Differential solenoid valve for fluid control

Claim 1

In a differential solenoid valve of the type comprising: a valve body, an inlet 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 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 being attached to said valve shutter, means tightly securing said diaphragm at its periphery to said valve body, a fixed lower intermediate 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 valve body includes a cylindrical part having an inner wall, said diaphragm is housed in said cylindrical part of said valve body, recesses in said inner wall of said cylindrical part of said valve body, said intermediate element has an axial tubular part with a closed end and an open end, a radial flange part at said open end of said axial tubular part, said radial flange part forming one wall of said pilot chamber, and said axial tubular part housing said movable core of said electromagnet, resilient biasing means in said axial tubular part resiliently biasing said movable core of said electromagnet towards said open end of said axial tubular part, a locking ring surrounding said axial tubular part of said intermediate element, and radial teeth projecting from said locking ring, said radial teeth of said locking ring being engageable in said recesses in said inner wall of said cylindrical part of said valve body to form a bayonet coupling therewith connecting said intermediate element to said valve body.