Abstract: A claw pump includes: a housing; two rotating shafts which are disposed parallel; a pair of rotors respectively fixed to the two rotating shafts; a rotary drive device driving the pair of rotors; and a suction port and discharge ports formed in a partition wall of the housing. The discharge ports are constituted by a first discharge port and a second discharge port. The first discharge port is formed at a position that communicates with an initial stage compression space formed at an initial stage of a compression stroke in a compression space that is formed by joining a first pocket and a second pocket. The claw pump includes an opening/closing mechanism which opens the first discharge port when a pressure of the initial stage compression space reaches a threshold and closes the first discharge port when the pressure does not reach the threshold.

Abstract: A claw pump includes: a housing; two rotating shafts which are disposed parallel; a pair of rotors respectively fixed to the two rotating shafts; a rotary drive device driving the pair of rotors; and a suction port and discharge ports formed in a partition wall of the housing. The discharge ports are constituted by a first discharge port and a second discharge port. The first discharge port is formed at a position that communicates with an initial stage compression space formed at an initial stage of a compression stroke in a compression space that is formed by joining a first pocket and a second pocket. The claw pump includes an opening/closing mechanism which opens the first discharge port when a pressure of the initial stage compression space reaches a threshold and closes the first discharge port when the pressure does not reach the threshold.

Abstract: In a scroll fluid machine, a driving shaft has an eccentric axial portion around which an orbiting scroll revolves while the orbiting scroll engages with a fixed scroll. A cooling path extends through the driving shaft to a gap between the outer circumferential surface of the eccentric axial portion and the inner circumferential surface of an axial hole of the orbiting scroll. A cooling gas is introduced into the cooling path to cool bearings around the driving shaft. A forced convection generating portion is provided on the driving shaft for sucking the cooling gas into the gap and discharging the 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.

Abstract: In a scroll fluid machine, a driving shaft has an eccentric axial portion around which an orbiting scroll revolves while the orbiting scroll engages with a fixed scroll. A cooling path extends through the driving shaft to a gap between the outer circumferential surface of the eccentric axial portion and the inner circumferential surface of an axial hole of the orbiting scroll. A cooling gas is introduced into the cooling path to cool bearings around the driving shaft. A forced convection generating portion is provided on the driving shaft for sucking the cooling gas into the gap and discharging the gas.

Abstract: In a scroll fluid machine, an orbiting scroll is eccentrically revolved with respect to a stationary scroll so that fluid in a sealed chamber between the stationary and orbiting scrolls may be compressed toward a center. A first magnet is mounted on the stationary scroll and a second magnet is mounted on the orbiting scroll so that the same poles of the first and second scrolls may be opposite to each other thereby preventing the orbiting scroll from pressing the stationary scroll excessively.

Abstract: In a scroll fluid machine, an orbiting scroll is eccentrically revolved with respect to a stationary scroll so that fluid in a sealed chamber between the stationary and orbiting scrolls may be compressed toward a center. A first magnet is mounted on the stationary scroll and a second magnet is mounted on the orbiting scroll so that the same poles of the first and second scrolls may be opposite to each other thereby preventing the orbiting scroll from pressing the stationary scroll excessively.

Abstract: A scroll vacuum pump has an orbiting scroll and fixed scrolls. The orbiting scroll is rotatably mounted to an eccentric portion of a driving shaft and revolved by the driving shaft, so that a gas is sucked into a compression chamber between the orbiting scroll and fixed scrolls through a sucking bore. External air is introduced through a ventilating hole axially formed in the driving shaft and into the compression chamber via a check valve that opens by centrifugal force when the driving shaft rotates, thereby cooling the eccentric portion and bearings to increase durability thereof. When the driving shaft stops, the check valve closes, so that a toxic gas in the compression chamber is not leaked to the outside to prevent environment pollution.