JP7501136B2 - Showcase - Google Patents

Description

The present invention relates to a showcase, and more specifically to a showcase that stores products placed on a product shelf at a desired temperature.

Conventionally, the following types of showcases are known that store products placed on product shelves at a desired temperature.

For example, multiple product placement shelves are arranged vertically in the storage chamber of the case body, and products are placed and displayed on each product placement shelf. Furthermore, inside the case body but outside the storage chamber, a ventilation passage is formed through which air sucked in through an intake port provided at the front lower part of the storage chamber passes. An evaporator is provided in this ventilation passage, which cools the air passing through by driving an installed circulation fan, and the air cooled by this evaporator is blown out from an outlet provided at the front upper part of the storage chamber.

As a result, in the showcase, the internal atmosphere of the storage chamber is cooled, allowing the products placed on the product storage shelves to be cooled to a desired temperature and stored (see, for example, Patent Document 1).

JP 2015-116202 A

However, in the above showcase, if the product placement shelves are left pulled out to the front or if a box or the like is placed on the showcase in such a way that it blocks the suction port, there is a risk that the air blown out from the air outlet will not be sucked into the suction port, and an air curtain will not be formed.

If such an air curtain could not be formed, outside air would be allowed to enter through the front opening of the case body, and there was a risk that the products on each product shelf could not be adjusted to the desired temperature.

In view of the above-mentioned circumstances, the present invention aims to provide a showcase that can effectively form an air curtain and adjust the temperature of products placed on the product storage shelves to a desired temperature.

In order to achieve the above object, the showcase according to the present invention is configured in such a manner that at least the front surface is open inside the case body, and is equipped with a storage chamber in which product placement shelves are arranged in multiple stages in the vertical direction, a ventilation passage that communicates with the storage chamber through an air outlet that opens at the front upper part of the storage chamber and an air inlet that opens at the front lower part, a circulation fan that circulates air between the storage chamber and the storage chamber, and a temperature adjustment means that adjusts the temperature of the air passing through the ventilation passage, and is characterized in that it stores products placed on the product placement shelves at a desired temperature by adjusting the temperature of the internal atmosphere of the storage chamber, and has a light-emitting element disposed at one of the air outlet and the air inlet, and a light-receiving element disposed at the other of the air outlet and the air inlet, and is characterized in that it is equipped with a detection unit that, in an operating state, turns off when the light-receiving element receives light from the light-emitting element, but turns on when the light-receiving element cannot receive light from the light-emitting element, and a control unit that causes the alarm unit to perform an alarm operation as if an abnormality has occurred when the duration that the detection unit remains on is equal to or longer than a predetermined reference time.

The present invention is also characterized in that in the above-mentioned showcase, the detection units are multiple and arranged side by side at a predetermined interval along the left-right direction, and when one of the adjacent detection units is in an operating state, the other detection unit is in an inoperable state.

The present invention is also characterized in that in the above showcase, the detection units are driven at different times.

The present invention also provides a showcase comprising: an axis portion provided below the suction port in a manner extending in the left-right direction; and a plurality of lever members provided to be swingable about the central axis of the axis portion at predetermined intervals along the extension direction of the axis portion, the lever members normally being in an advanced position in which their tips move forward and backward into the upper region of the suction port, but when pressed by an article placed thereon in a manner blocking at least a portion of the suction port, the lever members move backward and forward from the upper region of the suction port; and a posture detection unit that detects when at least one of the lever members is in the retreated position; and the control unit causes the alarm unit to perform an alarm operation as if an abnormality has occurred when the posture detection unit detects a lever member in the retreated position.

The present invention is also characterized in that the showcase is provided with a lower detection unit that is disposed at the bottom of the case body and that turns on when it detects an object in the front area of the bottom of the case body in an operating state, and the control unit determines that an abnormality has occurred and causes the alarm unit to perform an alarm operation when the duration that the lower detection unit remains on is equal to or longer than a predetermined time.

The present invention is also characterized in that in the above showcase, the temperature adjustment means is an evaporator that is installed in the ventilation duct and cools the air passing through the ventilation duct.

According to the present invention, a detection unit having a light-emitting element disposed at one of the air outlet and the air inlet, and a light-receiving element disposed at the other of the air outlet and the air inlet, turns off when the light-receiving element receives light from the light-emitting element in an operating state, and turns on when the light-receiving element cannot receive light from the light-emitting element. When the control unit is turned on for a period of time that is longer than a predetermined reference time, it causes the notification unit to perform a notification operation as an abnormality has occurred. This allows the user to recognize that the air curtain created by the air blown out from the air outlet being sucked into the air inlet is not being properly formed, and by encouraging the user to remove elements that hinder the formation of the air curtain, the air curtain can be properly formed and the products placed on the product placement shelf can be adjusted to the desired temperature.

FIG. 1 is a cross-sectional side view showing a schematic view of a showcase according to an embodiment of the present invention. FIG. 2 is a block diagram showing a typical control system of the showcase according to the embodiment of the present invention. FIG. 3 is a cross-sectional side view showing a schematic state in which the shelf board has been slid forward and left in the showcase according to the embodiment of the present invention. FIG. 4 is a cross-sectional side view showing a schematic diagram of a showcase according to an embodiment of the present invention in a state in which an article is placed so as to close at least a part of the suction port. FIG. 5 is a cross-sectional side view showing a state in which a product storage box as an article is placed in the front area of the lower part of the case body in the showcase according to the embodiment of the present invention. FIG. 6 is a flowchart showing the contents of the abnormality occurrence determination process executed by the control unit shown in FIG. FIG. 7 is a flowchart showing another abnormality occurrence determination process executed by the control unit shown in FIG. FIG. 8 is a sectional side view showing a main part of a modified example of a showcase according to an embodiment of the present invention. FIG. 9 is a sectional side view showing a main part of a modified example of a showcase according to an embodiment of the present invention.

The following describes in detail a preferred embodiment of the showcase according to the present invention with reference to the attached drawings.

Figure 1 is a cross-sectional side view showing a typical showcase according to an embodiment of the present invention, and Figure 2 is a block diagram showing a typical control system of the showcase according to an embodiment of the present invention. The showcase shown here is used to store products in a store such as a supermarket or convenience store, and is configured with a case body 10.

The case body 10 has a bottom surface 11, a rear surface 12, and a top surface 13, and a storage chamber 14 with openings on the front and both left and right sides is formed in the area surrounded by the bottom surface 11, the rear surface 12, and the top surface 13. The case body 10 also has a ventilation passage 15 in a manner that separates it from the storage chamber 14. The ventilation passage 15 is formed inside the bottom surface 11, the rear surface 12, and the top surface 13, and includes a lower ventilation duct 15a, a rear ventilation duct 15b, and an upper ventilation duct 15c.

The lower ventilation duct 15a is configured in a portion of the bottom surface 11 that is lower than the bottom plate 11a that constitutes the bottom surface of the storage chamber 14. An intake port 16a that extends in the left-right direction is formed in the front end portion of the bottom plate 11a. In other words, the intake port 16a opens to the front lower portion of the storage chamber 14.

The rear ventilation duct 15b is configured in a portion of the rear surface 12 that is rearward of the rear plate 12a that constitutes the rear surface of the storage chamber 14. The lower end portion of this rear ventilation duct 15b is connected to the rear end portion of the lower ventilation duct 15a.

The upper ventilation duct 15c is configured in a portion of the top surface 13 that is above the top panel 13a that constitutes the top surface of the storage room 14. The rear end of this upper ventilation duct 15c is connected to the upper end of the rear ventilation duct 15b. An air outlet 16b extending in the left-right direction is formed in the front end of the top panel 13a. In other words, the air outlet 16b opens to the front upper part of the storage room 14.

A circulation fan 17 is installed inside such ventilation passage 15. The circulation fan 17 circulates air. In the above showcase, when the circulation fan 17 is driven, air sucked into the ventilation passage 15 through the suction port 16a is sent to the outlet port 16b, and then blown out from the outlet port 16b into the storage room 14, thereby circulating air between the storage room 14 and the ventilation passage 15. As a result, an air curtain is formed in the storage room 14 from the outlet port 16b toward the suction port 16a.

The storage room 14 is provided with multiple product placement shelves 18 (six in the illustrated example) arranged vertically. The product placement shelves 18 are configured with shelf boards 18b supported via sliders (not shown) on shelf support members 18a attached to shelf posts (not shown) provided on both the left and right sides of the back panel 12a. In these product placement shelves 18, the shelf boards 18b can slide in the front-to-rear direction, and products are placed on the top surfaces of the shelf boards 18b for display.

An evaporator 19 is installed in the rear ventilation duct 15b of the ventilation passage 15. The evaporator 19 is connected in a ring shape to a compressor 20, a condenser 21, and an expansion mechanism 22 by a refrigerant pipe 23, forming a refrigerant circuit that circulates the refrigerant.

The compressor 20 is installed in the machine room 24 below the storage room 14. When the compressor 20 is in operation, it draws in the refrigerant from the evaporator 19, compresses it, and discharges the high-temperature, high-pressure refrigerant.

The condenser 21 is installed in the machine room 24, ahead of the compressor 20. This condenser 21 condenses the refrigerant (high-temperature, high-pressure refrigerant) discharged from the compressor 20 to release heat. The expansion mechanism 22 is composed of, for example, an electronic expansion valve or a capillary tube, and adiabatically expands the refrigerant condensed in the condenser 21 and circulating therethrough to a low-temperature, low-pressure state.

The evaporator 19 exchanges heat between the air passing through the ventilation passage 15 by driving the circulation fan 17 and the refrigerant that has been brought to a low-temperature, low-pressure state by the expansion mechanism 22, and more specifically, cools the air passing through the ventilation passage 15 by evaporating the low-temperature, low-pressure refrigerant. The refrigerant evaporated by the evaporator 19 is sucked into the compressor 20 and circulates through the refrigerant circuit.

As a result, in the showcase, when the compressor 20 and the circulation fan 17 are driven, the air that has passed through the evaporator 19 is circulated and supplied to the storage chamber 14 through the ventilation passage 15, and the storage chamber 14 is maintained at the desired refrigeration temperature.

An opening is also formed on the front of the machine room 24, and a kick plate 25 is installed in a manner that closes this opening. The kick plate 25 is detachable from the case body 10, and although not shown in the figure, multiple ventilation holes are formed in the area in front of the condenser 21. These ventilation holes are used to draw outside air into the machine room 24 by driving the blower fan 26 located on the rear side of the condenser 21.

In addition to the above configuration, the showcase according to the embodiment of the present invention also includes a detection unit 31, a lower detection unit 32, an alarm unit 33, and a control unit 40, as shown in FIG. 2.

The detection unit 31 is composed of, for example, an optical sensor, and has a pair of light-emitting element 31a and light-receiving element 31b. The light-emitting element 31a is installed at the air outlet 16b, and the light-receiving element 31b is installed at the air inlet 16a. There are multiple such detection units 31, and they are arranged side by side at a predetermined interval in the left-right direction.

In the driving state, the detection unit 31 outputs an off signal or an on signal to the control unit 40. To explain in more detail, in the driving state, the detection unit 31 turns off and outputs an off signal to the control unit 40 when the light receiving element 31b receives light from the light emitting element 31a, and turns on and outputs an on signal to the control unit 40 when the light receiving element 31b cannot receive light from the light emitting element 31a.

The detection unit 31 may be turned on when, as shown in FIG. 3, the shelf 18b of one of the product placement shelves 18 is left in a slid forward position, blocking the light from the light-emitting element 31a and preventing the light-receiving element 31b from receiving it, or when, as shown in FIG. 4, an item W1 is placed in a manner that blocks part of the suction port 16a, blocking the light from the light-emitting element 31a and preventing the light-receiving element 31b from receiving it.

The lower detection unit 32 is, for example, a reflection sensor, and is installed on the kick plate 25, which is the lower part of the case body 10. There are multiple lower detection units 32, which are arranged side by side at a predetermined interval along the left-right direction.

In the driven state, the lower detector 32 detects the presence or absence of a product storage box (item) W2 in the front area of the lower part of the case body 10. To explain in more detail, in the driven state, the lower detector 32 turns off and outputs an OFF signal to the control unit 40 when a product storage box W2 is not detected in the front area of the lower part of the case body 10, whereas the lower detector 32 turns on and outputs an ON signal to the control unit 40 when a product storage box W2 placed in the front area is detected as shown in FIG. 5.

When a notification command is output from the control unit 40, the notification unit 33 performs notification operations such as emitting a buzzer sound and displaying a warning on the display means.

The control unit 40 comprehensively controls the operation of each part of the showcase according to the programs and data stored in the memory unit 44, and as a characteristic feature of this embodiment, it determines whether or not an abnormality has occurred based on the detection results of the detection unit 31 and the lower detection unit 32, and causes the alarm unit 33 to perform an alarm operation as necessary. This control unit 40 has an input processing unit 41, a judgment processing unit 42, and an output processing unit 43.

The control unit 40 may be realized, for example, by having a processing device such as a CPU (Central Processing Unit) execute a program, i.e., by software, or may be realized by hardware such as an IC (Integrated Circuit), or may be realized by a combination of software and hardware.

The input processing unit 41 inputs signals sent from the detection unit 31 and the lower detection unit 32. The judgment processing unit 42 judges whether an abnormality has occurred. Specifically, the judgment processing unit 42 judges whether the duration of an ON signal input from any of the detection units 31 through the input processing unit 41 (the duration during which the detection unit 31 is on) is equal to or longer than a predetermined first reference time (e.g., 10 minutes) to judge whether an abnormality has occurred. The judgment processing unit 42 also judges whether the duration of an ON signal input from any of the lower detection units 32 through the input processing unit 41 (the duration during which the lower detection unit 32 is on) is equal to or longer than a predetermined second reference time (predetermined time: e.g., 10 minutes) to judge whether an abnormality has occurred. The first reference time and the second reference time are thresholds for judging whether an abnormality has occurred, and the specific length of time is determined individually.

The output processing unit 43 outputs a notification command to the notification unit 33 when it is determined through the judgment processing unit 42 that an abnormality has occurred.

Figure 6 is a flowchart showing the process of determining whether an abnormality has occurred, which is performed by the control unit 40 shown in Figure 2. The premise of this process of determining whether an abnormality has occurred is that all detection units 31 are in an operational state.

In this abnormality occurrence determination process, the control unit 40 determines whether an ON signal has been input from any of the detection units 31 through the input processing unit 41 (step S101). If it is determined that an ON signal has not been input from any of the detection units 31 (step S101: No), the control unit 40 repeats this process.

On the other hand, if it is determined that an ON signal has been input from any of the detection units 31 (step S101: Yes), the control unit 40 determines through the judgment processing unit 42 whether the duration of the input ON signal (the duration during which the detection unit 31 is ON) is equal to or longer than a predetermined first reference time (e.g., 10 minutes) (step S102).

If it is determined that the duration of the input ON signal is less than the first reference time (step S102: No), the control unit 40 determines through the judgment processing unit 42 that no abnormality has occurred, and then returns the procedure to end the current processing.

On the other hand, if it is determined that the duration of the input ON signal is equal to or longer than the first reference time (step S102: Yes), the control unit 40 determines through the judgment processing unit 42 that an abnormality has occurred, outputs a notification command to the notification unit 33 through the output processing unit (step S103), and then returns the procedure to end the current processing.

The notification unit 33 will then issue a notification by sounding a buzzer or the like, making store employees aware that the air curtain is not properly formed because the shelf 18b has been left in a slid forward position or at least a portion of the suction port 16a is blocked by the item W1, and encouraging them to slide the shelf 18b backward or remove the item W1, etc.

Figure 7 is a flowchart showing the processing contents of another abnormality occurrence determination process performed by the control unit 40 shown in Figure 2. The premise of such an abnormality occurrence determination process is that all lower detection units 32 are in an operating state.

In this abnormality occurrence determination process, the control unit 40 determines whether an ON signal has been input from any of the lower detection units 32 through the input processing unit 41 (step S201). If it is determined that an ON signal has not been input from any of the lower detection units 32 (step S201: No), the control unit 40 repeats the process.

On the other hand, if it is determined that an ON signal has been input from any of the lower detection units 32 (step S201: Yes), the control unit 40 determines through the determination processing unit 42 whether the duration of the input ON signal (the duration during which the lower detection unit 32 is ON) is equal to or longer than a predetermined second reference time (e.g., 10 minutes) (step S202).

If it is determined that the duration of the input ON signal is less than the second reference time (step S202: No), the control unit 40 determines through the judgment processing unit 42 that no abnormality has occurred, and then returns the procedure to end the current processing.

On the other hand, if it is determined that the duration of the input ON signal is equal to or longer than the second reference time (step S202: Yes), the control unit 40 determines through the judgment processing unit 42 that an abnormality has occurred, outputs a notification command to the notification unit 33 through the output processing unit (step S203), and then returns the procedure to end the current processing.

This allows the alarm unit 33 to issue an alarm by emitting a buzzer sound or the like, thereby letting store employees and the like know that the product storage box W2 placed in the lower front area of the case body 10 may be blocking part of the ventilation holes formed in the kick plate 25, preventing good heat exchange in the condenser 21, and encouraging them to remove the product storage box W2, etc.

As described above, according to the showcase of the embodiment of the present invention, the detection units 31 having the light-emitting element 31a arranged in the air outlet 16b and the light-receiving element 31b arranged in the air inlet 16a are arranged in parallel at a predetermined interval along the left-right direction, and in the operating state, when the light-receiving element 31b receives light from the light-emitting element 31a, it is turned off, and when the light-receiving element 31b cannot receive light from the light-emitting element 31a, it is turned on. When the duration that any of the detection units 31 is turned on is equal to or longer than a predetermined first reference time, the control unit 40 causes the alarm unit 33 to perform an alarm operation as if an abnormality has occurred, so that it is possible to recognize that the air curtain is not formed properly, and by encouraging the removal of elements that hinder the formation of the air curtain, the air curtain can be formed properly and the products placed on the product placement shelf 18 can be adjusted to the desired temperature.

In addition, according to the above showcase, the lower detection units 32 arranged at predetermined intervals along the left-right direction on the kick plate 25 turn on when they detect a product storage box W2 in the front area of the lower part of the case body 10 in the driven state, and when the duration that any of the lower detection units 32 remains on exceeds a predetermined second reference time, the control unit 40 causes the alarm unit 33 to issue an alarm, indicating that an abnormality has occurred. This makes it possible to recognize that heat exchange in the condenser 21 may not be performed properly, and by prompting the user to remove the product storage box W2, etc., the products in the storage chamber 14 can be cooled properly.

In the above-mentioned showcase, the detection units 31 are arranged side by side at a predetermined interval in the left-right direction, and it is preferable that when one of the adjacent detection units 31 is in an operating state, the other detection unit 31 is in an inoperable state. This makes it possible to prevent erroneous detection caused by the light receiving element 31b of one of the adjacent detection units 31 receiving light from the light emitting element 31a of the other detection unit 31.

Furthermore, it is preferable that the timing at which each detection unit 31 becomes in the drive state is different. This can extend the service life of the detection units 31, and reduce the number of times the detection units 31 need to be replaced. When changing the timing of the drive state of the detection units 31 in this manner, when any of the detection units 31 sends an ON signal to the control unit 40, the drive state of that detection unit 31 continues even after the drive release time of that detection unit 31 has elapsed.

Figures 8 and 9 are cross-sectional side views showing the main parts of a modified showcase according to an embodiment of the present invention. Note that the same components as those in the above-described embodiment are denoted by the same reference numerals.

As shown in FIG. 8, the showcase includes an axis portion 50, a lever member 51, and a position detection unit 60. The axis portion 50 is provided in a manner that extends in the left-right direction in the lower ventilation duct 15a, which is the area below the suction port 16a.

There are multiple lever members 51, which are provided at predetermined intervals along the extension direction (left-right direction) of the shaft portion 50 so as to be able to swing around the central axis of the shaft portion 50. In the normal state, as shown in FIG. 8, these lever members 51 are in an advanced position in which the tip portion 51a moves forward and backward into the area above the suction port 16a, but when pressed by an article W1 placed in such a manner as to block at least a portion of the suction port 16a, as shown in FIG. 9, they are in a retracted position in which the tip portion 51a moves backward from the area above the suction port 16a.

The posture detection unit 60 is, for example, composed of an optical sensor, and is installed on the left and right side walls of the lower ventilation duct 15a in a left-right pair of light-emitting elements and light-receiving elements (not shown). When all lever members 51 are in the advanced position, the posture detection unit 60 turns off because the light emitted from the light-emitting elements can be received by the light-receiving element, whereas when at least one lever member 51 is in the retracted position, the light emitted from the light-emitting elements is blocked by the lever member 51 in the retracted position and cannot be received by the light-receiving element, turning on and sending an on signal to the control unit 40. In other words, the posture detection unit 60 detects that at least one of the multiple lever members 51 is in the retracted position.

When the position detection unit 60 detects that the lever member 51 is in the retracted position, the control unit 40 outputs a notification command to the notification unit 33 to perform a notification operation, determining that an abnormality has occurred.

By providing multiple lever members 51 in this way and providing one position detection unit 60 that detects when any of the lever members 51 is in the retracted position, it is possible to effectively detect when an item W1 has been placed in a manner that blocks at least a portion of the suction port 16a, and it is possible to reduce the number of detection units 31 that are arranged side by side at a predetermined interval along the left-right direction.

The above describes preferred embodiments and modifications of the present invention, but the present invention is not limited to these and various modifications can be made.

In the above-described embodiment, the detection unit 31 and the lower detection unit 32 are arranged side by side at a predetermined interval along the left-right direction, but in the present invention, the detection unit and the lower detection unit may be singular.

In the above-described embodiment, the light-emitting element 31a constituting the detection unit 31 is disposed at the air outlet 16b, and the light-receiving element 31b is disposed at the air inlet 16a. However, in the present invention, the light-emitting element constituting the detection unit may be disposed at the air inlet, and the light-receiving element may be disposed at the air outlet. Also, in the present invention, when the light-emitting element constituting one detection unit is disposed at the air outlet and the light-receiving element is disposed at the air inlet, between adjacent detection units, the light-emitting element constituting the other detection unit may be disposed at the air inlet and the light-receiving element may be disposed at the air outlet. This also makes it possible to prevent erroneous detection.

10...case body, 14...storage chamber, 15...ventilation passage, 15a...lower ventilation duct, 15b...rear ventilation duct, 15c...upper ventilation duct, 16a...suction port, 16b...blowout port, 17...circulation fan, 18...product storage shelf, 19...evaporator, 31...detection unit, 31a...light-emitting element, 31b...light-receiving element, 32...lower detection unit, 33...alarm unit, 40...control unit, 41...input processing unit, 42...judgment processing unit, 43...output processing unit, 44...memory unit, 50...axis unit, 51...lever member, 60...posture detection unit.

Claims (5)

A storage chamber having at least a front opening inside the case body and including multiple product placement shelves arranged vertically;
a ventilation passage communicating with the storage chamber through an air outlet opening at an upper front portion of the storage chamber and an air inlet opening at a lower front portion of the storage chamber, and a circulation fan for circulating air between the storage chamber and the ventilation passage;
and a temperature adjusting means for adjusting the temperature of the air passing through the ventilation passage,
A showcase that stores products placed on the product placement shelf at a desired temperature by adjusting the temperature of the interior atmosphere of the storage chamber,
a detection unit having a light-emitting element disposed at one of the air outlet and the air inlet, and a light-receiving element disposed at the other of the air outlet and the air inlet, the detection unit being turned off when the light-receiving element receives light from the light-emitting element in an operating state, and being turned on when the light-receiving element cannot receive light from the light-emitting element;
a control unit that, when a duration during which the detection unit is turned on is equal to or longer than a predetermined reference time, causes a notification unit to perform a notification operation, determining that an abnormality has occurred ;
A shaft portion is provided below the suction port so as to extend along the left-right direction;
a plurality of lever members that are provided at predetermined intervals along the extending direction of the shaft portion so as to be swingable about the central axis of the shaft portion, the lever members normally being in an advanced position in which their tip portions move forward and backward into the area above the suction port, and when pressed by an article placed in such a manner as to block at least a portion of the suction port, being in a retracted position in which their tip portions move backward from the area above the suction port;
a position detection unit that detects when at least one of the plurality of lever members is in a retracted position;
Equipped with
The control unit, when the position detection unit detects that the lever member is in the retracted position, determines that an abnormality has occurred and causes the notification unit to perform a notification operation . The detection units are provided in plurality and are arranged side by side at predetermined intervals along the left-right direction,
2. The showcase according to claim 1, wherein when one of the adjacent detectors is in an operating state, the other detector is in an inoperable state. The showcase according to claim 2, characterized in that the detection units are driven at different times. a lower detection unit that is disposed in a lower portion of the case body and that is turned on when an object is detected in a front area of the lower portion of the case body in a driven state;
The showcase described in any one of claims 1 to 3, characterized in that the control unit causes the alarm unit to issue an alarm when the duration during which the lower detection unit remains on is longer than a predetermined specified time, indicating that an abnormality has occurred. 5. The showcase according to claim 1, wherein the temperature adjusting means is an evaporator that is installed in the ventilation passage and cools the air passing through the ventilation passage.

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