A screw compressor includes: a male rotor 2 and a female rotor 3 including a rotor tooth section 21, 31 that has multiple helical teeth, the male rotor 2 and the female rotor 3 rotating in engagement with each other; a casing 4 including a main casing 41 with a bore 45 formed to accommodate the male rotor 2 and the female rotor 3, and a discharge-side casing 43 closing a discharge side of the bore 45; and a discharge passage 60 including a discharge port 61 that opens in a rotational axis direction of the male rotor 2 and the female rotor 3 on a bore side surface of the discharge-side casing 43, compressed gas flowing from the discharge port 61 circulating in the discharge passage 60. The male rotor 2 and the female rotor 3 are configured such that a discharge-side end surface 21a, 31a of the rotor tooth section 21, 31 serves as a discharge-side distal end of the male rotor 2 or the female rotor 3 in the rotational axis direction. The discharge passage 60 includes an enlarged flow passage section 63 formed such that the enlarged flow passage section 63 extends from the discharge port 61 in the rotational axis direction of the male rotor 2 and the female rotor 3 and that a flow passage cross-sectional area is gradually enlarged from the discharge port 61 to a downstream side in a compressed gas flow direction.

A screw compressor includes a first rotor and a second rotor, and each rotor is provided with a synchronisation gear. The screw compressor is further provided with an electric motor and one or two driving gears for driving the first rotor or second rotor. At least one of the synchronisation gears or driving gears is provided with spokes between a rim supporting a gear mesh and a corresponding gear hub.

An oil-injected vacuum pump element, where two mating helical rotors are rotatably provided in a housing, where this housing includes an inlet port and an outlet end face with an outlet port, where compression chambers are formed between the helical rotors and the housing. The vacuum pump element is provided with a connection that extends from a first compression chamber to a second smaller compression chamber at the outlet end face, where this first compression chamber is at a lower pressure than the second compression chamber and where this second compression chamber can make connection with the outlet port upon rotation of the helical rotors, where the connection is such that a flow from the second compression chamber to the first compression chamber is possible, where the connection is not directly connected to the outlet port.

The present invention relates to highly efficient suction and compression rotating mechanisms, particularly the compression mechanism with piston blocks mounted on two axes and driven by a pair of matching gears in the field of compressors and vacuums or hydraulic system such as oil pump, hydraulic motor, hydraulic gearbox, specifically there is application that uses this mechanism to create one rotary motor with multi compression stages, force-generating stages and continuous fuel burning regime. The new rotary lobe structure in this invention provides a close contact between curved surfaces with the same radius, which is a Surface-to-surface contact, with much better tightness than line contact.

A transmission between a drive shaft and a driven shaft comprises a housing and at least a driven gearwheel that is mounted on the driven shaft and a drive gearwheel that is mounted on a drive shaft. The housing comprises two separated chambers, i.e. a first chamber that is connected to the driven shaft and a second chamber which is separate from the first chamber, whereby the first chamber is connected via a channel with the second chamber, whereby around the drive gearwheel or driven gearwheel the second chamber is formed, whereby the form of the second chamber is such that when the gearwheel in question rotates, a gas flow is created around this gearwheel which causes a negative pressure in the channel by the venturi effect.

A method for repairing a worn portion in an inner diameter surface of a bore of a cast iron part is disclosed. The inner diameter surface of the bore may have an original surface geometry prior to wear. The method may comprise forming a crescent-shaped pocket in the inner diameter surface of the bore to remove the worn portion, installing an insert in the crescent-shaped pocket, and post-machining the insert to form a crescent-shaped insert that is flush with the original surface geometry of the bore inner surface diameter.

Transmission between drive shaft and a driven shaft, which transmission includes a housing and at least a driven gearwheel that is mounted on the driven shaft and a drive gearwheel that is mounted on a drive shaft. The housing is provided with an outlet opening, which outlet opening is placed in the radial extension of one of the gearwheels.

A compressor provided with a compressor element with a driven shaft, a motor with a drive shaft to drive the compressor element, and a transmission between the drive shaft and the driven shaft. The transmission includes a housing and at least a driven gearwheel that is mounted on the driven shaft and a drive gearwheel that is mounted on a drive shaft. The housing includes two separated chambers, a first chamber that is connected to the driven shaft and a second chamber which is separate from the first chamber. The first chamber is connected via a channel with the second chamber, whereby around the drive gearwheel or driven gearwheel, the second chamber is formed. The form of the second chamber is such that when the gearwheel in question rotates, a gas flow is created around this gearwheel which causes a negative pressure in the channel by the venturi effect.

The invention relates to a rotor pair for a compressor block of a screw machine, wherein the a rotor pair comprises a secondary rotor that rotates about a first axis and a main rotor that rotates about a second axis, wherein the number of teeth of the main rotor is 3 and the number of teeth of the secondary rotor is 4. The relative profile depth of the secondary rotor is at least 0.5, preferably at least 0.515, and at most 0.65, preferably at most 0.595. rk1 is an addendum circle radius drawn around the outer circumference of the secondary rotor and rf1 is a dedendum circle radius starting at the profile base of the secondary rotor, wherein the ratio of the axis distance of the first axis from the second axis and the addendum circle radius rk1 is at least 1.636, and at most 1.8, preferably at most 1.733.

A Rotary Claw Pump with at least one pair of intermeshing rotors has the same shape within a tolerance of 3% of the radii from edges to rotational centers. A convex portion of the claws has a nominal uniform rate of radius change with angle of rotation. There may be multiple stages wherein the thickness of each successive rotor pair maintains profile but has a thickness within 20% of the thickness of the first stage rotor pair multiplied by the inverse products of the compression ratios of the preceding stages. A discharge port is at least partially uncovered at any position of rotation from where intermeshing claw rotor tips are closest to where they are most distant. The discharge port is at least partially connected with a region connected with the rotor tips of both claws during rotation. The discharge port limits pressure increase in the region.