| 摘要 |
<p>PURPOSE: A steam supplying valve is provided to secure the combination of a control valve and a stop valve with optimal flow characteristic by mounting a bleed opening and a balance chamber for quickly closing the control valve. CONSTITUTION: A steam valve has a fast-acting stop valve(19) and a control valve(17) acting against a valve seat(21) in a steam flow passage in a closed position. An outlet passage below the valve seat has transition walls for supplying a smooth and continuous flow passing the seat into an outlet and accordingly the losses of head are reduced. An annular screen(54) near the valve has a support structure recessed in the walls of the inlet to reduce flow blockage and vortex formation. A balance chamber(60) disposed above the control valve has a bleed hole(62) for equalizing steam pressure in the balance chamber and steam valve, inhibits depressurization of the balance chamber, and facilitates fast closing of the control valve. Buttress threads(66) interconnect a control valve stem and a control valve head to preclude binding of the parts caused by oxide buildup.</p> |
