JP2004215704A - Showcase - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the inconvenience of causing an abnormal increase in temperature of goods displayed at the ends of a shelf board in a showcase displaying goods on the shelf board while heating with an electric heater. <P>SOLUTION: The showcase is made by installing shelf boards 2 for displaying goods and mounting the electric heater to heat goods on the shelf. On the basis of a temperature which a temperature sensor detecting the temperature of the shelf detects, the showcase has a control device controlling the turning on and off of the power to the electric heater between the prescribed minimum temperature of the shelf board and the maximum temperature of the shelf. The electric heater is made up of a first heater 24 provided nearly in accordance with the end of the shelf board and a second heater 29 provided nearly in accordance with the center of the shelf board. The control device controls independently the application of power to the first and second heaters and reduces the amount of power applied to the first heater when the first heater is continuously energized for a prescribed period of time. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a showcase in which products such as canned beverages and beverages in PET bottles are displayed on shelves installed in a display room, and these products are heated by an electric heater.
[0002]
[Prior art]
Conventionally, showcases have been installed in stores such as supermarkets and convenience stores. The showcase has a display shelf for commodities in a main body, and a code heater (electric heater) is attached to the display shelf. Then, a product such as canned coffee is placed on the shelf and heated by an electric heater (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-6-165721
[Problems to be solved by the invention]
Here, the goods on the shelves are taken out from the central one (where the best selling goods are placed) by the buyer. Therefore, a new product (a product with a low temperature) is replenished to the center of the shelf with the product remaining at the end of the shelf, and the electric heater is used to raise the temperature of the product with a low temperature. Normally, the power is continuously supplied.
Therefore, there has been a problem that the temperature of the product at the end of the shelf that has already been warmed becomes abnormally high.
[0005]
The present invention has been made in order to solve the conventional technical problem, and in a showcase in which a product on a shelf is displayed while being heated by an electric heater, a product displayed at an end on the shelf. It is an object of the present invention to solve the problem of abnormally high temperatures.
[0006]
[Means for Solving the Problems]
In the showcase according to the first aspect of the present invention, a display room is formed in a main body that opens to the front, a shelf for displaying goods is erected in the display room, and the shelf is used to heat the goods on the shelf. A temperature sensor for detecting the temperature of the shelf, and based on the temperature detected by the temperature sensor, energizing the electric heater between a predetermined shelf lower limit temperature and a predetermined shelf upper limit temperature. A control device for performing OFF control, wherein the electric heater comprises a first heater provided substantially corresponding to an end of the shelf, and a second heater provided substantially corresponding to the center of the shelf. The control device controls the energization of the first and second heaters independently, and when the first heater is energized continuously for a predetermined time, thereafter, the control device reduces the energization amount to the first heater. It is characterized by reduction.
[0007]
According to the first aspect of the present invention, a display room is formed in the main body that opens to the front, a shelf for displaying goods is erected in the display room, and the shelf is used to heat the goods on the shelf. In a showcase equipped with an electric heater, a temperature sensor for detecting the temperature of the shelf and, based on the temperature detected by the temperature sensor, turning on / off the energization of the electric heater between a predetermined shelf lower limit temperature and a predetermined shelf upper limit temperature. A control device for controlling the electric heater, wherein the electric heater includes a first heater provided substantially corresponding to an end of the shelf, and a second heater provided substantially corresponding to the center of the shelf. The control device controls the energization of the first and second heaters independently, and when the first heater is energized continuously for a predetermined time, thereafter reduces the amount of energization to the first heater. So the product is replenished in the center on the shelf and In a situation where the heaters are continuously energized, when the first heater provided substantially corresponding to the end of the shelf is continuously energized for a predetermined time, then the first heater is energized. The amount of energization is reduced.
[0008]
As a result, the amount of heating of the product displayed at the end on the shelf is reduced, and the problem that the temperature of the product becomes abnormally high can be avoided beforehand.
[0009]
In the showcase according to the second aspect of the present invention, a display room is formed in a main body that opens to the front, a shelf for displaying goods is erected in the display room, and the shelves for heating the goods on the shelf. A temperature sensor for detecting the temperature of the shelf, and based on the temperature detected by the temperature sensor, energizing the electric heater between a predetermined shelf lower limit temperature and a predetermined shelf upper limit temperature. A control device for performing OFF control, wherein the electric heater comprises a first heater provided substantially corresponding to an end of the shelf, and a second heater provided substantially corresponding to the center of the shelf. The control device independently controls the energization of the first and second heaters, and detects the temperature detected by the temperature sensor when the energization of the first heater was stopped last time and the current detected by the temperature sensor. Temperature difference is larger than the specified value. If, characterized by thereafter reducing the energization amount of the said first heater.
[0010]
According to the invention of claim 2, a display room is formed in the main body that opens to the front, a shelf for displaying goods is erected in the display room, and the shelf is used for heating the goods on the shelf. In a showcase equipped with an electric heater, a temperature sensor for detecting the temperature of the shelf and, based on the temperature detected by the temperature sensor, turning on / off the energization of the electric heater between a predetermined shelf lower limit temperature and a predetermined shelf upper limit temperature. A control device for controlling the electric heater, wherein the electric heater includes a first heater provided substantially corresponding to an end of the shelf, and a second heater provided substantially corresponding to the center of the shelf. The control device independently controls the energization of the first and second heaters, and detects the temperature detected by the temperature sensor when the energization of the first heater was stopped last time and the current temperature detected by the temperature sensor. Is larger than the specified value. In such a case, since the amount of electricity supplied to the first heater is reduced thereafter, the product is replenished to the center on the shelf, and in a situation where the electric heater is continuously energized, the temperature detected by the temperature sensor is reduced. Is increased from the time when the power supply to the first heater was stopped last time, and when the power supply becomes larger than the predetermined value, the amount of power supply to the first heater provided substantially corresponding to the end of the shelf is reduced. become.
[0011]
As a result, the amount of heating of the product displayed at the end on the shelf is reduced, and the problem that the temperature of the product becomes abnormally high can be avoided beforehand.
[0012]
A showcase according to a third aspect of the present invention is characterized in that, in each of the above inventions, the control device stops the power supply amount reduction control of the first heater when the temperature detected by the temperature sensor rises to the shelf upper limit temperature. .
[0013]
According to the third aspect of the present invention, in addition to the above aspects, the control device stops the power supply reduction control of the first heater when the temperature detected by the temperature sensor rises to the shelf upper limit temperature. When the temperature of the replenished commodities has been raised, the control of the first heater also returns to normal without any problem.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional side view of a showcase 1 according to an embodiment to which the present invention is applied, and FIG. 2 is a plan view of a shelf 2 of the showcase 1.
[0015]
In FIG. 1, a showcase 1 is, for example, a cold / hot switching type open showcase installed in a convenience store, and includes a heat insulating wall 3 having a substantially U-shaped cross section and side plates 4 attached to both sides thereof. A main body 6 opening to the front surface is configured.
[0016]
Partition walls 7 are attached to the inside of the heat insulating wall 3 at intervals, a duct 8 is formed between the partition walls 7 and the heat insulating wall 3, and a display room 9 opened to the front inside the partition wall 7 is formed. Have been. A discharge port 11 and a suction port 12 are formed on the upper and lower edges of the front opening of the display room 9 (main body 6), and communicate with the duct 8. Inside the duct 8, a cooler 13 of a cooling device (not shown) and a blower 14 are provided. And are arranged.
[0017]
On the other hand, a plurality of upper and lower shelves 2... (Six in this embodiment) for merchandise display are installed in the display room 9, and on each shelf 2, products G such as canned beverages and PET bottled beverages are placed. Placed and displayed. Each of the shelves 2... Is constructed such that the front side is inclined low so that when the commodity G at the forefront is taken out, the commodity G at the rear of the row is sequentially moved forward. Each of the shelves 2... Is configured to be detachable by engaging a bracket 16 with a support (not shown) in order to change the number of shelves and the spacing between shelves. Each of the shelves 2... Has a slide structure that can be pulled out forward, and is held in a state held in the display room 9 as shown in FIG. It is possible.
[0018]
Next, the structure of each shelf 2... Will be described with reference to FIGS. 2, 5 and 6. The shelf 2 is made of a metal plate made of heat conductive aluminum or the like, and the upper surface thereof is a shelf plate 41 on which a product G is placed, and a back plate attached below the shelf plate 41 with a space therebetween. 42, and a molded heat insulating material 43 loaded between the two plates 41, 42 and the like.
[0019]
In this case, plate members 44, 44 made of a heat conductive metal plate such as aluminum are attached to the left and right sides of the back surface (lower surface) of the shelf board 41 in a heat-exchange manner (FIG. 6). ). Each of the plate members 44 corresponds to a range of substantially the entire width extending from the left and right front corners of the shelf 41 to the rear thereof, and accordingly, the thickness of the shelf 41 of the shelf 2 in the portion of the plate 44 is It is thicker by the plate material 41.
[0020]
Further, electric heaters 21, 22, 23, 26, 27, and 28 for heating the product G are mounted on the back surface (lower surface) of the shelf plate 41 of each shelf 2 in a heat-exchange manner. Among them, the electric heaters 21, 22, and 23 have substantially the entire width of the front part and both left and right parts (the two side parts will be attached to the back surface of the plate member 44) of the shelf 2 (shelf plate 41), and the left and right parts of the rear part, The electric heaters 26, 27, and 28 are attached substantially evenly corresponding to the ends of the shelves 41 (shelf 2), and the electric heaters 26, 27, and 28 extend from the rear center to the center of the shelves 2 (shelf 41). It is attached substantially evenly corresponding to the center of the shelf board 41 (shelf 2). The three electric heaters 21 to 23 constitute a first heater 24 as a first heater, and the electric heaters 26 to 28 constitute a second heater 29 as a second heater.
[0021]
Further, the three electric heaters 21 to 23 constituting the first heater 24 have the same capacity, and the three electric heaters 26 to 28 constituting the second heater 29 also have the same capacity. . At this time, the plate members 44 correspond to both side portions of the first heater 24 and also correspond to a part of the second heater 29 (FIG. 2).
[0022]
A first temperature sensor 31 is mounted on the front rear surface of the shelf plate 41 of each shelf 2 in the left-right direction at the center in the left-right direction, and a second temperature sensor 32 is mounted on the rear rear surface. Each is attached in a heat exchange manner (FIG. 5). In this case, a portion (indicated by 24A in FIG. 2) of the first heater 24 corresponding to the central front portion of the shelf board 41 in the left-right direction is arranged offset to the front. Thus, even if the first temperature sensor 31 is mounted as close to the front side of the shelf board 41 as possible, a sufficient space can be secured between the first temperature sensor 31 and the first heater 24.
[0023]
The wires of the electric heaters 21 to 23 and 26 to 28 and the temperature sensors 31 and 32 are pulled out from the shelf 2 and are detachably connected to an outlet (not shown) provided on the partition wall 7 via a socket. Will be. Further, these wirings are routed with a margin so that there is no problem even when the shelf 2 is pulled out as described above.
[0024]
Next, FIG. 3 shows an electric circuit of the electric heaters 21 to 23 and 26 to 28 constituting the first heater 24 and the second heater 29. To supply power to these heaters, a three-phase 200V power supply AC is used. That is, the voltage between the R, S, and T phases of the power supply AC is 200 V AC. The electric heater 21 of the first heater 24 of each shelf 2 is connected to the R phase of the power supply AC, the electric heater 22 is connected to the S phase, and the electric heater 23 is connected to the T phase. The electric heater 26 is connected to the R phase of the power supply AC, the electric heater 27 is connected to the S phase, and the electric heater 28 is connected to the T phase.
[0025]
Three relay contacts R1 are connected between the electric heaters 21 to 23 of the first heater 24 and the power supply AC, and three relay contacts R1 are connected between the electric heaters 26 to 28 of the second heater 29 and the power supply AC. Are connected. A current transformer CT is provided in each of the power supply lines of the electric heaters 21 to 23 and 26 to 28. FIG. 3 shows a circuit of one shelf 2, and it is assumed that a similar circuit is configured for each shelf 2.
[0026]
Next, FIG. 4 shows a block diagram of an electric circuit of the control device C of the showcase 1. The control device C is constituted by a general-purpose microcomputer 34. The output of the microcomputer 34 includes coils R1C and R2C of the relays R1 and R2 of the electric heaters 21 to 23 and 26 to 28 of the respective shelves 2. It is connected. With such a configuration, the electric heaters 21 to 23 of the first heater 24 and the electric heaters 26 to 28 of the second heater 29 can be independently controlled. A display circuit 36 composed of an LED or the like is connected to the output of the microcomputer 34, and a control output of the cooling device (not shown) is also performed.
[0027]
The shelves 2... For detecting that the shelves 2... Have been pulled out and pushed into the display room 9 again are connected to the input of the microcomputer 34. Are also connected. Further, the microcomputer 34 includes various operation switches via the sensor / switch circuit 37, the temperature sensors 31 and 32 of each of the shelves 2,..., A temperature sensor (not shown) for detecting the temperature of the cold air discharged from the discharge port 11, and cooling. An output of a temperature sensor or the like for detecting the temperature of the vessel 13 is input.
[0028]
Next, the operation of the above configuration will be described. The showcase 1 of the embodiment can be switched between a refrigeration mode and a warm storage mode, and the mode is switched by a switching operation switch of the sensor switch circuit 37.
[0029]
(1) Refrigeration mode In the refrigeration mode, the microcomputer 34 inhibits energization of the electric heaters 21 to 23 and 26 to 28, and based on the output of the temperature sensor for detecting the temperature of the discharge port 11, the cooling device. Operation control.
[0030]
When the cooling device is operated, the cooler 13 exerts a cooling function. The cool air that has exchanged heat with the cooler 13 is blown up in the duct 8 by the blower 14, is discharged from the discharge port 11 toward the opening of the display room 9, and is sucked into the duct 8 from the suction port 12. As a result, a cool air curtain is formed at the front opening of the display room 9 and a part of the cool air circulates also in the display room 9 to cool the storage room 9 to a predetermined refrigeration temperature.
[0031]
(2) Preservation Mode On the other hand, control when the preservation mode is set will be described with reference to the timing chart of FIG. 7. The microcomputer 34 operates the cooling device (including the cooler 13 and the blower 14). The relays R1 and R2 turn on the electric heaters 21 to 23 and 26 to 28 of the first heater 24 and the second heater 29 of each shelf 2 based on the outputs of the temperature sensors 31 and 32, respectively. Control. The following control is performed independently for each of the shelves 2..., And in the following description, one shelf 2 will be described.
[0032]
Now, it is assumed that, on the shelf board 41 of the shelf 2, a plurality of rows of products G, for example, beverages containing tea bottles (tea, etc.) are placed on the left, right, front and rear, and are fully loaded. It is also assumed that all the shelves 2 have been pushed into the display room 9 and that all the shelf switches 2D have detected this. Further, the microcomputer 34 controls the energization of the relay coil R1C based on the temperature at the front center of the shelf 41 detected by the temperature sensor 31, and controls the energization of the electric heaters 21 to 23 of the first heater 24 by the relay R1. .
The relay coil R2C is energized and controlled based on the temperature at the center of the shelf 41 detected by the temperature sensor 32, and the electric heaters 26 to 28 of the second heater 29 are energized and controlled by the relay R2.
[0033]
Assuming that the set temperature (shelf set value) of the shelf 2 (shelf plate 41) is set to + 70 ° C., energization of the heaters 24 and 29 is started and the temperature detected by the temperature sensor 32 is, for example, When the shelf upper limit temperature of the shelf set value + 2 ° C. is reached, the relay R2 is opened to stop (OFF) the energization of the electric heaters 26 to 28 of the second heater 29, and the temperature detected by the temperature sensor 32 becomes, for example, the shelf set value− When the temperature drops to the shelf lower limit temperature of 2 ° C., the relay R2 is closed and the heating control for energizing (ON) the second heater 29 is executed. When the temperature detected by the temperature sensor 31 reaches the above-mentioned shelf upper limit temperature, the relay R1 is opened to stop (OFF) the energization of the electric heaters 21 to 23 of the first heater 24, and the temperature detected by the temperature sensor 31 becomes lower. When the temperature drops to the shelf lower limit temperature, the relay R1 is closed, and heating control for energizing (ON) the first heater 24 is executed.
[0034]
Thereby, the commodity G on the shelf board 41 of the shelf 2 is heated to a drinking temperature of about + 58 ° C. on average. FIG. 7 shows the surface temperature of the shelf 41 of the shelf 2, the temperature detected by the temperature sensor 31 (the temperature sensor 32 is substantially the same), the temperature of the product G at both ends of the shelf 2 (shelf 41), and the shelf 2 ( The temperature of the product G at the center (addition) of the shelf board 41) is shown. Note that the microcomputer 34 can set the above-mentioned shelf set values independently for each of the temperature sensors 32 and 31. However, in the embodiment, the same description will be given.
[0035]
Here, at the time of selling the goods, usually the best-selling goods are displayed at the center of the shelf board 41 of the shelf 2, and the goods with little sales are displayed at the left and right side positions. Therefore, when the goods G are taken out from the near side by the purchaser, the goods on the shelf board 41 disappear from the center rear part by sequentially moving to the near side, and the goods G at the already warm both ends on the shelf board 41 are removed. Is a situation that remains before and after.
[0036]
Then, when a new commodity G having a relatively low temperature is refilled on the shelf 41 of the shelf 2, the temperatures detected by the temperature sensors 31 and 32 and the surface temperature of the shelf 41 rapidly decrease, and the shelf lower limit temperature is reduced. The microcomputer 34 closes the relays R1 and R2 and starts energizing the first heater 24 and the second heater 29. Thereby, the product G on the shelf 41 is also heated.
[0037]
At this time, although the temperatures detected by the temperature sensors 31 and 32 also gradually rise, since the temperature is lowered by the replenishment of a new product G, it takes time to rise to the shelf upper limit temperature. As a result, both heaters 24 and 29 are continuously energized.
[0038]
The temperature of the commodity G in the central part on the shelf board 41 newly replenished by the heating by the first and second heaters 24 and 29 rises from a low value, but rises on the shelf board 41 already warmed. The temperature of the product G at both ends will further rise from the appropriate temperature, and will be heated to an abnormally high temperature as it is.
[0039]
Therefore, when the first heater 24 substantially corresponding to the end of the shelf 2 is continuously energized, for example, for one hour after the replenishment of the product G, the microcomputer 34 supplies the first heater 24 with power. The energization is duty-controlled. With this duty control, the microcomputer 34 controls the relay R1 so that when the first heater 24 is energized for 10 minutes, it is de-energized for 1 minute. As a result, the amount of electricity supplied to the first heater 24 is reduced to 10/11, and the temperature rise of the product G at both ends on the shelf board 41 becomes slow. The disadvantage that only the temperature becomes abnormally high is eliminated or suppressed.
[0040]
The microcomputer 34 continuously energizes the second heater 29 even during the duty control. Then, after that, the temperature of the replenishment product G also rises, and when the temperature detected by the temperature sensors 31 and 32 reaches the shelf upper limit temperature, the microcomputer 34 turns on the power to the first and second heaters 24 and 29. After that, the duty control is terminated, and thereafter, the control returns to the normal heating control.
[0041]
Here, in the above-described embodiment, the duty control is performed when the first heater 24 is continuously energized for one hour. However, the present invention is not limited thereto. The duty control may be executed when the temperature detected by the controller decreases. In this case, the microcomputer 34 stores the temperature T1 detected by the temperature sensor 31 at the time when the power supply to the first heater 24 was stopped (OFF) last time. When the temperature T2 detected by the sensor 31 decreases and T1−T2 becomes larger than, for example, 15 deg, the amount of power to the first heater 24 is reduced.
[0042]
Such control also makes it possible to eliminate or suppress the abnormal temperature rise of the product G at both ends on the shelf board 41. In this case as well, the duty control is to be terminated when the temperature detected by the temperature sensor 31 rises to the shelf upper limit temperature.
[0043]
【The invention's effect】
As described in detail above, according to the first aspect of the present invention, a display room is formed in a main body that opens to the front, a shelf for displaying goods is erected in the display room, and a product on the shelf is mounted on the shelf. In a showcase equipped with an electric heater for heating the shelf, a temperature sensor for detecting the temperature of the shelf, and a temperature of the electric heater between a predetermined shelf lower limit temperature and a shelf upper limit temperature based on the temperature detected by the temperature sensor. A control device for ON-OFF control of energization, wherein an electric heater is provided with a first heater provided substantially corresponding to an end of the shelf and a second heater provided substantially corresponding to a central portion of the shelf. The controller is configured to independently control the energization of the first and second heaters, and when the first heater is continuously energized for a predetermined time, thereafter, the controller controls the power supply to the first heater. Since the amount of electricity is reduced, the center Is supplied, and the electric heater is continuously energized. When the first heater provided substantially corresponding to the end of the shelf is continuously energized for a predetermined time, the electric heater is thereafter energized. The amount of electricity supplied to the first heater is reduced.
[0044]
As a result, the amount of heating of the product displayed at the end on the shelf is reduced, and the problem that the temperature of the product becomes abnormally high can be avoided beforehand.
[0045]
According to the second aspect of the present invention, a display room is formed in the main body that opens to the front, a shelf for displaying goods is installed in the display room, and the products on the shelf are heated on the shelf. Sensor that detects the temperature of the shelf, and based on the temperature detected by the temperature sensor, turns on the electric heater between a predetermined shelf lower limit temperature and a shelf upper limit temperature based on the temperature detected by the temperature sensor. A control device for performing OFF control, wherein the electric heater comprises a first heater provided substantially corresponding to an end of the shelf, and a second heater provided substantially corresponding to the center of the shelf. The control device independently controls the energization of the first and second heaters, and detects the temperature detected by the temperature sensor when the energization of the first heater was stopped last time and the current detected by the temperature sensor. Temperature is larger than the specified value If this happens, the amount of power supplied to the first heater is reduced thereafter, so that in a situation where the product is replenished in the center of the shelf and the electric heater is continuously supplied with electricity, the temperature sensor detects When the temperature of the first heater is increased from the last time the first heater was stopped, and when the temperature becomes larger than a predetermined value, the amount of electricity to the first heater provided substantially corresponding to the end of the shelf is reduced. Become so.
[0046]
As a result, the amount of heating of the product displayed at the end on the shelf is reduced, and the problem that the temperature of the product becomes abnormally high can be avoided beforehand.
[0047]
According to the third aspect of the present invention, in addition to the above aspects, the control device stops the power supply amount reduction control of the first heater when the temperature detected by the temperature sensor rises to the shelf upper limit temperature. When the temperature of the replenished commodities has been raised, the control of the first heater also returns to normal without any problem.
[Brief description of the drawings]
FIG. 1 is a vertical sectional side view of a showcase according to an embodiment of the present invention.
FIG. 2 is a plan view of a shelf of the showcase of FIG. 1;
FIG. 3 is an electric circuit diagram of an electric heater of one shelf of the showcase of FIG. 1;
FIG. 4 is a block diagram of an electric circuit of the control device of the showcase of FIG. 1;
FIG. 5 is a vertical sectional side view of a shelf of the showcase of FIG. 1;
FIG. 6 is another longitudinal side view of the shelf of the showcase of FIG. 1;
FIG. 7 is a timing chart illustrating control of an electric heater by the control device of FIG. 4;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Showcase 2 Shelf 3 Heat insulation wall 9 Display rooms 21-23, 26-28 Electric heater 24 First heater 29 Second heater 31, 32 Temperature sensor 34 Microcomputer C Controller

Claims (3)

In a showcase, a display room is formed in a main body that opens to the front, and a shelf for displaying products is erected in the display room, and an electric heater for heating the products on the shelf is attached to the shelf. ,
A temperature sensor that detects the temperature of the shelf, and a control device that performs ON-OFF control of energization of the electric heater between a predetermined shelf lower limit temperature and a shelf upper limit temperature based on the temperature detected by the temperature sensor,
The electric heater includes a first heater provided substantially corresponding to an end of the shelf, and a second heater provided substantially corresponding to a center of the shelf. When the first and second heaters are independently energized, and when the first heater is continuously energized for a predetermined time, the amount of energization to the first heater is reduced thereafter. Showcase featuring. In a showcase, a display room is formed in a main body that opens to the front, and a shelf for displaying products is erected in the display room, and an electric heater for heating the products on the shelf is attached to the shelf. ,
A temperature sensor that detects the temperature of the shelf, and a control device that performs ON-OFF control of energization of the electric heater between a predetermined shelf lower limit temperature and a shelf upper limit temperature based on the temperature detected by the temperature sensor,
The electric heater includes a first heater provided substantially corresponding to an end of the shelf, and a second heater provided substantially corresponding to a center of the shelf. Controlling the energization of the first and second heaters independently, the temperature detected by the temperature sensor when the energization of the first heater was last stopped, and the current temperature detected by the temperature sensor. The showcase characterized in that, when the difference between the first and second heaters becomes larger than a predetermined value, the amount of power to the first heater is reduced thereafter. 3. The showcase according to claim 1, wherein the control device stops the power supply reduction control of the first heater when the temperature detected by the temperature sensor rises to the shelf upper limit temperature. 4. .

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