Positive displacement pump controller and method of operation
AssigneeGraco Minnesota Inc.
InventorBryan K. Colby
Life of this patent
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Abstract
Non-limiting exemplary embodiments of a pumping system and methods for operating the pumping system in a region of high pressure or a region of high flow are disclosed. The pumping system includes a piston disposed within a piston cylinder, a drive shaft, an eccentric coupled to the drive shaft, a connecting arm having opposing first and second ends, and a controller for controlling the rotation of the drive shaft such that the piston oscillates within a region of high pressure or a region of high flow.
Claims12
A pumping system comprising:
- an electric motor;
- a piston disposed within a piston cylinder;
- a drive shaft configured to be rotatably driven by the electric motor;
- a connecting arm;
- an eccentric connected between the drive shaft and the connecting arm, wherein the eccentric and the connecting arm convert rotation of the drive shaft into linear reciprocation of the piston within the piston cylinder;
- and
- a controller communicatively coupled to the electric motor;
- wherein the controller is configured to operate the electric motor in a first mode and a second mode;
- wherein in the first mode the controller causes the electric motor to rotate the drive shaft through a series of full rotations in which the drive shaft rotates continuously in a first rotational direction to cause a first series of stroke cycles of the piston, each stroke cycle of the first series of stroke cycles comprising one upstroke and one downstroke of the piston;
- and
- wherein in the second mode the controller causes the electric motor to oscillate the drive shaft in a series of arc cycles corresponding to a second series of stroke cycles of the piston, each arc cycle of the series of arc cycles comprises the drive shaft rotating through a first arc in the first rotational direction less than one full rotation and through a second arc in a second rotational direction less than one full rotation, each stroke cycle of the second series of stroke cycles comprising one upstroke and one downstroke of the piston, and
- wherein each stroke cycle of the first series of stroke cycles causes greater displacement of the piston than each stroke cycle of the second series of stroke cycles.
A method of operating a pumping system including a piston disposed within a piston cylinder, a drive shaft rotatably driven by an electric motor, an eccentric connected between the drive shaft and a connecting arm, the eccentric and the connecting arm configured to convert rotation of the drive shaft into linear reciprocation of the piston within the piston cylinder, and a controller communicatively coupled to the electric motor, the method comprising:
- causing, by the controller, the electric motor to operate in a first mode in which the electric motor rotates the drive shaft through a series of full rotations in which the drive shaft rotates continuously in a first rotational direction to cause a first series of stroke cycles of the piston, each stroke cycle of the first series of stroke cycles comprising one upstroke and one downstroke of the piston;
- and
- causing, by the controller, the electric motor to operate in a second mode in which the electric motor oscillates the drive shaft in a series of arc cycles corresponding to a second series of stroke cycles of the piston, each arc cycle of the series of arc cycles comprises the drive shaft rotating through a first arc in the first rotational direction less than one full rotation and through a second arc in a second rotational direction less than one full rotation, each stroke cycle of the second series of stroke cycles comprising one upstroke and one downstroke of the piston;
- wherein each stroke cycle of the first series of stroke cycles causes greater displacement of the piston than each stroke cycle of the second series of stroke cycles.
Dependencies are inferred from the claim text.