JPS5519942A - Compressor - Google Patents

Abstract

PURPOSE: To reliably prevent reverse flow of gas irrespective of whether the compressor is in full load operation or reduced capacity operation and improve the compression efficiency by providing a valve mechanism for preventing reverse flow of gas from a release circuit into a cylinder chamber.

CONSTITUTION: When operating the compressor under a reduced capacity condition by reducing the load in a freezing cycle, an electromagnetic valve 26 is opened. When a release hole 17 is brought to a position on the discharge chamber side with the excentric rotation of a roller 12, part of the gas being compressed flows into a release duct 30 by forcing down a release valve 22. When the release hole 17 is brought to a position on the intake chamber side, the release valve 22 is displaced to close the release valve 17, thus preventing the reverse flow of gas into a cylinder chamber 10 similar to the case of the full load time. In this way, the compression efficiency can be improved. Meanwhile, the compressed gas discharged into a sealed vessel 5 is reduced compared to the case of the full load operation, at which time the electromagnetic valve 26 is closed, to an extent corresponding to a portion led to the release duct 30, thus meeting the requirement for reduction of the freezing capacity.

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