Electro-magnetical fluid flow control valve with differential action

Claim 1

In a electromagnetically operated differential action fluid flow control valve of the type comprising: a valve body, an inlet to the valve body, an outlet from the valve body, an outer annular chamber communicating with said inlet, an inner chamber coaxial with said outer annular chamber and communicating with said outlet, a disc-like valve shutter located coaxially at one end of said inner and outer chambers, said valve shutter being movable axially of said chambers between a first position where it interrupts communication between said inner and outer chambers and a second position where it permits communication between said inner and outer chambers, a diaphragm of resilient material, said diaphragm comprising: an outer annular part, an intermediate annular part the thickness of which is less than that of said outer annular part, said intermediate annular part being resiliently deformable, and a central part of the thickness of which is greater than that of said intermediate annular part, means tightly securing said outer annular part at its periphery to said valve body, a fixed lower insert element housed in said valve body and defining a cavity in said valve body with which said diaphragm cooperates to define a pilot chamber separated by said diaphragm from said inner and outer coaxial chambers, means defining a communication passageway between said pilot chamber and said outer annular chamber, means defining a discharge opening between said pilot chamber and said outlet of said valve body, and an axially movable electromagnet core the position of which is controlled by an electromagnet to close or open said discharge opening of said pilot chamber, the improvement wherein said communication passageway between said annular outer chamber and said pilot chamber is formed by an axial conduit loacted radially outwardly of said annular flexible intermediate part of said diaphragm, there being means defining a radial opening in said fixed lower insert element which forms one wall of said pilot chamber, said radial opening communicating with one end of said communication conduit, means defining an intermediate chamber communicating with the other end of said communication conduit, a wall having a plurality of filtering orifices therein separating said intermediate chamber from said annular outer chamber and an annular upper insert element having a tubular axial projection extending therefrom, said axial projection forming at least part of said axial communication conduit between said annular outer chamber and said pilot chamber, said annular upper insert element forming part of the wall of said annular outer chamber and engaging said outer annular part of said diaphragm, a plurality of openings in one wall of said annular upper insert element forming said filtering orifices permitting communication between said annular outer chamber and said intermediate chamber.