Patent ID: 8091576

Claim:
A by-pass and pressure regulator valve exhibiting: an inlet mouth and an outlet mouth set in reciprocal communication by a main conduit; a by-pass mouth; the by-pass and pressure regulator valve comprising: an obturator, mobile between at least a closed position, in which it interrupts fluid communication between the main conduit and the by-pass mouth, and at least an open position, in which the fluid communication is not interrupted; operating pressure control means, predisposed to move the obturator from the closed position to the open position when fluid pressures internally of the main conduit exceed a threshold level; means for determining a flow pressure loss in fluids crossing the main conduit, arranged along the main conduit in order to separate a first tract upstream of the main conduit from a second tract downstream thereof; wherein it comprises obturator command means governed by a fluid pressure difference between the first tract and the second tract of the main conduit, distinct from the operating pressure control means but operatively connected to the obturator, the obturator command means being predisposed to exert an action on the obturator which maintains said obturator in the closed position thereof when a fluid pressure in the first tract is greater than a fluid pressure in the second tract; wherein the means for determining a flow pressure loss are predisposed to induce a flow pressure loss which is substantially constant on varying the fluid flow rate through the main conduit, at least for flow rate levels which do not exceed a maximum limit and comprise an auxiliary obturator mobile internally of the main conduit but constrained upstream by a presence of a choke, and elastic means predisposed to exert a direct force in an upstream direction of the main conduit on the auxiliary obturator, wherein a passage hole extends through the auxiliary obturator.