Hitachi Industrial Equipment Systems Co., Ltd.

Hitachi Global Air Power Us, LLC

Hideki Fujimoto

Hitoshi Nishimura

Natsuki Kawabata

Jonathan D Batdorff

Christian Vaughn

Hiroshi Ohta

Yusuke Nagai

Yuusuke Nagai

Don Weinkauf

Edward Noble

A screw compressor and a variable capacity bypass valve therefor are provided. The variable capacity bypass valve includes a bore formed in a rotor bore discharge face of the compressor housing upstream of a compression chamber outlet end of the compression chamber, a slide valve member inserted into the bore to fill a cavity, the valve member having a sealing surface configured to interact with a thread of a compressor screw during operation of the screw compressor, an actuator structure coupled to the valve member and oriented to move the valve member radially along the bore to open a fluid pathway communicatively coupling the compressor chamber to a bypass chamber configured to return compressed fluid to a fluid inlet of the compression chamber.

Variable capacity bypass valve for screw compressor

A screw compressor and a compact variable volume index valve therefore are provided. The compact variable volume index valve includes a linear valve member positioned adjacent a compression chamber outlet end of a compression chamber of the screw compressor, an actuator structure coupled to the liner valve member and oriented to move the linear valve member radially along the compression: chamber outlet end of the compression chamber to adjust a radial location where gas exits the compression chamber, wherein the actuator structure is coupled to a shutter of a spiral valve of the screw compressor such that the actuator structure moves the liner valve based on a position of the spiral valve of the screw compressor.

Compact variable volume index valve for screw compressor background

A spiral valve and a screw compressor having a compressor housing and the spiral valve are provided. The spiral valve includes an actuator module having an electric motor and a gearbox mechanically coupled to the electric motor to transmit a torque from the electric motor, and a spiral valve body coupled to the gearbox to rotate in response to the transmitted torque from the electric motor. The spiral valve body has a first shutter positioned to open and close one or more of a plurality of bypass ports formed in the compressor housing based on a rotational position of the second shutter, a second shutter positioned to progressively open and close a compressor inlet transfer duct formed in the compressor housing based on a rotation position of second shutter, and a gap formed between the first and second shutters.

Spiral valve for screw capacity control

Provided is an air compressor which exhibits improved reliability by resolving problems relating to drainage discharge defects, and exhibits improved energy efficiency. The air compressor comprises: a compressor body which compresses air; a compressed air flow path through which the compressed air from the compressor body flows; a heat exchanger which is provided to the compressor flow path so as to cool the compressed air from the compressor body; and a drainage pipe () which branches from the compressed air flow path so as to connect to the exterior, and through which drainage condensed from the compressed air cooled in the heat exchanger flows. A strainer () which removes foreign matter contaminating the drainage is provided to the drainage pipe (). An on-off valve () at the downstream side of the strainer (), and a pressure sensor () at the upstream side thereof, said sensor detecting pressure inside the drainage pipe (), are each provided so as to resolve drainage discharge defects.

Air compressor with drain pipe arrangement

Provided is a highly reliable oil free screw compressor including a first sensor for detecting a temperature of lubrication oil, second sensors for detecting temperatures of intake air, and a cooling fan controller having a storage portion storing therein a set temperature of lubrication oil and a set temperature of intake air, and a computing portion for computing a control signal for increasing the speed of the cooling fan if a detected value of a temperature of the lubrication oil, delivered from the first sensor, becomes higher than the set value of lubrication oil stored in the storage portion, and computing a control signal for increasing the speed of the cooling fan if a detected value of a temperature of the intake air, delivered from the second sensor, becomes higher than the set temperature of the intake air, stored in the storage portion.

Oil free screw compressor

An oilless screw compressor incorporating water-cooled cooling units for cooling compressed air discharged from compressor bodies having a pair of male and female screw rotors which can be rotated in a contactless and oilless manner, the cooling units comprising a plate type heat-exchanger, and the amount of cooling water for the plate type heat-exchanger being adjustable. With this configuration, a difference between a temperature during load operation and a temperature upon automatic stopping and during unload operation of the compressor can be reduced, so that the cooling unit can be restrained from being damaged or broken within a short period, thereby it is possible to provide a highly reliable oilless screw compressor.

Oilless screw compressor and compressed air cooling unit

A multi-stage oil-free screw compressor includes: a suction throttle valve for controlling air intake into the compressor; a piston assembly for operating the suction throttle valve; and a structure for supplying a working pressure to the piston assembly. In order to reduce startup load at the time of startup of the compressor, the suction throttle valve is fully closed while a secondary side of a compressor body is opened to the atmosphere. When a negative pressure and the air pressure, that provide the working pressure, are used for slightly opening the suction throttle valve in order to switch the compressor to a loaded mode after a motor for driving the compressor is accelerated to its top speed, the air pressure is provided by a control pipe line that is defined by the same pipe line that forms a drain pipe line. This permits the control pipe line to be opened to the atmosphere as needed during the startup time. Thus is provided the oil-free screw compressor achieving improved startup reliability.

A screw compressor comprising: a pair of male and female screw rotors; and an air-cooled heat exchanger, wherein the air-cooled heat exchanger is provided above a motor for driving the compressor body; wherein, with respect to a cooling wind for the air-cooled heat exchanger, the air-cooled heat exchanger is inclined to the upstream side; wherein the uppermost portion of a unit suction port for the air-cooled heat exchanger cooling winds is positioned below the uppermost portion of the air-cooled heat exchanger positioned at the uppermost portion; wherein the lowermost portion of the unit suction port for the air-cooled heat exchanger cooling wind is positioned below the lowermost portion of the air-cooled heat exchanger positioned at the lowermost portion; and wherein the cooling wind for the air-cooled heat exchanger is exhausted from a ceiling portion of the compressor unit. With this structure, it becomes possible to provide a compact screw compressor with less noise whose installation area can be reduced.

Growing community of inventors

Shizuoka, Japan

Hideki Fujimoto