US 11,655,810 B2
Electrically operated displacement pump control system and method
Bradley H. Hines, Andover, MN (US); Paul W. Scheierl, Chisago City, MN (US); Brian W. Koehn, Minneapolis, MN (US); Jacob D. Higgins, White Bear Township, MN (US); Benjamin J. Paar, Minneapolis, MN (US); and David L. Fehr, Dayton, MN (US)
Assigned to Graco Minnesota Inc., Minneapolis, MN (US)
Filed by Graco Minnesota Inc., Minneapolis, MN (US)
Filed on Nov. 15, 2021, as Appl. No. 17/526,329.
Application 17/526,329 is a continuation of application No. 17/313,663, filed on May 6, 2021, granted, now 11,174,854.
Application 17/313,663 is a continuation of application No. PCT/US2021/025121, filed on Mar. 31, 2021.
Claims priority of provisional application 63/002,674, filed on Mar. 31, 2020.
Prior Publication US 2022/0074402 A1, Mar. 10, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. F04B 43/04 (2006.01); F04B 17/03 (2006.01); F04B 49/06 (2006.01); F04B 49/20 (2006.01); F04B 53/18 (2006.01)
CPC F04B 43/04 (2013.01) [F04B 17/03 (2013.01); F04B 49/065 (2013.01); F04B 49/20 (2013.01); F04B 53/18 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A pump for pumping a fluid, the pump comprising:
a first fluid displacement member configured to reciprocate to pump the fluid by alternatively moving in a first linear direction along an axis to perform a pumping stroke and in a second linear direction along the axis to perform a suction stroke;
an electric motor comprising a stator and a rotor, the rotor configured to generate rotational output;
a drive mechanism comprising a screw and a drive nut, the drive mechanism configured to receive the rotational output and convert the rotational output into linearly reciprocating motion, wherein rotation of the rotor in a first rotational direction drives the first fluid displacement member to linearly move in the first linear direction along the axis, and rotation of the rotor in a second rotational direction drives the first fluid displacement member to linearly move in the second linear direction along the axis; and
a controller configured to regulate current flow to the electric motor, wherein:
the controller regulates output pressure of the fluid by regulating the current flow to the electric motor such that the rotor rotates to cause the first fluid displacement member to reciprocate to pump the fluid until the pressure of the fluid stalls the rotor while the first fluid displacement member is in either the pump stroke or the suction stroke even while current is supplied to the electric motor by the controller so that the rotor applies torque to the screw while the rotor remains stalled, the first fluid displacement member configured to resume pumping when the pressure of the fluid drops enough for the rotor to overcome the stall and resume rotating; and
wherein the controller is configured to provide a first power signal having a first waveform to the electric motor while the rotor is rotating and is configured to provide a second power signal having a second waveform to the electric motor while the rotor is stalled such that the controller switches from delivering the first waveform during pumping to delivering the second waveform during rotor stall and then switches back to delivering the first waveform based on the rotor overcoming the stall to resume pumping, the first waveform different from the second waveform.