Valve shaft drive for stop valve with leakage safety device

摘要

The drive operates two cooperating valve shafts. It has a first working piston (I) consisting of parts (10, 11), with driver elements (14, 15) on their neighbouring surfaces (12, 13). The elements connect the parts for a common switching function, and also permit a relative movement between the parts. The relative movement is limited in one direction by the driver elements. The inner piston part is connected to the tubular valve shaft (8), and charged from above by a compression spring (17). The outer piston part engages sliding on the inner wall (14) of the cylinder (4) and the neighbouring surface (13) of the first part, and is charged from below by a compression spring (18).