US 11,891,987 B2
Piston pump and method for operating a piston pump
Andreas Lehmann, Moers (DE); and Friedrich Schwing, Herten (DE)
Assigned to SCHWING GMBH, Herne (DE)
Appl. No. 17/413,814
Filed by Schwing GmbH, Herne (DE)
PCT Filed Dec. 3, 2019, PCT No. PCT/EP2019/083534
§ 371(c)(1), (2) Date Jun. 14, 2021,
PCT Pub. No. WO2020/120234, PCT Pub. Date Jun. 18, 2020.
Claims priority of application No. 102018132270.4 (DE), filed on Dec. 14, 2018; and application No. 102018132309.3 (DE), filed on Dec. 14, 2018.
Prior Publication US 2022/0025874 A1, Jan. 27, 2022
Int. Cl. F04B 1/02 (2006.01); F04B 17/00 (2006.01); F04B 9/109 (2006.01); F04B 15/02 (2006.01)
CPC F04B 1/02 (2013.01) [F04B 9/109 (2013.01); F04B 15/02 (2013.01); F04B 17/00 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A method for operating a piston pump with a differential cylinder drive with a first differential cylinder and a second differential cylinder for respectively driving a first conveying piston and a second conveying piston respectively movable in a first conveying cylinder and a second conveying cylinder, the first conveying cylinder being driven via the first differential cylinder of the differential cylinder drive, the second conveying cylinder being driven via the second differential cylinder of the differential cylinder drive, with a hydraulic circuit for controlling the differential cylinder drive and/or for driving the differential cylinder drive by action of hydraulic fluid, the method comprising the following cyclically performed steps:
suctioning material to be conveyed via the first conveying cylinder by driving the first differential cylinder and simultaneously discharging material to be conveyed via the second conveying cylinder by driving the second differential cylinder;
pre-compressing the sucked-in material via the first conveying cylinder by driving the first differential cylinder and simultaneously discharging material via the second conveying cylinder by driving the second differential cylinder;
discharging material via the first conveying cylinder by driving the first differential cylinder and simultaneously suctioning material to be conveyed via the second conveying cylinder by driving the second differential cylinder; and
discharging material via the first conveying cylinder by driving the first differential cylinder and simultaneously pre-compressing the sucked-in material via the second conveying cylinder by driving the second differential cylinder,
wherein the pre-compressing steps are divided into at least two phases,
wherein in a first phase the hydraulic circuit causes pre-compression using a first conveying piston speed by controlling the hydraulic fluid at a first volume flow and a first pressure,
wherein in a second phase the hydraulic circuit causes pre-compressing using a second conveying piston speed, which is lower than the first conveying piston speed, by controlling a second volume flow and a second pressure,
wherein the second volume flow is lower than the first volume flow and the second pressure is higher than the first pressure.