Abstract: Disclosed is a screw type mechanical supercharger which is small in size but has a large capacity. The supercharger includes a pair of female and male screw rotors held in a mutully meshing condition with each other, and a pair of synchronizing gears mounted for integral rotation with the screw rotors and held in meshing engagement with each other to establish synchronous rotation of the female and male screw rotors. The female rotor has six teeth while the male rotor has three teeth, and the synchronizing gear for the female rotor has a number of teeth equal to twice that of the other synchronizing gear for the male rotor. The female rotor is connected to be driven by a reciprocating internal combustion engine so as to serve as an input power shaft of the supercharger. The screw rotors are preferably formed from a lighter weight material than the remainder of the supercharger.

Abstract: A screw supercharger is provided having a set of male and female screw rotors rotatably supported in a casing and driven through a wrapping transmission including belts and pulleys by a prime mover, wherein a through hole is formed in the wall of the causing at a position through which the input shaft of the screw rotor or the extension of the axis of the input shaft of the screw rotor extends, in that a cylindrical bearing supporting part is formed around the through hole so as to project outside from the casing, and in that a driven pulley is supported through bearings on the bearing supporting part and is fixedly mounted on the input shaft.

Abstract: Described herein is a method for operating an oil-free screw compressor and an oil-free screw compressor construction, the method including the step of feeding a gas of a temperature Ta to a discharge space in the vicinity of the discharge port of the compressor, the temperature Ta satisfying the relationshipTa.ltoreq.Tl/kwherein Ta is the temperature (.degree.K.) of said feed gas; Tl is the temperature (.degree.K.) of the compressed gas before feeding; and k is a polytropic index number.

Abstract: A screw vacuum pump which includes a pair of screw rotors meshed with each other. The vacuum pump includes an oilless screw vacuum pump suitable for application to industries where air containing foreign matter is detrimental to the products to be produced and for application to the food industry where odorous air must be avoided.

Abstract: A screw vacuum pump which includes a casing having a rotor chamber opened at its one end to a suction opening and opened at the other end to a discharge opening; a pair of male and female screw rotors rotatably received in the rotor chamber, each of the screw rotors having a pair of rotor shafts supported by forcibly lubricated bearings on both sides of the suction opening and the discharge opening; at least one first sealing member provided between the bearing on at least the suction opening side and the rotor chamber and communicated with a space under pressure less than atmospheric pressure which space is out of communication with the suction opening; and at least one second sealing member provided between the bearing on at least the suction opening side and the rotor chamber and communicated with the atmosphere, the first and second sealing members being arranged in this order from the rotor chamber side.

Abstract: A pair of dry-sealed screw rotors for compressors which includes rotor tooth profiles in which an inter-tooth gap at a profile point on male and female rotor of a normal temperature is determined by an amount of interference due to thermal expansion caused during the operation of the compressors and an amount of minimum safety clearance necessary for the operation. The inter-tooth gap is further determined by a total thickness of seal coatings applied to the peripheral surfaces of the rotors at a profile point at which the thus determined gap is smaller than the total thickness of seal coatings. With the thus shaped rotor teeth, a most preferable seal line is achieved so as to produce an improved compression efficiency.

Abstract: A screw rotor mechanism which includes a female rotor F having tooth crests each being formed by a leading side arc g2-a2 overlying a tooth tip circle Cf thereof and a following side are a2-b2 having its center at a point 07 on a pitch circle Pf thereof, and a male rotor M having tooth tips each being formed by an arc c1-d1 having its center at an interaxial line passing through axes Of,Om of the female and male rotors F,M. The male rotor M also has tooth bottoms being complementary to tooth female tooth crests or tips and forms no seal grooves thereon. The thus shaped rotors are adapted to be machined with a high efficiency by a gear hobbing machine.