초록 ▼

A protective mechanism is provided for valves having a nut through which a power-driven valve stem is threaded. The mechanism functions to protect the valve seat against the continuation of thrust of the valve-stem closure element against the valve seat after the valve has been fully closed. The con

A protective mechanism is provided for valves having a nut through which a power-driven valve stem is threaded. The mechanism functions to protect the valve seat against the continuation of thrust of the valve-stem closure element against the valve seat after the valve has been fully closed. The continuation of thrust force, unless prevented, occurs due to inertia of the drive motor after torque-sensing or other means have shut off the power to the motor. The protective mechanism includes energy-absorbing means for absorbing the kinetic energy of the over-running drive motor and for stopping further rotation of the valve stem.

대표청구항 ▼

An energy-absorbing valve protective mechanism for protecting a valve against the application of excessive thrust or torque by an axially-movable rotatable shaft driven by a power drive which tends to overdrive in the valve-closing direction, said protective mechanism comprising: a. a valve housing;

An energy-absorbing valve protective mechanism for protecting a valve against the application of excessive thrust or torque by an axially-movable rotatable shaft driven by a power drive which tends to overdrive in the valve-closing direction, said protective mechanism comprising: a. a valve housing; b. a drive housing mounted on and fixed to said valve housing; c. a nut fixed in said valve housing against axial and rotational displacement; d. an externally-threaded rotatable stem threaded through said nut for axial movement relative to said nut in response to rotation of said stem; e. an internally-keyed drive sleeve mounted for rotation in said drive housing but fixed against axial displacement; f. power drive means for driving said drive sleeve rotationally, said power drive means including a gear connected to said drive sleeve, said gear being fixed in said drive housing against axial movement; g. an externally-keyed internally-threaded torque sleeve coaxially disposed with said drive sleeve and in keyed engagement therewith, said torque sleeve being aDapted to be driven rotationally by said drive sleeve, said torque sleeve being movable axially on said keys relative to said drive sleeve; h. external thread means on said stem in engagement with the threads of said torque sleeve and adapted to be driven rotationally by the threads of said torque sleeve; i. a stem extension in said drive housing fixed to and projecting beyond the driven end of said stem, said stem extension being rotatable with, and movable axially with, said stem; j. energy-absorbing compression spring means supported coaxially on said stem extension and rotatable therewith; k. said spring means being disposed in the path of axial movement of said torque sleeve so as to be compressed by axial movement of said torque sleeve relative to said stem for absorbing the kinetic energy of the torque applied to said torque sleeve after said stem has reached a valve-closed position, thereby inhibiting further rotational or axial movement of said stem, and thereby causing said torque sleeve to move axially relative to said stem.