According to one aspect of the invention, a reversible centrifugal pump comprises a rotor drivable in rotation in both directions about an axis by a motor, the rotor being mounted in a casing having an inlet and a peripheral outlet for fluid to be pumped, the rotor comprising impeller blades which are pivoted to the rotor to rotate relative thereto between two extreme positions, and stop means preventing rotation of the blades beyond said extreme positions.

The stop means may comprise pins extending through the rotor parallel to the rotor axis and positioned to abut the blades.WATER POWER CONTROL VALVE Each blade may be associated with a pair of pins, the pins being a greater distance from the rotor axis than the blade pivots and the blades being between the pins so that the blades may rotate about their pivots between two extreme positions defined by the pins. Under the effect of the pressure of the fluid being pumped the blades will be urged against one pin or the other, depending on the direction of rotation of the rotor, and the pins may be located to give the optimum blade position in both directions of rotation.

The blades may be flexible so that they are capable of bending under the fluid pressure to further optimize the blade orientations during pumping. Balance Valves The blades may be of a flexible plastics material or of a metal such as stainless steel.

According to another aspect of the invention a centrifugal pump which may or may not be reversible comprises a rotor drivable in rotation about an axis, the rotor being mounted in a casing having an inlet and a peripheral outlet for fluid to be pumped, the rotor comprising impeller blades which are pivoted to the rotor to rotate relative thereto and stop means preventing rotation of the blades beyond an extreme position, the stop means being adaptable to vary said extreme position. Forged Steel ValvesIn this pump the stop means may comprise pins inserted through holes provided in a pair of plates forming the sides of the rotor and a number of pairs of holes in the respective plates may be provided at different locations to define different extreme positions for the blades.

Varying the extreme position of the blades in this way allows the pump to be readily adapted to different pressures and rates of flow. It also allows the blades to be set to their optimum positions empirically, by running a series of tests with the blades in different positions. The blade position may be easily and quickly adjusted by removing the appropriate pins and re-inserting them at a different location. This arrangement may also be used for optimizing the performance of a pump at the design stage.

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2011-12-28

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