Abstract: A gas cooler includes a drain recovery part, a drain discharge flow path, a drain tank, and a ventilation flow path. In the drain recovery part, drain separated from gas is accumulated by cooling the gas in a cooling part. The drain tank includes a separation part in which the drain and the gas are separated, and a storage part in which the separated drain is stored. The drain discharge flow path has one end communicating with the drain recovery part and the other end communicating with the separation part. The ventilation flow path has one end communicating with the separation part, and the other end communicating with a gas flow path that leads to a downstream space above the drain recovery part and to a gas lead-out port.

Abstract: The present invention is to provide a screw rotor including a resin rotor formed around a metallic shaft without generation of cracks. Spiral chamfers are formed on surfaces of metallic shafts around which resin rotors are formed. Preferably the surfaces of the shafts may be sandblasted, and after the surfaces of the shafts are preliminarily coated with resin and then the rotors may be molded.

Abstract: The present invention is to provide a screw rotor including a resin rotor formed around a metallic shaft without generation of cracks. Spiral chamfers are formed on surfaces of metallic shafts around which resin rotors are formed. Preferably the surfaces of the shafts may be sandblasted, and after the surfaces of the shafts are preliminarily coated with resin and then the rotors may be molded.

Abstract: An oil-cooled screw compressor which can maintain the discharge temperature of discharge gas at an appropriate level is provided. The oil-cooled screw compressor comprises a compressor body, an oil separation/recovery unit disposed in a discharge path extending from a discharge port of the compressor body, and an oil feed path extending from the oil separation/recovery unit and communicating with the compressor body 12. The oil feed path is branched at an intermediate position thereof into a first feed path portion and a second feed path portion. An opening/closing valve is disposed in the first feed path portion, a pressure gauge is disposed in the discharge path, and a control unit is provided to control opening and closing of the opening/closing valve on the basis of a correlation between a discharge pressure detected by the pressure gauge and a predetermined pressure.

Abstract: A multi-stage variable speed compressor includes a pressure detector provided for each compressor on and after the second stage for detecting a discharge pressure of a compressor of a stage preceding the corresponding compressor or a suction pressure of the corresponding compressor, wherein the control device controls the rotational speeds of the compressor of the first stage using a deviation of discharge pressure from a desired target pressure, and controls the rotational speed of each compressor on and after the second stage based on the discharge pressure of the compressor in a stage before each compressor or the suction pressure of each compressor, using a pressure signal from the pressure detector provided for each compressor on and after the second stage for detecting a discharge pressure of a compressor of a stage preceding the corresponding compressor or a suction pressure of the corresponding compressors.

Abstract: An oil-cooled screw compressor which can maintain the discharge temperature of discharge gas at an appropriate level is provided. The oil-cooled screw compressor comprises a compressor body, an oil separation/recovery unit disposed in a discharge path extending from a discharge port of the compressor body, and an oil feed path extending from the oil separation/recovery unit and communicating with the compressor body 12. The oil feed path is branched at an intermediate position thereof into a first feed path portion and a second feed path portion. An opening/closing valve is disposed in the first feed path portion, a pressure gauge is disposed in the discharge path, and a control unit is provided to control opening and closing of the opening/closing valve on the basis of a correlation between a discharge pressure detected by the pressure gauge and a predetermined pressure.

Abstract: A compressor that enables the increase of compression efficiency, the prevention of abnormal temperature rising in the discharge, and the reduction of power loss, includes a compressor body 11, an intake registration valve 12 in the inlet side, and a pressure sensor 18 provided in the discharge side to be able to detect pressure.

Abstract: It is an object of the present invention to make it possible to control a discharge pressure in a multi-stage variable speed compressor always to be a desired target pressure, whereby the multi-stage variable speed compressor can be operated with a discharge pressure of a good precision and to make it possible to perform the control without needing operation data as used in the prior art, at all.

Abstract: The present invention provides a compressor that enables the increase of compression efficiency, the prevention of abnormal temperature rising in the discharge, and the reduction of power loss.