JP3238973B2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for improving the reliability of a refrigeration system having a compressor of a liquid injection cooling system.

[0002]

2. Description of the Related Art For a refrigerating apparatus using a compressor of a rotary scroll screw type or the like having a large compression ratio, a liquid injection cooling system is adopted in order to suppress a rise in the temperature of gas refrigerant discharged from the compressor. It is common. This is because a part of the liquid refrigerant can be injected into the intermediate pressure portion of the compressor, and the refrigeration capacity is not affected by the injection. However, since excessive injection appears as an increase in input rather than an increase in the amount of compression, it has been conventionally performed to detect the temperature or the like of the discharge gas refrigerant compressed by the compressor and suppress the amount of injection. .

A refrigeration system having an injection control valve whose valve opening increases with an increase in the temperature of the discharged gas refrigerant,
For example, it is disclosed in Japanese Patent Application No. 1-290230. Here, in order to detect the temperature of the gas refrigerant discharged from the compressor, a temperature-sensitive cylinder installed with a fixture on the discharge gas refrigerant pipe or the like is used, and injection is controlled so that the difference between this temperature and the condensing temperature is constant. A refrigeration system using a control valve is shown.

Since the injection control valve can change the valve opening linearly, it is possible to obtain an optimal liquid injection for each operating condition. For this reason, the degree of superheat of the discharged gas refrigerant is kept constant, and in particular, refrigeration operation with a wide evaporation temperature using the refrigerant R-22 is possible.

However, there is a danger that the oil film of the refrigerating machine oil is broken at the sliding portion of the compressor to which the refrigerant such as R-22 is blown by the liquid injection, and the sealing performance of the compression chamber is impaired. In particular, under an operating condition in which the refrigerant evaporation temperature in the evaporator is reduced, the amount of the circulated refrigerant decreases, and the refrigerating machine oil separated from the refrigerant in the oil separator is supplied to the low-pressure crank chamber of the compressor with an oil level. In a refrigeration system having only a mechanism for returning oil when the pressure drops, the supply of refrigerating machine oil to the compression chamber is insufficient, and the sealing performance of the compression chamber is further impaired, resulting in a significant decrease in compression efficiency. There is.
For this reason, the lower limit of the usable evaporation temperature is usually determined.

[0006]

That is, the conventional refrigeration system has a problem that the lower limit of usable evaporation temperature is regulated from the viewpoint of refrigeration oil supply and the range of use conditions is narrowed. The solution of this point was an issue.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and a compressor, an oil separator, a condenser, a decompressor, an evaporator, etc. are sequentially connected by a refrigerant pipe. In a refrigeration system in which an injection pipe for supplying a condensed liquid refrigerant to an intermediate pressure section of a compressor is provided with flow control means,
And a refrigerating device of a first configuration, wherein the low-pressure part of the compressor and the oil storage part of the oil separator are connected to be able to communicate with each other by an oil return pipe provided with flow rate control means and pressure reduction means,
In the refrigerating device of the first configuration, a flow control valve of an oil return pipe that communicably connects the injection pipe and the oil storage unit of the oil separator is provided so as to be controllable based on a physical quantity of the refrigerant in the evaporator. And a refrigeration system having a second configuration characterized by the following.

[0008]

When the evaporation temperature of the refrigerant in the evaporator decreases and the amount of circulating refrigerant decreases, the refrigerating machine oil accumulated in the oil storage part of the oil separator is communicated with the oil storage part of the oil separator by connecting the oil storage part and the injection pipe. (At the time of liquid injection)
Since the refrigerant is supplied to the intermediate pressure part of the compressor, the evaporation temperature of the refrigerant decreases, the refrigerant circulation amount decreases, and even if the amount of the refrigerator flowing into the compressor through the refrigerant suction pipe decreases, the compressor does not There is no shortage of the refrigerating machine oil at the sliding part of. Therefore, the sealing performance of the compression chamber is not impaired, and the refrigeration operation at a lower evaporation temperature becomes possible.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described in detail with reference to FIG. Compressor 1, Oil separator 2, Condenser 3, Decompressor 4,
The evaporators 5 are sequentially connected by refrigerant tubes.

[0010] The refrigerant gas sucked into the compressor 1 is compressed here and is discharged as a high-temperature and high-pressure gas.
Flows into. Most of the refrigerating machine oil discharged from the compressor 1 together with the high-temperature and high-pressure refrigerant gas is separated from the refrigerant by the oil separator 2 and accumulates in an oil storage section (not shown) provided at a lower portion of the oil separator 2.

The refrigerant gas containing a small amount of refrigerating machine oil and leaving the oil separator 2 flows into an air-cooled condenser 3 where it is condensed to become a low-temperature and high-pressure liquid refrigerant. Further, the low-temperature and high-pressure liquid refrigerant is depressurized by the decompressor 4, flows into the evaporator 5, evaporates, becomes a low-temperature and low-pressure gas refrigerant, and returns to the compressor 1 to perform a refrigeration cycle.

Reference numeral 6 denotes an injection pipe provided with a control valve 7 for controlling a flow rate on the way, and supplies a part of the low-temperature and high-pressure liquid refrigerant condensed in the condenser 3 to an intermediate pressure section of the compressor 1. Piping is connected as possible. And the control valve 7
Means for detecting the temperature of the high-temperature and high-pressure gas refrigerant compressed and discharged by the compressor 1, for example, the opening degree increases when the degree of superheat of the refrigerant detected by the warming cylinder 8 attached to the discharge-side gas refrigerant pipe increases. Since proportional control is performed so as to increase, overheating of the compressor 1 and the gas refrigerant compressed and discharged from the compressor 1 is effectively prevented.

Reference numeral 9 includes an electromagnetic valve 11 and a capillary tube 13 on the way to enable communication between the oil storage section of the oil separator 2 and the control valve 7 of the injection pipe 6 and the compressor 1 when desired. Numeral 10 is an oil return pipe which is provided with a solenoid valve 12 and a capillary tube 14 on the way, and connects the oil storage section of the oil separator 2 and the low-pressure crank chamber of the compressor 1 so that they can communicate with each other when desired. It is an oil return pipe. Oil return pipe 9/10
The side communicating with the oil separator 2 may be a common pipe as in the embodiment, or may be a separate pipe.

The solenoid valve 11 is opened when a refrigerant (evaporation) temperature detected by a temperature sensor 15 installed in a refrigerant pipe on the discharge side of the evaporator 5 becomes lower than a predetermined temperature. The compressor oil stored in the oil storage section can be supplied to the intermediate pressure section of the compressor 1 and a function of resolving a shortage of the amount of the refrigerating machine oil in a compression chamber (not shown) of the compressor 1 is achieved. For this reason, even if the refrigerant evaporation temperature in the evaporator 5 decreases, the refrigerant circulation amount decreases, and even if the refrigerating machine oil amount supplied to the compressor 1 via the evaporator 5 decreases, the oil amount becomes insufficient. And the compression chamber is not inadequately sealed.

As a specific example of the opening / closing operation of the solenoid valve 11, when the refrigerant evaporation temperature becomes equal to or lower than the predetermined temperature, the solenoid valve 11 is opened / closed in synchronization with the opening / closing of the control valve 7, and the oil storage of the oil separator 2 is performed. It is desirable that the refrigerating machine oil stored in the section is controlled so as to be injected into the intermediate pressure section of the compressor 1 together with the liquid refrigerant.

The solenoid valve 12 is controlled to open when the oil level of the refrigerating machine oil in the low-pressure crank chamber of the compressor 1 drops below a predetermined position, and close when the oil level is restored to the predetermined position. Therefore, whenever the amount of refrigerating machine oil in the low-pressure crank chamber of the compressor 1 decreases, the refrigerating machine oil is appropriately supplied from the reservoir of the oil separator 2, and the amount of refrigerating machine oil in the low-pressure crank chamber is constantly controlled within a predetermined range. Is done.

Incidentally, since the present invention is not limited to the above-described embodiment, it can be modified as appropriate without departing from the spirit of the appended claims. For example, since the evaporation temperature of the refrigerant in the evaporator 5 depends on the refrigerant pressure in this part, a pressure sensor capable of detecting the refrigerant pressure is installed at the same position instead of the temperature sensor 15, and the pressure sensor detects the refrigerant temperature. Depending on the refrigerant pressure
It is also possible to provide so as to control the opening and closing of the electromagnetic valve 11 provided in the oil return pipe 9.

FIG. 1 shows a refrigeration apparatus having a simple structure for clarifying the purpose of the present invention. However, when the refrigeration apparatus is actually designed, the pressure reducing valve 4 and the evaporator 5 are connected to each other. Needless to say, an appropriate device such as a liquid receiver is installed in between.

[0019]

As described above, the present invention provides a compressor
An oil separator, a condenser, a decompressor, an evaporator, and the like are sequentially connected by a refrigerant pipe, and an injection pipe for supplying a condensed liquid refrigerant to an intermediate pressure portion of the compressor is provided with a flow control means. In the apparatus, the injection pipe and the oil storage section of the oil separator, and the low-pressure section of the compressor and the oil storage section of the oil separator are communicably connected by an oil return pipe provided with flow control means and pressure reduction means, respectively. And a flow control valve of an oil return pipe that communicably connects the injection pipe and the oil storage section of the oil separator is provided so as to be controllable based on the physical quantity of the refrigerant in the evaporator. Because it is a refrigeration system,

Even if the evaporation temperature of the refrigerant is reduced and the amount of refrigerant recirculated to the low pressure side of the compressor is reduced, the refrigerating machine oil stored in the oil storage portion of the oil separator is compressed (when the liquid refrigerant is injected). It can be supplied together to the intermediate pressure section of the machine, and the sliding section does not run out of refrigeration oil. Therefore, not only does the sealing performance of the compression chamber not be impaired, but also a refrigeration operation at a lower evaporation temperature becomes possible. In addition, since the sealing performance of the compression chamber is improved, the amount of liquid injection can be reduced as compared with the conventional device, and a remarkable effect such as downsizing of the condenser can be achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of one embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Oil separator 3 Condenser 4 Decompressor 5 Evaporator 6 Injection pipe 7 Control valve 8 Heat sensing cylinder 9.10 Oil return pipe 11.12 Solenoid valve 13.14 Capillary tube 15 Temperature sensor

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshio Ida 2--18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Tsutomu Mori 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Inside Hiro Electric Co., Ltd. (72) Inventor Hiroshi Nishikawa 2--18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (56) References JP-A-2-85649 (JP, A) 73872 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 1/00

Claims (2)

(57) [Claims] 1. A compressor, an oil separator, a condenser, a decompressor, an evaporator, and the like are sequentially connected by a refrigerant pipe, and an injection pipe for supplying a condensed liquid refrigerant to an intermediate pressure section of the compressor is provided with a flow control means. In a refrigeration system equipped with a pipe, the injection pipe and the oil storage section of the oil separator, and the low-pressure section of the compressor and the oil storage section of the oil separator can be connected to each other by the oil return pipe provided with flow control means and pressure reduction means. A refrigeration device, which is connected. 2. A flow control valve of an oil return pipe, which connects the injection pipe and an oil storage section of the oil separator so as to communicate with each other, is provided so as to be controllable based on a physical quantity of the refrigerant in the evaporator. Item 4. The refrigeration apparatus according to Item 1.