JPH01200181A - Cold air circulation type open show case - Google Patents

Abstract

PURPOSE:To enable a uniform increasing of a temperature of a cooling unit to be carried out and a defrosting operation to be performed within a short period of time by a method wherein a changing-over switch for making a selective energization of heaters arranged at two locations of an air flow outlet and a central part of the cooling unit when a defrosting operation is carried out. CONSTITUTION:Defrosting heaters 18A and 18B are arranged near an air flow inlet port of a cooling unit 11, and a defrosting heater 18C is arranged at a central part of the cooling unit 11. A changing-over switch 20 installed in the midway part between set positions of the defrosting heaters 18A and 18B and the defrosting heater 18C may close an energization circuit for the defrosting heater 18B at first. As the set locations show a predetermined temperature, a circuit for the defrosting heater 18B is opened and a circuit for the defrosting heater 18C is closed. With this arrangement, when a defrosting operation is carried out, at first a defrosting at the lower part of the cooling unit is carried out and after that, a defrosting at the upper part is carried out, so that the defrosting can be entirely performed within a short period of time.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a cold air circulation type open showcase in which warm air heated by a heater during defrosting operation is passed through a cold air circulation path to defrost the air. , relates to an improvement in which the cooler is heated uniformly and defrosted efficiently.

[Conventional technology]

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

Further, a partition plate 6 is provided between the outer box 2 and the inner box 3 to divide the gap into two, thereby forming a cold air circulation path 7 and a circulation path 8. Both ends of the cold air circulation path 7 form a blowout lower a and a suction lower b that face each other above and below the opening 1a, and both ends of the circulation path 8 are adjacent to the blowout lower a and suction lower b, respectively, and have blowout ports on the outside thereof. 8a and a suction port 8b. The air outlet ports 7a and 8a are equipped with an air regulating fluid 9 having honeycomb-shaped ventilation holes, and the cold air circulation path 7 includes a fin-tube cooler 11, a fan 12,
A defrosting heater 18 and a temperature sensor 19 are provided, and a fan 13 capable of reversible rotation is also provided within the circulation path 8 . The heater 19 is placed near the air inlet side of the cooler 11, and the temperature sensor 19 is placed near the air inlet side of the cooler 11.
is located inside.

In the above-mentioned open showcase, during the cooling operation, indoor air sucked in from the suction lower b by the fan 12 is cooled by the cooler 11 and turned into a cold air flow, which is circulated in the direction of the arrow A through the cold air circulation path 7. This cold air flow is at opening 1
An air curtain 15 is formed in the space a, and a part of the air curtain 15 flows into the display room 5 to insulate the room from outside air and cool it.

Furthermore, the circulation path 8 is moved in the direction of the arrow by the fan 13? # Form an air curtain 16 on the outside of the air curtain 15 so that the circular air flow protects the air curtain 15. The air curtain 16 cools and keeps the interior of the display room 5 more efficiently.

In order to remove frost formed on the cooler 11 and the like due to the cooling operation, a defrosting operation is performed at appropriate intervals. During this defrosting operation, the operation of the cooler 11 is stopped, the fan 13 is reversely rotated, and the heater 18 is energized.

As shown in FIG.
It flows in the direction of and is discharged from the suction port 8b. This outside air is transferred to the cold air circulation path 7 as shown by arrow C by a fan 12 that forms an air curtain 15 with uncooled air during defrosting operation.
The air is sucked into the air, heated by the heater 18, becomes a warm air flow, and flows through the cold air circulation path 7 in the direction of arrow A. As the warm airflow washes the cooler 11, the cooler 11 is warmed and frost is melted. When the cooler 11 is defrosted, the defrosting operation is stopped based on a signal from the temperature sensor 19 that detects the temperature at that time, and the cooling operation is performed again.

[Problem to be solved by the invention]

By the way, in the conventional open showcase, the cooler 11
The warm air flow that defrosts the washing liquid loses heat as it travels through the cooler 11, and the defrosting ability of the upper part of the cooler, which is on the warm air outlet side, is significantly lower than that of the lower part, which is on the inlet side. However, as shown in FIG. 6, the defrosting operation time (H2-Hl) during which the cooler 11 is defrosted takes quite a long time, and when the defrosting of the cooler 11 is completed, i.e. The temperature T3 of the lower part of the cooler becomes considerably higher than the temperature T2 of the upper part of the cooler, and the time required for the cooler 11 to cool down in the next cooling operation becomes longer. Due to these factors, the products in the display room 5 will rise for a considerable time after the start of the next cooling operation, that is, until time H'. Become. This has the disadvantage of causing damage to the product and sometimes resulting in large product losses.

This invention is a cold air circulation type open show that during defrosting operation, the cooler is heated uniformly, defrosting is performed in a short time, the temperature rise of the product is small, the temperature rise time is short, and there is no product loss. The purpose is to provide a case.

[Failure to solve the problem]

This invention is achieved by providing defrosting heaters on the air inlet side and in the center of the cooler, as well as providing a changeover switch for selectively energizing both of the heaters.

[Function] According to the above means, the present invention suppresses the temperature rise in the lower part of the cooler during defrosting operation, and recovers and increases the defrosting ability of the warm air flow flowing inside the cooler by the heater in the center, thereby improving cooling. This ensures that the temperature of the container rises uniformly and defrosts in a short time.

[Example] Figures 1 to 3 show examples of this invention.
Components common or identical to those in FIGS. 4 to 6 are designated by the same reference numerals.

In Figures 1 to 3, 18A and 18B are two defrosting heaters arranged near the air inlet side of the cooler 11, and the two heaters generate the same amount of heat as the conventional heater. We are prepared. 18C is a defrosting heater installed in the center of the cooler 11, and 20 is installed between the installation positions of heaters 18A and 18B and that of heater 18C. Initially, the energizing circuit of heater 18B is closed, and the installation location is determined. When the temperature is reached, the circuit of the heater 18B is opened and the heater 18
This is a changeover switch that closes the circuit of C. Thus, FIG. 2 shows the electrical circuit of the heaters 18A, 18B and 18C and the changeover switch 20.

In the above configuration, during the defrosting operation, the air flow sucked into the cold air circulation path 7 from the suction lower b by the fan 12 is heated by the heaters 18A and 18B, becomes a warm air flow, washes the cooler 11, and flows as shown by arrow A. flows. The cooler 11 is heated by this warm air flow, and defrosting progresses quickly, especially in the lower part. When the temperature at the lower part of the cooler reaches T6, the changeover switch 20 is activated to cut off the power to the heater 18B and turn on the heater 18C, and the warm air flow is heated again by the heater 18C to increase the defrosting ability. After the temperature T6 has been reached, the lower part of the cooler 11 is warmed and the upper part is rapidly warmed, so that the entire cooler 11 has a substantially uniform temperature Tz.
Defrosting is complete when the temperature is reached.

The defrosting operation time H'' during this period is much shorter than before.
Furthermore, in the next cooling operation, the cooler 11 cools down in a short time. Therefore, shortly after the start of the next cooling operation, the temperature of the products in the display room 5 stops rising at time H3, which is much earlier than in the past, and is cooled again at a very low temperature, T5. Therefore, it is possible to avoid damage to the product due to an increase in the temperature of the product, and no product loss occurs.

The above-described embodiment is of a multi-stage type, and the opening 1 is closed during cooling operation.
Although the open showcase in which air curtains are formed in two layers has been described in FIG. A similar effect can be obtained.

〔Effect of the invention〕

According to this invention, the defrosting heater is provided at least in two places, the air inlet side and the central part of the cooler, and
A changeover switch is provided to selectively energize both heaters during defrosting operation, and in the middle of defrosting operation, heating of the lower part of the cooler is suppressed, and the central heater is used to defrost the warm air flow. Since the capacity is restored and increased, the temperature of the cooler increases almost evenly and the frost is removed in a short time, and the temperature increase of the product due to defrosting operation remains at an extremely low temperature. Therefore, product damage is avoided and product loss is prevented.

[Brief explanation of the drawing]

Fig. 1 is a sectional view explaining the state of an open showcase during defrosting operation showing an embodiment of the present invention, - Fig. 2 is an electric circuit diagram, and Fig. 3 is a line showing the temperature rise of the cooler and products. Figures 4 and 5 are cross-sectional views explaining the states of a conventional open showcase during cooling operation and defrosting operation, respectively, and Figure 6 is a line diagram corresponding to Figure 3 of the conventional open showcase. It is. DESCRIPTION OF SYMBOLS 1... Main body case, 5... Display room, 7... Cold air circulation path, 11... Cooler, 12... Fan, 15...
・Air curtain, 18A, 18B, 18C... Heater, 20... Selector switch. Figure 1 Figure 2 Figure 4 Figure 5

Claims (1)

[Claims] 1) A cold air circulation path containing a built-in cooler, fan, and heater is formed between an outer box and an inner box of the main body case having an opening on the front or top surface, and during cooling operation, the cold air is circulated through the cooler by the fan. A cold air circulation type that forms an air curtain in the opening and cools the inside of the display room using the cold air flow, and defrosts the display room by the warm air heated by the heater and forced through the cold air circulation path by the fan during defrosting operation. At the open showcase,
The heater is provided in at least two locations, one on the air inlet side of the cooler and the other in the center, and a changeover switch is provided for selectively energizing both of the heaters during defrosting operation. Cold air circulation type open showcase.