Job Training Mechanical Technician Course Module 7 (Valves)

Introduction  

Valves were mentioned in the earlier module Pipework, where they were listed with other pipe fittings. Because they are the most important part of any piping system, they are described more fully in this module. The gas liquefaction process uses a lot of valves. ADGAS uses many different types of valves in a large range of sizes.  

Valves control the flow of fluids through pipes by:  

• starting and stopping the flow—to control the process or isolate part of a pipeline
• changing the flow rate—allowing more or less fluid to flow
• re-directing flow from one line to another at a pipeline junction
• allowing flow in one direction only
• reducing fluid pressure
• keeping the pressure in a container or pipeline below a fixed maximum
• preventing accidents by relieving overpressure in a container or pipeline.

It is very important to use the correct:  

• valve type—to suit the task it performs, as described above
• size—to suit the pipe size and the flow rate required
• material—to suit the fluid passing through it and to avoid corrosion The ADGAS Piping Specifications list the valves used for all applications on the plant.