JPH06105147B2 - Low temperature showcase - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a low temperature showcase in which a forward / reverse blower fan and two evaporators are provided in a passage.

(B) Conventional technology JP-A-57-47176 (F25D21 / 06) and JP-A-58-178176
In Japanese Patent Publication (F25D21 / 06), a heat insulating wall having an opening for storing and taking out a product on one side and an inner wall of the heat insulating wall are arranged at an appropriate interval and face each other through the opening. A forward and reverse direction supported by a partition plate that forms a passage and a storage chamber in the heat insulating wall, the passage having both ends of which one is an outlet and the other is an inlet, and a fan case that divides the passage. It is possible to provide a blower fan and two evaporators, which are arranged between the fan case and the both vents, respectively, and one of which is a defrosting operation when the other is a cooling operation. A low temperature showcase is disclosed in which, during defrosting operation, the evaporator is defrosted with the high temperature refrigerant that has passed through the condenser.

(C) Problems to be Solved by the Invention In the above conventional technique, both evaporators that are alternately cooled are provided with an evaporation pipe that evaporates and vaporizes the decompressed refrigerant, and a defrost pipe that allows the high-temperature refrigerant to pass therethrough, respectively. During defrosting of one evaporator, the temperature of the air passing through the evaporator during defrosting is high to heat the entire evaporator with the defrost pipe, which causes a refrigerating load on the evaporator during cooling, and the storage room Does not fall to a predetermined temperature, and because the high-pressure refrigerant flows through the defrosting pipe to defrost regardless of the outside air temperature, the temperature of the evaporator during cooling rises significantly. When switching from cooling to defrosting, the defrosting time is prolonged due to the residual liquid refrigerant in the evaporation tube, and there is also a problem that the evaporator is running out of refrigerant during cooling. .

(D) Means for Solving the Problems The present invention not only solves the above problems, but also defrosts two evaporators alternately using an electric heater,
The low temperature showcase of the present invention has a heat insulating wall formed with an opening for storing and taking out products on one surface thereof in order to efficiently defrost ice burns on the bottom wall of the heat insulating wall. And a partition plate having a pair of vents at opposite ends with the pair of vents facing each other across the opening and forming a storage chamber therein, and the passages having the vents. In the passage, there are a fan case divided into front and rear, two evaporators arranged between the fan case and the both vents and alternately cooled, and an evaporator under cooling operation in the passage. A blower fan capable of forward and reverse operation that is blown so as to be on the downstream side of the other evaporator, and provided in each of the evaporators on the air inlet side that is on the windward side when the evaporator is not cooled. Electric heater A and each of the evaporators And the electric heater B provided on the air outlet side that is on the leeward side during the non-cooling operation of the evaporator, the electric heater A having a larger calorific value than the electric heater B, and the electric heater. B is provided at a position lower than the mounting position of the electric heater A and near the bottom wall of the heat insulating wall.

(E) Action According to the embodiment, when the blower fan (9) is normally rotated to cool the evaporator (11), the electric heater (14A) (1
Since the evaporator (12) defrosted from (4B) is on the windward side of the evaporator (11), the circulating air flow is the evaporator (12).
After passing through the evaporator, it is cooled by the evaporator (11) and becomes a cool air flow. When the blower fan (9) is reversed to cool the evaporator (12), the electric heaters (13A) (13B) are used. Since the evaporator (11) to be defrosted is on the windward side of the evaporator (12), the circulated air flow is cooled by the evaporator (12) after passing through the evaporator (11) and is cold. It becomes an air flow.
This air flow is generated by electric heaters (13A) (13B), (14A) (14
Although it is heated in B), the latent heat is removed to remove the frost, and therefore the temperature does not rise so much even when passing through the evaporators (11) and (12). Therefore, of the electric heaters (14A) (14B) that are energized during the cooling operation of one evaporator (11), the electric heater (14A) as the electric heater A that generates a large amount of heat is the evaporator during the defrosting operation. The electric heater (14B) as the electric heater B, which has a function of heating the entire evaporator (12) from the windward side of (12) to defrost it and has a small amount of heat generation, is used during the cooling operation of the evaporator (12). In addition to heating the surface that becomes the air inlet surface and has the largest amount of frost, the electric heater B is located at a position lower than the mounting position of the electric heater A and near the bottom wall of the heat insulating wall. Since it is provided, when an ice burn is formed on the bottom wall of the heat insulating wall (3), it also has a function of defrosting by heating this ice burn, and both electric heaters (14A) (14B) The defrosting from both sides of the evaporator (12) can be done and the defrosting time can be shortened. It The evaporator (1
During the defrosting operation of 1), the electric heaters (13A) (13B) also perform the same function.

(F) Example An example of the present invention will be described below with reference to the drawings.
The (1) shown in the figure is an open type low temperature showcase in which the main body is composed of a heat insulating wall (3) having an opening (2) for storing and taking out products on the upper surface thereof. A vent hole in which a partition plate (4) made of metal is arranged at an appropriate distance from the inner wall and faces each other through the opening (2), and when one becomes an outlet, the other becomes an inlet. A passage (7) having (5) and (6) at both ends and a storage chamber (8) are formed. (9) is a blower fan that is arranged in the bottom area (7A) of the passage (7) and is capable of forward and reverse rotation, and is supported by a fan case (10) that divides the passage (7) into front and rear.
(11) and (12) are the bottom area (7A) of the passage (7) between the air vents (5) and (6) and the fan case (10).
In the plate fin type evaporators, each of which is arranged so as to incline low toward the blower fan (9), when one evaporator is in cooling operation, the other evaporator stops cooling operation. That is, the cooling operation is alternately performed by a timer (not shown) at a predetermined cycle. Then, the other evaporator is defrosted by an electric heater as described later while the cooling operation is stopped.

(13A) and (13B) are electric heaters for defrosting provided at the air inlet and air outlet of the evaporator (11), and are energized when the evaporator (11) is defrosted. The electric heater (13A) as the electric heater A provided on the surface which becomes the air inlet surface during defrosting of the evaporator (11) is provided on the surface which becomes the air outlet surface during defrosting of the evaporator (11). Electric heater as electric heater B (13
Since it is located on the windward side of B) and has a function of heating substantially the entire evaporator (11), it has a larger calorific value than the electric heater (13B). The evaporator (1
During the cooling operation of 1), the surface provided with the electric heater (13A) is the air outlet surface, and the surface provided with the electric heater (13B) is the air inlet surface.

(14A) and (14B) are electric heaters for defrosting provided at the air inlet and air outlet of the evaporator (12), and are energized during defrosting of the evaporator (12). The electric heater (14A) as the electric heater A provided on the surface serving as the air inlet surface during defrosting of the evaporator (12) was provided on the surface serving as the air outlet surface during defrosting of the evaporator (12). Electric heater as electric heater B (14
Since it is located on the windward side of B) and has a function of heating substantially the entire evaporator (12), it has a larger heat generation amount than the electric heater (14B). The evaporator (1
During the cooling operation of 2), the surface provided with the electric heater (14A) is the air outlet surface, and the surface provided with the electric heater (14B) is the air inlet surface.

(15) and (16) are metal covers that cover the upper surfaces of the evaporators (11) and (12), respectively, and the direction of the blower fan (9) according to the inclination of the evaporators (11) and (12). That is, they are inclined so as to become lower toward the fan case (10) side. An end of the blower fan (9), which is the lower end of the evaporator (11), serves as an air outlet surface of the evaporator when the evaporator is defrosted, that is, an electric heater ( 13B), and in the evaporator (12), they extend in the direction of the blower fan (9) from the surface on which the electric heater (14B) is provided. Further, the lower end of the blower fan (9) side is bent downward at a position slightly separated from the air outlet surface at the time of defrosting of each evaporator, and the water section (15A) (16A ) Has been made. This cover (15) (16) acts as a wind vane, and most of the air flow passing through the bottom area (7A) of the passage (7) is from the air inlet surface of both evaporators (11) (12). It is designed to flow toward the air outlet surface, that is, to impart straightness to the air flow. Reference numeral (17) denotes a fan case (10) and a metal directing plate that covers an upper part of air between the fan case and the evaporator (12), and the evaporator (11) reverses the blower fan (9). When defrosting, the air flow that has passed through the blower fan (9) is directed toward the evaporator (12) that is being cooled, and this effect causes the air flow to flow to the bottom wall of the partition plate (4). It is possible to avoid spreading when hit. One end of the directing plate (17) is attached to the fan case (10), and the other end is attached to the cover (16).
Reference numerals (18) and (19) denote one end of the fan case (10) in contact with the cover (15) and a directing plate (1) in contact with the cover (16).
In the drainage channel formed at the other end of 7), the both evaporators (11)
The dew generated on the upper surfaces of the covers (15) and (16) when one of the (12) is defrosted is removed from the water section (15A).
Take you to (16A). (20) is a drain port formed in the bottom wall of the heat insulating wall (3), which is covered with the cover (15) and the direction plate (17) and is located near the electric heater (13B). is doing. Numerals (21) and (22) are rectifying devices provided in the ventilation holes (5) and (6) respectively, and when the ventilation holes (5) and (6) are outlets, openings (2) as shown by arrows in FIG. Rectifies the air flow that is blown out to form the air curtain.

(23) is a machine room formed below the heat insulation wall (3), and constitutes a refrigeration cycle with the both evaporators (11) and (12), a refrigerant compressor (24), a condenser (25) and a blower. A fan (26) is stored and installed. The refrigeration cycle is the third
Evaporator (11) (12) and solenoid valve (27) (28) as shown
And the expansion valves (29) and (30) are connected in series in two systems, and both systems are connected in parallel with each other. Incidentally, (31)
Is a liquid receiver, and (32) is a gas-liquid separator.

The solenoid valves (27) (28) are opened and closed by a timer (not shown) as described above, and the electric heaters (13A) (13B)
The following controls are performed in association with (14A) (14B) and the blower fan (9).

That is, for example, when the solenoid valve (27) is opened, the solenoid valve (2
8) is closed, and at the same time, the electric heaters (14A) and (14B) are energized, and the blower fan (9) is normally rotated. At this time, the air flow circulating in the passage (7) flows as shown by the solid line arrows in FIGS. 1 and 2, and the evaporator (11) is cooled and the evaporator (1)
2) is defrosted by electric heaters (14A) and (14B).

Then, when, for example, 2 hours have elapsed since the cooling operation of the evaporator (11) was started, the solenoid valve (28) is opened and the solenoid valve (27) is opened.
Is closed, and at the same time, the electric heaters (13A) and (13B) are energized and the blower fan (9) is reversed. At this time, the air flow circulating in the passage (7) flows as shown by the chain line arrow in FIG. 1 and FIG. 2, the evaporator (12) is cooled, and the evaporator (11) is cooled.
Is defrosted by electric heaters (13A) (13B).

Then, thereafter, this operation is alternately repeated to continue the operation. The electric heaters (13A) (13B) (14A) (1
4B) is de-energized when the temperature switch (33) provided in the bottom area (7A) of the passage (7) reaches 8 ° C.

According to the above configuration, when the blower fan (9) is normally rotated to cool the evaporator (11), the electric heaters (14A) (1
The evaporator (12) defrosted by 4B) is the evaporator (11).
Due to the windward side of the
After passing through 2), it is cooled in the evaporator (11) to form a cold air flow, and the blower fan (9) is reversed to move the evaporator (1
When cooling the 2), the electric heater (13A) (13A
The evaporator (11) defrosted by B) is the evaporator (12)
Due to the windward side of the
After passing through 1) it is cooled in the evaporator (12) to a cold air stream. This air flow is an electric heater (13A) (13B),
It is heated by (14A) and (14B), but the latent heat is taken away to remove the frost, and therefore the temperature does not rise so much even though it passes through the evaporators (11) and (12). Therefore, during the cooling operation of one of the evaporators (11), the electric heater (14A) that generates a large amount of heat among the electric heaters (14A) and (14B) that are energized is from the windward side of the evaporator (12) during defrosting. This has the function of heating the entire evaporator (12),
The electric heater (14B), which generates less heat, is the evaporator (12).
Since it was the air inlet surface during the cooling operation, the surface with the largest amount of reverse frost was directly heated,
Since the electric heater B is provided at a position lower than the mounting position of the electric heater A and near the bottom wall of the heat insulating bottom, an ice burn is formed on the bottom wall of the heat insulating wall (3). When this is done, it also acts to defrost by heating this ice burn, and both electric heaters (14A) and (14B) can defrost both sides of the evaporator (12), reducing the defrosting time. . When the evaporator (11) is defrosted, the electric heaters (13A) (13B) also have the same function.

In addition, the frost that adheres to the covers (15) (16) that cover the upper surfaces of the respective evaporators (11) (12) and act as wind direction plates during the cooling operation is removed by the electric heaters (13A) (14A) during defrosting. After being unwound, it flows along the inclination of the covers (15) (16) and extends toward the blower fan (9) rather than the air outlet surface of the evaporators (11) and (12), that is, the air inlet surface during cooling operation. From the water slices (15A) (16A) that come out, it will be dripped directly onto the bottom wall of the heat insulating wall (3) without passing through the surface, which will improve the dew treatment of the covers (15) (16), It is possible to avoid early clogging due to frost on the air inlet surface during the cooling operation of the evaporators (11) and (12) due to the dew of the covers (15) and (16).

(G) Effects of the Invention According to the present invention described above, the effects listed below occur.

During the cooling operation of one evaporator, the other evaporator being defrosted is located on the windward side as viewed from the one evaporator, so the evaporator being defrosted does not touch the outside air at the opening. By heating the air that has entered the passage through the vent after the temperature rises, defrosting can be performed with a small amount of heating heat. Moreover, since the electric heater A, which generates a lot of heat, among the electric heaters therefor is provided on the air inlet side on the windward side as viewed from the evaporator during defrosting, the entire evaporator can be heated to defrost. In addition, the air heated by the electric heater A gradually loses the latent heat for defrosting the frost adhering while flowing from the air inlet side to the air outlet side in the evaporator during defrosting, and its temperature drops. After that, since the cool air that is heat-exchanged by the evaporator during the cooling operation and forms the air curtain at the opening does not affect the heat, the cooling effect of the storage chamber is improved, and a thing with a small refrigerating capacity is used as the evaporator. Can be used.

During the cooling operation of one of the evaporators, the electric heater A, which generates a large amount of heat among the electric heaters that are energized, sufficiently defrosts the entire evaporator from the windward side of the other evaporator during defrosting. Act. In addition, the electric heater B, which generates a small amount of heat,
When the evaporator was in cooling operation, the surface with the largest amount of frost was directly heated and defrosted because it was the air inlet surface, and in addition, the electric heater B was positioned lower than the electric heater A. Moreover, since it is provided in the vicinity of the bottom wall of the heat insulating wall, when an ice burn is formed on the bottom wall of the heat insulating wall, the ice burn is also heated to defrost. Therefore, defrosting from both sides of the evaporator can be efficiently performed with a small amount of heat generated by both electric heaters, the defrosting time can be shortened, and the thermal load on the evaporator during cooling operation can be reduced to reduce the storage room temperature. It is possible to improve the cooling condition and use an evaporator having a small refrigerating capacity.

[Brief description of drawings]

Each of the drawings shows an embodiment of the low temperature showcase of the present invention,
FIG. 1 is an enlarged vertical sectional view of an essential part, FIG. 2 is an overall vertical sectional view, and FIG. 3 is a refrigeration cycle diagram. (2) ... Opening, (3) ... Insulating wall, (4) ... Partitioning plate, (5) (6) ... Vent, (7) ... Passage, (7A)
…… Bottom area, (8) …… Storage room, (9) …… Blower fan, (10) …… Fan case, (11) (12) …… Evaporator, (13A) (13B) (14A) ( 14B) ... Electric heater.

Claims (1)

[Claims] 1. A heat insulating wall having an opening for storing and taking out a product on one surface, and a passage having a pair of vent holes facing each other with the opening at both ends is formed between the inner surface of the heat insulating wall. In addition, a partition plate that forms a storage chamber inside, a fan case that divides the passage into front and rear parts on the side of each of the vents, and a fan case that is disposed between the fan case and the vents and are alternately cooled. In each of the two evaporators, a blower fan capable of forward and reverse operation, in which the evaporator in the cooling operation is blown so that the evaporator is located on the downstream side of the other evaporator in the passage. An electric heater A provided on the air inlet side that is on the windward side during the non-cooling operation of the evaporator, and an electric heater A provided on the air outlet side that is on the leeward side during the non-cooling operation of the evaporator in each of the evaporators. Consisting of heater B,
The electric heater A has a larger amount of heat generation than the electric heater B, and the electric heater B is provided at a position lower than the mounting position of the electric heater A and near the bottom wall of the heat insulating wall. A low-temperature showcase characterized by