Steam valve closes with leak, partly opens under high pressure - and has auxiliary valve spring with damping at end of stroke

摘要

The Parent Patent describes a valve for a steam line having a passage equal to the cross-section of the line; when a leak occurs in the live steam line, a valve plate is closed by a pressurized fluid; a pressure-dependent opening mechanism opens a valve to the max. of its half cross-section when the pressure in the line rises above the operating pressure. The smaller passage cross-section of the valve is composed of a portion of the area of the valve plate and can be closed by a piston operated auxiliary valve plate equipped with a spring to bias it to its closed position. In the Patent of Addition, this spring is mounted on that side of the piston for the auxiliary valve plate which is nearest to the valve seating; the spring also bears against the main valve plate via a rod passing through the piston. Pref. the spring is mounted inside the cavity of the hollow auxiliary valve plate. More specifically, this cavity is subject to the pressure of the actuating fluid for the auxiliary valve plate piston by means of an upper bore leading out from the cvity; bores at the bottom of the cavity permit the fluid to leave the auxiliary valve plate. The cylinder containing the piston can act as a damping cylinder to retard the opening movement of the auxiliary valve plate at the end of its opening stroke.