JPS6284280A - Defrostation operating method of freezing-refrigeration openshowcase - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention provides inner and outer ventilation passages so that a two-layer air curtain is formed at the opening during cooling operation, and the outer ventilation passage during defrosting operation. This invention relates to a defrosting operation method for a cold air circulation type freezer/refrigerator open showcase in which defrosting is performed by stopping a fan and sucking outside air into an inner ventilation passage.

[Prior art and its problems] A multi-tiered open showcase as shown in FIG. 4 is known as this type of open showcase. In FIG. 4, the main case 1 has an opening 1a on the front for taking out the product, an outer box 2 formed of a heat insulating wall, and an inner box 3 disposed with an appropriate gap between the outer box 2 and the outer box 2. A display room 5 partitioned into multiple stages by shelf boards 4 is formed inside the inner box 3.

Further, a partition wall 6 is provided between the outer box 2 and the inner box 3 so as to divide the gap into two, thereby forming an inner ventilation passage 7 and an outer ventilation passage 8.

Both ends of the inner ventilation passage 7 form Suita lower a and suction lower b above and below the opening 1a, respectively, and both ends of the outer ventilation passage 8 are adjacent to Suita lower a and suction lower b, respectively, and have air outlets 8a and A suction port 8b is formed. The blowout lowers a and 8a are equipped with an air regulating fluid 9 having honeycomb-shaped ventilation holes.Inside the inner ventilation passage 7, a cooler 11, a fan 12) and a defrosting heater 21 are installed.
A fan 13 is arranged inside.

In this oven case, during cooling operation, indoor air is circulated through the inner ventilation passage 7 in the direction of arrow A by the fan 12 and cooled by the cooler 11 to become cold air, and this cold air is blown out from the Suita lower a. [An air curtain 15 is formed in the opening 1a to isolate the inside of the display room 5 from outside air and to cool the inside of the display room 5. Furthermore, an air curtain 16 is formed on the outside of the air curtain 15 so as to protect the air curtain 15 by indoor air circulating through the outside ventilation path 8 in the direction of arrow B by the fan 13, and the inside of the display room 5 is more efficiently cooled and kept cool. Ru.

Further, during the defrosting operation, the operation of the cooler 11 is stopped, and the defrosting heater 21 is energized.

Defrosting is performed by removing frost formed on the cooler 11 by heating the air sucked from the suction lower b by the fan 12 by the defrosting heater 21. When the cooler outlet air temperature or the temperature of the entire cooler 11 reaches the defrosting end temperature T2, defrosting is ended by sensing with a defrosting thermometer or the like.

In this case, the temperature of the cooler 11 gradually rises from below due to the heated air, and since defrosting is performed while melting the frost, there is a large temperature difference between the upper and lower parts of the cooler 11 at the end of defrosting. There is. Then, when the next cooling operation begins, the air flowing through the inner ventilation passage 7 is cooled, but it takes time for the entire cooler 11 to cool down to a predetermined temperature.
Since the temperature of the products in the display room 5 rises for a certain period of time even at the beginning of the cooling operation, there is a problem that the products are likely to spoil, shorten the storage period, and cause product loss.

FIG. 5 is an explanatory diagram showing the above-mentioned temperature change characteristics.

[Purpose of the invention]

In view of the above points, this invention aims to shorten the defrosting time,
The purpose of the present invention is to provide a defrosting method for a cold air circulation type refrigerated open showcase that suppresses the temperature rise of products and maintains their freshness for a long period of time.

[Key points of the invention]

The present invention achieves the above object by providing an inner ventilation passage containing a cooler and a fan and an outer ventilation passage containing a fan between an outer box and an inner box of a main body case having an opening on the front or top surface. A defrosting operation method for a cold air circulation type refrigeration/refrigeration open showcase in which a two-layer air curtain is formed in the opening by the respective fans during cooling operation, and when defrosting operation starts, outside air flows into the inner ventilation passage. To make it easier for air to be sucked in, the operation of the fan in the outside ventilation path is stopped, and when the cooler outlet air temperature or the temperature of the cooler reaches a predetermined temperature lower than the defrost end temperature, the fan in the outside ventilation path is stopped before the defrosting operation ends. This is achieved by starting the operation of the fan.

In other words, the above objective is achieved by using different defrosting methods at the start of defrosting operation and before the end of defrosting operation, and at the start of defrosting operation, the operation of the fan in the outside ventilation path is stopped. This system performs air defrosting by introducing outside air into the inner ventilation duct to melt the frost on the cooler, and before the end of defrosting, the fan in the outside ventilation duct is switched on to perform air defrosting. . The defrosting heater may be energized only while the fan in the outside ventilation path is stopped. [Embodiments of the Invention] The present invention will be described in detail below with reference to drawings showing embodiments of the invention. FIG. 1 shows the flow of air at the start of defrosting operation according to the present invention, and the same parts as in the conventional example are given the same reference numerals and the explanation thereof will be omitted.

In FIG. 1, at the start of defrosting, power is applied to the defrosting heater circuit from a timer (not shown), and the defrosting heater 21
Then, the fan switching relay is energized and the outer fan 13 is switched from operation to stop. The arrows indicate the air flow at this time. Since the outside fan 13 stops at the same time as the defrosting starts, the air curtain 16 that protects the air curtain 15 disappears, so outside air is mixed into the air curtain 15 and the temperature entering the suction lower b increases. The sucked air is heated by the defrosting heater 21, and the frost generated in the cooler 11 is removed. Then, the air is blown out from the blowout lower a to form an air curtain 15.

Next, the cooler outlet air temperature or the entire cooler temperature is T6 (
In other words, when the frost formed on the cooler turns into water at 0°C, the overheating prevention thermometer 20 operates, de-energizing the defrosting heater 21, and switching the outside fan 13 from stop to operation. Then, a few minutes after the water in the cooler has finished flowing, the temperature thermostat operates, and the defrosting operation ends and the cooling operation begins. Needless to say, during cooling operation (as in the conventional example, arrow A shown in Fig. 4)
The products in the display room 5 are cooled by circulation in the direction of B and B. FIG. 2 is an explanatory diagram showing temperature change characteristics in the operating method according to the present invention. FIG. 3 shows a connection diagram between the outside fan 13 and the defrosting heater circuit, and the operating setting value of the heating prevention thermostat 20 is set to a temperature lower than the defrosting end temperature T2. A switching relay 14 for operating and stopping the outside fan 13 is disposed between the heating prevention thermostat 20 and the defrosting heater 21.

〔Effect of the invention〕

Compared to the conventional defrosting method using only a defrosting heater, this invention introduces outside air with high temperature and high energy into the cooler and heats it with the defrosting heater to make the energy even higher. will be significantly shortened. In addition, after using this high-energy air to change the state in a short time to turn the 0°C hoarfrost that has formed in the cooler into water at 0°C, outside air is introduced by stopping the power to the defrosting heater and starting the operation of the outside fan. By stopping the air flow, high-energy air no longer flows through the cooler, and as shown in Figure 2, the temperature difference between the upper and lower parts of the cooler Ts - T2 is shown in Figure 5. Offshore cooling energy is effectively used to lower the product, and the temperature of the product quickly drops to the appropriate temperature. In addition, the temperature rise of products during defrosting operation is reduced compared to conventional methods because the defrosting method changes to a low-energy defrosting method during defrosting, and the temperature rise of products during defrosting is reduced. Since the influence of temperature is also small, it can be expected that the temperature rise of the product will be kept to a minimum, and the product will be less susceptible to spoilage and discoloration, making it possible to maintain the freshness of the product for a long period of time.

[Brief explanation of drawings]

1 to 3 show embodiments of this invention,
Figure 1 is a sectional view of the open showcase showing the air flow at the start of defrosting operation, Figure 2 is an explanatory diagram showing its temperature change characteristics, Figure 3 is a wiring diagram of the defrosting heater circuit, 4 and 5 show a conventional example. FIG. 4 is a sectional view of an open showcase showing the air flow during defrosting operation, and FIG. 5 is an explanatory diagram showing its temperature change characteristics. 1... Main case, 2... Outer box, 3... Inner box, 4
... Shelf board, 5... Display room, 6... Partition wall, 7...
Inner ventilation duct, 7a...Blowout port, 7b...Suction port, 8
...Outside ventilation duct, 8a...Sζ outlet, 8b...Suction port, 9...Hontan blade f body, 11...Cooler, 12
...Fan, 13...Fan, 14...Relay,
15...Inner air curtain, 16...Outer air curtain, 20...Heating prevention thermo, 21...Excluding 1
1 heater. Figure 1 Figure 2 WI Figure 4 Time (H) Figure 5

Claims (1)

[Claims] 1) An inner ventilation passage containing a cooler and a fan and an outer ventilation passage containing a fan are provided between an outer box and an inner box of the main case having an opening on the front or top surface. , a defrosting operation method for a cold air circulation type open showcase in which a two-layer air curtain is formed in the opening by each of the fans during cooling operation, the outside air flowing into the inner ventilation passage when defrosting operation starts; The operation of the fan in the outer ventilation passage is stopped to facilitate suction, and when the cooler outlet air temperature or the cooler temperature reaches a predetermined temperature lower than the defrosting end temperature before the defrosting operation ends, the fan in the outside ventilation passage is stopped. A defrosting operation method for a frozen/refrigerated open showcase, characterized in that the operation is started. 2) The defrosting operation method for an open showcase according to claim 1 is characterized in that the defrosting heater is energized only while the operation of the fan in the outside ventilation path is stopped during the defrosting operation. Defrosting operation method for frozen and refrigerated open showcases.