A rotary positive displacement pump comprises a housing rotationally supporting first and second parallel and axially extending drive shafts having constantly meshing gears such that the drive shafts rotate in opposite directions. A rotor casing is connected to a front side of the housing and has axial rear and front walls and a circumferential side wall jointly defining a pumping cavity. The casing houses first and second rotors drivingly connected to the first and second drive shafts respectively. The rotors rotate in opposite directions and mutually interact to provide a positive pumping effect on fluid product entering the cavity. First and second sealing arrangements prevent leakage of fluid product from the cavity towards the rear side of the casing along the first/second drive shafts. A heating device is detachably fastened to the rear casing wall to heat the casing, the first/second sealing arrangements and/or any fluid product within the casing.

A method for operating a progressive cavity pump wherein the stator has at least first and second active stator sections that are at different locations on the stator, comprising inserting a first rotor having a first active rotor section that is aligned with the first active stator section, and rotating the first rotor relative to the first active stator section such that the aligned first active rotor and stator sections generate a pumping force. Subsequently, the first rotor is removed and a second rotor is inserted having a second active rotor section that is aligned with the second active stator section, and rotating the second rotor relative to the second active stator section such that the aligned second active rotor and stator sections generate a pumping force.

A method for operating a progressive cavity pump wherein the stator has at least first and second active stator sections that are at different locations on the stator, comprising inserting a first rotor having a first active rotor section that is aligned with the first active stator section, and rotating the first rotor relative to the first active stator section such that the aligned first active rotor and stator sections generate a pumping force. Subsequently, the first rotor is removed and a second rotor is inserted having a second active rotor section that is aligned with the second active stator section, and rotating the second rotor relative to the second active stator section such that the aligned second active rotor and stator sections generate a pumping force.

The present invention relates to improvements in the area of flexible impeller pumps. In particular, the present invention relates to flexible impellers with improved profiles(such as dual sealing lips), which are particularly well-suited to multiple cam pumps. A novel mounting hub configuration for mounting an impeller on a drive shaft is also provided. Pumps comprising such impellers and/or mounting hubs are provided, as are associated methods of installation and removal.

The invention relates to a screw spindle pump, with a housing (2) which surrounds a delivery chamber (5), two spindles (7, 8), namely a drive spindle (7) and an opposed running spindle (8), a housing insert (6) which is arranged in the housing (2) and in which the spindles (7, 8) are accommodated, at least one bearing element (13, 13), which is connected to the housing insert (6) and on which bearings (12) of the spindles (7, 8) are arranged, and with at least one housing cover (14, 14), closing a housing opening. It is the object of the invention to provide a screw spindle pump at which maintenance and inspection work can be carried out more simply and cost-effectively. The invention achieves this object in that the bearing element (13, 13) together with the housing insert (6) and the spindles (7, 8) accommodated therein forms a unit (15) which, after the housing cover (14, 14) is taken off, is removable from the housing (2) through the housing opening.

An improved repair method and repair kit for gerotor pumps that have become damaged or worn in order to allow the pump to create a sound seal once more.

The present invention relates to improvements in the area of flexible impeller pumps. In particular, the present invention relates to flexible impellers with improved profiles (such as dual sealing lips), which are particularly well-suited to multiple cam pumps. A novel mounting hub configuration for mounting an impeller on a drive shaft is also provided. Pumps comprising such impellers and/or mounting hubs are provided, as are associated methods of installation and removal.

A seal assembly for sealing a power input shaft of a progressive cavity pump can include a seal housing arranged around the power input shaft, the seal housing can include a mounted portion, mounted to the progressive cavity pump, a removable portion, removably coupled to the mounted portion, which can be configured to apply a compression force to a seal within the seal assembly, and a sealing element, which can be configured to seal an interface between the mounted portion and the removable portion. The seal housing can be configured so that a portion of the mounted portion can be in direct contact with a portion of the removable portion.