JP2000320993A - Fan coil evaporator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fan coil evaporator in which liquefied refrigerant does not drip from into a gas header during when a refrigeration system is not operating and liquid back can be prevented and refrigerating machine oil can be returned smoothly back to a compressor during normal operation of the refrigeration system. SOLUTION: The fan coil evaporator 1 comprises a plurality of parallel rows of cooling coil 2 where the open end of a plurality of horizontal cooling tubes 4 penetrating a large number of radiation fins 3 are coupled sequentially through a U-shaped bend tube 5. A cooling coil 2 is arranged between the horizontal cooling tubes 4 on the refrigerant inlet 2a side and the refrigerant outlet 2b side of each cooling coil by coupling the horizontal cooling tubes at a lower position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fin coil evaporator used for a vapor compression refrigeration system.

[0002]

2. Description of the Related Art A fin coil evaporator used in a vapor compression refrigeration system has a plurality of rows of cooling coils each having a refrigerant inlet and an outlet, which are arranged in parallel. Fins are provided.

As shown in FIG. 4, the cooling coils are connected in a row by connecting the open ends of a plurality of horizontal cooling pipes 32 penetrating the heat radiation fins 31 with a U-shaped bend pipe 33. 34, a refrigerant inlet 34a is provided on the downstream side of the air to be processed, and a refrigerant outlet 34b is provided on the upstream side. A distribution pipe branched from a distributor (not shown) is connected to the refrigerant inlet 34a. On the other hand, each refrigerant outlet 34b is connected to a gas header 35, and the outlet of the gas header is connected to a suction pipe 36 of the compressor.

In a conventional fin coil evaporator, a single row of cooling coils 34 are connected to a horizontal cooling pipe 32 at a lower position from the refrigerant inlet 34a to the outlet 34b.
Is configured so that the refrigerant flows in the cooling coil from top to bottom.

During operation of the refrigeration system, the refrigerant from the refrigerant inlet 34a is vaporized in the cooling coil 34, enters the gas header 35 from the refrigerant outlet 34b, passes through the suction pipe 36, and enters the compressor as a gas refrigerant. When the refrigerating apparatus is stopped, the compressor is kept driven for a predetermined time to suck (pump down) the cooling coil, the gas header, and the refrigerant in the suction pipe, and the liquid is backed up at the time of restart. Prevents refrigerant from flowing into the compressor and damaging the compressor.

However, if the refrigeration system stops abnormally due to a power failure or the like, the pump is not down, and there is a possibility that the liquid may be backed up when the refrigeration system is restarted. In order to prevent the liquid back, an accumulator may be provided between the gas header and the compressor. However, there is a problem that the cost of the apparatus increases and the size of the apparatus increases.

Further, in the fin coil evaporator, the liquid back is prevented by connecting the refrigerant to the horizontal cooling pipe at a higher position from the refrigerant inlet to the refrigerant outlet so that the refrigerant flows inside the cooling coil from the bottom to the top. Although it can be used, when using refrigerating machine oil that is incompatible with the refrigerant and the viscosity of the refrigerating machine oil is relatively high, the refrigerating machine oil accumulates in the evaporator during normal operation and is difficult to return to the compressor. This may cause seizure of the compressor.

[0008]

It is an object of the present invention to prevent liquefied refrigerant from an evaporator from flowing down into a gas header when the operation of a refrigeration system is stopped, thereby preventing liquid backing. Is to provide a fin coil evaporator that can satisfactorily return to the compressor.

[0009]

In order to achieve the above object, in a fin coil evaporator according to the present invention, the opening ends of a plurality of horizontal cooling pipes penetrating a large number of radiating fins are sequentially formed by U-shaped bend pipes. In a fin coil evaporator having a plurality of rows of connected cooling coils in parallel, a lower position than the horizontal cooling pipes between the horizontal cooling pipes on the refrigerant inlet side and the refrigerant outlet side of each cooling coil. Are connected to form the cooling coil.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fin coil evaporator according to the present invention will be described below with reference to a specific example shown in the accompanying drawings. The fin coil evaporator 1 includes a plurality of heat radiating fins 3 outside the cooling coil 2, and the cooling coil 2 connects a horizontal cooling pipe 4 penetrating the heat radiating fin and a horizontal cooling pipe.
It is composed of a bend tube 5 having a V-shape.

The cooling coil 2 has one end of a horizontal cooling pipe located at the most downstream side in the flow direction of the air to be treated as a refrigerant inlet 2a, and the other end connected to one end of another horizontal cooling pipe by the bend pipe. Similarly, a plurality of horizontal cooling pipes are sequentially connected, and one end of the horizontal cooling pipe located on the most upstream side in the flow direction of the air to be processed is set as the refrigerant outlet 2b. In FIG. 2, one cooling coil is composed of six horizontal cooling pipes and five bend pipes.

The refrigerant inlet 2a is connected to the tip of a distribution pipe 6a branched from the distributor 6, and the refrigerant outlet 2b is connected to a gas header 7.

The fin-coil evaporator according to the present invention is provided between the horizontal cooling pipe having the refrigerant inlet 2a and the horizontal cooling pipe having the refrigerant outlet 2b. The horizontal cooling pipe at a lower position is connected, so that the refrigerant flowing from the refrigerant inlet 2a flows from top to bottom once, then flows upward and reaches the refrigerant outlet 2b. In FIG. 2, the two horizontal cooling pipes at the highest position are closed between the front and rear open ends by a bend pipe so that the refrigerant does not flow.

Next, the configuration of the vapor compression refrigeration system including the fin coil evaporator 1 configured as described above will be described with reference to FIG. 3 which shows an example of a specific configuration when the refrigeration system is an ammonia spot cooler. Will be explained.

The ammonia spot cooler shown in FIG. 1 has a compact structure in which a compressor 9, a condenser 10, an evaporator 1 and a blower 11 for cold air are integrated in a casing 8, and a partition wall is provided in the casing. 12 form an air passage 13 to be processed.
The air filter 15, the evaporator 1, and the cool air blower 11 are provided in this order from the suction port 14 side of 3, and the outlet 11 a of the cool air blower 11 faces the outside of the casing 8. Note that the reference numeral 11b in FIG.
Is shown.

A condenser air passage 17 is formed in the casing 8 and divided by a partition plate 16. The condenser air passage 17 has a condensing coil 19 inside an outside air intake 18 opened in the casing. In addition, a condenser blower 21 is provided at an exhaust port 20 also opened in the casing, and the condensation coil 19 is air-cooled by driving the blower.

The refrigerant from the compressor 9 is sent to the condensing coil 19 of the condenser 10 where it is condensed and sent to the distributor 6 via the expansion valve 22. From the distributor 6, the fins are connected by a plurality of distribution pipes 6a. The refrigerant is supplied to a plurality of refrigerant inlets 2a of the coil evaporator 1.

The refrigerant flowing into the cooling coil 2 from the refrigerant inlet 2a is vaporized in the cooling coil 2 to generate cold heat, and the cold heat cools the air to be processed from the suction port 14 so that the cool air blower 11 Is blown out from the outlet. At this time, since a large number of radiating fins 3 are provided around the cooling coil and the contact area with the air to be processed is large, the air to be processed is efficiently cooled.

The refrigerant having passed through the cooling coil 2 flows into the gas header 7 from the refrigerant outlet 2b, and is returned to the compressor 9 by the suction pipe 9a.

In the cooling coil 2, the refrigerant flowing from the refrigerant inlet 2a once flows down into the lower horizontal cooling pipe, evaporates and becomes a gaseous refrigerant, and flows into the higher horizontal cooling pipe. It reaches the exit 2b.

The refrigerating machine oil contained in the refrigerant flows into the cooling coil from the refrigerant inlet 2a together with the refrigerant, flows down once into the lower horizontal cooling pipe, and is blown out to the refrigerant outlet 2b by the flow of the gas refrigerant. The refrigerant is returned to the compressor 9 through the gas header 7 and the suction pipe 9 together with the refrigerant.

When the refrigeration system is stopped, the pump 9 is normally pumped down by the compressor 9 so that the refrigerant does not remain in the evaporator 1. Is not performed, the refrigerant remains in the cooling coil 2 of the evaporator.

In the evaporator of the present invention, the cooling coil 2
The refrigerant remaining in the cooling coil accumulates in the horizontal cooling pipe at a low position between the refrigerant inlet 2a and the outlet 2b, so that the refrigerant in the cooling coil hardly flows down into the gas header 7 or the suction pipe 9a. When the refrigerant is restarted, the liquid bag is prevented from being sucked into the compressor as the liquid refrigerant.

[0024]

In the fin coil evaporator according to the present invention, between the refrigerant inlet and the horizontal cooling pipe on the outlet side,
Since the horizontal cooling pipe at a position lower than these horizontal cooling pipes is connected, even if the refrigeration system stops abnormally due to a power failure or the like, the refrigerant in the cooling coil remains at a lower position between the refrigerant inlet and the same outlet. Pool in the horizontal cooling pipe, and hardly flows down into the gas header or the suction pipe.

Therefore, when the refrigeration system is restarted,
The compressor is not likely to be damaged by the liquid bag in which the liquid refrigerant is sucked into the compressor, and it is not necessary to provide an accumulator, which is usually used for preventing liquid bag, in the suction pipe. Costs can be reduced.

During normal operation of the refrigerating apparatus, the refrigerating machine oil contained in the refrigerant flows into the cooling coil from the refrigerant inlet together with the refrigerant, and once flows down into the lower horizontal cooling pipe to be vaporized in the cooling coil. The refrigerant is blown out to the refrigerant outlet by the flow of the refrigerant, so that the return of the refrigerating machine oil to the compressor can be kept good.

[Brief description of the drawings]

FIG. 1 is a side view of a fin coil evaporator according to the present invention.

FIG. 2 is a front view showing an arrangement of cooling coils of the fin coil evaporator according to the present invention.

FIG. 3 is a longitudinal sectional front view showing an example of an ammonia spot cooler provided with a fin coil evaporator according to the present invention.

FIG. 4 is a front view showing an arrangement of cooling coils of a conventional fin coil evaporator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fin coil evaporator 2 Cooling coil 2a Refrigerant inlet 2b Refrigerant outlet 3 Radiation fin 4 Horizontal cooling pipe 5 Bend pipe 6 Distributor 7 Gas header 8 Casing 9 Compressor 10 Condenser 11 Cold air blower 12 Partition wall 13 Air passage to be treated Reference Signs List 14 suction port 15 air filter 16 partition plate 17 air passage for condenser 18 outside air intake 19 condensing coil 20 exhaust port 21 blower for condenser 22 expansion valve

Claims (1)

[Claims] 1. A fin coil evaporator provided with a plurality of rows of cooling coils arranged in parallel, the opening ends of a plurality of horizontal cooling pipes penetrating a plurality of heat radiation fins being sequentially connected by U-shaped bend pipes. A fin coil evaporator comprising a cooling coil formed by connecting a horizontal cooling pipe at a position lower than both horizontal cooling pipes between the horizontal cooling pipe on the refrigerant inlet side and the horizontal cooling pipe on the refrigerant outlet side of the cooling coil. vessel.