out temperature sensor during the opening of the store for exhibiting and selling the products in the refrigerator. Since the defrosting operation based on this blowout temperature has a smaller amount of defrosting heat radiation than the defrosting operation based on the evaporator temperature, it does not raise the temperature inside the refrigerator excessively, and there is a demand for proper cooling during the exhibition and sale of products. Can be satisfied.

On the other hand, when the store is closed at night, the defrosting operation stop time is controlled based on the evaporator temperature. In the defrosting operation based on this evaporator temperature, a large amount of defrost heat is released, and a large amount of defrost heat flows into the refrigerator. However, during this closing time, many of the products stored in the refrigerator have already been sold, the number of products that are a heat load has decreased, and the lighting equipment that illuminates the inside of the refrigerator has been turned off. Therefore, the temperature inside the compartment is low, and therefore the temperature influence due to the inflow of the defrosting heat is small.

According to the second aspect of the present invention, the lighting device for illuminating the inside of the warehouse is turned on during the opening of the store, and the lighting device is turned off during the closing of the store. Therefore, the lighting switch of the lighting device is turned on / off. Is synchronized with the opening and closing of the store, the on / off control of this lighting switch controls the stop of the defrosting operation, and the requirements of proper cooling during opening and complete defrosting during closing can be satisfied.

According to the invention of claim 3, the opening time and the closing time are determined depending on whether the store is open or closed. Therefore, by setting these times in advance by the timer, the opening time can be increased. It is possible to control the stoppage of the defrosting operation during and during closing, and it is possible to satisfy the requirements for proper cooling during opening and complete defrosting during closing.

[0014]

1 to 3 show a first embodiment of a defrosting control device for a showcase according to the present invention. FIG. 1 is a sectional view of a showcase, that is, an open showcase, and FIG. 2 is a defrosting device. FIG. 3 is a block diagram showing the configuration of the control device, and FIG. 3 is a control flowchart of the defrost control device.

The open showcase 1 has an opening on the front side, and a plurality of shelves 3 for exhibiting and selling products are installed vertically in the storage 2. In order to illuminate the products placed on the shelves 3, for example, vegetables and fruits, fluorescent lamps 4 which are lighting devices are installed on the respective shelves 3 and the open showcase 1.

Further, in order to cool the inside 2, a cold air duct 5 extending vertically is formed around the inside 2, and an evaporator 6 for a cooling device is installed in the cold air duct 5. This evaporator 6 circulates a cooling medium for cooling, cools the air passing through the cold air duct 5, and cools this cooled air from the upper part of the cold air duct 5 along the front opening of the open showcase 1. The air is blown downward (so-called air curtain), and this air is further sucked in from the lower part of the cold air duct 5 to form a cold air circulation for cooling the inside of the refrigerator (one-dot chain line arrow in FIG. 1).

In this cold air circulation, since frost adheres to and grows on the evaporator 6, after the cooling operation of the inside 2 is continued for a predetermined time, the defrost heater 7 for melting the frost of the evaporator 6 is energized. Further, in order to control the operation stop timing of the defrost heater 7, an evaporator temperature sensor 8a for detecting the temperature of the evaporator 6 and a blowout temperature sensor 8b for detecting the blowout temperature of the cold air of the cold air duct 5 are provided. is doing.

The configuration of the defrosting control device for the evaporator 6 will be described with reference to FIG. That is, based on the open / close signal of the illumination switch 4a of the fluorescent lamp 4 and the detection signals of the evaporator temperature sensor 8a and the blow-out temperature sensor 8b, the CPU 9 of the microcomputer configuration operates the defrost heater 7 via the defrost heater drive circuit 7a. Have control. This drive control will be explained based on the control flow chart of FIG.

That is, the evaporator temperature sensor 8a detects the temperature TA of the evaporator 6, and the blowout temperature sensor 8b detects the blowout temperature TB of the cold air duct 5 (S1, S2). Then, it is determined whether or not the defrost heater 7 is energized and whether or not the illumination switch 4a is turned on (S3, S4). Here, when the defrost heater 7 is energized and the lighting switch 4a is turned on, that is, when the defrost operation is performed during opening of the store, the blowing temperature TB reaches the defrost stop temperature TC. It is determined whether or not there is (S5). Here, when the blowout temperature TB is higher than the defrost stop temperature TC, the power supply to the defrost heater 7 is stopped (S6), and the defrosting of the evaporator 6 is completed.

On the other hand, when the illumination switch 4a is off in step 3, that is, when the store is closed, it is determined whether the evaporator temperature TA has reached the defrost stop temperature TC (S7), and the defrosting is performed. When the temperature is higher than the stop temperature TC, the power supply to the defrost heater 7 is stopped, and the defrosting of the evaporator 6 is completed.

As described above, in the present embodiment, the lighting switch 4a of the fluorescent lamp 4 is used as the opening / closing store detecting means for detecting whether the store is open or closed, and the control is performed based on the blowing temperature TB during the store opening. Then, a large amount of heat from the defrost heater is prevented from flowing into the interior 2 during defrosting, and the interior 2 is always maintained at an appropriate cold insulation temperature.

On the other hand, when the store is closed, the evaporator 6 is controlled based on the temperature TA to completely defrost the evaporator 6. Also, when the store is closed, most of the products in the refrigerator 2 are sold and there are few products that have a heat load. Also, since the fluorescent lamp 4 is turned off and the radiant heat of the fluorescent lamp 4 is gone, the temperature inside the refrigerator is lower by that amount. As a result, the influence of the defrosting heat that has flowed into the interior 2 is small.

4 and 5 show a second embodiment of the defrosting control device for a showcase according to the present invention, FIG. 3 is a block diagram showing the configuration of the defrosting control device, and FIG. 5 is a defrosting control device. It is a control flowchart of the apparatus.

In this embodiment, a timer 9a mounted on the CPU 9 is used as an opening / closing store detecting means for detecting whether the store is open or closed. For example, 12 hours from 9 am to 9 pm are set, and other times are set as the closing time.

According to this embodiment, the temperature TA of the evaporator 6 is detected, and the blowout temperature TB is detected (S1, S2). Then, it is determined whether or not the defrosting operation is being performed, and whether or not the time is from 9:00 pm to 9:00 pm (S3, S4). Here, at the time when the store is open, it is determined whether or not the blowout temperature TB has reached the defrost stop temperature TC (S5), and based on this blowout temperature TB, as in the first embodiment. The defrosting operation is controlled (S6). On the other hand, when it is not the time when the store is opened in step 4, that is, when the store is closed, it is judged whether the evaporator temperature TA has reached the defrost stop temperature TC (S7), and the evaporator temperature TA is determined. The defrosting operation is controlled based on (S6).

Although the defrosting heater 7 is used as the defrosting means in the above embodiment, the defrosting means may be, for example, a hot gas defroster that circulates a high temperature gas refrigerant in the evaporator 6, or a high temperature liquid. Liquid defrosting in which a refrigerant is circulated in the evaporator 6 and further water sprinkling defrosting in which water is sprinkled in the evaporator 6 may be adopted.

[0027]

[Effect of device]

 As described above, according to the first aspect of the present invention, the defrosting operation is stopped based on the temperature detected by the blowout temperature sensor during the opening of the store when the products in the refrigerator are on display and for sale. The amount of defrost heat released during operation is small, and the internal temperature does not rise excessively. On the other hand, when the store is closed at night, there are few products that have a heat load due to sales, and the interior temperature is low because the lighting equipment is off, so defrost control based on the evaporator temperature is performed. Even if the above is performed, there is an advantage that the temperature influence due to the inflow of defrosting heat is small and the evaporator can be completely defrosted.

According to the invention of claim 2, the lighting device for illuminating the inside of the store is turned on during the opening of the store, and the lighting device is turned off during the closing of the store. Therefore, the lighting switch of the lighting device is turned on / off. Is synchronized with the opening and closing of the store, and the stop of the defrosting operation is controlled by the on / off control of this lighting switch, and it is possible to satisfy the requirements for proper cooling during opening and complete defrosting during closing.

According to the third aspect of the invention, the timer controls the stop of the defrosting operation during opening and closing of the store, so that the requirements of proper cooling during opening and complete defrosting during closing can be satisfied.

[Brief description of drawings]

[Figure 1] Cross-section of the open showcase

FIG. 2 is a block diagram showing a configuration of a defrost control device according to the first embodiment.

FIG. 3 is a control flowchart of the defrost control device according to the first embodiment.

FIG. 4 is a block diagram showing a configuration of a defrost control device according to a second embodiment.

FIG. 5 is a control flowchart of a defrost control device according to a second embodiment.

[Explanation of symbols]

1 ... Open showcase, 2 ... Inside, 4 ... Fluorescent light, 6
... evaporator, 7 ... defrost heater, 8a ... evaporator temperature sensor,
8b ... Blowout temperature sensor, 9 ... μCPU, 9a ... timer.

Claims (3)

[Scope of utility model registration request] 1. A defrost control device for a showcase, which cools commodities in a refrigerator by cold air blown through the evaporator and defrosts frost attached to the evaporator by defrosting means. An evaporator temperature sensor that detects the temperature of the container, an outlet temperature sensor that detects the temperature of the cold air that is blown into the refrigerator, an opening / closing store detection unit that detects whether the store is open or closed, and the opening / closing When the store is open based on the detection signal of the store detection means, the stop time of the defrosting means is controlled based on the detection temperature of the blowout temperature sensor, and when the store is closed, the evaporator temperature sensor is detected. A defrost control device for a showcase, comprising: a control unit that controls a stop time of the defrost unit based on a temperature. 2. The opening / closing point detection means is composed of a lighting switch of a lighting device that illuminates the inside of the refrigerator. When the lighting switch is on, it detects that the store is open, and when the lighting switch is off, it is close. The defrosting control device for a showcase according to claim 1, wherein: 3. The opening / closing store detection means is composed of a timer, and the opening time set by the timer detects that the store is open, and the closing time set by the timer detects that the store is closed. The defrost control device for a showcase according to claim 1.