Patent ID: 8554425
Filing Date: 2013-10-08
Classification: A01D,F15B

Abstract:
1. A method of controlling pressure rise rates in a hydraulic lift and flotation system comprising: providing a hydraulic lift and flotation system comprising a pump, a hydraulic cylinder, a first valve, a second valve and a fluid reservoir, the first valve being positioned to control fluid flow at the hydraulic cylinder; operating the hydraulic lift and flotation system with the second valve in an open position to permit fluid to flow from the reservoir to the pump through the second valve and back to the reservoir; receiving a command to operate the hydraulic cylinder; selecting a control algorithm configured to close the second valve, wherein closing the second valve prevents return flow of fluid to the reservoir and builds pressure in the hydraulic lift and flotation system; applying control signals to the second valve with the control algorithm using a programmed controller until the second valve is in a closed position, wherein each control signal is configured to close the second valve a predetermined amount and the closing of the second valve by a predetermined amount controls the rate of pressure rise in the hydraulic lift and flotation system.