Compressor

Abstract

A dry-compressing compressor comprises two screw rotors in a housing defining a suction chamber. At a compressor inlet of the compressor preferably atmospheric pressure prevails and at a compressor outlet of the compressor preferably a pressure of more than 2 bars (absolute) prevails. For each screw rotor at least one displacement element including a helical recess defining a plurality of windings is provided. The at least one displacement element per screw rotor has a single-pass asymmetrical profile.

Description

BACKGROUND1. Field of the Disclosure[0001]The disclosure relates to a compressor, in particular a screw compressor.2. Discussion of the Background Art[0002]For compressing gases, in particular for providing compressed air, primarily oil-injected screw compressors are nowadays used. They can usually perform a compression from 1 bar (absolute) to 8.5 to 14 bars (absolute) in one compressor stage. Here, the delivered intake volume flows range from 30 to 5000 m3 / h. Such screw compressors comprise two counter-rotating screw rotors. The screw rotors each comprise at least one helical deepened portion such that a displacement element is formed. The injection of oil into the suction chamber, where the two screw rotors are arranged, serves for sealing the gaps between the rotors and the housing and / or the inner wall of the suction chamber. By providing oil, a sufficient tightness can be attained for realizing high compression pressures of in particular up to 14 bars in one compressor stage. ...

AI Technical Summary

Benefits of technology

The patent text describes a new design for a rotor that improves tightness and energy conversion efficiency. By using a single-pass rotor profile and evenly spaced displacement elements, the system can achieve better performance. Additionally, the rotor and displacement elements can be coated with layers to decrease gap heights without compromising safety. These improvements can lead to more effective utilization of energy and better production of gas.

Problems solved by technology

An essential disadvantage of the use of oil is that the oil enters the gas to be delivered.

As a result, such compressors are complex and require a large installation space.

The use of oil-injected screw compressors in particular in areas where a high purity of the compressed air is required, such as in the field of pharmaceutical or food industry, is not possible or possible only when using extremely complex multi-stage oil separators.

However, dry-compressing screw compressors have the drawback that one compressor stage only allows for a compression to 4 to 5 bars (absolute).

The reason for this is in particular that large leakages occur through the gaps between the rotors and the housing.

Besides the two compressor stages, an intermediate cooling of the compressed air is necessary, which results in complex equipment comprising many components and requiring a large installation space.

These, too, have the drawback that they must be of a multi-stage configuration for achieving high pressures of approximately 9 bars (absolute).

However, spindle compressors are so far not commercially available such that there is no evidence that high compression pressures can be reached with a one-stage design.

Although the manufacture is complex due to the required two separate operating steps, an extremely tight working chamber can be realized.

In the case of profiles having two more passes of the respective meshing displacement elements, connections across several chambers are formed through the gaps such that the leakage affects the delivered gas flow and the energy conversion quality.

Further, the thermal load is small.

This results in unfavorable ratios of delivered gas volume and leakage areas.

On the other hand, very high speeds of more than 10,0000 1 / min entail very high demands on the balancing of the rotors or the displacement elements.

This is difficult to achieve in the case of single-pass screw threads.

In addition, with increasing power density due to high speeds, it becomes more and more difficult to cool the compressor.

Another drawback of very high speeds with very small tooth gaps is the high gas friction in the gas paths.

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