JPH07109345B2 - Defrosting method and apparatus for cooling showcase - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defrosting method and a device thereof in a cooling showcase, and more particularly to a defrosting method and a device thereof in a cooling showcase capable of preventing a temperature rise of a product due to defrosting. Regarding

[Conventional technology]

For refrigerated open showcases and other cooling showcases,
Products to be cooled are displayed on a display shelf, and the products are cooled by a cooler arranged in the cooling showcase.

In this cooling showcase, defrosting of the cooler is conventionally performed as follows.

Defrosting methods include a heater method that energizes a defrosting heater to defrost it, and a hot gas method that defrosts hot gas by passing it through a cooler. The interval is kept constant by a timer. The defrosting time for one time is set by the timer to a length with which the defrosting of the cooler is surely completed.

When performing defrosting by so-called demand defrosting,
Defrosting is performed by changing the defrosting interval by detecting the amount of frost formed on the cooler or by detecting environmental conditions such as the temperature around the showcase, which are factors related to the amount of frost formed on the cooler. I am trying. The defrosting time for one time is not set by a timer, but the temperature of the cool air outlet of the showcase rises sharply after the defrosting is completed. Another method is to stop defrosting when the temperature reaches a certain value.

[Problems to be solved by the invention]

By the way, in such a conventional defrosting method, defrosting is performed by the same one method, for example, day and night, and one defrosting is performed until the defrosting is surely completed. Since this defrosting is repeated cyclically, the temperature W ₂ in the showcase greatly rises with each defrosting, as shown in FIG. 6, especially during the daytime when the store is open (V _D period). . The V _N period is closed.
Therefore, conventionally, there has been a problem that the temperature W ₁ of the displayed product is increased as the temperature inside the showcase is increased.

Therefore, the present invention has been proposed in order to solve such a conventional problem, the temperature rise of the product in the showcase can be prevented during defrosting of the cooler, and the product can be efficiently cooled. An object of the present invention is to provide a defrosting method for a showcase and an apparatus thereof.

[Means for solving problems]

To achieve this object, the defrosting method in the cooling showcase of the present invention is an off-cycle method in which the operation of the cooler is stopped by the defrosting method and air is defrosted over time during opening of a store with a large load. The defrost stop temperature is set low, the time until the next defrost is set to be short, and defrosting is performed.When the store is closed with a light load, the defrosting method is used to stop the operation of the cooler and heater. Features a defrosting method that uses a heating device such as hot gas to heat the cooler to defrost it, sets the defrost stop temperature high, and sets the time until the next defrost is long to perform defrosting. I am trying.

In addition, the device stops the operation of the cooler during the opening of a store with a large load, outputs a selection signal to select the off-cycle defrosting method that defrosts with time with air, and closes the store with a small load. In addition, the selection circuit that outputs the selection signal that selects the defrosting method of the forced defrosting method that defrosts by stopping the operation of the cooler and heating the cooler with a heater or hot gas, etc., the cycle is short during opening Defrost cycle timer that outputs a defrost cycle signal, defrost cycle timer that outputs a long defrost cycle signal when the store is closed, and each defrost stop that is set low when the store is open and high when the store is closed A comparison calculation that compares the temperature and the blowing temperature of cold air, and outputs a comparison output when the blowing temperature of the cold air exceeds the defrost stop temperature during opening, and a comparison output when the cooling temperature exceeds the defrost stop temperature during opening. From the circuit and comparison operation circuit, turn off during opening When the comparison output is supplied while the icicle method is being used for defrosting, a defrosting stop signal for defrosting using the off-cycle method is output, and defrosting is performed using the forced defrosting method while the store is closed. The defrost stop signal sending circuit that outputs the defrost stop signal for defrosting by the forced defrost method when the comparison output is supplied while the defrosting method selection signal, the defrost cycle signal, and the defrost stop signal are Defrosting method, supplied and selected
Defrosting control section that outputs defrosting execution signal by off-cycle method or defrosting execution signal by forced defrosting method to execute defrosting based on defrosting cycle and defrosting stop temperature, defrosting execution signal is input By doing so, a defrosting drive signal output section that outputs a signal for controlling the equipment in the case is provided.

[Action]

In the above-mentioned present invention, defrosting can be performed by changing the defrosting stop temperature according to the magnitude of the load.

Therefore, when the cooling showcase is operating and the store is opened with a large load, the defrosting end temperature is set low to defrost the cooler to increase the air temperature inside the showcase due to defrosting. It is possible to prevent the temperature rise of the displayed products.

Further, when the store is closed with a light load, the defrosting temperature is set high to defrost the cooler, whereby the defrosting can be sufficiently performed and the store can be prepared for opening.

〔Example〕

Hereinafter, embodiments of the defrosting method and apparatus for a cooling showcase according to the present invention will be described in detail.

First, the defrosting method according to the present invention will be described. In the present invention, defrosting is performed by changing the defrosting method, the defrosting stop temperature, and the defrosting cycle in correspondence with the opening of a large load and the closing of a small load. I am trying to do.

During the opening of a store where a cooling showcase such as a refrigerating open showcase is operated with a large load, defrosting of the cooler provided in the cooling showcase is performed by an off-cycle method. This off-cycle defrosting is a method in which the cooling operation of the cooler is stopped, the air outside the showcase is taken in, and the defrosting is performed by the heat load of this air, and the cooler is heated by a heater or hot gas. Defrost without doing it.

If the cooling showcase is, for example, a refrigerated open showcase, the opening of the showcase is opened during opening, so the heat load from the air outside the showcase taken in from the opening is large and the operation of the cooler is stopped. You can remove the frost by doing.

When defrosting by the off-cycle method during opening,
The defrost stop setting temperature is set low so that defrost is stopped at a low temperature.

In addition, the defrost cycle is set to be short during opening. That is, the period from the defrosting stop to the next defrosting is set short and the number of defrosting is increased. In this way, even if the defrosting stop set temperature is set low, the defrosting interval is short, frost can be gradually removed, and the cooler does not cause poor cooling due to frost formation.

By doing so, the temperature rise in the showcase due to defrosting can be suppressed to a low level, and there are many displayed products.
Even when the showcase lighting is turned on and the product temperature is likely to rise due to radiant heat, defrosting can be performed without raising the temperature of the displayed product, and a great effect on maintaining the freshness of the product can be obtained.

Further, when the store is closed with a small load of displayed merchandise and a light switch of the showcase, or by a schedule timer, defrosting by an off-cycle system during opening is switched to forced defrosting by a heater system, for example. The defrosting by the heater method is a method of defrosting by stopping the operation of the cooler and energizing a heater provided near the cooling coil to heat the cooler.

In addition to the heater method described above, the forced defrosting method includes a hot gas method in which hot gas is flowed in the cooling coil to defrost.

Further, in defrosting while the store is closed, the set temperature at the end of defrosting is set higher than that during opening to ensure that the cooler is defrosted, and the defrost cycle is set longer than during opening.

While the store is closed, the lighting of the showcase is turned off, and the opening is covered with the curtain or the heat insulating plate as described above, so the temperature of the product is low, and even if defrosting is performed in this way, the temperature of the product does not rise much.

Next, a defrosting device for carrying out the above-described defrosting method according to the present invention will be described.

FIG. 1 is a block circuit diagram of a defrosting device according to the present invention.

In the figure, there are two exceptions depending on whether the cooling showcase is operating with a large load (mainly in the daytime) or the cooling showcase is closed with a small load (mainly at night). To the selection circuit 1 which selects one of the defrosting methods from among the frosting methods, an on / off identification signal a of the lighting switch 33 for the fluorescent tube 35 that illuminates the inside of the cooling showcase is input from the input terminal 2. At the same time, the schedule timer signal b is input from the schedule timer 3 which stores the schedules of opening and closing. In the selection circuit 1, the identification signal a or the schedule timer signal b
Based on the input of, the selection signal c of the off-cycle method that is the defrosting method during opening of the store or the selection signal d of the forced defrosting method that is the defrosting method during the closing of the store is generated. d is supplied to the defrost control unit 4.

As shown in FIG. 5, the defrosting control unit 4 receives the defrosting cycle signal from a defrosting cycle timer 5 that produces a defrosting cycle signal e that determines the defrosting repetition cycle X _A of the off-cycle method during opening. In addition to being supplied with e, the defrost cycle signal f is supplied from the defrost cycle timer 6 that produces the defrost cycle signal f that determines the defrost repetition cycle X _B in the forced defrosting method during the closing of the store. Here, each cycle is X _A <X _B.

Further, the detection output g of the temperature sensor 7 that detects the blowing temperature T of the cold air is supplied to the analog / digital converter (A / D converter) 8. The sensor 7 is provided at the cold air outlet 9 as shown in FIG. In addition, the defrost stop temperature T _A (for example, +
The defrosting stop temperature setting signal h is input to the A / D converter 8 from the setting unit 10 capable of setting the defrosting stop temperature T _B (for example, + 10 ° C) in the forced defrosting method while the store is closed. The defrosting stop temperature setting signal i is input to the A / D conversion unit 8 from the setting unit 11 capable of setting the (degree). Here, each stop temperature is set so that T _A <T _B.

In the A / D converter 8, the detection output g and the setting signals h and i are respectively digital signals (detection signal G and setting signals H and I).
And supplies these signals G, H, and I to the comparison operation circuit 12. In the comparison operation circuit 12, the detection signal G is the setting signals H, I.
Whether or not it is above, that is, whether or not the blowing temperature T of the cold air is above the defrost stop temperatures T _A and T _{B is} compared by the calculation of T−T _A and T−T _B , and T−T _A ≧ When 0, that is, T ≧ T _A , the comparison output j is supplied to the defrosting stop signal sending circuit 13, and when T−T _B ≧ 0, that is, T ≧ T _B , the comparison output k is supplied to the defrosting stop signal sending circuit 13.

In the sending circuit 13, when defrosting is performed by the off-cycle method during opening, when T ≧ T _A and the comparison output j is supplied, the defrosting stop signal 1 is sent to the defrosting control unit. 4 and when the comparison output k is supplied with T ≧ T _B while the defrosting is performed by the forced defrosting method while the store is closed, the defrosting stop signal m is defrosted. It is sent to the section 4.

The defrost control unit 4 generates a defrost execution signal n for executing the off-cycle method during opening of the store based on each input signal, and a defrost execution signal for executing the forced defrost method during closing of the store. 0 is generated, and the defrosting execution signal n or 0 is supplied to the defrosting drive signal output unit 14.

Here, the defrosting execution signal n output during the opening of the store rises by the defrosting cycle signal e of the cycle X _{A in} the positive logic, and T ≧
It is a pulse signal that falls due to the defrosting stop signal 1 output at the time of T _A. Further, the defrosting execution signal o output during closing of the store is a pulse signal which rises by the defrosting cycle signal f of the cycle X _B and falls by the defrosting end signal m output when T ≧ T _B.

The defrosting drive signal output unit 14 outputs a speed increasing signal p for speeding up the inner layer fan motor 15 and a stop signal q for stopping the outer layer fan motor 16 based on the input of the defrosting execution signal n during opening of the store. And an off signal r for turning off the solenoid valve 17 provided in the refrigerant pipe 19 is output. As a result, during the opening of the store, defrosting with a low defrosting stop temperature is performed by the off-cycle method.

While the store is closed, the speed increase signal p, the stop signal q, and the off signal r are output based on the input of the defrosting execution signal o, and the energization signal s for energizing the defrosting heater 18 is supplied.
Is output. As a result, while the store is closed, defrosting at a high defrost stop temperature is performed by a forced defrosting method, for example, a heater method.

Here, the inner layer fan motor 15 is a motor that drives an inner layer fan 23 that blows air to a cooler 22 provided with a cooling coil 21, and the outer layer fan motor 16 is a refrigerating open case.
Outer fan that creates an air curtain 26 in 24 openings 25
It is a motor that drives 27. The solenoid valve 17 is for turning on / off the supply of the refrigerant to the cooling coil 21. The heater 18 is provided between the cooler 22 and the inner-layer fan 23, for example, below the cooler 22.

Due to the output from the defrosting drive signal output unit 14, the blown state during cooling (shown by an arrow) shown in FIG. 2 is changed to the blown state shown in FIG. While the store is closed with the opening 25 covered by the cover 28, the ventilation state is changed to that shown in FIG.

In the defrosting device configured as described above, the defrosting of the cycle X _A can be performed at a low defrosting temperature by the off-cycle method during the period when the store is open as indicated by V _D as shown in FIG. The increase in the product temperature W ₁ of the product displayed on the display shelf 29 can be suppressed to a lower level than in the conventional case. Note that W _{2 in} Fig. 5
Indicates the air temperature in the refrigerator.

Further, during the period during which the store is closed, which is indicated by V _N , defrosting is performed, for example, by the heater method, and the cycle of defrost X _B is the period X _A during opening of the store.
It is longer and the defrost stop temperature is higher than the defrost stop temperature during opening.

By the way, in the above description, the operation of performing defrosting by selecting different defrosting methods during opening and closing of the store has been described, but different defrosting is performed in the summer when the load is large and in the winter when the load is small as follows. It is also possible to defrost by selecting the frost method.

In FIG. 1, the selection circuit 1 is supplied with a detection output t from a sensor 30 for detecting the temperature and humidity in the store, and an operation rate signal u indicating the operation rate of the refrigerator connected to the cooler 22 is supplied. Supplied from input terminal 31. Based on the temperature / humidity detection output t in the store and the operating rate signal u of the refrigerator, the size of the load is identified, and an appropriate defrosting method corresponding to the heavy load summer or the light load winter is selected. Selected by circuit 1.

As described above, in the defrosting device of this embodiment, defrosting is performed by changing the defrosting method, the defrosting stop temperature, and the defrosting cycle during opening of the store with a large load and during closing of the store with a small load. Since the defrosting is performed by an off-cycle method with a low defrosting stop temperature and a short defrosting cycle during opening, it is possible to prevent an increase in the product temperature of the displayed product and perform efficient cooling.

In addition, since defrosting is performed by the forced defrosting method with a high defrosting stop temperature and a long defrosting cycle while the store is closed, it is possible to sufficiently perform defrosting and prepare for opening.

〔The invention's effect〕

As described above, in the present invention, defrosting is performed by changing the defrosting method, the defrosting stop temperature, and the defrosting cycle during opening of the store with a large load and closing of the store with a small load.

Therefore, during opening, defrosting is performed by the off-cycle method, the defrosting end temperature is set low, and the defrosting cycle is shortened to perform small defrosting. The rise is suppressed, and the temperature of the products displayed in the showcase can be prevented from rising.

As a result, the product can be cooled efficiently and a great effect can be obtained in maintaining the freshness of the product. In addition, since defrosting is performed by the off-cycle method during opening of the store, energy saving of defrosting can be achieved.

While the store is closed, defrosting is performed using a forced defrosting method such as a heater method, the defrosting end temperature is set high, and the defrosting cycle is extended to perform defrosting. The illumination is turned off, the opening is covered with a cover or the like, the number of displayed products is small, and the temperature of the products is kept low, so that an increase in the product temperature due to defrosting can be suppressed. Further, by adopting such a defrosting method while the store is closed, it is possible to completely defrost the cooler and provide it when the store is opened.

[Brief description of drawings]

FIG. 1 is a block diagram of a defrosting apparatus according to the present invention, FIG. 2 is a sectional view of a cooling showcase showing a flow of cold air during cooling,
3 is a sectional view of the cooling showcase showing the flow of cold air during defrosting while the store is open, FIG. 4 is a sectional view of the cooling showcase showing the flow of cold air during defrosting when the store is closed, and FIG. 5 is FIG. 6 is a waveform diagram showing the operation of the defroster, and FIG. 6 is a waveform diagram showing the operation of the conventional defroster. In the figure 1 …… Selection circuit, 2,31 …… Input terminal 3 …… Schedule timer 4 …… Defrost control section 5,6 …… Defrost cycle timer 7 …… Temperature sensor, 8 …… A / D converter 9 …… Cold air outlet, 10,11 …… Setting section 12 …… Comparison circuit 13 …… Defrosting end signal sending circuit 14 …… Defrosting drive signal output section 15 …… Inner layer fan motor 16 …… Outer layer fan motor 17 …… solenoid valve, 18 …… heater 19 …… pipe, 21 …… cooling coil 22 …… cooler, 23 …… inner fan 24 …… refrigerating open showcase 25 …… opening, 26 …… air curtain 27 …… Outer layer fan, 28 …… Cover 29 …… Display shelf, 30 …… Sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuyuki Fukunaga 2-15-4 Shibaura, Minato-ku, Tokyo Nakano Refrigerator Co., Ltd. (72) Inventor Kazuo Ujiie 2-154-4 Shibaura, Minato-ku, Tokyo Co., Ltd. (72) Inventor Tatsuo Kikuchi 2-15-4 Shibaura, Minato-ku, Tokyo Nakano Refrigerator Co., Ltd. (56) Reference JP 58-219381 (JP, A) Actually developed 56-8287 (JP) , U)

Claims (2)

[Claims] 1. When a store with a large load is opened, (a) the defrosting method is an off-cycle method in which the operation of the cooler is stopped and defrosting with time is performed by air, and (b) the defrosting stop temperature is low. (C) Set the time until the next defrost to a short time for defrosting, and (a) defrosting the system to stop the operation of the cooler and close the heater or hot when the store is closed with a light load. A forced defrosting method in which a cooler is heated by a heating means such as gas for defrosting is used. (B) The defrosting stop temperature is set high, and (c) the time until the next defrosting is set long to remove the defrosting. A defrosting method in a cooling showcase, characterized by performing frosting. 2. (a) The operation of the cooler is stopped during the opening of a heavy load, and a selection signal c for selecting an off-cycle defrosting method for performing defrosting with time by air is output, Selection signal d for selecting the defrosting method of the forced defrosting method in which the operation of the cooler is stopped and the cooler is heated by heating means such as a heater or hot gas to defrost during the small closing of the store.
(B) Defrost cycle timer 5 that outputs a defrost cycle signal e with a short cycle during opening, and defrost cycle signal f with a long cycle during closing.
Defrosting cycle timer 6, which outputs (c) is low when the store is open and high when the store is closed.
A comparison calculation circuit 12 that outputs a comparison output j when the temperature of the cold air blown out exceeds the defrosting stop temperature during opening, and outputs a comparison output k when the temperature exceeds the defrosting stop temperature during closing the store, (d) comparison calculation circuit 12 When the comparison output j is supplied during defrosting by the off-cycle method during opening, the defrosting stop signal 1 for defrosting by the off-cycle method is output, and the forced defrosting method during closing the shop. Defrosting stop signal sending circuit 13 for outputting defrosting stop signal m for forced defrosting when comparison / output k is supplied during defrosting in A defrosting method using an off-cycle method for performing defrosting based on the selected defrosting method, defrosting cycle, and defrosting stop temperature when a method selection signal, a defrosting cycle signal, and a defrosting stop signal are supplied. The execution signal n or the defrosting execution signal o by the forced defrosting method is output. Control unit 4, (f) By the defrosting executing signal is input, defrosting driving signal output unit 14 for outputting a signal allowed to control the equipment in the case, removal of the cooling showcase with a capital frost device.