JPH07101136B2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The refrigeration system of the present invention is used for indoor cooling of refrigerated warehouses and other structures.

[Prior art and its drawbacks] In a refrigerating device of a means for supplying high-pressure, high-temperature refrigerant gas (hot gas) from a compressor to a cooler as defrosting for the cooler, while the cooler is being defrosted, The refrigerant gas cooled to the above temperature is condensed and causes a liquid back phenomenon, which causes damage to the compressor.

[Object of the present invention] The object of the present invention is that in a refrigerating apparatus that performs defrosting with hot gas, the liquid that has passed through the cooler during defrosting is not re-evaporated and the liquid back phenomenon does not occur.
Moreover, since the re-evaporation of the refrigerant from the cooler is performed by heat exchange with the hot gas from the compressor, the structure of the re-evaporating exchange section can be simplified, and the capacity of the cooler during the cooling operation can be improved. Is to be able to improve.

[Configuration of the Present Invention] In the refrigerating apparatus according to the present invention, during the cooling operation, the refrigerant from the compressor is sent to the cooler via the high pressure gas pipe, the condenser, the liquid sending pipe, the first opening / closing valve, and the expansion valve. The refrigerant from the cooler is sucked into the compressor through the suction pipe having the second opening / closing valve,
Further, during the defrosting operation, the refrigerant from the compressor passes through the hot gas pipe branched from the high pressure gas pipe, and then passes through the liquid feed pipe and the fourth opening / closing valve of the bypass pipe provided in parallel with the liquid feed pipe. In the refrigerating apparatus fed into the cooler, the liquid pipe is branched from the primary side of the second opening / closing valve in the suction pipe from the main cooler, and the liquid pipe is connected to the precooler,
Moreover, the liquid pipe is provided with a fifth on-off valve and an expansion valve that are opened during the defrosting operation of the cooler, and the refrigerant outlet of the pre-cooler is connected with a return pipe to the secondary side of the on-off valve of the suction pipe.
A bypass pipe connected to the secondary side of the expansion valve in the precooler liquid pipe is provided from the liquid supply pipe, and a sixth opening / closing valve that is opened during defrosting operation of the precooler is provided in the bypass pipe. And a part of the suction pipe on the downstream side of the connection between the return pipe from the precooler and the suction pipe and a part of the liquid delivery pipe are in parallel contact with each other to form a heat exchange part. is there.

EXAMPLES One example of the present invention will be described below with reference to a specific example shown in the accompanying drawings.

In the figure, reference numeral 1 is a compressor, and refrigerant gas from the compressor is sent to a condenser 3 by a high-pressure gas pipe 2, and the liquefied refrigerant liquid passes through a first opening / closing valve V ₁ of a liquid sending pipe 4. Expansion valve EV
_It is blown into the cooling coil 5a of the main cooler 5 from ₁ .

The first on-off valve V ₁ is a valve that is opened during the cooling operation and closed during the defrosting operation.

The refrigerant vapor leaving from the cooler coil 5a is in the cooling operation is sucked from the suction pipe 6 having a second on-off valve V ₂ which is opened to the compressor 1.

A hot gas pipe 7 having a third defrosting on-off valve V ₃ that is closed during the cooling operation but is opened during the defrosting operation branches off from the high-pressure gas pipe 2.
Is connected to the liquid delivery pipe 4.

Further, a defrosting bypass pipe 8 that straddles the first on-off valve V ₁ and the expansion valve EV ₁ is provided in parallel in the liquid feed pipe, and this bypass pipe is
A fourth opening / closing valve V ₄ for defrosting, which is closed during the cooling operation but opened during the defrosting operation, is provided.

In the apparatus as described above, the present invention is to remove the liquid pipe 9 by branching the liquid pipe 9 from the primary side of the second on-off valve V ₂ in the suction pipe 6 connected to the outlet of the cooler. Connected to the coil 10a of the precooler 10 for frost, and the liquid pipe 9
Although it closed during the cooling operation in a fifth on-off valve V ₅ that opens during the defrosting operation, is provided with an expansion valve EV ₂ which follow,
The outlet of the coil 10a of the precooler is connected to the secondary side of the on-off valve V ₂ in the suction pipe 6 by a return pipe 11.

Further, a bypass pipe 12 connected to the inlet side of the coil 10a of the precooler is provided from the primary side of the first on-off valve V ₁ in the liquid supply pipe 4, and this bypass pipe 12 is used for defrosting. A sixth on-off valve V ₆ is provided which is open (and therefore closed during the cooling operation).

Further, in the present invention, a part of the suction pipe 6 is in parallel contact with a part of the liquid supply pipe 4 to form the heat exchange part 13.

The heat exchange section 13 binds the liquid supply pipe 4 and the suction pipe 6 with a band 14 and covers the surroundings with a heat insulating material 15.

The operation of the apparatus of this embodiment is carried out as follows.

Cooling operation of this cooler During the cooling operation, the on-off valves V ₁ and V 2 shown in Figs. ₁ and ₂ are open, and the other on-off valves V ₃ , V ₄ , V ₅ and V ₆ are closed.

Therefore, the refrigerant from the compressor enters the coil 5a of the cooler 5 through the condenser 3, the on-off valve V ₁ and the expansion valve EV ₁ as shown by the solid arrow, and the on-off valve V ₂ opens for the refrigerant from the cooler. It is sucked into the compressor through the suction pipe 6 that is present.

Third during defrosting operation the operation of the cooler, fourth, fifth on-off valve V _3, V _4, V ₅ is opened, first, second, on-off valve V _1, V ₂ of the 6, V ₆ Is closed.

Therefore, the high-temperature and high-pressure hot gas from the compressor does not pass through the condenser 3 as shown by the broken line arrow, but passes through the defrosting fourth opening / closing valve V ₄ of the defrosting side pipe 8 and enters the coil 5a of the cooler. , Thereby defrosting the coil.

Refrigerant liquid leaving the coil 5a of the cooler pre-cooler 10 from the expansion valve EV ₂ through the fifth on-off valve V ₅ that is the open (hot gas is cooled liquefied by defrosting refrigerant) is liquid pipe 9 Is blown into the coil 10a, re-evaporated, and the precooler is cooled.

The evaporative refrigerant exiting the coil 10a of the precooler is returned to the return pipe 11,
Although it is sucked into the compressor 1 through the suction pipe 6, it is heated by the hot gas from the compressor in the heat exchange section 13 while passing through the suction pipe 6, and is thereby sufficiently vaporized.

Therefore, the refrigerant from the precooler is gasified and sucked into the compressor, and does not liquid back.

Defrosting operation of precooler After defrosting of this cooler is completed, the precooler is subsequently defrosted (since frost is generated in the precooler during the defrosting operation of this cooler).

Third In this case, the sixth on-off valve V _3, V ₆ is opened, the other on-off valve _{V 1, V 2, V 4} , V 5 is closed.

Thus, the hot gas from the compressor, as the chain line arrow 2 dot third on-off valve V _3, the bypass pipe 12 is fed to the sixth on-off valve V ₆ through to pre cooler coils 10a, defrosting of the coil Is performed.

The refrigerant from the pre-cooler is sucked into the compressor through the return pipe 11 and the suction pipe 6, but in this case as well, it is heated and vaporized by the hot gas from the compressor in the heat exchange section 13 to be liquid-backed. Not sucked into the compressor.

[Effect] According to the present invention, since the precooler performs the cooling operation during the defrosting operation of the main cooler, it is possible to prevent the temperature of the air-conditioning room from rising during the defrosting operation of the main cooler as much as possible.

When defrosting this cooler or pre-cooler, this cooler,
The refrigerant discharged from the precooler is heated and vaporized by the hot gas from the compressor in the heat exchange section, so that there is no risk of liquid backing and the compressor can be operated safely.

Further, during the cooling operation, the refrigerant liquid from the condenser is pre-cooled in the heat exchange section by the low temperature refrigerant passing through the suction pipe, so that the cooling capacity of the cooler is improved.

Further, since the heat exchange section is such that a part of the liquid supply pipe and a part of the suction pipe are in parallel contact with each other, and the contact part is covered with a heat insulating material as needed, the structure is simple. Therefore, it is not necessary to provide another device for preventing liquid bag, and the cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is an overall view showing an example of an apparatus according to the present invention, and FIG. 2 is a sectional view of a heat exchange section. In the figure, 1 ... Compressor, 2 ... High-pressure gas pipe, 3 ... Condenser, 4 ... Liquid supply pipe, 5 ... Cooler, 5a ... Coil, 6 ... Suction pipe, 7 ... Hot gas pipe, 8 ... … Bypass pipe, 9 …… Liquid pipe 10 …… Precooler, 10a …… Coil 11 …… Return pipe, 12 …… Bypass pipe 13 …… Heat exchange part, 14 …… Band 15 …… Insulation material, V _1- V ₆ ...... Open / close valve EV ₁ , EV ₂ ...... Expansion valve

Claims (1)

[Claims] 1. During cooling operation, the refrigerant from the compressor is sent to the main cooler through the high pressure gas pipe, the condenser, the liquid sending pipe, the first on-off valve and the expansion valve, and the refrigerant from the cooler is on the second on-off valve. And a side provided in parallel with the liquid feeding pipe through the hot gas pipe in which the refrigerant from the compressor is sucked from the suction pipe having the In a refrigeration system in which the liquid is fed to a main cooler through a fourth open / close valve of a passage pipe, a liquid pipe is branched from a primary side of the second open / close valve in a suction pipe from the main cooler, and the liquid pipe is precooled. Further, the liquid pipe is provided with a fifth on-off valve and an expansion valve which are opened during the defrosting operation of the cooler, and the refrigerant outlet of the pre-cooler has a return pipe on the secondary side of the on-off valve of the suction pipe. Connected to the pre-cooler from the liquid delivery pipe. -A side pipe connected to the secondary side of the expansion valve in the liquid pipe for use is provided with a sixth opening / closing valve that opens during defrosting operation of the precooler, and a return pipe from the precooler. A refrigerating apparatus comprising a part of the suction pipe and a part of the liquid feed pipe, which are located on the downstream side of the connection between the suction pipe and the suction pipe, in parallel with each other to form a heat exchange part.