Disclosed is a gear pump (10) comprising a contra rotating gear element pair (30 and 40) mounted within a housing (20), each gear element having complementary gear teeth sets providing a pumping action in use, said teeth being formed from an annulus (34 and 44) of generally rigid construction mounted on a relatively flexible inner section (35 and 45), the gear pair being mounted such that their respective annuli are biased into resilient contact with the housing to provide a sliding seal.

A gear pump for low speed transfers of viscous liquid slurries promotes growth of suspended particles, such as sugar crystals, by avoiding crushing of the particles. The pump includes a rotor gear in mesh with an eccentrically mounted idler gear supported on a boss of a pump head that includes a crescent seal extending into an opening resulting from the eccentricity of the idler gear relative to the rotor gear. The idler gear contains a radially extending land on each tooth profile, symmetrically oriented on adjacently spaced pairs of teeth. The lands, configured to minimize crushing of crystals passing through the pump, engage mating rotor teeth for sealing between inlet and outlet ports of the pump. To promote crystal growth, the lands cover only 10% to 30% of profile surface area of each tooth. To minimize gear tooth wear, the lands are axially staggered between successive adjacent pairs of teeth.

Overheating of a process liquid retained in a reservoir of a multiphase pump during extended gas slugs is avoided by circulating a cooling liquid in thermal contact with a process liquid through an external cooling apparatus, which can include a heat exchanger. In some embodiments, process liquid from the reservoir is circulated through the cooling loop, while in other embodiments a separate cooling liquid is circulated between a reservoir heat exchanger and the external cooling apparatus. The liquid in the cooling loop can be circulated by a separate cooling pump, or process liquid can be circulated through the cooling loop due to a pressure differential between an inlet and an outlet of the cooling loop within the multiphase pump. The multiphase pump can be a twin screw pump, and the reservoir can be formed between outer and inner casings of the multiphase pump.

In a gear pump device for rubber extrusion, prolongation of the maintenance intervals is intended by preventing rubber scorch occurring at the gear support-shaft portion. It has a bushing ring 5 inserted in a gear-housing bore 3 of a housing 4. The bushing ring 5 rotatably supports a support-shaft portion 7 of a gear 2 accommodated in the gear-housing bore 3. The bushing ring 5 has a bearing 15 and a sealing means 16 built-in. The sealing means 16 includes a seal ring 22 of which cross section is ]-shaped and which has a first lip portion 22i contacting with the outer peripheral surface of the support-shaft portion 7, a second lip portion 22o disposed outside thereof in the radial direction, and a side wall portion 22m connecting between outer ends in the axial direction, of the first and second lip portions 22i, 22o.

The present invention relates to an improved liquid pump (1) comprising at least one rotating pumping member (2, 3) and a drive shaft (4) rigidly constrained to said at least one rotating pumping member (2) and configured to drive said at least one rotating pumping member (2) into rotation, said at least one rotating pumping member (2, 3) being completely housed in a pumping chamber (6) formed within a pump casing (7), said drive shaft (4) being partially housed within said pump casing (7), between said drive shaft (4) and said pump casing (7) there being provided at least one liquid-tight seal (8) for preventing leakage of said liquid along said drive shaft (4), said pump (1) comprising a suction duct (9) in liquid communication with said pumping chamber (6) and a delivery duct (11) in liquid communication with said pumping chamber (6).

According to the invention, inside said pump casing (7) a flushing chamber (13) is formed in liquid communication with said suction duct (9) or with said delivery duct (11), said drive shaft (4) passing through said flushing chamber (13), said at least one seal (8) having at least one portion (80) facing said flushing chamber (13) so that the flow of said liquid running inside said flushing chamber (13) laps said portion (80) of said seal (8).

A motor pump unit with a multipart housing comprises a reversible internal gear machine and an electric motor with a rotor and a stator, which is coupled to the internal gear machine via a shaft rotatably mounted in the housing. One shaft end extends from the internal gear machine axially through the rotor that is carried by the shaft. First and second connecting channel ends in the working chamber of the internal gear machine are connected via check valves in the housing to a leakage channel loop, which is fluidically connected to a leakage channel that is fluidically connected to the working chamber, and which has a shaft leakage channel extending axially through the shaft and a rotor leakage channel that is fluidically connected thereto and extends axially through the rotor and/or a gap leakage channel between the rotor and stator, which is fluidically connected to the shaft leakage channel.

A high speed, rotary lobe gear pump assembly is provided which combines a positive displacement lobe gear pump having wipers with a centrifugal pump utilizing an impeller. The centrifugal pump feeds high pressure fluid flow directly into the lobe gear pump allowing the gear pump to rotate at high speeds without cavitation. The high speed capability of the pump assembly allows the lobe gear pump to operate without speed reduction gearing for the motor shaft.

A pump fluid driving apparatus includes a housing having a chamber, with two gears mounted within the chamber. The housing includes a first rounded wall section and a second rounded wall section, the first and second rounded wall sections defining at least a portion of the chamber. The gears have teeth located about their respective peripheries and operatively positioned with the teeth of the first gear and the teeth of the second gear intermeshed. The teeth include slotted teeth and solid teeth arranged with uniform spacing in a repeating pattern about the periphery of each of the gears, with each of the slotted teeth having a vane slot and a radially extending vane extending from the vane slot, and each radially extending vane being movable within the respective vane slot and being configured to contact the respective first or second rounded wall sections.

A hypotrochoid positive-displacement machine includes an inner rotor and an outer rotor with intermeshing projections. During rotation of the rotors, the inward-most tips of the outer rotor trace hypotrochoid paths relative to the inner rotor. A driven rotor, for example the inner rotor, drives a driven rotor, for example the outer rotor, by contact between driving surfaces and driven surfaces of the respective rotors. Improvements are provided, for example in relation to the contact between the rotors. In use of the device contact between the driving surfaces and driven surfaces may move radially outward from a point of initial contact. The driving or driven surfaces or both may be arranged to flex under contact between the rotors. The driving surfaces may be convex. The driven surfaces may be concave.

The invention relates to an internal gear machine (10) having a housing (12) which forms a cavity (14) in which an internally toothed ring gear (18) and an externally toothed pinion (16) are arranged, the toothings (24, 26) of which are in meshing engagement with one another in certain regions and the axes of rotation (20, 22) of which run parallel to and spaced apart from one another, wherein at least one filler piece (30, 30) rests against the first and second toothings (24, 26), which divides the cavity (14) into two fluidically separate regions. It is provided that the toothing (24, 26) is designed as helical toothing or arrow toothing.