JP2007078228A - Cold air circulation type show case - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve evaporating coil piping structure for an evaporator capable of controlling the increase of windage and the impairing of cold insulation performance of the evaporator caused by frost formation on an evaporating coil and a fan. <P>SOLUTION: In this cold air circulation type show case wherein a refrigerant is supplied to the fin tube type evaporator 6 of a refrigerating machine mounted in an inside cold air circulation passage through high pressure-side refrigerant piping 10 and an expansion valve 9, and the air exchanging heat with the evaporator is circulated and distributed inside to keep displayed articles cold, an evaporating coil part at an air inlet end side (lower end side of evaporator) of the evaporating coil 6a arranged while meandering over the whole area of the evaporator 6 is a fin-free bare pipe 6a-1, the liquid refrigerant is supplied to the bare pipe through the expansion valve 9, and a piping route of the evaporating coil in the whole evaporator is determined in such manner that a coil part continued from the bare pipe is once led to an air outlet side (upper end side of evaporator) of the evaporator, and then successively arranged while meandering toward the air inlet side, and its terminal end is connected with low pressure-side refrigerant piping 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cold air circulation type showcase intended for an open showcase, and more particularly to a piping structure of an evaporation coil in an evaporator of a refrigerator arranged in a cold air circulation ventilation path of a showcase.

First, for the open showcase, FIG. 3 shows the overall structure of the cool air circulation type showcase. In the figure, 1 is an outer box of a front open type case main body that becomes a heat-insulating housing, 2 is an inner box, 3 is a product display shelf, 4 is a deck pan arranged at the bottom of the cabinet, and 5 is the outer box 1 and inner box 2 , A cold air circulation passage defined between the two, 6 is an evaporator (evaporator) of the refrigerator arranged in the cold air circulation passage 5, 7 is a fan plenum arranged upstream of the evaporator 6, and 8 is an internal fan is there.
With the above configuration, during the cool-down operation of the showcase, the air in the cabinet is circulated as indicated by the arrows in the figure, and the cold air that has become cold due to heat exchange with the evaporator 6 is blown into the cabinet in the course of the circulating ventilation. 3. It is well known that the goods displayed on the deck pan 4 are kept cold.
Here, in order to increase the cooling area in the conventional showcase, a fin tube type evaporation coil is generally adopted as the evaporator 6, and the evaporation coil is connected to the liquid via a high pressure side refrigerant pipe through an expansion valve. Supplying refrigerant.

By the way, in the evaporator of the fin tube type evaporation coil, frost is generated on the surface (low temperature) of the evaporation coil and the fin because the inside air containing moisture passes through the evaporator during the cooling operation. When the amount of frost formation increases and the ventilation path between the fins becomes narrower, the windage loss of the evaporator increases and the circulation ventilation amount in the cabinet decreases, which causes the cooling performance of the showcase to deteriorate. In addition, the showcase periodically repeats the cold insulation operation and the defrosting operation, and during the defrosting operation, the air heated by the heater is sent to the evaporator to remove the frosting of the evaporation coils and the fins.
Therefore, as a measure to prevent the ventilation path from becoming clogged with frost that has formed on the evaporator's evaporator coil and fins during the cool-down operation of the showcase, the evaporator coil particularly at the air inlet end side of the evaporator into which humid air flows. A configuration in which the fin arrangement pitch is widened to prevent clogging of the air passages in this portion with frost has been conventionally known (see, for example, Patent Document 1).

Next, the conventional structure of the above-described evaporator is shown in FIGS. First, in the evaporator 6 shown in FIG. 4, 6a is an evaporation coil, 6b is left and right end plates, 6c is a fin, and the evaporation coil 6a is piped in a zigzag manner between the end plates 6b and fins 6c. 6, the refrigerant introduction side of the evaporation coil 6 piped to the air outlet end side (upper end side of the evaporator 6) is connected to the high-pressure side refrigerant pipe 10 via the expansion valve 9, and piped to the air inlet side (lower end side of the evaporator 6). The end of the evaporation coil is connected to the low-pressure refrigerant pipe 11. Moreover, in this evaporator 6, as shown in the figure, the pitch between the fins is increased by shortening every other fin 6c at the air inlet side end (lower end side of the evaporator 6).
FIG. 5 is a side view of the evaporator actually mounted on the showcase. In the evaporator 6 of the illustrated example, the evaporation coil 6a is divided into two systems, and the evaporation coils of each system are connected via the branch headers 12 and 13, respectively. The high-pressure side refrigerant pipe 10 and the low-pressure side refrigerant pipe 11 are connected in parallel. The expansion valve 9 employs a temperature type expansion valve, and a temperature sensing cylinder 14 connected to the expansion valve 9 is attached to the refrigerant outlet side of the evaporation coil 6 a drawn from the evaporator 6.

With the above configuration, the internal air flows through the inside of the evaporator 6 from the lower side to the upper side as indicated by the arrows of the fan 8 and is cooled to a low temperature by exchanging heat with the surfaces of the evaporation coils 6a and fins 6c. . Further, the moisture contained in the air blown from the inside of the cabinet to the evaporator 6 during this blowing process changes to frost and forms frost on the surfaces of the evaporation coils 6 a and fins 6 c, and the dehumidified air passes through the evaporator 6. Then it will be recirculated into the cabinet.
In this case, the dehumidification of the air proceeds in order from the air inlet side end of the evaporator 6 toward the outlet side end, and the frosting amount of the evaporation coils and fins also increases at the air inlet side portion of the evaporator. In addition, by thinning the arrangement of the fins 6c on the air inlet end side to widen the ventilation gap between the fins, the ventilation path of the evaporator is less likely to be clogged with frost during the cooling operation.
Japanese Utility Model Publication No. 60-68365

By the way, in the conventional evaporator 6 shown in FIG. 4, since the liquid refrigerant is supplied to the evaporation coil 6a from the air outlet end side (the upper end side of the evaporator 6) through the expansion valve 9, the air inlet end side (the evaporator 6). The refrigerant gas almost completely evaporated flows through the coil portion on the end side (the farthest position as viewed from the refrigerant supply end) piped on the lower end side of the gas.
Therefore, the amount of frost and dehumidification at the evaporation coil portion piped on the air inlet end side of the evaporator 6 is not so large, and the air passes through this portion without being sufficiently dehumidified. Therefore, a lot of frost forms on the portion of the evaporation coil on the air outlet side near the supply end of the liquid refrigerant.
For this reason, even if the fin pitch is widened on the air inlet end side of the evaporator as shown in FIG. 4, the function of preventing the clogging of the ventilation path due to frost formation is not sufficiently exhibited when viewed from the whole evaporator. Over time, the air passage between the fins on the air outlet side is narrowed due to frost formation, so that the windage loss of the evaporator increases and high cooling performance cannot be maintained.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and its object is to solve the above-mentioned problems, and to prevent an increase in windage loss and a decrease in cooling performance caused by frosting of the evaporation coil and fan. The purpose is to provide an improved showcase.

In order to achieve the above object, according to the present invention, a refrigerant is supplied to a fin-tube evaporator of a refrigerator arranged in a cold air circulation passage in a warehouse through a high-pressure side refrigerant pipe and an expansion valve, and heat exchange with the evaporator is performed. In a cool air circulation showcase that circulates and blows air into the cabinet to keep the displayed products cool,
Among the evaporation coils meandering over the whole area of the evaporator, the evaporation coil portion connected to the air inlet end side is used as a bare pipe without fins, and a refrigerant pipe on the high-pressure side is connected to the bare pipe to supply refrigerant ( Claim 1).
In addition, the evaporator is arranged vertically with the air inlet facing down and the air outlet facing up, and the evaporation coil piping path of the entire evaporator is the coil part that continues to the bare pipe that is piped to the air inlet end side of the evaporator. Are routed to the air outlet end side of the evaporator, and meandering pipes are sequentially arranged from here to the air inlet side (claim 2).

According to said structure, the liquid refrigerant | coolant supplied to an evaporator through an expansion valve flows through the part of the bare pipe initially piped to the air inlet side end. Therefore, the high-humidity air that contains a lot of moisture and is blown toward the evaporator from the inside of the cabinet is first cooled and dehumidified by exchanging heat with the liquid refrigerant flowing in the bare pipe. In addition, the air dehumidified here flows through the inside of the evaporator while receiving the cooling action from the finned evaporation coil, and is sent to return to the interior from the air outlet end side again.
Therefore, a large amount of frost adheres to the surface of the bare pipe piped to the air inlet end side of the evaporator, but since there is no fin in the bare pipe, there is a possibility that the ventilation path of this part may be clogged by frost. Almost no. And since the air which passed the piping part of the bare pipe is fully dehumidified, the amount of frost which generate | occur | produces in an evaporation coil and a fin on the ventilation path from here to the air outlet end side of an evaporator decreases. Therefore, in the entire evaporator, the ventilation gap between the fins can be extremely narrowed or clogged due to frosting during the cooling operation, thereby suppressing increase in windage loss and deterioration in cooling performance. You can drive with performance.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on the examples shown in FIGS. In the drawing of the embodiment, members corresponding to those in FIG. 4 and FIG.
In the evaporator 6 of the illustrated embodiment, the evaporation coil 6a is piped along the following piping path. That is, the evaporation coil 6a connected to the high-pressure side refrigerant pipe 10 via the expansion valve 9 pipes the first one turn to the air inlet end side (lower end side of the evaporator) of the evaporator 6 while keeping the bare pipe 6a-1. The coil pulled out from the end plate 6b is routed outward of the evaporator 6 to rise to the air outlet side end (upper end side of the evaporator), and between the fins 6c arranged at a constant pitch between the left and right end plates 6b from here. The pipes are formed in a meandering manner (zigzag) and connected to the low-pressure side refrigerant pipe 11. In FIG. 2, the arrows in the figure indicate the direction of refrigerant flow.

Due to the piping path of the evaporation coil 6a described above, the liquid refrigerant supplied to the evaporator 6 from the high-pressure side refrigerant pipe 10 through the expansion valve 9 during the cool-down operation of the showcase is the bare pipe 6a-1 first piped to the air inlet end side. Here, the air (containing a lot of humidity) blown from the inside of the warehouse through the circulation ventilation path 5 shown in FIG. 3 and flows into the evaporator 6 exchanges heat with the liquid refrigerant flowing in the bare pipe 6a-1. It receives strong cooling and dehumidifying action. As a result, a large amount of frost is formed on the bare pipe 6a-1 piped on the air inlet end side of the evaporator 6; Absent.
Further, the refrigerant flowing through the bare pipe 6a-1 flows down through the evaporation coil 6a meandering downward from the upper air outlet end side along the illustrated piping path, and the low pressure side refrigerant pipe from the end thereof. In this process, the air is cooled to a low temperature by exchanging heat with the circulating air flow passing through the inside of the evaporator 6. In this case, the air flowing through the evaporator 6 is strongly dehumidified by the heat exchange with the bare pipe 6a-1 when passing through the air inlet end side of the evaporator, and the humidity is reduced. However, there is little possibility that the ventilation gap between the fins 6c becomes extremely narrow due to frosting, thereby increasing windage loss or clogging, and thus the showcase can be kept cold while maintaining high cold insulation performance.

  Note that the evaporator coil 6a of the evaporator 6 disposed vertically in the circulation passage of the showcase is once raised upward as shown in the illustrated piping path and piped to the evaporator 6 through the high-pressure refrigerant pipe 10. Even if refrigeration oil is mixed in the refrigerant to be supplied, the refrigerant is discharged from the evaporator in association with the flow of the refrigerant. .

The figure showing the piping path | route of the evaporation coil of the evaporator by the Example of this invention The side view which shows the arrangement structure of the evaporator corresponding to FIG. Overall configuration of open showcase The figure showing the piping route of the evaporation coil of the evaporator mounted in the conventional showcase The side view which shows the arrangement structure of the evaporator corresponding to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body case of a showcase 5 Cold air circulation ventilation path in the chamber 6 Evaporator 6a Evaporating coil 6a-1 Bare pipe 6c Fin 8 Fan in the chamber 9 Expansion valve 10 High pressure side refrigerant piping 11 Low pressure side refrigerant piping

Claims (2)

Supply refrigerant to the finned-tube evaporator of the refrigerator placed in the cold air circulation passage in the refrigerator through the high-pressure side refrigerant piping and expansion valve, and circulate and blow low-temperature air heat-exchanged with the evaporator into the refrigerator to display products. In the cool air circulation showcase to keep cool,
Among the evaporation coils meanderingly piped to the evaporator, the evaporation coil piped on the air inlet end side is used as a bare pipe, and a refrigerant is supplied by connecting a high-pressure side refrigerant pipe to the bare pipe. Cold air circulation showcase. 2. The showcase according to claim 1, wherein the evaporator is arranged vertically with the air inlet facing down and the air outlet facing up, and the coil portion following the bare pipe piped on the evaporator air inlet end side is connected to the evaporator air. A cold air circulation showcase, characterized in that it is routed to the outlet end side, and meandering pipes are sequentially arranged from here to the air inlet side.

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