Steam Stop Valve ~ Boiler Mountings

Functions of a Steam Stop Valve:

    → It is used to regulate the flow of steam from boiler to the steam pipe or from one steam pipe to the other.  

Constructions of a steam stop valve:

    → The flange of valve body bolted to the boiler at the highest part of steam space. It consists of valve seat and nut. The main body of valve is made of cast iron and valve seat made from gun metal. 
    → When steam stop valve is placed directly over the boiler and connected to the steam pipe line is called the junction valve. If it is placed near to prime mover than normally called steam stop valve. 
    → The lower ends of spindle connected to valve upper and pass through gland and yoke, and  connected with hand wheel. The gland is used to prevent the leakage of steam.

Schematic Diagram of a Steam Stop Valve

Working Principle of a steam stop valve:

    → The spindle it rotated by help of hand wheel due to rotation of spindle the valve move up and down. 

    → When the valve sits over the valve seat, the passage of steam is completely closed. 

    → The steam passage may be partially or fully opened by moving the valve up, help of rotating the hand wheel the clearance (passage) between valve and valve seat regulates the flow of steam out of boilers. in locomotive boilers, the supply of the steam is regulated by means of a regulator which is placed inside boiler cell and operated by a handle from driver’s cabin.