JP2604326Y2 - Refrigerator cooler - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chiller for a multi-stage refrigeration system in which a plurality of chillers are connected in multiple stages, and more particularly to a chiller improved so that efficient defrosting can be performed.

[0002]

2. Description of the Related Art Recently, the frozen storage temperature of fresh fish such as tuna has become extremely low at -60.degree. C. to -70.degree.
In order to cool the storage of fresh fish to such a low temperature, a multi-component freezer is used.

In this multi-stage refrigeration apparatus, the condenser of the high-side refrigerator is cooled by cooling water, and the high-side cooling coil condenses the refrigerant gas discharged from the compressor of the low-side refrigerator. By connecting to a condenser and connecting a plurality of refrigerators by a heat exchanger, the heat load of a freezer or the like can be cooled to a very low temperature by a lower cooler.

By the way, in such a multi-unit refrigeration system, defrosting of a cooler is mainly performed by an electric heater or sprinkling defrost, and even in the case of using a hot gas defrost, a low element side contributing to cooling is used. Was performed only by the heat source of the refrigerant.

[0005]

By the way, when defrosting is performed only by the heat source of the lower refrigerant (Freon 13, Freon 23 or other refrigerants), the nature of the lower refrigerant causes the refrigerant to be defrosted. Since only the sensible heat portion can be used, particularly in an apparatus using a large-sized cooler, problems such as poor defrost and a long defrost time occur.

This is due to the following reasons. The condensing temperature of the low element side refrigerant is generally about -25 ° C., and if it is to be used up to the latent heat side, the melting temperature of frost is 0%.
This is because it is not available for defrosting because it is lower than ℃.

In the two-way refrigeration system and the three-way refrigeration system, the air temperature is usually −70 ° C. or lower in many cases, and a defrost defect and a long defrost time are required due to the supply amount and temperature of the hot gas. This leads to problems such as an increase in the internal temperature.

The present invention has been proposed in order to solve such problems of the prior art, and it is an object of the present invention to provide a cooler for a multi-stage refrigeration system capable of efficiently performing defrost in a short time. Aim.

[0009]

According to one aspect of the present invention in order to achieve the object, a plurality of refrigerators, <br/> the cooler of a multiple refrigeration system connected in multiple stages in cascade condenser which forms a condenser There it is connected to the discharge side of the compressor of the high-stage-side, the hot gas feed pipe provided with a solenoid valve in the middle part, and the drain pan heating coil disposed on at least a minimum root side of the cooler, the cold <br / > heating only coil provided in the cooling coil bottom of却器, and heating only coil provided on the cold air suction side of the <br/> cooling coil,
A heating-only coil provided on the cold air blow side of the cooling coil,
In this order , place the heating-only coil in the proper location between the cooling coils.
And the outlet of the heating coil provided between the cooling coils is connected to the suction side of the compressor on the higher side via a defrost heat exchanger, so that the solenoid valve is opened during the defrost operation.
Formed by the compressor discharged from the high-pressure side compressor.
The drain gas rises from the hot gas supply pipe to the drain pan.
After passing through the warm coil, the lower part of the cooling coil
Heating, blow-out side, and cooling coil
Through the chiller in this order to ensure that the cooler is defrosted.
The configuration is as follows .

[0010]

According to the above-described structure, the hot gas discharged from the compressor on the high-end side is first sent to the drain pan heating coil to warm the drain pan, and then the heating-only coil below the cooling coil and the cold air suction side. The heating coil is sent in the order of the heating coil and the heating coil on the side of the cool air blowout, and finally passes through the heating coil between the cooling coils to heat the cooler. From the part that becomes
As described above, the heat of the hot gas is effectively used, and defrosting is performed efficiently.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a cooling device of a multi-stage refrigeration apparatus according to the present invention. FIG. 1 is a system diagram showing an embodiment of a multi-stage refrigeration apparatus configured as a binary refrigeration system. In this figure, a discharge pipe extending from a high-stage compressor 1 on the high side is connected to a water-cooled condenser 2, and the outlet of the condenser 2 is connected via an expansion valve 3 to a cascade condenser 4.
Connected to the condensing coil 4a. The outlet of the condensing coil 4a is connected to the high-stage compressor 1 by a suction pipe.

Further, the discharge pipe of the lower compressor 5 on the lower side is:
The cascade condenser 4 is connected via an oil separator 6, and the outlet of the condenser 4 is connected via an expansion valve 7 to a cooling coil 8 a of a cooler 8. This cooling coil 8a
Is connected to the low-pressure compressor 5 by a suction pipe via a liquid separator 9 and a suction pressure regulating valve 10. Note that reference numeral 1
Reference numerals 1 and 12 are pressure protection containers.

Next, a connection system for defrost will be described. The discharge port of the high-pressure compressor 1 is provided with a hot gas supply pipe 14 provided with a hot gas supply solenoid valve 13 in the middle part.
As shown in FIG. 2, the coil is connected to drain pan heating coils 19a, 19b installed outside the drain pan 22 of the cooler 8 in order, and the outlet of the coil 19b is installed inside the cooler 8 so as to surround the cooling coil 8a. A lower heating coil 19c, a lower heating coil 19d,
The heating only coil 19e of the cold air blowing portion and the heating only coil 19f arranged at an appropriate position between the cooling coils are connected in series in this order.

The heating-specific coils 19a, 19b, 1
9c, 19d, 19e and 19f are schematically indicated by stars, and the outlet of the heating coil 19f therein is connected to a defrost air heat exchanger 18 via a refrigerant flow control valve 17, and this heat exchanger 18 May be connected to the suction pipe of the high-pressure compressor 1, and the heat exchanger 18 may be configured by another method other than the pneumatic type.

Reference numeral 15 in FIG. 2 denotes an air inlet, 16 denotes a cool air outlet, and P denotes a blowing direction.

When the heating-dedicated coils 19d, 19e, and 19f that do not contribute to cooling are installed before and after the cooling coil 8a and inside the coil, there is a concern that the airflow resistance to the cooling fan 23 driven by the motor 24 increases. However, in order to minimize the increase in resistance, the cooling coil 8a and the heating coil 1
9d, 19e and 19f are arranged.

Conventionally, coils are often arranged in a staggered manner in terms of cooling efficiency, but in this cooler 8, the coils 8a, 19d, 19e, and 19f are arranged in parallel. Further, the heating coil 19 is inserted into the cooling coil 8a.
The arrangement of “f” was unevenly arranged at intervals of about 1 to 3 rows. As a result, an increase in the airflow resistance with respect to the cooling fan 23 could be reduced. Specifically, the increase in the airflow resistance is 1 compared to the case where the heating coil is not provided.
It can be increased from 2.3 mmAq to 13.6 mmAq, and the cooling efficiency does not decrease.

Next, the place where the heat insulating material provided in the cooler 8 is applied will be described. As shown in FIG. 3, the upper plate 20a and the side plate 2 of the outer plate 20 of the cooler 8 are used in the cooler 8 in order to make effective use of precious heat during defrosting.
0b and heat insulating materials 25 on both surfaces of the intermediate support plate 21.
a, 25b, and 25c are stuck on each other, and a heat insulating material 25d is placed inside the drain pan 22.

In the multi-unit refrigeration system configured as described above,
During the refrigeration operation, the gas refrigerant from the high-pressure compressor 1 is condensed by the cooling water in the condenser 2, and the liquid refrigerant flowing out of the condenser 2 passes through the expansion valve 3 to the coil 4 a of the cascade condenser 4.
To evaporate in the coil 4a. The gas refrigerant from the low-pressure compressor 5 is condensed by this evaporative action, and the liquefied refrigerant is sent to the cooling coil 8a via the expansion valve 7, so that the cooler 8 cools the heat load of a freezing warehouse or the like. Done.

In such a multi-stage refrigerator, the heat taken by the low-stage refrigerator becomes the heat load of the high-stage refrigerator, so that the cooling temperature of the cooler 8 on the low-stage refrigerator is set to an extremely low temperature. Can be.

On the other hand, at the time of defrosting, the heat source (condensation temperature + 40 ° C.) of the high-side refrigerant composed of Freon 22 and other refrigerants
The defrosting is performed by using. At this time, the hot gas refrigerant that has exited the high-pressure compressor 1 as shown by the dashed arrow indicates the flow of the refrigerant, passes through the solenoid valve 13 and enters the hot gas supply pipe 14, and is cooled to improve defrosting efficiency. Amount of frost in the vessel
Heating coil and heating coil installed in the area where
After first being sent to the drain-pan heating coils 19a and 19b to warm the drain pan 22, a heating-only coil 19c below the cooling coil, a heating-only coil 19d on the cold-air suction side, and a cool-air blowing side are also provided. , And finally reaches the heating coil 19f between the cooling coils. Thereby, these parts are usually heated from 10 ° C. to 15 ° C. to perform defrosting. The refrigerant liquid condensed at the time of defrost is depressurized by the refrigerant flow control valve 17 after leaving the heating exclusive coil 19f, and is supplied to the defrost air heat exchanger 18. The refrigerant evaporated and gasified in the heat exchanger 18 is returned to the high-pressure compressor 1 by a suction pipe.

As described above, at the time of defrosting, the cooling coil 8a is heated so as to be wrapped from the part facing the outside, and finally the inside of the coil is heated. I can do it.

Further, since the heat insulating material is also attached to the inner surface of the outer plate 20 of the cooler 8 and the portion of the intermediate support plate 21,
The heat source for defrosting hardly escapes to the outside, and defrosting is performed efficiently even at an extremely low temperature of -70 ° C.

In the above-described embodiment, the high-stage compressor 1
The defrosting of the cooler 8 is performed using only the hot gas discharged from the compressor, but by connecting the low-pressure compressor 5 and the inlet of the cooling coil 8a with a hot gas supply pipe via an electromagnetic valve. Defrosting using hot gas from the low-pressure compressor 5 is also possible.

Further, the present invention is not limited to a two-way refrigeration system, but can be applied to a three-way refrigeration system including a low-stage chiller, a middle-stage chiller and a high-stage chiller.

[0026]

As described above, according to the present invention , not only the hot gas on the high side where the condensation temperature is high (for example, + 40 ° C.) can be used for defrosting, but also the cooling.
Hot gas is generated in the vessel in order from the part with the largest amount of frost.
Passed. In other words, a large part of the amount of frost
Degassing is performed by the gas, and the part with the large amount of frost
After defrosting the part, defrost the part with the smaller amount of frost sequentially
Therefore, the heat of the hot gas can be used effectively,
The frost can be reliably and sufficiently performed.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of a multiple refrigerating apparatus according to the present invention.

FIG. 2 is a cross-sectional view taken along line AA of FIG. 3, showing an arrangement of a heating-only coil in a cooler through which hot gas from a high-pressure compressor is passed.

FIG. 3 is a layout diagram of a heat insulating material in a cooler included in the multi-stage refrigeration apparatus of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High-stage compressor 2 Water-cooled condenser 3, 7 Expansion valve 4 Cascade condenser 4a Condensing coil 5 Low-stage compressor 6 Oil separator 8 Cooler 8a Cooling coil 9 Liquid separator 10 Suction pressure regulating valve 11, 12 Pressure protection container 13 Solenoid valve for hot gas supply 14 Hot gas supply pipe 15 Suction port 16 Cold air outlet 17 Refrigerant flow control valve 18 Defrost air heat exchanger 19a, 19b Drain pan heating coil 19c, 19d, 19e Heating coil 20 Outer plate 21 Middle Support plate 22 Drain pan 23 Cooling fan 24 Motor 25a, 25b, 25c, 25d Thermal insulation

Claims (1)

(57) [Scope of request for utility model registration] The method according to claim 1] plurality of the refrigerator, condenser <br/> Oite condenser multiple refrigeration system connected in multiple stages in cascade condenser which forms a connected to the discharge side of the compressor of the high-stage-side, in the hot gas feed pipe provided with a solenoid valve in the middle part, and the drain pan heating coil disposed on at least a minimum root side of the cooler, a heating only coil provided in the cooling coil under the cold <br/>却器, and heating only coil provided on the cold air suction side of the <br/> cooling coil,
A heating-only coil provided on the cold air blow side of the cooling coil,
In this order , place the heating-only coil in the proper location between the cooling coils.
And the outlet of the heating coil provided between the cooling coils is connected to the suction side of the compressor on the higher side via a defrost heat exchanger, so that the solenoid valve is opened during the defrost operation.
Formed by the compressor discharged from the high-pressure side compressor.
The drain gas rises from the hot gas supply pipe to the drain pan.
After passing through the warm coil, the lower part of the cooling coil
Heating, blow-out side, and cooling coil
Through the chiller in this order to ensure that the cooler is defrosted.
Cooler multiple refrigeration system comprising Te.