Valves used in Pipelines - TYPES OF VALVES - GATE VALVE PDF Print E-mail
Written by Norrie   
Sunday, 02 May 2010 18:18
Article Index
Valves used in Pipelines
TYPES OF VALVES - GATE VALVE
TYPES OF VALVES - THE GLOBE VALVE
TYPES OF VALVES - NEEDLE, ANGLE, PLUG, BALL, BUTTERFLY, CHECK VALVE
SAFETY RELIEF VALVES
VALVE ACCESSORIES
VALVE OPERATORS
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TYPES OF VALVES

1. THE GATE VALVE (See Figure : 13)

This is the most common type of valve in use in industry and is used to start or stop the flow of fluids. It gives a positive shut-off when closed and is often used as a 'Block Valve' for isolating systems.

The gate valve MUST be either FULLY CLOSED or FULLY OPEN and NEVER USED TO CONTROL FLOW, as the fluid velocity will erode the valve internals - gate and body seats .. etc.

A gate valve may be of the 'RISING STEM' type as in Figure: 13 or a 'NON-RISING STEM', in which the stem threads are 'Left-hand' threads set into the gate itself as in Figure: 14.

The valve consists of a body which houses the valve mechanism - the stem (or spindle), the disc(s) (or gate), and the disc and body seats. Gate valves can be operated by a hand-wheel, an electric motor (MOV), or by an air powered diaphragm, or motor, or a piston actuator.

THE RISING STEM GATE VALVE

Figure : 13

NON-RISING STEM

Figure : 14