Abstract: 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.

Abstract: Disclosed is a method for hybrid welding in which a laser beam is applied to the welding position of objects to be welded, and at the same time, a first wire is fed to the welding position so as to perform arc welding using an arc generated between the objects to be welded and the first wire. In this method, one or more second wires are fed to a molten weld pool formed by the laser beam and arc welding, thereby increasing the amount of welding without increasing the arc current.

Abstract: A laminated ceramic capacitor is provided which is excellent in reliability even when its dielectric ceramic layers thinned. For a dielectric ceramic in a laminated ceramic capacitor, a ceramic is used which includes a main component containing a barium titanate based composite oxide represented by the general formula: (Ba1-h-m-xCahSrmRex)k(Ti1-n-yZrnMy)O3, where Re is La or the like, M is Mg or the like, and the respective relationships of 0.05?x?0.50, 0.02?y?0.3, 0.85?k?1.05, 0?h?0.25, 0?m?0.50, and 0?n?0.40 are satisfied; and an accessory component as a sintering aid, wherein the average grain diameter of crystal grains in a sintered body is 0.6 ?m or less.

Abstract: 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.

Abstract: The invention downsizes and simplifies structures of a compressor and its driving system apparatus, and achieves a reduction of a noise. An oil free screw compressor is constituted by compressor main bodies compressing a gas, a motor driving rotors of the compressor main bodies via step-up gears, a gear casing storing the step-up gears, cooling apparatuses cooling a discharge air and the like. An oil tank is provided independently from the gear casing, the motor is fixed to a common base, the gear casing is integrally attached to the motor via a flange, and the compressor main bodies are integrally attached to the gear casing via the flange. Further, the cooling apparatuses are arranged in an upper side of the driving system apparatus, and a cooling fan is installed in an upper side thereof.

Abstract: A screw compressor comprising: a low pressure stage compressor body; a high pressure stage compressor body that further compresses a compressed air compressed by the low pressure stage compressor body; pinion gears for example, respectively, provided on, for example, a male rotor of the low pressure stage compressor body and, for example, a male rotor of the high pressure stage compressor body; a motor; a bull gear for example, provided on a rotating shaft of the motor; and an intermediate shaft supported rotatably and provided with a pinion gear, which meshes with the bull gear, and a bull gear, which meshes with the pinion gears. Thereby, it is possible to make the motor relatively low in rotating speed while inhibiting the gears from being increased in diameter, thus enabling achieving reduction in cost.

Abstract: 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.

Abstract: 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.

Abstract: A water-injected compressor, which injects the water inside the separator 3 into the compressor and discharges the water along with compressed air into the separator and then gains condensed and separated water, has the compressor stopping and then, if staying at a stop for a predetermined duration of time without activating, becoming activated and operating for a set duration of time.

Abstract: The invention downsizes and simplifies structures of a compressor and its driving system apparatus, and achieves a reduction of a noise. An oil free screw compressor is constituted by compressor main bodies compressing a gas, a motor driving rotors of the compressor main bodies via step-up gears, a gear casing storing the step-up gears, cooling apparatuses cooling a discharge air and the like. An oil tank is provided independently from the gear casing, the motor is fixed to a common base, the gear casing is integrally attached to the motor via a flange, and the compressor main bodies are integrally attached to the gear casing via the flange. Further, the cooling apparatuses are arranged in an upper side of the driving system apparatus, and a cooling fan is installed in an upper side thereof.

Abstract: A screw compressor comprising: a low pressure stage compressor body; a high pressure stage compressor body that further compresses a compressed air compressed by the low pressure stage compressor body; pinion gears for example, respectively, provided on, for example, a male rotor of the low pressure stage compressor body and, for example, a male rotor of the high pressure stage compressor body; a motor; a bull gear for example, provided on a rotating shaft of the motor; and an intermediate shaft supported rotatably and provided with a pinion gear, which meshes with the bull gear, and a bull gear, which meshes with the pinion gears. Thereby, it is possible to make the motor relatively low in rotating speed while inhibiting the gears from being increased in diameter, thus enabling achieving reduction in cost.

Abstract: A fuel cell stack has an air chamber to which is introduced compressed air that is produced by compressing the atmosphere with a compressor. Energy is recovered from exhaust discharged from the air chamber as it is expanded by an expander. The compressor and the expander are connected to each other via the air chamber of the fuel cell stack through piping. The pressure of the exhaust flowing through the piping is detected by a pressure sensor and, based on the detected pressure, a throttle valve controls a flow rate of the exhaust drawn into the expander.

Abstract: A screw compressor includes a compressor main body, a male rotor having a screw-like male tooth shape and a female rotor having a screw-like female tooth shape meshing with the screw-like male tooth shape or the male rotor. The male and female motors are provided within the compressor main body. A motor casing is operably connected to the compressor main body, and a high speed electric motor provided within the motor casing. The motor includes a motor rotor, a motor stator and a motor shaft for driving at least one of the male and female rotors. A speed ratio of the motor shaft and the at least one of the male and female rotors driven by the motor shaft is in a range of 2:1 to 1:2.

Abstract: It is an object of the present invention to provide a touch mode capacitive pressure sensor having higher pressure durability than conventional sensors. In this invention, a touch mode capacitive pressure sensor has a diaphragm made from boron-doped silicon, and the boron concentration at the top face of the diaphragm is equal to or greater than 1×1019 cm?3 and less than 9×1019 cm?3. Further, in this invention, a touch mode capacitive pressure sensor has a conductive diaphragm made by doping of an impurity and anisotropic etching, and the etch pit density on the top face of the diaphragm is equal to or less than five per ?m2, and preferably equal to or less than one per ?m2. As a result, the pressure durability of the diaphragm is greatly improved.

Abstract: An oil free screw compressor having a low-pressure stage compressor body and a high-pressure stage compressor body. Power of a motor driven by an inverter is transmitted to the compressor bodies through gears. A low-pressure stage blow-off two-way valve is provided in a pipe branching off midway an air pipe connecting between the high-pressure stage compressor body and the low-pressure stage compressor body, and a high-pressure stage blow-off two-way valve is provided in a pipe branching off from a discharge air pipe provided on a discharge side of the high-pressure stage compressor body. During no-load operation, a controller gives a command to the inverter to make the rotational speed of the motor a set lower limit rotational speed, and also gives an open command to the low-pressure stage blow-off two-way valve.

Abstract: A screw compressor includes a compressor main body, a male rotor having a screw-like male tooth shape and a female rotor having a screw-like female tooth shape meshing with the screw-like male tooth shape or the male rotor. The male and female motors are provided within the compressor main body. A motor casing is operably connected to the compressor main body, and a high speed electric motor provided within the motor casing. The motor includes a motor rotor, a motor stator and a motor shaft for driving at least one of the male and female rotors. A speed ratio of the motor shaft and the at least one of the male and female rotors driven by the motor shaft is in a range of 2:1 to 1:2.

Abstract: A screw compressor includes a compressor main body, a male rotor having a screw-like male tooth shape and a female rotor having a screw-like female tooth shape meshing with the screw-like male tooth shape or the male rotor. The male and female motors are provided within the compressor main body. A motor casing is operably connected to the compressor main body, and a high speed electric motor provided within the motor casing. The motor includes a motor rotor, a motor stator and a motor shaft for driving at least one of the male and female rotors. A speed ratio of the motor shaft and the at least one of the male and female rotors driven by the motor shaft is in a range of 2:1 to 1:2.

Abstract: An oil free screw compressor having a low-pressure stage compressor body and a high-pressure stage compressor body. Power of a motor driven by an inverter is transmitted to the compressor bodies through gears. A low-pressure stage blow-off two-way valve is provided in a pipe branching off midway an air pipe connecting between the high-pressure stage compressor body and the low-pressure stage compressor body, and a high-pressure stage blow-off two-way valve is provided in a pipe branching off from a discharge air pipe provided on a discharge side of the high-pressure stage compressor body. During no-load operation, a controller gives a command to the inverter to make the rotational speed of the motor a set lower limit rotational speed, and also gives an open command to the low-pressure stage blow-off two-way valve.

Abstract: An oil free screw compressor includes a low-pressure stage compressor body and a high-pressure stage compressor body. Power of a motor driven by an inverter is transmitted to the compressor bodies through gears. A low-pressure stage blow-off two-way valve is provided in a pipe branching off midway an air pipe connecting between the high-pressure stage compressor body and the low-pressure stage compressor body, and a high-pressure stage blow-off two-way valve is provided in a pipe branching off from a discharge air pipe provided on a discharge side of the high-pressure stage compressor body. During no-load operation, a controller gives a command to the inverter to make the rotational speed of the motor a set lower limit rotational speed, and also gives an open command to the low-pressure stage blow-off two-way valve.