JPS62123276A - Method of defrosting freezing refrigerating open showcase - 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] The present invention provides a cooling system which includes inner and outer ventilation passages so that double air curtains are formed at the opening during cooling operation;
This invention relates to a defrosting method for a cold air circulation type freezing/refrigerating open showcase in which defrosting is performed by sucking outside air introduced so as to flow backward through an outside ventilation path into an inside ventilation path during defrosting.

[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, a main case 1 having an opening 1a on the front for taking out products is arranged with an appropriate gap between an outer box 2 formed of a heat insulating wall and an inner box 8. A display room 5 partitioned into multiple stages by shelf boards 4 is formed inside the inner box 8.

Further, a partition wall 6 is provided between the outer box 2 and the inner box 8 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 have openings 1a.
The upper and lower sides form a Suita lower a and a suction lower b, respectively, and both ends of the outer ventilation passage 8 are adjacent to the blowout lower a and the suction lower b, respectively, and form a blowout port 8a and a suction port 8b on the outside thereof. The blowout lowers a and 8a are equipped with an air regulating fluid 9 having honeycomb-shaped ventilation holes, and a cooler 11, a fan 12) and a defrosting heater 21 are installed in the inner ventilation passage 7, and a defrost heater 21 is installed in the outer ventilation passage 8. A fan 18 is provided.

In this open showcase, during cooling operation, Tomioka air is circulated through the inner ventilation passage 7 in the direction of the arrow by the fan 12 and cooled by the cooler 11 to become cold air, and this cold air is transferred from Suita lower a to Suita. An air curtain 15 is formed in the opening 1a to isolate the inside of the display room 5 from outside air, and at the same time, the inside of the display room 5 is cooled. Furthermore, an air curtain 16 is formed on the outside of the air curtain 15 so as to protect the air curtain 15 by the indoor air circulating through the outside ventilation passage 8 in the direction of arrow B by the fan 13, and the display room 5 yen can be cooled and kept cool even more efficiently. Ru.

Further, during the defrosting operation, the operation of the cooler 11 is stopped, and the defrosting heater 21 is energized. Fan 1 for defrosting
2, the air sucked in from the suction lower b is heated by the defrosting heater 21 to remove frost formed on the cooler 11. Then, the air temperature at the outlet of the cooler or the temperature of the whole cooler 11 is the defrosting end temperature T! When the temperature reaches , defrosting is terminated by sensing the defrosting thermostat.

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. . When the next cooling operation is started, 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.
The temperature of the 5 yen products in the display room remains elevated for a certain period of time even at the beginning of the cooling operation, which causes damage to the products, resulting in a shortened storage period and product loss.

Note that FIG. 2 is an explanatory diagram showing the above-mentioned temperature change characteristics.

[Purpose of the invention]

In view of the above-mentioned points, the present invention aims to shorten the defrosting time during defrosting operation, and provides a defrosting method for a cold air circulation type frozen/refrigerated open-sea case that suppresses the temperature rise of products and maintains their freshness for a long period of time. The purpose is to

[Key points of the invention]

The present invention achieves this objective by using different defrosting methods at the start of defrosting and before the end of defrosting. In other words, at the start of defrosting, the fan in the outside ventilation path is rotated in the opposite direction, and the fan in the inside ventilation path is rotated at high speed to perform outside air defrosting, which melts the frost on the cooler with the outside air introduced into the inside ventilation path. Before the end of the process, defrost the air by switching the outside fan to normal rotation and the inside fan to low speed rotation, and if you use a defrost heater at the same time, synchronize it only when the fan in the outside ventilation path rotates in reverse. This is what I did.

[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 air flow at the start of defrosting according to the present invention. Note that the same parts as in the conventional example are given the same reference numerals, and the explanation thereof will be omitted.

FIG. 8 shows a wiring diagram of the inner fan 12), the outer fan 13, and the defrosting heater circuit. The operation setting value of the heating prevention thermometer 20 is the defrosting end temperature T! Set the temperature lower than that. The inner fan 12 is a fan that can be switched between low speed and high speed.
The outer fan 18 is a reversible fan. A fan switching relay 14 for switching the fan is disposed between the heating prevention thermostat 20 and the defrosting heater 21. 1st
In the figure, when defrosting, the defrost heater circuit is activated by a timer (not shown)! When the power source is applied, the defrost heater 21 and fan switching relay are energized, and the inner fan 12 rotates from low speed to high speed (the outer fan 13 switches from forward rotation to reverse rotation. The air flow at this time is indicated by the arrow). As soon as defrosting starts, the outside fan 13 rotates in reverse and warm air flows to the Suita exit 8.
It is sucked in through the air passage a, flows backward through the outer ventilation passage 8 in the direction of the arrow C, and is blown out through the suction port 8b. In this case, the suction port 8b
Almost all of the warm air blown out is sucked into the inner ventilation passage 7 as shown by the arrow by the fan 12 which rotates at high speed, and is made to flow in the direction of the arrow A to the defrosting heater 21.
The defrost generated in the cooler 11 is removed by heating. Then, the air is blown out from the Suita lower a to form the air curtain 15, and a part of it flows to the Suita exit 8a. Next, when the cooler outlet air temperature or the temperature of the entire cooler is T. Turn off the heater, switch the inner fan from high speed to low speed operation, and switch the outer fan from reverse rotation to forward rotation.And,
A few minutes after the water in the cooler has finished flowing, the temperature thermostat operates, defrosting is finished, and cooling operation begins. Needless to say, during the cooling operation, the products in the display room 5 are cooled by circulation in the directions of arrows A and B shown in FIG.

〔Effect of the invention〕

As described above, compared to the conventional weight removal method using only a defrosting heater, the present invention introduces multiple violets of high-temperature, high-energy outside air into the cooler and heats it with a defrosting heater. It becomes energy and the gradual opening time is greatly shortened. In addition, after changing the state in a short time using the high energy described above to convert the 0°C box ice generated in the cooler into 0°C water, the defrosting heater is energized, the internal fan is rotated at high speed, and the external fan is reversed. By stopping the introduction of outside air through rotation with a heating preventer, 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 gradually disappears. The temperature Tt at the end of frost is uniform y7. Therefore, during the next cooling operation,
Temperature difference TI −'l between the upper and lower parts of the cooler shown in the conventional example
The cooling energy for 1 minute is effectively used to lower the temperature of the product, and the temperature of the product quickly drops to the appropriate temperature. In addition, the temperature rise of the product during defrosting is reduced compared to conventional methods because the defrosting method changes to a low-energy defrosting method during defrosting, and the temperature rise of the product during defrosting is reduced. Since there is less shadow spring, it is possible to keep the temperature rise of the product to a minimum, and there is less damage and discoloration of the product, making it possible to maintain freshness for a long period of time.

[Brief explanation of drawings]

1 to 3 show embodiments of this invention,
Figure 1 is a cross-sectional view of the showcase showing the air flow at the start of defrosting, Figure 2 is an explanatory diagram showing its temperature change characteristics,
FIG. 8 is a wiring diagram of the defrosting heater circuit, FIG. 4 is a sectional view of a showcase showing the flow of air during defrosting in a conventional example, and FIG. 5 is an explanatory diagram showing its temperature change characteristics. 1... Main body case, 2... Outer box, 8... Cylinder, 4
... Shelf board, 5... Display room, 6... Partition wall, 7...
Inner ventilation duct, 7a...Blowout port, 7b...Suction port, 8
...Outside ventilation duct, 9...Air conditioner, 11...Cooler, 12...Fan, 18...Fan, 14...
・Relay, 15...Inner air curtain, 16...
Outside air curtain, 20...heating prevention thermo, 21
...Defrost heater. Figure 1 Figure 3

Claims (1)

[Claims] 1) An inner ventilation passage with a built-in cooler and fan and an outer ventilation passage with a built-in fan are provided between the outer box and the inner box of the main body case having an opening on the front or top surface, During operation, each of the fans forms a layered air curtain in the opening, and during defrosting operation, the fan in the outer ventilation path is rotated in the opposite direction, so that the outside air introduced by flowing backward through the outer ventilation path is introduced into the inner ventilation. In a cold air circulation type open showcase in which the fan in the air passage is rotated at high speed to suck air into the inner ventilation passage, when the cooler outlet air temperature or the cooler temperature reaches a predetermined temperature lower than the defrosting end temperature during defrosting operation. A defrosting method for a frozen/refrigerated open showcase, characterized in that the fan in the outer ventilation passage is operated in forward rotation, and the fan in the inner ventilation passage is operated in slow rotation. 2) In the freezer/refrigerator open showcase according to claim 1, the defrosting heater is energized only while the fan in the outside ventilation path is rotating in reverse during defrosting operation. How to defrost a showcase.