An improved screw pump such as, for example, a twin screw pump, includes a casing including an internal chamber, and first and second rotors rotatably positioned within the chamber of the casing. The first and second rotors have an intermeshing threaded-shape profiling. A plurality of bearing seal assemblies are provided at each end of the first and second rotors. Each bearing seal assembly includes a bearing positioned about an end portion of a rotor to facilitate rotation of the rotor, and a seal positioned about an end portion of a rotor to seal passage of the rotor through the casing. The bearing is coupled to the seal so that the seal may be secured to the casing via the coupling of the bearing to the casing.

Provided is a mechanical seal that eliminates the need to provide an additional bearing, enables size reduction and cost reduction, and can provide stable performance as a bearing. A stationary-side seal ring 20 is disposed on the high-pressure fluid side of a rotating-side seal ring 21, and fixed to a housing 1 and has sliding surfaces 20a, 20c, and 20d supporting a rotating shaft 2 in both a radial direction and a thrust direction. The rotating-side seal ring 21 is axially movably fitted by an urging means 25 fitted on the rotating shaft 2. The rotating shaft 2 has an outer peripheral surface 2a a contacting and sliding on the radial sliding surface 20a of the stationary-side seal ring 20 to be supported radially. Thrust rings 10a and 10b are provided between the stationary-side seal ring 20 and the rotating shaft 2, for supporting the rotating shaft 2 in thrust directions.

The present invention relates to a device (1, 30) for the recirculation of an at least partially gaseous composition containing hydrogen, wherein the device (1, 30) is a dry rotary pump comprising a first rotating shaft (13) and a second rotating shaft (14) driving respectively a first piston with claws (8) and a second piston with claws (9) in rotation in a pumping chamber (2) comprising an inlet orifice (11) and an outlet orifice (10) for the gaseous composition, the first rotating shaft (13) and the second rotating shaft (14) being configured to be driven in rotation by a drive system (17,18) situated in a gear chamber (4), wherein the device (1, 30) comprises a first pair of seals (19) and a second pair of seals (20), each comprising a first shaft seal (19a, 20a) and a second shaft seal (19b, 20b), the first pair of seals (19) being provided around the first rotating shaft (13) and the second pair of seals (20) being provided around the second rotating shaft (14) between the pumping chamber (2) and the gear chamber (4), wherein the device (1, 30) comprises a pressure equalization chamber (25) which is in fluid connection with a gap (24) present between the first shaft seal (19a, 20a) and the second shaft seal (19b, 20b) of the first and of the second pair of seals (19, 20) to regulate the pressure in the gap (24), wherein the gear chamber (4) is in fluid connection with the gap (24), and wherein the pumping chamber (2) is in fluid connection with the first shaft seal (19a) of the first pair of seals (19) and with the first shaft seal (20a) of the second pair of seals (20) by means of a pulsation attenuation chamber (22). The present invention also relates to a fuel cell system (40, 50, 60, 70, 80, 90) comprising a device for recirculation according to the present invention.

A pump for applying fluid, the pump including: a pump housing, including: a fluid inlet on a low-pressure side; an fluid outlet on a high-pressure side; a circumferential wall surrounding the pump delivery chamber; and an end-facing wall featuring an outer end-facing surface facing axially away from the delivery chamber and at which the outlet emerges; a delivery member, moveable in the delivery chamber, for delivering the fluid from the low-pressure side to the high-pressure side; a gasket including a gasket loop which surrounds the outlet to seal it off on the outer end-facing surface of the end-facing wall; a female joining element featuring an axially extending hollow space; and a male joining element protruding through or from the pump housing or the gasket. The male joining element is in a joining engagement, which can be subjected to axial tensile stress, with the female joining element in the hollow space.

A fluid transfer pump that has a housing, a body portion movable within the housing between a first position and a second position, a gear coupled to the housing, a body cavity defined partially between the body portion and the housing, and an aperture defined in the housing that selectively provides a fluid to the body cavity. When the fluid is applied to the body cavity at or above a pilot pressure, the body portion is in the first position adjacent to the gear and when the fluid is applied to the body cavity at a fluid pressure lower than the pilot pressure, the body portion is in the second position and spaced from the gear.

One or more techniques and/or systems are disclosed for mitigating fluid loss or leakage from a fluid pump with a rotating shaft driving a pumping mechanism. A packing gland component can have an internal seal formed by two dynamic O-rings that allows for use of lubricants at high pressures, as well as an outer seal for greater prevention of fluid loss. Further, the packing gland component can be a retrofit for existing packing gland components to provide for greater life and efficiency as compared to the existing packing gland components. Additionally, in some implementations, a sleeve may be fixedly attached to the rotating shaft between the packing gland and the shaft to provide a wear point for the packing gland.

A low pressure gear pump and wear plate is disclosed. The wear plate may comprise a sidewall, a drive portion, a driven portion, and a transition portion. The sidewall is free of a sealing member or a recess configured to receive the sealing member. The drive portion includes a drive inlet lip, a drive outlet lip, a drive recessed trough and a drive bore. The drive bore is configured to receive the drive shaft of the gear pump. The driven portion may that include a driven inlet lip, a driven outlet lip, a driven recessed trough, and a driven bore. The driven bore is configured to receive the driven shaft of the gear pump. The transition portion may include a transition aperture configured to receive a first fastener configured to mount the wear plate to the gear housing. The wear plate is made of bronze, aluminum or non-magnetic material.

An example assembly comprises: a pump cover; a thrust plate configured to interface with the pump cover at a first side of the thrust plate and interface with gears of a gear pump at a second side of the thrust plate; and a seal disposed within a seal cavity formed at an interface between the thrust plate and the pump cover, wherein the seal defines multiple partitions at the interface between the thrust plate and the pump cover and seals each partition of the multiple partitions from other partitions.

A transfer pump configured to move a hydraulic fluid in a hydraulic fluid management system of a hydraulic system of a vehicle including a transmission. In one embodiment, the transfer pump moves the fluid from a differential case to a hydraulic reservoir coupled to the transmission. The transfer pump is a positive displacement pump including an unloading device, such as a sealing plate, that is resiliently biased against the pump during a normal operation but is moved away from the pump upon the application of a pilot pressure. The result is an open chamber for the pump gears to turn without developing pressure, to thereby reduce parasitic losses.

A sectional sealing system for water-spray type screw rotor compressor that is configured to prevent the intermixing of coolant and working fluid from a compression chamber with lubricant used to lubricate at least a bearing system of a rotor. The sealing system may include suction side and discharge side sealing portions that are positioned about first and second shafts, respectively, of the rotor. The suction side sealing portion may include a first seal, a first labyrinth seal, and a second labyrinth seal, the first seal being in proximity to a suction side of the compression chamber. The discharge side sealing portion may include a plurality of first seals, a second seal, a first labyrinth seal, and a second labyrinth seal, the plurality of first seals of the discharge side sealing portion being in proximity to a discharge side of the compression chamber.