Pinch tube proportioning valve and control cam cartridge therefor

A control cam cartridge removably mounted as a unit in a valve body of a pinch tube proportioning valve, said control cam cartridge comprising:

• a housing including a cylindrical side wall having an axis and open and closed ends and an end wall closing said side wall at said closed end and cooperating therewith to define a cam chamber, said side wall having a pair of diametrically opposed openings therethrough adjacent to said open end communicating with said chamber, said openings being respectively defined by notches extending transversely through said housing on opposite sides of and orthogonal to said axis, each of said notches forming a part-cylindrical seat surface which defines the intersection between said housing and an imaginary cylindrical surface for receiving an associated pinch tube, a guide pin extending from said end wall into said chamber coaxially with said cylindrical side wall, and an elongated cam member telescopically received in said chamber through said open end of said housing and rotatable therein and axially slidably movable therein between retracted and extended positions, said cam member having an axial bore therethrough telescopically receiving said guide pin therein for guiding movement thereof between the extended and retracted positions thereof.

In a pinch tube proportioning valve including a support structure defining an elongated valve cavity having a longitudinal axis and a pair of spaced resilient valve tubes disposed in the cavity and respectively providing communication between two fluid supply conduits and a fluid outlet, the improvement comprising:

• a control cam cartridge removably insertable as a unit in the valve cavity between the valve tubes, said cartridge including a housing having a cylindrical side wall with open and closed ends and an end wall closing said side wall at said closed end and cooperating therewith to define a cam chamber, said side wall having a pair of notches therein at opposite sides thereof respectively forming openings communicating with said chamber, said closed end of said housing being removably insertable in the valve cavity between the tubes to a use position with the tubes respectively seated in said notches and projecting into said chamber, and an elongated tapered cam member telescopically received axially in said chamber for engagement with the tubes, said cam member being rotatable about the axis and axially movable between retracted closing and extended opening positions and having a cylindrical valve-closing portion and an eccentric frustoconical valve-opening portion which control the proportioning and the rate of flow through the valves tubes.