선박용 무급유 공기압축기의 밸브설계 및 피스턴링 소재의 특성에 관한 연구

Abstract

In recent years, medical, electricity, electronics, marine, rescue and various industrial fields are in need of purified compressed air. But, most of the parts for oilless air compressors for marine use are made locally except for main parts.

The reason for this study is mainly concerned with the material property of piston ring and valve design of the oilless air compressor.

In case of the valve plate, the heat treatment was carried out as many cycles and was compared with the results of the traditional products.

It was analyzed that the fluidity of compressed air in the valve part by simulation of FLUENT.

In case of the oilless piston ring, it was carried out the friction and wear test use self-lubricating materials that are PTFE, polyimide, carbon, copper and so forth.

The results are summarized as follow.

(1) In the results of heat treatment of domestic raw stainless steel, when they were quenched at 970℃ and tempered at 200℃, it was proven that they had same mechanical property and microstructure.

There were no problems in applying the modified valve plates to real air compressor for marine use.

(2) The valve design program was made based on Windows 98/NT. As the results, we can obtain the output data for delivery temperature, volumetric efficiency, mean flow velocity and effective flow area of compressed air.

(3) It was analyzed that the macroscopic fluidity of the compressed air in the valve by FLUENT program to interchange with CAD. As the result, we can get the flow characteristics of the valve before producing the valve.

(4) At the end, results of the material used consists of carbon, copper and cupric copper mixed with PTFE80%-polyimide20%.

In case of copper10%, at 0.94m/s sliding speed, the mean friction coefficient showed 0.087, which is the lowest value in all specimens.

In case of the specific wear rate, copper30% specimen showed the lowest value of 2.537E-5(mm3/Nm) in all specimens. From the above results, copper30% specimen showed the best performance for this work.