Abstract: The present invention relates to positive displacement pumps, and particularly to diaphragm positive displacement pumps. An inventive diaphragm positive displacement pump is provided comprising at least one pumping chamber containing a deformable hose diaphragm, a working fluid cylinder fluidly connected to the deformable hose diaphragm, and at least one linear motor to displace the working fluid within the working fluid cylinder and thereby increase and decrease the volume of the pumping chamber. An inventive method of controlling an inventive diaphragm positive displacement pump comprising at least one pumping chamber and powered by at least one linear motor is also provided.

Abstract: A device for releasing tension in a pump shaft is shown and described. An annular elastomeric member is positioned on the circumference of the pump shaft, the elastomeric member having circumferentially spaced holes provided in a surface distal to the shaft. The elastomeric member is confined in an axial direction, and a volume control member is positioned in each of the holes, such that the elastomeric member is also confined in a radial direction. During operation of the pump, the torque on the pump shaft induces a tensile load on the shaft which in turn causes a compression load on the components mounted on the shaft, the compression load being borne by the elastomeric member. After operation of the pump, the volume control members are retracted from the holes, such that the elastomeric member is allowed to compress, thereby unloading the shaft and connection to the pump impeller. The impeller may then be easily unscrewed and removed from the pump shaft.

Abstract: An improved device for adjusting the bearing clearance of a pump is shown and described. In a preferred embodiment, an annular piston is provided adjacent to a bearing assembly, and an elastomeric member is provided adjacent to the piston. The elastomeric member has a plurality of apertures circumferentially spaced around the elastomeric member, a volume control member being provided in each of the apertures. The volume control members are selectively advanced into and retracted from the apertures, the elastomeric member being compressed and expanding in an axial direction when the volume control members are advanced into the apertures, thereby forcing the piston to move toward the bearing assembly. When the volume control members are retracted from the apertures, the elastomeric member compresses in an axial direction, thereby allowing the piston to move away from the bearing assembly.