Abstract: A male rotor of a screw compressor has a cooling flow path extending in an axial direction inside a discharge-side shaft section. A groove structure is provided at at least a part of a region on a wall surface of the cooling flow path between the position of a discharge-side end face of the male rotor and a mounting position of a discharge-side bearing. The groove structure includes grooves or a groove that has a lengthwise component in a circumferential direction of the screw rotor and that are spaced apart in the axial direction. A nozzle which is a stationary member is arranged inside the cooling flow path with a gap between the nozzle and the wall surface of the cooling flow path. The nozzle is arranged in such a manner as to overlap at least a part of the groove structure in the axial direction.

Abstract: A male rotor of a screw compressor has a cooling flow path extending in an axial direction inside a discharge-side shaft section. A groove structure is provided at at least a part of a region on a wall surface of the cooling flow path between the position of a discharge-side end face of the male rotor and a mounting position of a discharge-side bearing. The groove structure includes grooves or a groove that has a lengthwise component in a circumferential direction of the screw rotor and that are spaced apart in the axial direction. A nozzle which is a stationary member is arranged inside the cooling flow path with a gap between the nozzle and the wall surface of the cooling flow path. The nozzle is arranged in such a manner as to overlap at least a part of the groove structure in the axial direction.

Abstract: The gas compressor comprising a pre-filter for compressed air is placed at the compressed air intake of the enclosure for primary removal of dust, and an intake filter for further secondary removal of dust, at least one compressor body that draws in and compresses air a motor that drives the compressor body, air cooler cools compressed air, a cooling fan that passes cooling air to the air cooler, a cooling air intake that draws in more than the outside air by means of a cooling fan, a pre-filter for cooling air installed in the cooling air intake, and a controller for controlling an operation of the gas compressor, wherein the controller determines the frequency of cleaning or replacement of the pre-filter for compressed air and the pre-filter for cooling air based on the load factor, which is an indicator of the operating condition.

Abstract: A multi-stage screw compressor includes a plurality of stages of compressor bodies that compress a gas in sequence. Each of the stages of compressor bodies has both male and female rotors that are housed revolvably in a casing in a mutually meshing state. The male and female rotors each include a rotor lobe section having a suction-side end face and a discharge-side end face on one end and the other end thereof in the axial direction and having a twisted lobe extending from the suction-side end face to the discharge-side end face. The male and female rotors in a downstream-stage compressor body of at least one certain stage, excluding an upstream-stage compressor body as the first stage, among the plurality of stages of compressor bodies are each configured such that their lead increases from the suction side in the axial direction of the rotor lobe section toward the discharge side.

Abstract: In a screw compressor, a lobe of a lobe profile of a female rotor includes: a first contour line defining a leading flank; a second contour line defining a trailing flank; and a third contour line defining a lobe tip having both endpoints at which the female has the maximum radius. In the lobe profile, when a first angle formed by two line segments linking a second rotation center as a vertex and both ends of the first contour line, a second angle formed by two line segments linking the second rotation center and both ends of the second contour line, and a third angle formed by two line segments linking the second rotation center and both ends of the third contour line, the third angle is greater on the delivery side in the axial direction, and the first angle is smaller on the delivery side in the axial direction.

Abstract: A multi-stage screw compressor includes a plurality of stages of compressor bodies that compress a gas in sequence, and each stage of the plurality of stages of compressor bodies has both male and female rotors that are housed revolvably in a casing in a mutually meshing state. The male and female rotors each include a rotor lobe section having a suction-side end face and a discharge-side end face on one end and the other end thereof in the axial direction and having a twisted lobe extending from the suction-side end face to the discharge-side end face. The male and female rotors in a downstream-stage compressor body as at least one certain stage, excluding an upstream-stage compressor body as the first stage, among the plurality of stages of compressor bodies are each configured such that their lead increases from the suction side in the axial direction of the rotor lobe section toward the discharge side.

Abstract: In a screw compressor, a lobe profile of cross-sections perpendicular to the axial direction in a female rotor that rotates about a second rotation center changes in the axial direction. One lobe of the lobe profile of the female rotor includes: a first contour line defining a leading flank on a rotation direction side of the female rotor with a lobe bottom as a boundary point; a second contour line defining a trailing flank on an opposite side of the rotation direction; and a third contour line defining a lobe tip having both endpoints at which the female has the maximum radius.

Abstract: Provided is an air compressor that suppresses a rise in delivery temperature due to a change in atmospheric pressure, and consequently improves the life of parts. The air compressor 1 includes a motor 2, a compressor main body 3 driven by the motor 2 to compress air, a delivery pressure sensor 12 that senses a delivery pressure of the compressor main body 3, an atmospheric pressure sensor 13 that senses an atmospheric pressure, and a controller 15. The controller 15 compares the delivery pressure sensed by the delivery pressure sensor 12 with a set pressure, and performs operation control based on a result of the comparison. The controller 15 corrects the set pressure such that a ratio between the atmospheric pressure sensed by the atmospheric pressure sensor 13 and the set pressure becomes a set value set in advance.

Abstract: In order to reduce operation in a rotation-prohibited frequency range and to prevent resonance in a gas compressor wherein inverter control is performed, this gas compressor has: a compressor main body that compresses a gas; a motor that rotationally drives the compressor main body; an inverter that changes the rotational speed of the motor; a check valve arranged downstream from the compressor main body; a pressure detection means that detects load-side pressure downstream from the check valve; and a control device that, in accordance with the pressure detected by the pressure detection means, controls the frequency output by the inverter.

Abstract: A screw rotor which is hollow has improved performance against heat, pressure, rust, and the like. A screw rotor includes a screw portion of which an outer periphery has teeth and grooves having a helical shape and extending by a predetermined length in an axial direction. A radial cross section of at least a part of the screw portion includes a cross section of an outer surface portion forming the teeth and the grooves, a cross section of an axial center portion, a cross section of a support portion that connects an axial center side of the outer surface portion and an outer diameter side of the axial center portion, and a cross section of a hollow portion formed by the support portions adjacent to each other in a rotational direction and an axial center side inner surface of a tooth bottom or a tooth tip.

Abstract: A screw rotor which is hollow has improved performance against heat, pressure, rust, and the like. A screw rotor includes a screw portion of which an outer periphery has teeth and grooves having a helical shape and extending by a predetermined length in an axial direction. A radial cross section of at least a part of the screw portion includes a cross section of an outer surface portion forming the teeth and the grooves, a cross section of an axial center portion, a cross section of a support portion that connects an axial center side of the outer surface portion and an outer diameter side of the axial center portion, and a cross section of a hollow portion formed by the support portions adjacent to each other in a rotational direction and an axial center side inner surface of a tooth bottom or a tooth tip.

Abstract: In order to reduce operation in a rotation-prohibited frequency range and to prevent resonance in a gas compressor wherein inverter control is performed, this gas compressor has: a compressor main body that compresses a gas; a motor that rotationally drives the compressor main body; an inverter that changes the rotational speed of the motor; a check valve arranged downstream from the compressor main body; a pressure detection means that detects load-side pressure downstream from the check valve; and a control device that, in accordance with the pressure detected by the pressure detection means, controls the frequency output by the inverter.

Abstract: A bearing oil feeding amount is appropriately controlled with respect to specifications of a discharge pressure (bearing load) and a rotation speed.

Abstract: In order to reduce operation in a rotation-prohibited frequency range and to prevent resonance in a gas compressor wherein inverter control is performed, this gas compressor has: a compressor main body that compresses a gas; a motor that rotationally drives the compressor main body; an inverter that changes the rotational speed of the motor; a check valve arranged downstream from the compressor main body; a pressure detection means that detects load-side pressure downstream from the check valve; and a control device that, in accordance with the pressure detected by the pressure detection means, controls the frequency output by the inverter.

Abstract: A bearing oil feeding amount is appropriately controlled with respect to specifications of a discharge pressure (bearing load) and a rotation speed.

Abstract: An oil free compressor includes a cooling fan, a low-pressure stage air-cooled heat exchanger, a high-pressure stage air-cooled heat exchanger, and a lubricating oil air-cooled heat exchanger. The cooling fan is provided independently from each of the low-pressure stage air-cooled heat exchanger, the high-pressure stage air-cooled heat exchanger, and the lubricating oil air-cooled heat exchanger.

Abstract: Provided are a structure of arranging a compressor main body and a compressor driving motor at a bottom of a package; including a duct on a top side thereof; arranging an inter cooler on a left side surface of the duct; arranging an after cooler on a top surface thereof; arranging an oil cooler on a front surface thereof; arranging a cooling fan inside of the duct; providing an exhaust port on a bottom surface of the duct; and respectively providing exhaust ducts connected to a top surface of the package on downstream sides of the coolers, and a structure of cooling air suctioned by the cooling fan from the suction port to the inside of the duct, passing through the coolers, and discharged upwardly from the package via the exhaust duct, implementing a compact oil free screw compressor with low noise capable of reducing an installation area.

Abstract: An oil-free scroll compressor prevents wraps from being broken and provides improved reliability. The oil-free scroll compressor includes an orbiting scroll member and fixed scroll members, and has compression channels into which water is injected each formed between the intake port and exhaust port provided in the fixed scroll member. The oil-free scroll compressor includes temperature sensors each of which detects temperature in the compression channel, regulating valves each of which controls ratio of the amount of the water to be injected into the respective compression channels to the total amount of the water to be injected into the compression channels, and controller which controls the opening degrees of the regulating valves such that a difference between the detected temperatures from the compression channels is small.

Abstract: A conventional machine package faces problems concerned with costs, weight, etc. and also a problem of antinomy that an attempt to enhance the noise reducing performance increases the airflow resistance and then deteriorates the cooling performance. Providing a sound absorbing structure with the heat radiation performance ensured within a practical range and then with considerably improved noise reducing effect achieves a low-noise machine package with a downsized casing and a reduced cooling fan power.