Patent ID: 7451781
Filing Date: 2008-11-18
Classification: G05D,Y10T

Abstract:
1. A pressure independent fluid flow regulating valve providing a substantially constant flow rate for each set position, comprises: a flow passage leading to a characterized valve wherein the degree of opening movement is proportional to flow rate having an inlet from and an outlet to said flow passage; upstream of said characterized valve, a seat orifice intersecting said flow passage; a moveable assembly, comprising a disk connected to by a stem, and operated by a pressure sensing means; wherein the disk is located downstream of the seat with which it interacts to vary the flow resistance, and the effective surface area of the disk is essentially the same as the effective surface area of said pressure sensing means; downstream of the disk, a baffle is mounted in a fixed position parallel to the disk, close to the disk but at a distance permitting the movement of the disk; the pressure sensing means operates inside a cylinder or chamber which it divides in two portions, wherein one portion is connected to the inlet, and the other portion is connected via reference pressure passage to a point downstream of the characterized valve; and spring means for biasing said moveable assembly.