Screw Compressors Improve Air Conditioning Reliability

—Free Literature Available Increased operating reliability, less maintenance, and better adaptability to different climatic conditions—these are some of the experiences reported by Swedish shipowners Johnson Line and Brostroms, who have become the first to test a new air-conditioning technique by putting it into full-scale shipboard operation.

These two companies have replaced piston compressors previously installed on two ships— Johnson's Chemspan and Brostroms' Vikingland— with screw compressors. These compressors, called Miniscrew and manufactured by Stal Refrigeration AB of Sweden, are the result of a new concept based on more than 20 years of successful development in cooling techniques for marine applications. The new compressors operate in a low-capacity range, 160-700 kw cooling power, which was previously considered uneconomical for screw compressors.

The Miniscrew range consists of six screw compressors with economizer versions. The compressors are also designed to work with high-pressure flow up to 380 psi. The system uses all standard refrigerants, and operates at power frequencies of 50 or 60 Hz.

Independent surveys have shown that maintenance costs can be halved compared with piston compressors. In addition, the risk of breakdown is minimal. According to the Marine Research Institute in Flensburg, West Germany, the ratio is given as 1:10 in comparison with piston compressors.

The Miniscrew range is designed with either horizontal or vertical compressor mounting.

This allows for compact installations and enables the units to be easily adapted to existing plant, foundations, etc.

Behind the newly launched Miniscrew concept, based on the operation of two asymmetrical rotors with four and six lobes, respectively, and in the smaller stroke volume ranges, is more than 20 years of experience in the development, manufacture, and installation of screw compressors and compressor units.

For further information and free literature on the Miniscrew compressors, Circle 12 on Reader Service Card

Other stories from September 1984 issue


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