Combined stop and control valve for supplying steam

A valve for supplying steam to downstream machinery, comprising:

• a generally annular valve seat defining a steam flow passage;
• a control valve in said passage including a control valve head having a recess on a downstream side of said control valve, said control valve head being movable toward and away from said valve seat;
• a stop valve having a stop valve head generally within said recess and a sealing surface for engagement with said valve seat in a stop valve closed position;
• an outlet passage below said valve seat and in communication with an outlet for directing the supply of steam to the machinery, said outlet passage and said valve seat having walls forming a smooth continuous transition therebetween without abrupt changes in flow direction for directing supplied steam past said seat, through said outlet passage and to said outlet substantially without formation of vortices to afford optimum steam flow characteristics with minimum losses;
• a valve stem coupled between said control valve and an actuator for moving said control valve toward said valve seat and buttress threads coupling said valve stem and said control valve head to one another.

A valve for supplying steam to a steam turbine, comprising:

• a generally annular valve seat defining a steam flow passage;
• a control valve in said passage including a control valve head having a recess on a downstream side of said control valve, said control valve head being movable toward and away from said valve seat;
• a stop valve having a stop valve head generally within said recess and a sealing surface for engagement with said valve seat in a stop valve closed position;
• an outlet passage below said valve seat and in communication with an outlet for directing the supply of steam to the turbine, a steam balance chamber above said control valve head defined in part by one side of said control valve head and which enlarges in response to movement of said control valve head toward said valve seat, and a bleed aperture in said control valve in communication with said balance chamber for precluding depressurization of the balance chamber in response to movement of said control valve head toward said valve seat;
• a valve stem coupled between said control valve and an actuator for moving said control valve head toward said valve seat and buttress threads coupling said valve stem and said control valve head to one another.

A valve for supplying steam to a steam turbine, comprising:

• a generally annular valve seat defining a steam flow passage;
• a control valve in said passage including a control valve head having a recess on a downstream side of said control valve, said control valve head being movable toward and away from said valve seat;
• a stop valve having a stop valve head generally within said recess and a sealing surface for engagement with said valve seat in a stop valve closed position;
• an outlet passage below said valve seat and in communication with an outlet for directing the supply of steam to the turbine, including a valve stem coupled between said control valve head and an actuator for moving said control valve head toward said valve seat and buttress threads coupling said valve stem and said control valve head to one another.