Abstract: A rotary shaft is rotatable relative to a motor rotor. A first end face of the motor rotor is exposed to the outside of a stator. A hammer portion is provided at the first end face. The hammer portion is configured to be movable as the motor rotor rotates. A collision portion rotating integrally with the rotary shaft is configured to collide with the hammer portion. The allowance space between the collision portion and the hammer portion allows the hammer portion to be move relative to the collision portion. Therefore, the electric pump is capable of detaching a rotor from a pump chamber without increasing the size of the pump.

Abstract: A roots type fluid machine includes a housing, a pair of parallel rotary shafts and two-lobe rotors. Each rotor includes two lobe portions and two well portions. Each lobe portion has a profile of convex arc with a radius R and each well portion has a profile of concave arc which is an envelope of the convex arc of the lobe portion. The rotor has a configuration defined by a curve which includes the convex arc, the concave arc and further an involute curve with a base radius r between the convex and concave arcs. The base radius r is set in a range L/(2?{square root over ( )}2)<r<0.3(?{square root over ( )}2)L where distance between axes of the rotary shafts is L, and the radius R is set in a range {(?{square root over ( )}2)/16}?L<R<{(27?5?{square root over ( )}2)/56}L.

Abstract: A compressor has a compression unit for compressing gas to a desired pressure, a drive shaft and a balancer. The drive shaft is connected to the compression unit for driving the compression unit. Imbalance on the drive shaft is generated due to movement of the compression unit. The balancer is mounted on the drive shaft and includes a main portion and adjustable portion for correcting the imbalance on the drive shaft. Preferably, at least one of the weight and the shape of the adjustable portion is adjustable.

Abstract: The present invention relates to a novel resin composition useful as a coating agent or a binder for medicines, drugs for animals, agricultural chemicals, fertilizers, foods or the like, which contains a polyvinyl alcohol copolymer as a main component. More particularly, the present invention relates to a resin composition, characterized in that the composition is obtained by copolymerizing a polyvinyl alcohol having an average polymerization degree of 1300 or less, and at least one polymerizable vinyl monomer in a weight ratio of 6:4 to 9:1.

Abstract: A roots compressor has a housing, a rotary shaft, a rotor and a layer. The housing defines a pump chamber, a suction port and a discharge port. The suction port and the discharge port adjoin to the pump chamber. The rotary shaft is rotatably supported by the housing. The rotor is connected to the rotary shaft and contained in the pump chamber. Fluid introduced into the pump chamber through the suction port is discharged to the outside of the pump chamber through the discharge port by rotation of the rotor which is driven through the rotary shaft. The layer is formed on an inner peripheral surface of the housing, which defines the pump chamber. The layer is thinner from a side adjacent to the suction port toward a side adjacent to the discharge port in circumferential direction of the housing.

Abstract: A motor-driven Roots compressor includes a drive shaft driven by a motor and a driven shaft connected to a drive shaft through a timing gear. A pair of rotors is respectively fixed to the drive shaft and the driven shaft. The rotors are rotated so that the compressor draws and discharges working fluid. The compressor also includes a casing having a plurality of shells which define a motor chamber for accommodating the motor, a gear chamber for accommodating the timing gear and a rotor chamber for accommodating the pair of rotors. A refrigerant passage is formed in at least one of the shells of the motor chamber and the gear chamber for flowing the working fluid therein. At least one of the motor and the timing gear is cooled by the working fluid in the refrigerant passage.

Abstract: A starting system for a pump includes a driving motor, an electric source, a selector switch, a starter sensor, a temperature sensor and a control unit. The selector switch is located between the driving motor and the electric source for reversing polarity of the electric power supplied from the electric source to the driving motor. The starter sensor senses whether or not the driving motor has been started. The temperature sensor senses a temperature. The control unit operates the selector switch so as to repeatedly give the driving motor indications of reverse rotation and normal rotation in a case where the starter sensor does not sense that the driving motor has been started even if the control unit operates the selector switch so as to give the driving motor the indication of normal rotation in a state where the temperature sensed by the temperature sensor is below a preset temperature.

Abstract: A compressor includes a housing member having a through hole. The compressor includes a conductive portion through which external electricity is supplied to a motor mechanism. The conductive portion has a lead extending from the motor mechanism, and a connector terminal. The connector terminal is connected to the lead to permit the external electricity to be conducted to the lead. The connector terminal is attached to the through hole such that a joint between the lead and the connector terminal is located in the through hole to face inward of the housing member. A viscoelastic insulating material fills the through hole. Therefore, the compressor ensures reliable insulation of the terminal from a housing member.

Abstract: A fluid machine includes a motor and a motor housing. The motor housing defines a motor chamber for accommodating the motor. The motor chamber is filled with inert gas. A rotor rotates in accordance with rotation of the motor. A pump housing defines a pump chamber for accommodating the rotor. A dividing wall is located between the pump housing and the motor housing. The pump housing and the motor housing are attached to each other via the dividing wall. Therefore, water is prevented from being generated in the motor chamber even if fluid that contains hydrogen leaks from the pump chamber to the motor chamber.

Abstract: A fuel cell system includes a fuel cell stack, a hydrogen flowing passage, an air flowing passage and a control valve. At least one of the gas flowing passages includes a bypass, a selecting means, a gas flowing means and a control unit. The bypass allows a gas to flow therethrough so as to detour the fuel cell stack and the control valve. The selecting means selects one of a passage which passes through the fuel cell stack and the bypass. The gas flowing means flows the gas to the bypass. In the control unit, the through passage is selected by the selecting means when the system is operated, The bypass is selected by the selecting means when the operation of the system is stopped. The gas is flowed to the bypass by operating the gas flowing means when the control valve is frozen thereby heating the control valve.

Abstract: A fluid compressor that ensures the discharge of water from a discharge port when water is drawn into or condensed in a pump chamber. The compressor includes a pump chamber for drawing in fluid. The pump chamber includes a bottom part located in a lower portion of the pump chamber. Two rotors arranged in the pump chamber are rotated to compress the fluid in the pump chamber. A discharge port located in the bottom part discharges the compressed fluid out of the pump chamber. The bottom part defines a guide surface formed continuously from the discharge port. The guide surface is sloped downward so that water on the guide surface moves downward to the discharge port due to gravitational force.

Abstract: A starting system for a pump includes a driving motor, an electric source, a selector switch, a starter sensor, a temperature sensor and a control unit. The selector switch is located between the driving motor and the electric source for reversing polarity of the electric power supplied from the electric source to the driving motor. The starter sensor senses whether or not the driving motor has been started. The temperature sensor senses a temperature. The control unit operates the selector switch so as to repeatedly give the driving motor indications of reverse rotation and normal rotation in a case where the starter sensor does not sense that the driving motor has been started even if the control unit operates the selector switch so as to give the driving motor the indication of normal rotation in a state where the temperature sensed by the temperature sensor is below a preset temperature.

Abstract: A compressor has a compression unit for compressing gas to a desired pressure, a drive shaft and a balancer. The drive shaft is connected to the compression unit for driving the compression unit. Imbalance on the drive shaft is generated due to movement of the compression unit. The balancer is mounted on the drive shaft and includes a main portion and adjustable portion for correcting the imbalance on the drive shaft. Preferably, at least one of the weight and the shape of the adjustable portion is adjustable.

Abstract: A multistage gear pump for pressurizing fluid includes a housing, a drive shaft and a gear assembly. The drive shaft is rotatably supported in the housing. The gear assembly is disposed in the housing. The gear assembly includes at least first and second gear trains. Each train has a pair of drive and driven gears that are engaged with each other. The drive gear is provided on the drive shaft and followed by the driven gear. The first gear train and the second gear train are arranged so that fluid sequentially passes therethrough as the drive shaft rotates. A theoretical discharge capacity of the first gear train is larger than that of the second gear train.

Abstract: An electric pump draws and discharges fluid. When the fluid receives heat from the pump, the fluid has a saturation vapor pressure that can surpass the pressure of fluid that is drawn into the pump and is lower than the pressure of fluid discharged from the pump. The pump includes an electric motor; a pump section that is driven by the electric motor to draw, pressurize, and discharge the fluid; and a housing for accommodating the pump section. The housing defines a motor chamber that accommodates the electric motor. The pressure in the motor chamber is equal to the pressure of fluid that is discharged from the pump section. Therefore, the pump prevents fluid in the motor chamber from vaporizing.

Abstract: A scroll type compressor includes a fixed scroll member and a movable scroll member to define compression chambers. The movable scroll member orbits relative to the fixed scroll member to compress gas in the compression chambers. The compressed gas is discharged to a discharge port. The compressor also includes a filter chamber and a cooling chamber. The filter chamber communicates with the discharge port for accommodating a first filter to at least partially filter the compressed gas. The cooling chamber is located adjacent to the filter chamber for containing coolant fluid that cools the compressed gas in the filter chamber.

Abstract: A two-stage gear pump has a pump section. The pump section has an internal space that is located adjacent to a driven gear and about a cylindrical surface of the driven shaft. A discharge section of a first gear train is connected to a suction section of a second gear train with a communication passage. The internal space is connected to the communication passage with a pressure introduction passage. The pressure of the communication passage is introduced to the internal space by the pressure introduction passage, so that the pressure atmosphere of the internal space is an intermediate pressure atmosphere of the suction pressure and the discharge pressure of the pump section.

Abstract: A scroll type compressor has a housing, a fixed metal scroll member and a movable metal scroll member. The fixed and the movable scroll members each have a base plate and scroll wall extending therefrom. The fixed scroll member is fixed to the housing. The movable scroll member engages the fixed scroll member to trace an orbital motion when driven by a crank mechanism. The scroll members define compression chambers. Resin tip seals are respectively provided on distal ends of the scroll walls and slidably engage the metallic surfaces of the facing base plates. The tip seals seal the compression chambers. A resin coating layer is formed on a region of at least one of the end surfaces of the base plates that is not contacted by a tip seal.

Abstract: A rotating shaft seal provided with a seal element, arranged between a housing and a rotation shaft, which contacts the rotation shaft, and a seal member made of rubber having a lip end portion, disposed on a fluid storing chamber side to the seal element, which contacts the rotation shaft, comprising a supporting metal for supporting a rear face of the seal member of rubber.

Abstract: A rotating shaft seal provided with a seal element, arranged between a housing and a rotation shaft, which contacts the rotation shaft, and a seal member made of rubber having a lip end portion, disposed on a fluid storing chamber side to the seal element, which contacts the rotation shaft, comprising a supporting metal for supporting a rear face of the seal member of rubber.