Screw compressor

Abstract

In order to obtain a screw compressor which is small in size and weight and has ease of maintenance and high reliability, the screw compressor comprises a screw rotor, a low-pressure-side bearing and a high-pressure-side bearing which support the screw rotor, a motor which drives the screw rotor, a motor casing which accommodates the motor, a main casing which accommodates the screw rotor and the low-pressure-side bearing, and a discharge casing which accommodates the high-pressure-side bearing. The motor casing, the main casing, and the discharge casing are accommodated in a steel pipe chamber, and the steel pipe chamber includes a low-pressure-side chamber and a high-pressure-side chamber which are able to be divided in the axial direction. By using a flange provided on an inner surface of the steel pipe chamber, a flange provided in the main casing, and a sealing component provided between the flanges, the steel pipe chamber is divided into a low-pressure-side space and a high-pressure-side space.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a screw compressor which compresses a fluid, and particularly, to a screw compressor which is used in a refrigeration cycle of an air conditioner, a refrigerating machine, or the like.DESCRIPTION OF RELATED ART[0002]In a screw compressor, a screw rotor having a three-dimensionally twisted curved surface is provided as a compression mechanism portion. For this reason, generally, a casing accommodating the compression mechanism portion is made from cast iron which is able to be formed in a complex shape. The cast iron generally used for the casing of the compressor has strength lower than that of steel for pressure pipe. In the case where a design pressure is the same, the cast iron casing needs to be thicker than the steel casing. For this reason, there is a problem in that the mass of the compressor increases. In addition, in the screw compressor, lubricant contained in a discharge gas needs to be separated. For this reaso...

AI Technical Summary

Benefits of technology

[0009]An object of the invention is to obtain a screw compressor which is small in size and weight and has ease of maintenance and high reliability.

[0019]According to the invention, since the steel pipe chamber accommodating the motor casing and the main casing is provided, the steel pipe chamber is able to be divided in the axial direction, and the space inside the steel pipe chamber which is able to be divided is divided into the low-pressure-side space and the high-pressure-side space through the sealing component, it is possible to obtain a screw compressor which is small in size and weight and has ease of maintenance and high reliability.

Problems solved by technology

For this reason, there is a problem in that the mass of the compressor increases.

At this time, since the oil separator is also made from cast iron, there is a problem in that the mass of the compressor largely increases.

However, the screw compressors of the related art have the following problems.

Due to this, there is a problem in that the motor may be overheated during an operation of the compressor, and the reliability thereof is not satisfactory.

However, in the configuration in which the pressure inside of the steel pipe chamber is dropped to a low pressure, it is difficult to install an oil separator in the steel pipe chamber.

For this reason, it is necessary to install the oil separator separately from the compressor, and hence there is a problem in that the entire compressor increases in size.

In addition, in the case of the structure in which different types of metals, that is, the steel pipe and the cast iron are welded to each other so as to obtain the low pressure portion and the high pressure portion divided from each other, the different types of metals can be welded to each other, but when the optimal welding condition is not set, cracks occur due to the insufficient welding penetration of the welded portion, and then a gas leakage or a leakage of a high-pressure refrigerant gas to the low pressure portion occurs, which causes a problem in that the performance thereof is degraded.

For this reason, there is a problem in that a potential of causing cracks in the welded portion increases, and this structure is difficult to be applied to a high capacity compressor.

In addition, when this structure is adopted, the compressor becomes a hermetic structure, and hence there is a problem in that maintenance such as an exchange of a bearing cannot be performed.

As described above, in the structure in which the steel pipe chamber accommodates the compression mechanism portion of the screw compressor, it is difficult to dispose the motor on the low pressure side and to dispose the oil separator on the high pressure side after making the compressor in a semi-hermetic state.

That is, although the steel pipe chamber structure is a remarkable structure in small size and weight, there is a problem in that ease of maintenance and reliability are degraded.

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