JP4562452B2 - Flat open showcase - Google Patents

Description

  The present invention relates to a flat open showcase in which the upper surface side of a product storage chamber is opened and a cold air circulation passage is provided below the product storage chamber.

  In the open showcase of the present invention, in order to prevent the temperature of the product storage chamber from rising during the defrosting operation, the defrosting warm air from the main evaporator is cooled by the auxiliary evaporator to the product storage chamber. Although it blows out, it is well-known in patent documents 1 and 2 to prevent the temperature rise of a goods storage chamber at the time of a defrost operation by using a several evaporator in this way.

  In the open showcase of Patent Document 1, two evaporators are installed in the cold air circulation passage so that when one evaporator is defrosting operated, the other evaporator can supply cold air. Yes. The evaporator during the defrosting operation melts the frost using a high-temperature (40 ° C.) refrigerant liquid as a heat source, and the passage on the outlet side is closed with a damper until the defrosting is completed.

  In the open showcase of Patent Document 2, two evaporators installed adjacent to each other in the cold air circulation passage are alternately defrosted. The evaporator during the defrosting operation melts frost using a heater for defrosting as a heat source. Since the defrosting warm air coming out of the evaporator is blown out from the blowout opening together with the cold air that has passed through the other evaporator, it is possible to prevent the temperature of the product storage chamber from rising suddenly during the defrosting operation.

Japanese Unexamined Patent Publication No. 63-49680 (the upper left column of the third page, FIG. 3) Japanese Patent Laid-Open No. 7-4826 (paragraph number 0015, FIG. 2)

  In a store that is open 24 hours a day, a refrigerated showcase or the like is operated continuously for 24 hours. Therefore, compared with the case where a refrigerated showcase is intermittently used in a conventional store, frost forms on the evaporator in a shorter time, and it is necessary to frequently perform a defrosting operation. In particular, in the case of a flat-type open showcase having an entire upper surface opened, ambient air can easily enter the showcase, so that the operation interval for defrosting is shorter than other types of open showcases.

  By the way, the flat-type open showcase is easy to see the displayed products, so it is often used when displaying fresh food such as sashimi and raw fish. However, if this type of fresh food is displayed, defrosting operation is performed. For example, sashimi is subjected to a heat shock by the defrosting warm air that blows out into the product storage chamber, and the freshness of the sashimi rapidly decreases. In this regard, if a cooling system such as Patent Documents 1 and 2 is employed, it is possible to supply cold air even during the defrosting operation, so that it is possible to eliminate the sudden drop in the freshness of displayed products. However, in the case of continuous operation for 24 hours, it is necessary to frequently perform the defrosting operation, and the loss of cooling heat accompanying the defrosting operation increases.

  The temperature at the inlet or outlet of the refrigerant pipe in the evaporator depends on the temperature of the refrigerant supplied to the evaporator. When the refrigerant temperature is kept constant, the refrigerant temperature at the inlet or outlet of the refrigerant pipe can be increased as the cross-sectional area of the refrigerant pipe and the effective number of refrigerant pipes in the evaporator are increased. This means that the higher the refrigerant temperature at the inlet or outlet of the refrigerant pipe, the smaller the difference between the temperature of the circulating cold air and the surface temperature of the evaporator, and the more the generation of frost can be suppressed. The present inventor has paid attention to this point and has come up with the idea of reducing the frosting of the evaporator, and has proposed the present invention.

  The object of the present invention is to maintain a freshness of fresh food such as sashimi and raw fish, while avoiding frost formation in the evaporator as much as possible to expand the defrosting operation interval and to suppress the loss of cold by that much. To provide a case. An object of the present invention is to provide a flat open showcase that can supply cold air during defrosting operation to maintain the freshness of goods and is suitable for continuous operation for 24 hours.

The flat open showcase of the present invention includes a product storage chamber 5 whose upper surface is open, and a cold air circulation passage 6 that surrounds the front side, the lower side, and the rear side of the product storage chamber 5. A main evaporator 12 and a blower fan 14 are disposed inside the cold air circulation passage 6. Between the outlet 9 of the cool air circulation passage 6 and the main evaporator 12, an auxiliary evaporator 15 for cooling the defrosting hot air coming out of the main evaporator 12 is arranged. The auxiliary evaporator 15 is provided in the middle in the vertical direction of the vertical passage defined between the outlet 9 and the main evaporator 12. A cold air chamber 7 communicating with the product storage chamber 5 is defined between the deck pan 4 disposed at the bottom of the product storage chamber 5 and the bottom wall of the inner box 2. The cool air chamber 7 communicates with the cool air circulation passage 6 on the outlet 9 side and the cool air circulation passage 6 on the suction port 8 side through the inlet 22 and the outlet 23 opened in the front and rear walls of the inner box 2, and accommodates goods. The cold air circulation path on the chamber 5 side is bypassed, and a part of the cold air cooled by the main evaporator 12 is circulated through the cold air chamber 7. In a state where the inlet 22 faces the lower end surface of the auxiliary evaporator 15 and the main evaporator 12 and the blower fan 14 are operated to circulate and supply the cold air, a part of the cold air from the main evaporator 12 is It is blocked by the auxiliary evaporator 15 and flows into the cold air chamber 7 from the inlet 22.

Compared with the conventional main evaporator, the main evaporator 12 having a reduced frost formation by increasing the cross-sectional area and the effective number of the refrigerant pipes 31 cools the cool air returning from the commodity storage chamber 5.

  An outer dam plate 17 and an inner dam plate 18 having a height lower than the outer dam plate 17 are arranged in the front edge of the product storage chamber 5 in the left-right direction so as to face each other. The suction port 8 of the cold air circulation passage 6 is opened. At that time, the upper end of the outer dam plate 17 is positioned at substantially the same height as the outlet 9 of the cold air circulation passage 6. A rectifying louver 19 is disposed at the outlet 9, and an air curtain that blows out from the outlet 9 can be formed so as to be directed obliquely downward toward the inner dam plate 18.

A blower fan 14 and a wind guide frame 13 that supports the blower fan 14 are arranged on the inlet side of the main evaporator 12, and the blower fan 14 rotationally drives the axial flow type fan 26. and a DC motor 27, pressurized圧風by the fan 26, so that the main evaporator 12 bottom wall collision to the direction of the cool air circulation passage 6 facing the inlet of the oblique blower fan 14 in Shirubefuwaku 13 you support.

  In the present invention, the defrosting warm air coming out of the main evaporator 12 during the defrosting operation is cooled by the auxiliary evaporator 15, so that the defrosting warm air is prevented from being directly fed to the product storage chamber 5. Thus, the temperature of the product storage chamber 5 rises or the sashimi exposed to the warm air can be cleared of heat shock, and the defrosting operation can be performed without any trouble in the state where the fresh food is displayed.

  Further, compared with the conventional main evaporator, the cross-sectional area and the effective number of the refrigerant pipes 31 are increased to cool the cold air returning from the product storage chamber 5 with the main evaporator 12 having a low frost formation, Since the frost formation on the main evaporator 12 during operation is suppressed, the defrosting operation interval of the main evaporator 12 can be expanded by that amount, and the loss of heat caused by frequently performing the defrost operation can also be suppressed. A flat open showcase suitable for continuous operation for 24 hours as a whole can be provided.

  According to the flat open showcase in which a cool air chamber 7 is defined below the product storage chamber 5 and a part of the cool air cooled by the main evaporator 12 circulates gently through the cool air chamber 7. The fresh air stored in the product storage chamber 5 can be cooled by the cold air circulating gently through the cool air chamber 7, and the amount of cold in the product storage chamber 5 is increased by the amount of cold in the cold storage chamber 7, so that the product storage chamber The temperature state of 5 can be maintained at a constant temperature. For example, when all the cool air cooled by the main evaporator is delivered to the product storage room, the temperature of the product storage room fluctuates greatly due to frequent loading and unloading of the product, and it takes time to restore it to an appropriate temperature. However, as described above, when new cool air is constantly circulated in the cool air chamber 7, the temperature rise in the product storage chamber 5 is absorbed by the cool air in the cool air chamber 7, or the product is stored in the cool air in the cool air chamber 7. Since the chamber 5 can be cooled to suppress the temperature rise, the temperature fluctuation of the commodity storage chamber 5 can be suppressed.

  Of the outer dam plate 17 and the inner dam plate 18 provided along the front edge of the product storage chamber 5, the outer dam plate 17 is set at substantially the same height as the outlet 9, and an air curtain that blows out from the outlet 9 is provided. If the air is directed obliquely downward toward the inner weir plate 18, it is possible to prevent the ambient air from being sucked into the suction port 8 while preventing the cool air in the product storage chamber 5 from leaking to the front of the case. Further, the inner dam plate 18 receives the air curtain that blows out from the outlet 9 and prevents the air curtain flow from being directly sucked into the inlet 8. By the damming action of both the inner and outer weir plates 17 and 18, the temperature variation in the product storage chamber 5 can be suppressed, wasteful consumption of cold air can be suppressed, and the freshness of the fresh food stored in the product storage chamber 5 can be maintained. .

  The blower fan 14 disposed on the inlet side of the main evaporator 12 is supported obliquely by the air guide frame 13, and the cool air sent from the fan 26 is directed to the bottom wall of the cool air circulation passage 6 facing the inlet of the main evaporator 12. When colliding toward the bottom, it is possible to guide the cold air that has collided with the bottom wall in the entire circumferential direction along the bottom wall and disperse it in the case width direction. Therefore, the cold air passing through the main evaporator 12 can be prevented from being concentrated on a part. Thereby, the space | interval of the defrost operation of the main evaporator 12 can be expanded, and the heat exchange efficiency of the main evaporator 12 at the time of steady operation improves.

(Example) FIG. 1 thru | or FIG. 5 shows the Example of the flat type open showcase which concerns on this invention. 1 to 3, the open showcase includes a horizontally long rectangular box-shaped outer box 1 whose upper surface is open, an inner box 2 having a U-shaped cross-section whose upper surface is open, and a case base 3 that supports the outer box 1. Have. A deck pan 4 is arranged in the middle of the inner box 2 and a product storage chamber 5 is defined above the deck pan 4.

  The commodity storage chamber 5 here is a space in which the upper and lower sides are sandwiched between the air curtain and the deck pan 4 and the front and rear are surrounded by the front and rear walls of the inner box 2. The volume and cross-sectional shape of the product storage chamber 5 change by changing the mounting posture of the deck pan 4 with respect to the inner box 2.

  The outer box 1 is formed of a heat insulating wall, and a cold air circulation passage 6 surrounding the front side, the lower side, and the rear side of the commodity storage chamber 5 is formed between the outer box 1 and the inner box 2. The inner box 2 is formed of a stainless steel plate, and a cold air chamber 7 is defined between the previous deck pan 4 and the bottom wall of the inner box 2.

  The cool air chamber 7 communicates with the product storage chamber 5 through a gap adjacent to the deck pan 4, and the products displayed by the cool air inside the cool air chamber 7 are cooled via the deck pan 4. Details thereof will be described later. Although not shown, the suction port 8 is covered with punching metal.

  The cold air circulation passage 6 is connected to the product storage chamber 5 through a suction port 8 that opens upward along the front edge of the outer box 1 and a blowout port 9 that opens forward along the upper rear edge of the outer box 1. Communicate. The main evaporator 12 is disposed near the rear end of the case inside the cool air circulation passage 6, specifically, in the front-rear direction passage defined between the bottom wall of the outer box 1 and the bottom wall of the inner box 2. A plurality of blower fans 14 are arranged on the air guide frame 13 fixed to the front portion. In FIG. 2, the left and right width of the main evaporator 12 is set to be slightly smaller than the left and right width of the cool air circulation passage 6.

  In the vertical passage defined between the outlet 9 and the main evaporator 12, an auxiliary evaporator 15 for cooling hot air for defrosting from the main evaporator 12 is provided in the middle of the upper and lower sides. Deploy. The left and right width of the auxiliary evaporator 15 is set to be the same as the left and right width of the main evaporator 12. A heater 16 dedicated to defrosting is disposed on the front surface of the main evaporator 12 (see FIG. 3). In the open showcase of this embodiment, a refrigeration device for supplying refrigerant is separately installed, and the refrigerant can be circulated by connecting both refrigerant pipes.

  In order to store the cold air blown out from the blowout port 9 in the product storage chamber 5 and to prevent the difference in the internal temperature of the product storage chamber 5 between the blowout port 9 side and the suction port 8 side, As shown in FIG. 3 and FIG. 4, an outer dam plate 17 and an inner dam plate 18 having a height lower than the outer dam plate 17 are opposed to each other at the edge in the front-rear direction. A suction port 8 is formed.

  A plurality of L-shaped rectifying louvers 19 are arranged in the outlet 9 provided at a high position behind the case, and the flow of the air curtain that blows out from the outlet 9 is directed toward the upper end of the inner weir plate 18. And diagonally downward.

  The outer dam plate 17 is formed of a transparent tempered plate glass, and the inner dam plate 18 is formed of a transparent acrylic plate. As shown in FIG. 1, the upper edge of the air outlet 9 that opens near the upper end of the rear wall of the outer box 1 and the upper end of the outer weir plate 17 are set at substantially the same height. A lighting tool 20 is disposed on the upper projecting portion of the outlet 9.

  The cold air chamber 7 communicates the cold air circulation passage 6 connected to the outlet 9 and the cold air circulation passage 6 connected to the suction port 8 through an inlet 22 and an outlet 23 provided on the front and rear walls of the inner box 2. As a result, the cold air chamber 7 bypasses the cold air circulation path on the commodity storage chamber 5 side. In FIG. 3, the inlet 22 and the outlet 23 are each formed by a group of punch holes in two upper and lower stages.

  The inlet 22 faces the lower end surface of the auxiliary evaporator 15. Therefore, in a state where the main evaporator 12 and the blower fan 14 are operated and the cool air is circulated and fed, a part of the cool air from the main evaporator 12 is blocked by the auxiliary evaporator 15, and the cool air chamber is opened from the inlet 22. Flows into 7.

  If a part of the cool air cooled by the main evaporator 12 is introduced into the cool air chamber 7 and circulated gently, the cool air temperature in the cool air chamber 7 can be maintained at a low temperature, and only the cool air in the cool air chamber 7 can be maintained. The amount of heat in the storage chamber 5 increases. Therefore, the temperature state of the product storage chamber 5 can be maintained at a constant temperature as compared with the case where all of the cool air cooled by the main evaporator 12 is supplied to the product storage chamber 5. This is because the temperature of the product storage chamber 5 is likely to change due to frequent loading and unloading of the product, but even in such a case, the product storage chamber 5 can be cooled by the cool air in the cool air chamber 7 to suppress the temperature rise.

  Since the cold air flowing out from the outlet 23 is fed to the main evaporator 12 in a state of being mixed with the cold air sucked from the suction port 8, the temperature of the cold air entering the main evaporator 12 can be lowered and the temperature loss can be reduced. . Furthermore, the amount of water vapor contained in the cold air entering the main evaporator 12 is reduced by the amount that a part of the cold air circulates in the cold air chamber 7, thereby suppressing the generation of frost. The blower fan 14 includes an axial flow type fan 26, a DC motor 27 that rotationally drives the fan 26, and a fan frame that supports them.

  Although the main evaporator 12 is arrange | positioned over the full width of the inner surface left-right width | variety of the outer case 1, the ventilation fan 14 is only arrange | positioned for every fixed space | interval of the case width direction. Therefore, the amount of cool air passing through the front entrance of the main evaporator 12 that faces the vicinity of the blower fan 14 is large, and the distance from the blower fan 14 tends to decrease the amount of cool air that passes through. Naturally, the amount of frost attached increases as the amount of cold air passes increases.

  In order to eliminate such variations in the frosting locations and the amount of frost formation in the main evaporator 12, the pressurized air by the fan 26 and the bottom wall of the cold air circulation passage 6 facing the inlet side of the main evaporator 12 The blower fan 14 is supported diagonally by the air guide frame 13 in the collision direction. The cold air sent out from the fan 26 collides with the bottom wall of the cold air circulation passage 6 and reverses, and is guided to change in the entire circumferential direction. Therefore, the amount of cool air passing through the front entrance of the main evaporator 12 is leveled in the width direction, so that the frosting points can be prevented from being concentrated in the vicinity of the blower fan 14. This contributes to increasing the interval of the defrosting operation and helps to improve the heat exchange efficiency in the main evaporator 12.

  Since the fan 26 is driven using the DC motor 27 as a drive source, the fan 26 can always be driven at a stable rotational speed regardless of fluctuations in the power source and operating frequency for driving the refrigeration equipment. Therefore, as compared with the case where the fan is driven by an AC motor, it is possible to eliminate the variation in the flow rate of the cold air and the unevenness in the flow rate in the width direction, and to form an air curtain that is always stable.

  In order to avoid the frost formation in the main evaporator 12 as much as possible and extend the defrosting operation interval, the main evaporator 12 of the present invention is formed of a thin aluminum plate as shown in FIG. By increasing the cross-sectional area and the effective number of the refrigerant pipes 31 as compared with a conventional main evaporator, Low frost formation is achieved.

The refrigerant pipe 41 of the main evaporator used by the applicant in a conventional flat open showcase was formed of a copper pipe having an outer diameter dimension of 9.52 mm as shown in FIG. Further, the effective number of the refrigerant pipes 41, that is, the number of copper pipe lines penetrating a group of the radiating fins 40 in the thickness direction is set to 16. In this case, the evaporation area (surface area) of the refrigerant pipe is 975700 mm ² .

According to the embodiment of the present invention, as shown in FIG. 5A, the refrigerant pipe 31 of the main evaporator 12 is formed of a copper pipe having an outer diameter of 15.8 mm. The effective number of refrigerant pipes 31 is set to 22. In this case, the evaporation area of the refrigerant pipe is 2226600 mm ² . Incidentally, compared with the conventional refrigerant pipe 41, the diameter of the refrigerant pipe 31 of this embodiment is 1.7 times, and the evaporation area of the refrigerant pipe is 2.3 times.

  As described above, by arranging the refrigerant pipe 31 to be thicker and denser and to enlarge the evaporation area, the refrigerant temperature at the inlet and outlet of the refrigerant pipe 31 of the main evaporator 12 becomes the conventional evaporation. It was possible to make it higher than the vessel.

  Specifically, the refrigerant temperature at the inlet of the refrigerant pipe 31 of the conventional main evaporator was −22 ° C., and the refrigerant temperature at the outlet was −21 to −16 ° C. On the other hand, according to the main evaporator 12 of the present embodiment, the refrigerant temperature at the inlet of the refrigerant pipe 31 of the main evaporator 12 is −17.5 ° C., and the refrigerant temperature at the outlet is −17 to −12 ° C. As a whole, the refrigerant temperature could be increased by 4 ° C. The test was performed under ambient conditions of an air temperature of 27 ° C. and a humidity of 70%.

  When the supply condition of the refrigerant to the main evaporator 12 is constant, if the refrigerant pipe 31 is made thicker, the refrigerant pressure in the pipe is reduced by an amount corresponding to the larger cross-sectional area, and as a result, the refrigerant temperature is increased. On the contrary, when the refrigerant liquid is vaporized by the thinner refrigerant pipe 41, the refrigerant pressure inside the pipe increases as the cross-sectional area of the refrigerant pipe 41 is smaller, and as a result, the temperature rise degree of the refrigerant liquid becomes smaller. In addition, the temperature rise of the refrigerant liquid increases as the effective pipe length of the refrigerant pipe 31 increases. For this reason, the temperature increase of the refrigerant exemplified above can be promoted, and low frosting of the main evaporator 12 can be realized.

  In the open showcase having the above-described configuration, the main evaporator 12 and the blower fan 14 are normally operated, and an air curtain is formed above the product storage chamber 5 so that the products on display on the deck pan 4 are in a low temperature state. To maintain. At this time, the auxiliary evaporator 15 is not operated, and the cold air cooled by the main evaporator 12 simply passes through the auxiliary evaporator 15 and is blown out from the outlet 9. Most of the air curtain is received by the inner dam plate 18 and circulates in the product storage chamber 5 along the deck pan 4 while cooling the displayed products, and then passes over the inner dam plate 18 so as to get over the suction port 8. The air is sucked from the main evaporator 12 and sent to the main evaporator 12 again. At this time, a part of the cool air cooled by the main evaporator 12 is gently circulated through the cool air chamber 7 as described above.

  The defrosting operation is performed every preset time. During the defrosting operation, while the blower fan 14 is driven, the switching valve 33 is switched to stop the supply of the refrigerant liquid to the main evaporator 12, and the refrigerant liquid is supplied only to the auxiliary evaporator 15. At the same time, the heater 16 for defrosting is energized. The cold air fed by the blower fan 14 is heated in contact with the heater 16 and melts frost adhering between the radiation fins 30 while passing through the main evaporator 12. The warm air that has passed through the main evaporator 12 is cooled while passing through the auxiliary evaporator 15, and is blown out from the outlet 9. The cold air temperature at this time is detected by a first temperature sensor 34 provided in the vicinity of the outlet 9, and the amount of refrigerant supplied to the auxiliary evaporator 15 is increased as the cold air temperature rises, and the cold air temperature is adjusted. It can be lowered.

  A part of the hot air that has passed through the main evaporator 12 circulates in the cold air chamber 7 side, but the circulation amount is only small. Therefore, the freshness of the merchandise displayed in the merchandise storage chamber 5 is not lowered by the warm air circulating in the cold air chamber 7 side. A second temperature sensor 35 for detecting the hot air temperature is provided on the rear exit side of the main evaporator 12. When the temperature detected by the temperature sensor 35 exceeds a certain temperature, the defrosting operation is terminated. Specifically, the operation of the auxiliary evaporator 15 is stopped, the energization to the defrosting heater 16 is stopped, the main evaporator 12 is operated, and the cooler air at a lower temperature is supplied to the product storage chamber 5. Supply.

  Thereafter, the freshness of the products displayed in the product storage chamber 5 can be maintained by repeating the steady operation state and the defrosting operation state. The main evaporator 12 in the steady operation state is operated or stopped according to the temperature state detected by the first temperature sensor 34 and the third temperature sensor 36 provided in the vicinity of the suction port 8, and the commodity storage chamber 5. Keep the inside temperature constant.

  In the above embodiment, defrosting is performed using the heater 16 as a heat source. However, defrosting may be performed using a high-temperature refrigerant liquid as a heat source. The refrigeration equipment can be built in the open showcase. The defrosting operation does not need to be performed every fixed time, and can be started by detecting the temperature state of the cold air circulation passage 6 and the amount of air passing through the main evaporator 12. A small blower fan with a small amount of blown air can be arranged at the outlet of the cold air chamber 7 to circulate the cold air in the cold air chamber 7 semi-forcefully. In that case, in addition to being able to introduce cold air from the inlet 22, a part of the cold air in the product storage chamber 5 can be introduced to the cold air chamber 7 side.

It is a vertical side view of a showcase. It is a vertical front view of a showcase. It is the perspective view which fractured | ruptured the showcase. It is sectional drawing which shows the detailed structure of a suction inlet. It is sectional drawing which shows the structure of a main evaporator notionally.

Explanation of symbols

2 Inner box 4 Deck pan 5 Product storage chamber 6 Cold air circulation passage 7 Cold air chamber 8 Suction port 9 Air outlet 12 Main evaporator 13 Air guide frame 14 Blower fan 15 Auxiliary evaporator 17 Outer weir plate 18 Inner weir plate 19 Rectifier louver 22 Inlet 23 outlet 26 fan 27 DC motor 31 refrigerant pipe

Claims (4)

A product storage chamber (5) having an open upper surface, and a cold air circulation passage (6) surrounding the front side, the lower side, and the rear side of the product storage chamber (5),
The main evaporator (12) and the blower fan (14) are arranged inside the cold air circulation passage (6),
An auxiliary evaporator (15) for cooling hot air for defrosting from the main evaporator (12) is disposed between the outlet (9) of the cold air circulation passage (6) and the main evaporator (12). And
The auxiliary evaporator (15) is provided in the middle in the vertical direction of the vertical passage defined between the outlet (9) and the main evaporator (12),
A cold air chamber (7) communicating with the product storage chamber (5) is defined between the deck pan (4) disposed at the bottom of the product storage chamber (5) and the bottom wall of the inner box (2). And
The cool air chamber (7) is connected to the cool air circulation passage (6) and the suction port (8) on the outlet (9) side through the inlet (22) and the outlet (23) opened in the front and rear walls of the inner box (2). ) Side cold air circulation passage (6), bypassing the cold air circulation path on the product storage chamber (5) side,
A part of the cold air cooled by the main evaporator (12) circulates through the cold air chamber (7),
In a state where the inlet (22) faces the lower end surface of the auxiliary evaporator (15) and the main evaporator (12) and the blower fan (14) are operated to circulate and feed the cold air, the main evaporator A flat open showcase characterized in that a part of the cold air from (12) is blocked by the auxiliary evaporator (15) and flows into the cold air chamber (7) from the inlet (22) . Compared to the conventional main evaporator, the main evaporator (12), which is reduced in frost by increasing the cross-sectional area and the effective number of the refrigerant pipes (31), cools the cold air returning from the product storage chamber (5). The flat open showcase according to claim 1. An outer dam plate (17) and an inner dam plate (18) having a height lower than that of the outer dam plate (17) are arranged on the front edge of the product storage chamber (5) so as to face each other along the left-right direction. The suction port (8) of the cold air circulation passage (6) is open between the both weir plates (17, 18),
The upper end of the outer weir plate (17) is located at almost the same height as the outlet (9) of the cold air circulation passage (6),
The rectifying louver (19) is disposed at the outlet (9), and the air curtain that blows out from the outlet (9) is formed so as to be directed obliquely downward toward the inner dam plate (18). The flat open showcase described. On the inlet side of the main evaporator (12), a blower fan (14) and a wind guide frame (13) that supports the blower fan (14) are arranged,
The blower fan (14) includes an axial-flow fan (26) and a DC motor (27) that rotationally drives the fan (26).
The blower fan (14) is directed to the wind guide frame (13) so that the pressurized air from the fan (26) collides with the bottom wall of the cool air circulation passage (6) facing the inlet of the main evaporator (12). flat open showcase in claim 1, wherein is supported at an angle.

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