Abstract: An impeller (1) for an implantable vascular support system (2) is provided. The impeller includes an impeller body (3) having a first longitudinal portion (4) and a second longitudinal portion (5) forming a first inner rotor (12) having at least one magnet encapsulated in the second longitudinal portion (5). At least one blade (6) formed in the first longitudinal portion (4) is configured to axially convey a fluid upon rotation. A second outer rotor (13) extends axially and includes at least one magnet. The first rotor (12) and the second rotor (13) form a magnetic coupling (14). The magnets of the first and second rotor being arranged to partially axially overlap with an axial offset and are entirely radially offset.

Abstract: Disclosed is a cabin air compressor (CAC) of an aircraft environmental control system, the CAC having: a CAC case defining a forward end, an aft end axially spaced apart from the forward end, wherein the forward end defines a compressor inlet; and a supplemental cooling jacket, positioned around at least a portion of the CAC case and at least partially conforming the CAC case, and wherein the supplemental cooling jacket is configured to direct a cooling medium through it.

Abstract: A seal section of a submersible well pump assembly has an expandable and contractible bag surrounded by a pressure equalizing chamber. A motor lubricant communication path communicates motor lubricant the bag interior. A well fluid port admits well fluid into the pressure equalizing chamber. A gas vent passage leads from the pressure equalizing chamber to the exterior of the enclosure. At least one membrane in the gas vent passage allows gas contained in the well fluid in the pressure equalizing chamber to vent. The membrane blocks liquid from flowing through the gas vent passage into and out of the pressure equalizing chamber.

Abstract: An electric motor-vehicle coolant pump includes a pump housing with a flow housing part and a separate motor housing part, a spiral flow channel with an axial inlet and a tangential outlet, a rotatably supported fluid-conveying element, an electric drive motor which drives the rotatably supported fluid-conveying element, and a mounting structure which mounts the pump housing to a vehicle structure. The mounting structure is only arranged on the flow housing part. The flow housing part at least partially surrounds the spiral flow channel and at least partially surrounds the rotatably supported fluid-conveying element. The separate motor housing part surrounds the electric drive motor.

Abstract: A coolant pump for a vehicle includes an impeller mounted at one side of a shaft and configured for pumping a coolant, a pulley mounted at the other side of the shaft and configured for receiving a torque, a pump housing including an inlet for allowing the coolant to flow in and an outlet for allowing the coolant to flow out, a shroud disposed within the pump housing for selectively closing or opening the outlet and an operation portion selectively moving the shroud.

Abstract: A submersible well pump assembly has a communication path for communicating motor lubricant to an interior of a pressure equalizer. A check valve passage with a check valve leads from the communication path to a pressure equalizing chamber. A dip tube has a dip tube inlet at the check valve passage below the check valve and a dip tube outlet in the pressure equalizing chamber. The dip tube is filled with motor lubricant to retard migration of well fluid from the pressure equalizing chamber into contact with the check valve.

Abstract: A milk pump that is connected to, but electrically isolated from dairy lines, pipes, and other electrically conductive components using insulators in the milk pump between a motor and a pump.

Abstract: A double-ended blower includes a blower motor assembly supporting opposed first and second shaft ends. The first and second shaft ends have respective first and second impellers attached thereto and enclosed within first and second volutes, respectively. The first volute is connected to an inlet and the second volute is connected to an outlet. The blower motor assembly is supported in a chassis enclosure and a radially outer inter-stage path is between the first and second volute. The second volute is at least partially substantially concentrically nested with the radially outer inter-stage gas path.

Abstract: A submersible well pump assembly includes a seal unit coupled between a pump and a motor. The seal unit has a forward guide member, a rearward guide member, and a labyrinth disc chamber connected between. The labyrinth disc chamber has an outer wall, a concentric guide tube and a number of axially spaced apart discs extending between the guide tube and the outer wall, defining cavities between the discs. Disc ports extend through the discs to communicate fluid between the cavities, the ports being at multiple angular locations relative to each other. A drive shaft extends through the guide tube, the forward guide member bore and the rearward guide member. The outer wall, the guide tube and the discs are made of a single-piece member.

Abstract: A motorized pump assembly includes a pump and a motor for driving the pump. The pump includes a pump housing that at least in part defines a pump chamber. The motor includes a stator, a rotor rotatable about an axis, a motor housing, and a bearing assembly. The rotor includes a motor shaft extending along the axis. The motor housing includes an endshield that at least in part defines a motor chamber in which the stator and the rotor are at least substantially received. The bearing assembly rotatably supports the motor shaft on the endshield. The pump housing and the endshield are fixed to one another and cooperatively at least in part define an overflow chamber adjacent the pump chamber. The endshield defines a drainage channel fluidly interconnected with the overflow chamber and configured to direct fluid from the overflow chamber away from the bearing assembly.

Abstract: The invention relates to a pump arrangement, in particular a centrifugal pump, in particular a main coolant pump for power stations, comprising a pump housing (2), which defines an interior (3) with an inlet opening (4) for aspirating a conveying medium and with an outlet opening (5) for expelling the conveying medium and which also defines a chamber (7) that is connected to the interior (3), a seal water system (22), which has a first conduit system (29) in order to supply seal water into the chamber (7) defined by the pump housing (2), a second conduit system (32) for evacuating a controlled leakage flow from the chamber (7) defined by the pump housing (2), and a protective valve (35), which is arranged in the second conduit system (32) in order to block the leakage flow that is evacuated from the chamber (7). The invention further relates to a protective valve (35) and to the use of a protective valve (35) in a pump arrangement (1).

Abstract: A modular seal section for use within a downhole pumping system includes an upper fluid compensation section, a lower fluid compensation section and a guide body connected between the upper fluid compensation section and lower fluid compensation section. The guide body includes a configuration selection mechanism that can be externally manipulated to selectively place the upper fluid compensation section in either a series or parallel configuration with the lower fluid compensation section.

Abstract: A milk pump that is connected to, but electrically isolated from dairy lines, pipes, and other electrically conductive components using insulators in the milk pump between a motor and a pump.

Abstract: An impeller comprising: a top shroud; a bottom shroud, a plurality of vanes extending from the top shroud to the bottom shroud, each said vane including a top edge at a radially inner portion of the vane in contact with the top shroud and a bottom edge at a radially outer portion of the vane in contact with the bottom shroud, such that a radially inner portion of the vane at the bottom edge of each vane is not in contact with or adjacent the bottom shroud and a radially outer portion of the vane at the top edge of each vane is not in contact with or adjacent the top shroud.

Abstract: A submersible pump assembly has modules, including a rotary pump, an electrical motor, and a seal section located between the motor and the pump. The seal section has a tubular housing with a lower adapter secured to the housing and joining the seal section with the motor. An upper adapter is secured to the housing and joins the seal section with another one of the modules. An inlet port in the upper adapter admits well fluid into the housing. A tubular, flexible compensator element has an upper end sealed to the upper adapter and a lower end sealed to the lower adapter. A communication passage in the lower adapter admits lubricant from the motor into the compensator element. A cap is mounted around the upper end of the compensator element. The cap has a skirt extending radially outward to limit upward expansion of the compensator element.

Abstract: An oil-hydraulic unit includes a power module generating heat when energized. The power module is provided on the bottom surface of a recess facing hydraulic oil in a tank. Thus, the power module is cooled by the hydraulic oil in the tank. This reduces the difference in temperature between the power module and the hydraulic oil in the tank. In the oil-hydraulic unit, the temperature sensor detects the temperature of the power module. The oil temperature in the tank is estimated based on the temperature detected by the temperature sensor.

Abstract: Apparatus is provided featuring a casing assembly, a shaft and an integral bellows type mechanical face seal. The casing assembly has an enclosing tube configured to house a stationary bearing and to contain lubricating oil. The shaft is configured to rotate in relation to the stationary bearing, the shaft having a rotating seal with a rotating sealing face.

Abstract: An apparatus, system and method for sealing an electrical submersible pump assembly are described. An electric submersible pump (ESP) system for pumping solid-laden fluid comprises a thrust chamber of an ESP seal section, the thrust chamber sealed from well fluid on a downstream side by a stationary sand barrier and on an upstream side by a mechanical seal, the thrust chamber further comprising, a rotatable shaft extending axially through the thrust chamber, a head tubularly encasing the thrust chamber and threadedly coupled to a centrifugal pump intake, and a diamond-coated hydrodynamic bearing set inside the thrust chamber, wherein well fluid enters and exits the chamber through cross-drilled apertures in the head of the chamber, and wherein the well fluid forms a hydrodynamic film between the bearing set.

Abstract: Embodiments of the invention provide a pump assembly and a method for assembly the pump assembly. The pump assembly includes a stator assembly, a lower pump housing, an upper pump housing, a rotor assembly, and an isolation cup. The method includes coupling the stator assembly to the lower pump housing, overmolding an overmold material over the stator assembly and the lower pump housing, positioning the isolation cup over the overmold, and positioning the rotor assembly inside the isolation cup. The method further includes placing the upper pump housing over the rotor assembly and coupling the upper pump housing to the lower pump housing.

Abstract: A wet rotor pump with an axial flux motor that includes a stator, a containment shell, and a rotor. The stator and the containment shell are arranged in a dry zone while the rotor on an impeller is arranged in a wet zone. The wet rotor pump further has an inlet line for a fluid to be pumped by the impeller, said inlet line extending through the stator and the containment shell in an axial direction, and power electronics for controlling the stator, said power electronics being arranged within the space delimited by the stator and the containment shell.

Abstract: A pump assembly with a stator housing (18), in whose inside a wet-running electric motor with a can (14) is arranged, and with a pump housing (2) connected to the stator housing (18). An annular shaped seal (22) is arranged between the stator housing (18) and a collar (34) of the can (14) on the one hand, and the pump housing (2) on the other hand.

Abstract: The invention relates to a pump for pumping contaminated liquid comprising solid matter, the pump comprising a hydraulic unit (2), a drive unit (3), and a sealing unit (4), the hydraulic unit having a pump chamber (5) and an impeller (8) that is suspended in a drive shaft (9), said impeller and said drive shaft forming a rotatable unit, the sealing unit comprising a seal housing cover (15) that delimits said pump chamber (5) and that forms a seat for a drive shaft sealing assembly (16), the seal housing cover (15) comprising a first gap-delimiting part (20) and the rotatable unit comprising a second gap-delimiting part (21), which jointly define an axially extending gap (22) situated in the pump chamber. The pump is characterized in that, in each arbitrary radially extending plane taken through said gap (22), the first gap-delimiting part (20) has a broken circular outer gap-delimiting surface (23) at the same time as the second gap-delimiting part (21) has a broken circular inner gap-delimiting surface (24).

Abstract: A thrust module and a seal module for use in an electric submersible pump assembly is provided. The thrust module provides increased lubrication and heat dissipation while increasing sealing redundancies within the module. The thrust module includes a thrust bearing that absorbs thrust from the primary pump. A circulation pump assembly is coupled to the thrust bearing to circulate fluid through the thrust bearing and dissipate heat generated in the thrust bearing through a plurality of fins formed on an exterior surface of the circulation pump assembly. The seal module has labyrinth discs positioned within the seal module that inhibit fluid flow through the seal module. The seal module also includes check valves that release fluid from and allow fluid into the seal module at predetermined pressures. The sealing assembly is interposed between the thrust bearing and a primary pump of the electric submersible pump.

Abstract: A thermal actuator for a rotating shaft shutdown seal that has a piston with a portion of its axial length enclosed within a chamber shell with a material that expands upon a rise in temperature. The portion of the actual length of the piston within the chamber has at least two different diameters with the larger diameter leading in the direction of travel of the piston. Upon a rise in temperature, expansion of the material surrounding the piston within the chamber creates a force on the piston in the desired direction of travel. Below a preselected temperature the piston is positively locked with a passive release when the preselected temperature is reached.

Abstract: A blood pump apparatus includes a housing having a blood inlet port and blood outlet port, a pump unit including an impeller that rotates within the housing, and an impeller rotational torque generation section. The housing includes a plurality of magnetic members embedded between the impeller and the impeller rotational torque generation section for transmitting a magnetically attractive force generated by the impeller rotational torque generation section to an impeller body. The pump device includes a non-contact bearing mechanism for rotating the impeller without contacting with the inner surface of the housing when the impeller is rotated by the impeller rotational torque generation section.

Abstract: An electric submersible pump device having a motor part, a pump part, and a protector part. The protector part includes redundant shaft seal parts.

Abstract: Disclosed is a motor driven fluid pump (e.g., water pump) including a pump body having a motor chamber and a pump chamber; a bearing supporting a rotary shaft of a motor which extends from motor chamber to pump chamber in pump body; a mechanical seal disposed between rotary shaft of the motor and pump body and blocking motor chamber from pump chamber; a bearing guide integrally fixed to rotary shaft of the motor between bearing and mechanical seal; a fluidproof plate fixed to pump body to overlap bearing guide, perpendicular to rotary shaft of the motor; and a leachate exhaust aperture and a vapor exhaust aperture which are formed through pump body to communicate with the space between fluidproof plate and mechanical seal.

Abstract: An electric pump for a vehicle includes a pump body that is divided into a motor room and a pump room, a shaft that is connected to the motor room and the pump room and a sealing unit is interposed therebetween, and an impeller that is mounted on the shaft in the pump room. More specifically, a leachate exhaust passage for exhausting leachate that is leaked through the sealing unit is formed in the pump body, and the leachate exhaust passage is connected to a reaction gas exhaust portion of a fuel cell stack to aide in the exhaust of the leachate accordingly.

Abstract: A circulation pump for a domestic appliance, including a motor body, a motor, a hydraulic body attached to the motor body and including an inlet and an outlet, and a closure mechanism or member attached to the hydraulic body, a hydraulic chamber where the fluid flows, which is delimited between the hydraulic body and the closure mechanism or member. The pump includes an impeller housed in the hydraulic body and rotating, causes a substantially circular flow of the fluid in the hydraulic chamber, and a stationary element suitable or configured for aiding in discharging the fluid from the pump. The stationary element may be attached to at least one of the elements demarcating the hydraulic chamber and may be arranged in the hydraulic chamber such that it blocks or resists against the flow of the fluid.

Abstract: A submersible pumping system for downhole use in extracting fluids containing hydrocarbons from a well. In one embodiment, the pumping system comprises a rotary induction motor, a motor casing, one or more pump stages, and a cooling system. The rotary induction motor rotates a shaft about a longitudinal axis of rotation. The motor casing houses the rotary induction motor such that the rotary induction motor is held in fluid isolation from the fluid being extracted. The pump stages are attached to the shaft outside of the motor casing, and are configured to impart fluid being extracted from the well with an increased pressure. The cooling system is disposed at least partially within the motor casing, and transfers heat generated by operation of the rotary induction motor out of the motor casing.

Abstract: A pump unit includes a motor, a pump, a shaft spanning the motor and the pump, and at least a first magnetic bearing supporting the shaft. A hydrocarbon production system includes an underwater well and a pump unit exposed to an underwater environment. The pump unit is operable to pump a production fluid from the well and includes a motor, a pump, a shaft spanning the motor and the pump, and at least a first magnetic bearing supporting the shaft.

Abstract: An electric pump which includes a rotor rotationally supported by a housing at a rotation shaft, a stator positioned at an outer side in radial direction of the rotor and fixed to the housing, a pump portion for taking in and discharging fluid in response to a rotation of the rotor, and a can positioned in between the rotor and the stator for preventing the fluid in the pump portion from flowing into the stator. The can possesses conductivity. The stator is grounded via the can.

Abstract: A centrifugal electric pump, of the type comprising a shell for the containment of a set of impellers, interleaved with fixed diffusers and of a motor that drives the impellers to rotate, since they are keyed on a same shaft as the motor, a sealing chamber is provided between the impellers and the motor and is extended around the shaft to collect condensation water and water seepage originating from the set of impellers, the sealing chamber is connected to the outside of the pump by means of at least one water discharge duct.

Abstract: Subsea turbomachine for boosting the pressure of petroleum fluid flow from subsea petroleum productions wells or systems, comprising an electric motor and a compressor or pump driven by the electric motor, a fluid inlet and a fluid outlet, distinctive that the turbomachine comprises a pressure housing common for the electric motor or stator, and compressor, pump or rotor; a magnetic gear inside the common pressure housing for operative connection between the motor or stator and compressor, pump or rotor; and a partition inside the common pressure housing, arranged so as to separate a motor or stator compartment from a compressor, pump or rotor compartment.

Abstract: The invention relates to a pump, in particular a centrifugal pump (1), comprising a pump housing (2) with an inlet (3) and an outlet (4), wherein a motor shaft (11), which is connected in a rotationally fixed manner to an impeller (12) arranged in the pump housing (2), is rotatable mounted in a rear wall (5) of the pump housing (2) by means of a primary mechanical seal arrangement (14), wherein a dry run protection system is assigned to the primary mechanical seal arrangement (14). In order to avoid downtimes and to keep maintenance costs low, the dry run protection system has a fluid volume (17) that is connected to a side of the primary mechanical seal arrangement (14), which side faces away from the impeller (12).

Abstract: An electric pump comprises a stator, a rotor, and an endshield. The interface plate is fixed to the stator and is configured to couple the electric motor to a pump. The pump volute is formed as an integral portion of the endshield, thereby minimizing the axial length of the electric pump. A drainage passageway is provided on the endshield to harmlessly drain away any fluid that seeps past the pump's seals. In one embodiment of the invention, the drainage passageway is a groove that faces the stator and is configured to facilitate the evaporation of and leak fluid by channeling the fluid near the stator, which warms the fluid and thereby increases the fluid's evaporation rate.

Abstract: A pump device has a motor rotation shaft and a pump rotation shaft whose end portion is connected to an end portion of the motor rotation shaft and which drives a pump unit. The pump device includes: an outer circumferential seal portion that is arranged at either one or both of radially outer sides of the end portion of the pump rotation shaft and the end portion of the motor rotation shaft so as to overlap with either one or both of the end portion of the pump rotation shaft and the end portion of the motor rotation shaft in axial directions of the pump rotation shaft and the motor rotation shaft and has an outer circumferential seal surface; and a seal unit that makes sliding contact with the outer circumferential seal portion.

Abstract: A power supply and control unit for submersed electric motors includes an enclosure which is jointly connected to the motor of a submersed electric pump and forms a hermetic chamber that contains an electronic power supply that can be connected to the motor. The unit includes a heat exchange means in the liquid state that completely fills the empty space within the hermetic chamber in order to transfer to the enclosure the heat generated by the electronic power supply.

Abstract: An electric pump has a stator, a rotor, a pump volute, and an endshield. The pump volute and the endshield are formed together as a single monolithic part, thereby minimizing the axial length of the electric pump. A drainage passageway is provided on the endshield to harmlessly drain away any fluid that seeps past the pump's seals. In one embodiment of the invention, the drainage passageway is a groove that faces the stator and is configured to facilitate the evaporation of and leak fluid by channeling the fluid near the stator, which warms the fluid and thereby increases the fluid's evaporation rate.

Abstract: A centrifugal electric pump (1) for suction of aeriform fluids with liquids anti-infiltration device, including: an electric motor (2) equipped with a shaft (3); a cylindrical suction box (4) associated with the motor (2), provided with an intake (5) for aeriform fluid, with at least one exhaust port (6) and with a closing cover (7) also arranged for acting as base for the motor (2); at least one fan (8), fitted onto the shaft (3) and driven in movement by the motor (2); a bearing (9) interposed between the shaft and the base of the suction box; a liquids anti-infiltration device (10) arranged between the electric motor (2) and the suction box (4), provided with a gasket (11), wherein the gasket (11) rotates with the drive shaft (3) and includes a cylindrical main body (13) associated with the shaft, and a truncated-cone shaped sealing lip that cooperates with the flat face of a metal ring (12), provided between the bearing and the cover (7) of the suction box (4) to produce watertight closure of the box.

Abstract: A pump assembly with an electric motor includes a stator having an iron core (16) and windings arranged thereon and being arranged in a stator housing surrounding the electric motor to the outside. The stator housing (6) is formed as a cast component, into which the iron core (16) is cast, and the windings have been deposited on the iron core (16) after the casting of the iron core (16) into the stator housing (6).

Abstract: This invention relates to a pump system, especially for boosting the flow rate of a fluid through a pipe (1, 2, 6), comprising a pump positioned in a pump chamber (10) for pumping at a chosen rate, and a motor driving said pump, the motor being positioned in a chamber (9) being provided with a pressurized fluid, the pressure of which being higher than the pressure in the pump chamber, the motor and the pump chambers being separated by a seal (8), the seal allowing a leakage of said pressurized fluid between them, wherein the pressurized fluid is acceptable to the pump environment and the system comprises a discharge branch line (3) coupled to the pipe(6) and positioned downstream from said pump, the discharge branch line having an outlet into the environment.

Abstract: A process fluid handling device in an electrochemical cell system having a sealing system assembly between a process fluid compartment and a drive compartment of the fluid handling device. The sealing system includes a double seal configuration forming an interconnection compartment which is supplied with barrier fluid. The sealing system provides isolation of pressurized process fluids from the drive compartment.

Abstract: An alternating current-to-direct current (AC-to-DC) power supply has a first stage providing a first DC voltage and a second stage providing a second DC voltage. The AC-to-DC power supply has a first efficiency at the first stage and a second efficiency at the second stage that is less than the first efficiency. The second DC voltage is also less than the first DC voltage. A blower is electrically connected to the first stage of the AC-to-DC power supply to receive the first DC voltage from the AC-to-DC power supply to power the blower. Electrical connection of the blower to the first stage of the AC-to-DC power supply instead of to the second stage of the AC-to-DC power supply wastes less power and is more efficient.

Abstract: A pump (1) is disclosed, the pump (1) comprising a shaft (21) for driving an impeller (81) in a pump chamber (80); an electrical motor chamber (60) extending essentially circumferentially around a motor section of the shaft (21); a cooling circuit chamber (30) for being filled with a cooling liquid; and a mechanical seal chamber (40) extending essentially circumferentially around a seal section of the shaft (21), with the mechanical seal chamber (40) adapted for being filled with oil. The pump (1) may be a submersible pump.

Abstract: An electrical submersible pumping assembly having a seal section and a motor section, and seals that prevent leakage from the seal section and the motor section during assembly. The seals cooperate with a coupling assembly for coupling together shafts from both the seal section and motor section. The coupling assembly outer diameter enlarges at a shoulder that circumscribes its outer surface. In one example, the seal that prevents leakage from the seal assembly provides a sealing interface around the larger diameter portion of the coupling assembly, that is removable by sliding the coupling so its smaller diameter portion is adjacent the seal assembly. The motor section is sealed by another sealing assembly that includes a body that circumscribes the motor shaft to define an annulus, a sealing disk selectively fills the annulus. The sealing disk can also be slid away from within the body while coupling the shafts with the coupling assembly.

Abstract: A vortex pump device may include a pump case which forms a pump chamber and a stator accommodating chamber partitioned from the pump chamber, and a wiring outlet part for taking out a wiring line within the pump case to an outer side. The pump case is provided with an outer peripheral wall surrounding an upper space formed on an upper side in the stator accommodating chamber. The wiring outlet part includes a wiring outlet port which is formed by cutting out the outer peripheral wall, a wire placing part on which the wiring line taken out from the wiring outlet port to the outer side is placed, and a fixing member with which the wiring line is sandwiched and fixed between the wire placing part.

Abstract: A high performance sealing device having an excellent pressure resistance and realizing a prevention of damage. The sealing device usable at a working pressure of 0 to 2 MPa, and not damaged even if the pressure of high-pressure fuel of 5 MPa or higher is applied thereto, wherein high pressure fuel on the high pressure side is sealed by a first seal part, oil from a cam side on a low pressure side is sealed by a second seal part, and the fuel slightly leaked due to failure of scraping at the first seal part is sealed by the second seal part to form a dual seal structure. A resin ring coming into slidable sealing contact with a shaft is used in the first seal part, whereby abnormal abrasion does not occur even when fuel having less lubricity is used, and the durability of the seal is increased.

Abstract: A seal actuated by generally atmospheric pressure helps protect the motor bearing of a vacuum appliances, such as a dry air vacuum cleaner, a wet/dry vacuum cleaner, a water extractor (e.g., carpet cleaner), etc. The generally atmospheric air pressure on a motor side of the seal and a vacuum on an opposite turbine side of the seal urges the seal in an axial direction toward an impeller of the vacuum appliance and presses the seal firmly against an axially abutting sealing surface. Sliding sealing contact between a broad axial surface of the seal and the abutting sealing surface helps prolong the life of the seal and the bearing.

Abstract: A refrigerant compressor is provided that can be assembled easily and can quickly discharge lubricating oil that leaks from contact sliding parts of its mechanical seal so as to prevent the oil from turning into sludge around the stationary ring. In a refrigerant compressor in which a mechanical seal which shaft seals the inner side and the outer side of a housing is installed at a portion of the housing through which a rotating shaft penetrates, a mechanical seal comprises a stationary ring securely fastened to the inner circumferential surface of a boss portion, a rotary ring securely fastened to the outer circumferential surface of the rotating shaft to the inside of the stationary ring so as to face the stationary ring, whereby sliding contact is formed between sides of the stationary ring and the rotary ring.