Automatic safety cutoff valve

Claim 1

An automatic safety cutoff valve, comprising in combination: a. a housing arrangeable in a flow path and having walls defining a passageway; b. a valve element movably arranged in the passageway; c. means including resilient elements arranged on the upstream and downstream sides of said valve element and biasing same toward one another for mounting said valve element in the passageway for positioning same in a position permitting flow through the passageway when pressures on an upstream side and a downstream side of said valve element are substantially equal, and permitting movement of said valve element to a position blocking flow when a pressure in the flow path downstream of said valve element is substantially less than a flow path pressure upstream of said valve element; and d. means for selectively varying the deflection of one of the resilient elements for adjusting the position of the valve element and including a further valve arranged in contact with said one resilient element for controlling fluid flow by the valve element as a function of the setting of the valve, said further valve having a hollow valve housing provided with internal screw threads and a valve member having a portion provided with screw threads arranged to threadingly engage with the valve housing screw threads for selective displacement of the valve member relative to the valve housing, a longitudinal member extending away from said valve member and contacting the resilient element, said member provided with screw threads of a reverse convention with respect to the housing threads and threadingly engageable with similar threads formed in a bore provided in said valve member, and means for restraining said member from movement about the longitudinal extent of same and causing said member to be displaced along its longitudinal extent when said valve member is displaced in said valve housing.