Understanding Boiler and Pipeline Valves

Valves are critical components in any steam system, including boilers and the associated pipelines. Their primary function is to control, isolate, or regulate the flow of the working fluid, which is steam in this case. Different types of valves are designed for specific purposes and are installed at various points within the system.

Junction Valves and Steam Direction Change

The question describes valves mounted on boilers that change the direction of steam flow by 90°. These specific valves are known as Junction valves. They are typically situated at the outlet of the boiler, connecting it to the main steam header or pipeline. Their design allows the steam exiting the boiler in one direction to turn and flow into the header which is usually oriented at a right angle (90°) to the boiler outlet. Besides changing direction, they also serve as the primary isolation valve for the boiler, allowing it to be taken offline when necessary.

Stop Valves and Steam Flow Control

The question also mentions valves fitted in pipelines that allow the steam to flow in the same direction. These are generally referred to as Stop valves. Stop valves are used extensively throughout the steam distribution network in pipelines to start, stop, or regulate the flow of steam. They are designed to be installed inline, meaning the fluid enters and exits the valve body along the same straight line, thus maintaining the direction of flow in the pipeline. Various types of stop valves exist, such as globe valves, gate valves, and ball valves, depending on the specific application requirements.

In summary, based on the functions and locations described in the question:

• The valves mounted on the boilers that change the direction of flow of steam by 90° are Junction valves.
• The valves fitted in the pipelines which allow the steam in the same direction are Stop valves.