JPH03177773A - Defrosting of cold air circulation type open showcase - Google Patents

Abstract

PURPOSE:To carry out sufficient defrosting while restraining the temperature rise of commodi ties in a showcase by a method wherein an outer fan is rotated reversely while conducting for the defrosting heater of a stopping side cooler when an illuminating lamp in the showcase is lighted;while to sets of coolers are stopped simultaneously and the outer fan is rotated reversely while conducting no defrosting heater when the illuminating lamp is extinguished. CONSTITUTION:When an illuminating lamp 5 in a showcase is lighted, it is judged that the time is daytime in which a shop is on business and one set of cooler among two sets of coolers 8a, 8b is stopped while continueing the operation of remaining one set of coolers 8a, 8b, further, the operation of an outer fan 11 is switched from normal rotation into reverse rotation and either one of defrosting heaters 9a, or 9b of stopping side cooler is energized to effect heater defrosting. On the other hand, when the illuminating lamp 5 in the showcase is extinguished upon the starting of defrosting, it is judged that it is a nighttime after closing the shop and two sets of coolers 8a, 8b are stopped simultaneously, then, the operation of the outer fan 11 is switched from the normal rotation into the reverse rotation of the same to effect air defrosting. Further, during the air defrosting, atmosphere, sucked from the circum ference of the showcase, flows through two sets of coolers 8a, 8b installed in an inner duct 6 to provide the coolers with the retaining heat of the atmosphere and defrost them.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a defrosting method for a cold air circulation type open showcase, which is intended for a two-layer air curtain type open jitter case.

[Conventional technology]

First, the configuration of a two-layer air curtain type cold air circulation type open sea case to which this invention is applied is shown in FIG.
In the figure, 1 is the case body with the front open, 2.3 is the outer box and inner box of the main case L, 4 is the vertical multi-tiered product display shelf installed inside the inner box 3, and 5 is the interior lighting. and outside n
An inner duct 6.7 is installed between the inner box 2 and the inner box 3 as a dual inner and outer air circulation duct surrounding the rf7iJWi of the inner box 3.
The outer duct 7 is partitioned, and inside the inner duct 6 there are two coolers 8a arranged side by side on the left and right,
8b, defrosting heaters 9a and 9b attached to each cooler, and an inner fan 10 are installed, and a reversible outer fan 11 is installed in the duct of the outer duct 7. Note that 6a and 6b are the air force tensile outlet 1 inlet of the inner duct 6, and 1a and 7b are the air curtain outlet and inlet of the outer duct 7. Further, 12 is a night cover provided at the upper front of the case body 1 so as to be pulled down after the store is closed to cover the front opening of the case body 1, and the illustration shows the night cover 12 rolled up.

Such a two-layer air curtain type oven showcase is well known, and includes two coolers 8a during cold storage operation.

8b are operated simultaneously, and inner fan 10. By operating the outer fan 11 (forward rotation), the inner duct 6
．． Air is circulated through the outer ducts 7 in the directions indicated by the solid arrows, forming a two-layer cold air curtain 13 and a protective air curtain 14 at the front opening of the main body case 1, thereby preventing outside heat from entering. The products arranged on the display shelf 4 inside the warehouse are kept cool by shielding them.

On the other hand, in oven showcases, in order to periodically remove dew that forms on the surface of the cooler during cold storage operation, defrosting is performed at a predetermined defrosting cycle (for example, every 6 hours, 4 times a day). There is. For the open showcase with the above configuration, defrosting is performed alternately on each side of the two coolers 8a and 8b, and when defrosting, only one of the coolers is stopped, and the cooler on the stopped side is Defrosting is carried out by energizing the defrosting heater attached to the defrosting heater and switching the outer fan 11 from normal rotation to reverse rotation.

That is, in the outer fan reversal/heater defrosting method described above, by switching the operation mode of the open showcase from cold storage operation to defrosting, air is sucked into the outer duct from the air curtain blowout lower a as shown by the dotted arrow in Fig. 2. After passing through the outer duct 7, the outside air is sucked into the air curtain suction port 6b of the inner duct 6 from the air curtain suction lower b, and further passes through the inner duct 6 from the air curtain outlet 6a to the front opening of the case body 1. Follow the ventilation route that blows out and dissipates to the surrounding area. In addition, during this ventilation process, the air flowing through the inner duct 6 is divided into two parts at the location where the cooler is installed, one of which becomes low temperature due to heat exchange with the operating cooler, and the other part of which is heated by the defrost heater while the electricity is on. After applying defrosting heat to the cooler on the stop side, it joins with low-temperature air again in the inner duct 6 and blows out toward the front of the case body 1.

In this way, by alternately defrosting the heaters on each side of the two coolers, and in conjunction with the heater defrosting, the outer fan is reversed to dissipate the air after defrosting to the surroundings, thereby improving the efficiency of the warehouse during defrosting. It is possible to effectively suppress the temperature rise of internal products.

In addition, defrosting is started by the time amplifier of the defrosting timer, and defrosting is completed by using both the surface temperature detection of the defrosting @ side cooler and the timer (setting the maximum defrosting time). .

[TL that the invention tries to solve! ! However, when looking at the total of 24 hours per day, there are serious problems if the conventional defrosting method described above is used as is.

In other words, oven showcases are installed and used in stores such as supermarkets, and during the night hours after the store is closed, the oven interior lights are turned off and the oven is turned off as shown in Figure 2. The cover 12 is pulled down to cover the front side of the case body, and the radiant heat from the interior illumination light 5 and the heat intrusion from the surroundings into the interior of the refrigerator are suppressed and the heat load on the Schiller case is managed to be reduced.

For this reason, if the two cooling units 1i8a and 8b installed in the inner duct 6 are defrosted alternately on one side using the defrosting method described above, there will be no problem in defrosting during store business hours (daytime). However, when defrosting is done after closing (at night), the internal lighting is turned off and a night cover is hung to reduce the heat load on the warehouse case. The cold retention power of the cooler is superior to the defrosting heat given to the defrost side cooler (stop), and as a result, defrosting of the stop side cooler does not progress sufficiently within the predetermined defrosting time, and the solution for n is The rest will arise. Moreover, the defrosting end temperature of Schiller Case is set as low as possible from the viewpoint of product quality control, so defrosting during the daytime will completely dissolve the remaining frost that occurs during defrosting at night. It is difficult to melt the ice, and as a result of repeated defrosting, the remaining frost gradually melts into large blocks of ice (ice banks), which eventually block the inner duct, resulting in an extremely poor cooling performance. may invite

The present invention has been made in consideration of the above points, and is aimed at the above-mentioned two-layer air curtain type open showcase equipped with two coolers in the inner duct, during daytime hours when stores are open. By changing the defrosting method depending on whether the store is closed or at night after closing, we provide a defrosting method that can completely defrost the entire 24 hours of the day and night, with no residual frost remaining. The purpose is to

[Means to solve the problem]

In order to solve the above FJ and B, the defrosting method of the present invention uses two units when defrosting during the time when the interior lighting is on, with the interior lighting being turned on and off. Defrosting is performed by stopping one side of the cooler and energizing the defrosting heater of the stopped side cooler while reversing the outer fan. When defrosting when the lighting lights are off, two Defrosting is performed by simultaneously stopping the cooler and turning the outer fan in reverse while the defrosting heater is de-energized.

[Effect]

According to the above defrosting method, during the day when the heat load is relatively large (
During store hours (when the store is open), only one side of the two coolers is stopped and the outer fan is defrosted using the heater defrosting method in reverse order. Defrosting can be performed without leaving any residue while suppressing the rise in product temperature.

On the other hand, at night (after closing) when the heat load is low, when the interior lights are turned off and the front of the case is covered with a night cover, the two coolers are stopped at the same time and the outer fan is reversed. By switching to the air defrosting method, unlike the defrosting method performed during daytime hours, it is not affected by the cooling ability of the operating side cooler, nor is it affected by the heating caused by the energization of the defrosting heater. , sufficient defrosting can be performed using the heat held by the surrounding air while suppressing the rise in the temperature of the products in the warehouse.

Moreover, the selection of each of the above-mentioned defrosting methods is performed by detecting whether the interior lighting of the Syrah case is turned on or off.

That is, the interior lighting is on during the daytime hours when the store is open, and the lighting is off during the nighttime hours after the store is closed. Therefore, by detecting whether the interior lighting is turned on or off and switching the defrosting method (heater defrosting, air defrosting) based on the signal, a defrosting method suitable for daytime or nighttime can be automatically selected.

〔Example〕

FIG. 1 is a flowchart of operation control of an open shutter case showing the defrosting method of the present invention.

In Figure 1, when the defrost start command is given by the defrost timer while cold storage operation is being performed, at that point the second
If the interior light 5 shown in the figure is on, it is determined that the store is open during the day, and the two coolers 8a are turned on.
, 8b continues to operate while the remaining one is stopped, the outer fan 11 is switched from forward rotation to reverse rotation, and then either one of the defrost heaters 9a and 9b of the stop side cooler is energized. defrost the heater.

On the other hand, if the interior lighting lamp 5 is off at the time of starting defrosting, it is determined that it is nighttime after the store is closed, and the two coolers 8a8b are stopped at the same time, and the outer fan 11 is switched from normal rotation to reverse rotation to air air. Perform defrosting, and during this air defrosting,
I! As shown by the dotted arrow J, outside air sucked in from the surroundings flows through two coolers 8a and 8b installed in the inner duct 6, and the heat retained in the outside air is given to the coolers to defrost. In addition, after the store is closed, the interior lighting 5 is turned off and there is no radiant heat.
Moreover, since the front surface of the case body 1 is covered with the night cover 12, the rise in temperature of the products in the refrigerator is slight, and there is no risk of quality deterioration.

When the removal is completed, the outer fan 11 is returned from reverse rotation to normal rotation, the defrosting heater is switched to non-energized state, and the two coolers 8a and 8b are restarted to shift to cold storage operation.

〔Effect of the invention〕

As explained above, according to the defrosting method according to the present invention,
Under the condition that the interior lighting is turned on and off, when defrosting during the time when the interior lighting is on, one side of the two coolers is stopped, and the heater of the cooler on the stopped side is turned off. Defrosting is performed by turning the outer fan in reverse while the power is on, and when defrosting when the lights are off, both coolers are stopped at the same time.
In addition, by defrosting by reversing the outer fan while the defrosting heater is de-energized, the products in the warehouse can be defrosted regardless of whether the store is open during the day or at night after the store is closed. It is possible to sufficiently defrost the frost without leaving any residue while suppressing temperature rise.

[Brief explanation of drawings]

Fig. 1 is a time chart of operation control of an open showcase showing the defrosting method of the present invention, and Fig. 2 is a configuration diagram of a two-layer air curtain oven case to which the present invention is implemented. In the figure, 1: case body, 5: interior lighting, 6: inner duct,
7: Outer duct, 8a, 8b: Cooler, 9a. 9b: Defrost heater, 10: Inner fan, 11: Out Figure 1

Claims (1)

[Claims] 1) The case body has a double inner and outer air circulation duct surrounding the inner box, and the inner duct has two parallel coolers, the defrost heater attached to each cooler, and the inner fan are connected to the outer duct. is a defrosting system for cold air circulation open showcases that is equipped with a reversible outer fan and forms a two-layered air curtain inside and outside the opening of the case body during cold storage operation. When defrosting while the interior light is on, with the lights off, one side of the two coolers is stopped, and the outer fan is reversed while energizing the defrost heater of the stopped cooler. When defrosting is performed during hours when the lights are off, both coolers are stopped at the same time, and the outer fan is reversed to defrost while the defrost heater is de-energized. A defrosting method for open showcases with cold air circulation.