Ronald D Jackson

US Patent:

47947853, Jan 3, 1989

Filed:

Aug 14, 1986

Appl. No.:

6/898763

Inventors:

Gary D. Cohrs - Tempe AZ
Ronald J. Jackson - Phoenix AZ
Edward E. Francisco - Paradise Valley AZ

Assignee:

Flow Technology, Inc. - Phoenix AZ

International Classification:

G01F 2500

US Classification:

73 3

Abstract:

A fluid displacement measuring cylinder has near its ends, respectively, an inlet and an outlet. A fluid displacement measuring piston is adapted to travel through the measuring cylinder as a fluid barrier. A control piston having first and second sides is adapted to travel through the control cylinder as a fluid barrier. A rod connects the control piston only to the side of the measuring piston facing toward one end of the measuring cylinder. A gas pressurized plenum chamber is connected to the control cylinder so the force of the gas pressure urges the measuring piston toward the other end of the measuring cylinder. The movement of the measuring piston through the measuring cylinder is sensed and the movement of the control piston through the control cylinder is fluidically controlled. The pressure in the plenum chamber, which has a substantially larger volume than the control cylinder, is selected so as to cancel the force imbalance caused by the rod.