Patent ID: 9488989
Filing Date: 2016-11-08
CPC Classification: F16K,G05D,Y10T

Claim Text:
1. A pressure-independent flow rate controller assembly, comprising: a flow inlet and a flow outlet through which fluid flows, wherein fluid pressure at the flow inlet is an inlet pressure (P an interior chamber with first and second chamber portions and a balance channel adjacent to the second chamber portion; an intermediate passageway interconnecting the flow outlet to the first chamber portion; a spring-biased piston slideably disposed in the interior chamber and having first and second piston portions axially spaced apart from each other by an intermediate space therebetween, wherein fluid is blocked from moving relative to the piston between the first chamber portion and the intermediate space and from moving relative to the piston between the intermediate space and the second chamber portion, and wherein the pressure of the fluid in the intermediate space being substantially at the outlet pressure (P a first throttling assembly having a first throttling seat with a throttling channel that receives fluid substantially at the inlet pressure (P a balance member coupled to the piston and having a fluid-acting surface with an area substantially equal to the first area of the end portion of the first throttling member, wherein fluid at the inlet pressure (P an adjustable restriction assembly configured to allow the fluid from the intermediate passageway to flow at a selected constant flow rate toward the flow outlet at the outlet pressure (P a second throttling assembly configured to receive the flow of fluid from the adjustable restriction assembly, the second throttling assembly having second throttling member coupled to a spring biased piston and having a second throttling seat configured to receive the flow of fluid from the adjustable restriction assembly in an under-then-over trim configuration.