Kabushiki Kaisha Kobe Seiko Sho

Kobe Steel, Ltd.

Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)

Junichiro Totsuka

Hajime Nakamura

Shoji Yoshimura

Yasuto Kataoka

Naoki Kikuchi

Naoya Fujiwara

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.

Resin screw rotor molded to a metallic shaft

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. 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.

Oil-cooled compressor

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.

Independent rotational speed control of multi-stage variable speed compressor

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 an intake registration valve in the inlet side, and a pressure sensor provided in the discharge side to be able to detect pressure. A control section outputs a control signal for controlling the rotational speed of a motor for driving the compressor body based on a pressure signal indicating a detected pressure from the pressure sensor when the rotational speed is higher than a predetermined value, the intake regulation valve is opened and a control signal for negating a deviation of the detected pressure to the predetermined target pressure is outputted from the control section thereby controlling the rotational speed, and when the rotational speed is reached to the predetermined value, the control is switched to the open/close control for opening/closing the intake regulation valve in response to a pressure fluctuation in the discharge side in place of the rotational speed control, thereby controlling pressure fluctuation in the discharge side. Here, the predetermined value is set to such a value that the leakage quantity of gas, compressed by the screw compressor, into the inlet side of the screw compressor will not be increased as rotational speed of the motor is decreased.

Growing community of inventors

Kako-gun, Japan

Junichiro Totsuka