Excess flow control device

Claim 1

An excess flow control device including a housing, a fluid inlet passage therein, and a fluid outlet passage in communication with said fluid inlet passasge, the fluid control device comprising: (a) a reciprocating valve capable of permitting, limiting or precluding communication between said inlet and outlet passasges, said valve comprising a ferromagnetic armature capable of receiving an axis of magnetic polarity substantially co-linear with its axis of reciprocation, said magnetic axis generally corresponding to the longitudinal center of a chamber within said housing, said chamber having a greater radius than the radius of said valve, in which said valve may reciprocate, said valve having a flow-responsive rear radial end face disposed within a region of communication between said inlet and outlet passages, said valve occupying at least a part of said region of inlet-outlet communication, said valve further having a front end face capable of closing said fluid outlet passage when said valve is reciprocated in the direction of said outlet passage; (b) bias and calibration means disposed within said housing and disposed co-linearly and distal-proximately to said reciprocating valve, near said rear radial end face thereof, and opposite to said flow-responsive rear end face of said valve, said bias and calibration means having an axis of magnetic polarity substantially co-linear with said magnetic axis of said reciprocating valve in which the magnetic polarities of said reciprocating valve and of said bias means define an attraction mode with respect to each other; and (c) means for changing the axial distal-proximate position of said bias means relative to said reciprocating valve to thereby calibrate the degree of attraction between bias means and said valve and to further thereby define the geometry of that part of the region of inlet-outlet communication that passes between said flow-responsive rear radial end face of said valve and said bias means, whereby the rate or pressure of flow through the inlet or outlet passage causing closure may be calibrated by a distal-proximate adjustment of said bias means relative to said flow-responsive rear end face.