Steam Stop Valve in Boiler:

Steam stop valves mount in boilers are important for the safe operation of the boiler. It is present at the top of the boiler. It is used to transfer the steam of the boiler to the place where it is needed.

It is commonly used to regulate the flow of steam from a boiler to a steam pipe or steam pipe to another steam pipe.

Parts of Steam Stop Valve:

The various parts of Steam Stop Valve are:-

1. Steam Passage.
2. Valve.
3. Valve Seat.
4. Hand Wheel.
5. Valve Body.
6. Spindle.
7. Yoke.
8. Stud.
9. Gland.

#1. Steam Passage-

Steam from the boiler enters here.

#2. Valve-

It is actually made of brass so that it is protected from wear and tear. This valve prevents steam from boiling.

#3. Valve Seat-

It is also made of brasses so that close-fitting between the brass and the brass sheet is obtained, and both of them last longer.

#4. Hand Wheel-

It is present at the top of the steams stop valves when it is mounted.

#5. Valve Body-

It is usually made of cast irons or cast steel.

#6. Spindle-

This is the long rod that connects the handwheel to the valve>

#7. Yoke-

It is served as a support for the handwheel rod. It is present on either side of the handwheel rod.

#8. Stud-

It is the yoke rod that gives the yoke a height.

#9. Gland-

It is present between the stud & rod of the handwheel. This prevents the leakage of steam from the space between the handwell rod and the valve body.

Constructions of Steam Stop Valve:

The flange of the valve body moves to the highest part of the steam space of the boiler. It consists of a valve seat and nut. The main body of the valve is a valve seat made of cast iron and gunmetal.

When the steam stop valve is placed directly above the boiler and connected to the stream pipeline, the junction valve is called. If it is placed near the prime mover, it is normally called a steam stop valve.

The lower end of the spindle is connected to the upper part of the valve and passes through the gland and yoke, and is connected to the handwheel. The gland is used to prevent leakage of steam.

Working of Steam Stop Valve:

By default, the value of the steam stop valve is turned off, and steam is not allowed to pass through the valve. When the spindles are rotated by rotating the handwheel, the valve is up-down according to the direction of rotation.

When the valve moves steam up into the boiler, it is allowed to pass through the steam stop valve and is moved to the area where it is needed.

Principle of Steam Stop Valve:

As the spindle rotates, the spindle is rotated with the help of the handwheel, and the valve moves up and down. When the valve sits on the valve seat, the passage of steam stops completely.

The steam passage can be partially or fully opened by moving the valve upwards; the clearance (passage) between the valve and the valve seat controls the flow of steam from the boiler with the help of rotating the handwheel.

In locomotive boilers, the supply of steam is regulated through a regulator that is placed inside the boiler cell and operated from the driver’s cabin.

Frequently Asked Questions (FAQ)

What Is the Primary Function of a Steam Stop Valve in a Boiler?

The primary function of a steam stop valve is to regulate and control the flow of steam from the boiler to the designated location. It ensures the safe transfer of steam by either allowing or restricting its passage through the valve.

Where Is the Steam Stop Valve Typically Located on a Boiler?

The steam stop valve is typically mounted at the top of the boiler. It is positioned where the steam exits the boiler and is routed to the steam pipe or other systems that require steam.

What Are the Main Components of a Steam Stop Valve?

The main components of a steam stop valve include:

1. Steam Passage: The entry point for steam from the boiler.
2. Valve: The component that regulates steam flow, often made of brass.
3. Valve Seat: A fitting surface that ensures a tight seal with the valve.
4. Hand Wheel: Used to operate the valve.
5. Valve Body: Usually made of cast iron or cast steel.
6. Spindle: Connects the handwheel to the valve.
7. Yoke: Supports the handwheel rod.
8. Stud: Provides height to the yoke.
9. Gland: Prevents steam leakage between the spindle and valve body.

How Does a Steam Stop Valve Work?

A steam stop valve operates by rotating the handwheel, which moves the spindle up and down. This movement adjusts the valve’s position, controlling the steam flow through the valve. When the valve is fully closed, steam flow is stopped, and when it is opened, steam passes through to the required area.

What Materials Are Commonly Used for the Construction of a Steam Stop Valve?

Common materials for constructing a steam stop valve include brass for the valve and valve seat, and cast iron or cast steel for the valve body. These materials are chosen for their durability and resistance to wear and tear.

What Is the Purpose of the Gland in a Steam Stop Valve?

The gland is used to prevent steam leakage between the spindle and the valve body. It seals the space between these components to ensure that steam does not escape.

How Is a Steam Stop Valve Operated in a Locomotive Boiler?

In locomotive boilers, steam supply is typically regulated by a separate regulator located inside the boiler cell. The regulator is operated from the driver’s cabin to control the flow of steam.

What Maintenance Is Required for a Steam Stop Valve?

Regular maintenance for a steam stop valve includes checking for leaks, ensuring the valve operates smoothly, and inspecting components like the spindle, handwheel, and gland. Any signs of wear or damage should be addressed promptly to maintain the valve’s functionality.