Abstract: In a pump chamber (12), a male rotor (20) having claw portions and a female rotor (24) having recesses into which the claw portions enter are secured to rotating shafts (18a and 18b), respectively. The female rotor is provided with hollows on an upstream side in the rotational direction of the female rotor relative to a plane L containing the rotating shafts. For the hollows, the disposed position, size and configuration are selected so that a compression pocket P and a discharge opening remain in communication with each other through the hollow throughout the time from when the compression pocket stops communicating with the discharge opening and separates from the discharge opening until the compression pocket gradually reduces to disappear, and so that the hollow stops communicating with the discharge opening at the same time as the compression pocket disappears.

Abstract: A scroll fluid machine includes a revolving scroll in which a revolving wrap stands upright on an end plate supported revolvably on a drive shaft, and a fixed scroll which is provided opposite the revolving scroll and in which a fixed wrap stands upright on an end plate. The revolving and fixed wraps overlap to form a compression chamber for compressing a fluid by causing the revolving scroll to revolve. The scroll fluid machine further includes a rod-shaped member attached to the end plate of the revolving scroll and extending to a rear surface side of the fixed scroll, which is a side not opposing the revolving scroll. A revolving plate is attached to the rod-shaped member, provided with a pin crank mechanism, and supported revolvably on the drive shaft. The revolving plate is provided with a sealing unit that seals the compression chamber in an axial direction.

Abstract: In a pump chamber (12), a male rotor (20) having claw portions and a female rotor (24) having recesses into which the claw portions enter are secured to rotating shafts (18a and 18b), respectively. The female rotor is provided with hollows on an upstream side in the rotational direction of the female rotor relative to a plane L containing the rotating shafts. For the hollows, the disposed position, size and configuration are selected so that a compression pocket P and a discharge opening remain in communication with each other through the hollow throughout the time from when the compression pocket stops communicating with the discharge opening and separates from the discharge opening until the compression pocket gradually reduces to disappear, and so that the hollow stops communicating with the discharge opening at the same time as the compression pocket disappears.

Abstract: A scroll fluid machine includes a revolving scroll in which a revolving wrap stands upright on an end plate supported revolvably on a drive shaft, and a fixed scroll which is provided opposite the revolving scroll and in which a fixed wrap stands upright on an end plate. The revolving and fixed wraps overlap to form a compression chamber for compressing a fluid by causing the revolving scroll to revolve. The scroll fluid machine further includes a rod-shaped member attached to the end plate of the revolving scroll and extending to a rear surface side of the fixed scroll, which is a side not opposing the revolving scroll. A revolving plate is attached to the rod-shaped member, provided with a pin crank mechanism, and supported revolvably on the drive shaft. The revolving plate is provided with a sealing unit that seals the compression chamber in an axial direction.

Abstract: A multistage vacuum pump has a pair of rotors disposed in each of pump chambers connected in stages. As the rotors rotate while intermeshing, a suctioned gas is compressed and discharged, angles of the rotors are adjusted so that a phase angle ?? of the rotors of adjacent pump chambers relative to a rotation angle C of the rotors during a single cycle of the pump chambers from intake to discharge and the number of stages S of the rotors satisfies ???C/S. When a rotor angle is ?1, an mth stage rotor angle is ?m, and an nth stage rotor angle is ?n in order from an upstream side of a gas flow direction, relationships of ?1<?m??n and ?1<?n, where n and m are natural numbers and n>m, are satisfied.

Abstract: A multistage vacuum pump unit can save a power requirement and prevent the gas discharged outside of the unit from flowing-back inside the pump unit. A plurality of vacuum pumps are connected in series to form the multistage vacuum pump unit. A suction inlet of a first stage vacuum pump thereof is connected to a to-be-vacuumized container so that the space inside of the container becomes under a high vacuum condition. In an operating method, part of the gas discharged into a first intermediate passage from the first stage vacuum pump is branched during a low vacuum operation, and discharged toward an air atmosphere through a low conductance line provided with check valves that prevent the branched gas from flowing back.

Abstract: A multistage vacuum pump has a pair of rotors disposed in each of pump chambers connected in stages. As the rotors rotate while intermeshing, a suctioned gas is compressed and discharged, angles of the rotors are adjusted so that a phase angle ?? of the rotors of adjacent pump chambers relative to a rotation angle C of the rotors during a single cycle of the pump chambers from intake to discharge and the number of stages S of the rotors satisfies ???C/S. When a rotor angle is ?1, an mth stage rotor angle is ?m, and an nth stage rotor angle is ?n in order from an upstream side of a gas flow direction, relationships of ?1??m??n and ?1<?n, where n and m are natural numbers and n>m, are satisfied.

Abstract: A multistage vacuum pump unit can save a power requirement and prevent the gas discharged outside of the unit from flowing-back inside the pump unit. A plurality of vacuum pumps are connected in series to form the multistage vacuum pump unit. A suction inlet of a first stage vacuum pump thereof is connected to a to-be-vacuumized container so that the space inside of the container becomes under a high vacuum condition. In an operating method, part of the gas discharged into a first intermediate passage from the first stage vacuum pump is branched during a low vacuum operation, and discharged toward an air atmosphere through a low conductance line provided with check valves that prevent the branched gas from flowing back.

Abstract: A drive transmission mechanism for transmitting torque between two or more rotary shafts in synchronization with one another without need for lubrication thereby eliminating occurrence of oil contamination, and an oil-free fluid machine equipped with the mechanism, are provided. A magnetic drive disk and a synchronization gear are attached to a rotary shaft connected to a drive motor, a magnetic drive disk and a synchronization gear is attached to a rotary shaft, torque transmission from the rotary shaft to the rotary shaft is carried out in two ways, via the magnetic drive disks and via the synchronization gears and at least one of the synchronization gears is made of plastic material. With the construction, torque transmit load between the rotary shafts via the synchronization gears is decreased, and a plastic gear or gears can be adopted for synchronization gears without reducing life of the gears without need for lubrication oil.

Abstract: A drive transmission mechanism for transmitting torque between two or more rotary shafts in synchronization with one another without need for lubrication thereby eliminating occurrence of oil contamination, and an oil-free fluid machine equipped with the mechanism, are provided. A magnetic drive disk 16 and a synchronization gear 18 are attached to a rotary shaft 14 connected to a drive motor 11, a magnetic drive disk 17 and a synchronization gear 19 is attached to a rotary shaft 15, torque transmission from the rotary shaft 14 to the rotary shaft 15 is carried out in two ways, via the magnetic drive disks 16, 17 and via the synchronization gears 18, 19, and at least one of the synchronization gears is made of plastic material. With the construction, torque transmit load between the rotary shafts via the synchronization gears is decreased, and a plastic gear or gears can be adopted for synchronization gears without reducing life of the gears without need for lubrication oil.

Abstract: An oil-free fluid machine unit is provided of which the fluid machine has two or more rotors and torque transmission between the rotors can be performed without a need of using lubrication oil thereby eliminating contamination induced by lubrication oil and without reduction of longevity of the synchronizing gears. The drive shaft 12 of the drive motor 11 is connected to the rotor shaft 14 of the fluid machine, synchronization gears 18 and 19 are attached to the rotor shafts 14 and 15 at the motor 11 side end of the rotor shafts respectively, and pulleys 16 and 17 are attached to the rotor shafts 14 and 15 at the other side ends respectively opposite to the motor 11 and a belt is looped over the pulleys so that the pulleys are rotated in counter direction to each other. At least one of the synchronization gears is made of plastic material. Thus, torque transmission between the rotors is done in two ways, via synchronization gear drive and belt drive.

Abstract: The present invention proposes an evacuation apparatus including a mechanical booster pump 5, a back pump 3 placed at a down-stream side of the mechanical booster pump in series, the booster pump 5 having discharge openings 27a and 27b for discharging a low compression gas and a discharge opening 29 for discharging a high compression gas, and, in a stage where gas-discharging is started, the gas is discharged toward the ambient side through the discharge opening 29 for discharging a high compression gas with the operation of the mechanical booster pump and, in a stage where the discharged gas pressure reaches afterward a medium vacuum, the back pump starts operation and the gas is sent to the back pump through the discharge openings 27a and 27b for discharging a low compression gas.

Abstract: The present invention discloses an evacuation apparatus for evacuating a tank, a chamber, and the like; wherein a mechanical vacuum booster pump is provided at an up-stream side of an exterior side vacuum pump; wherein the mechanical booster pump has a discharge openings for low compression and a discharge opening for discharging a high compression gas; wherein, in case when the exterior side vacuum pump starts discharging a gas, the gas is sent to the exterior side vacuum pump through all of the discharge openings for low compression and the discharge opening for discharging a high compression gas and, in case when the discharged gas pressure reaches afterward an ultimate pressure (a medium vacuum) attainable by the exterior side vacuum pump, the gas is sent to the exterior side vacuum pump only through the discharge opening for discharging a high compression gas.