Valves are mechanical devices that controls the flow and pressure within a system or process. They are essential components of a piping system that conveys liquids, gases, vapors, slurries etc.

Different types of valves are available: gate, globe, plug, ball, butterfly, check, diaphragm, pinch, pressure relief, control valves etc. Each of these types has a number of models, each with different features and functional capabilities. Some valves are self-operated while others manually or with an actuator or pneumatic or hydraulic is operated.

FUNCTIONS FROM VALVES ARE:

• Stopping and starting flow
• Reduce or increase a flow
• Controlling the direction of flow
• Regulating a flow or process pressure
• Relieve a pipe system of a certain pressure

There are many valve designs, types and models, with a wide range of industrial applications. All satisfy one or more of the functions identified above. Valves are expensive items, and it is important that a correct valve is specified for the function, and must be constructed of the correct material for the process liquid.

Regardless of type, all valves have the following basic parts: the body, bonnet, trim (internal elements), actuator, and packing.