VALVE TYPES AND REFINERY

VALVE FOUNDATIONMechanical device to regulate: flow, pressure

Duty: stopping& starting, flow rate, diverting, preventing back flow, relieving pressureRange size: automobile tires to locks & damsMore than 5m(16ft) diameterMaterial: Small and low-pressure valves are usually made of brass, cast iron, or plastic Large pressure valves are made of cast or forged steel, stainless steel.

Manual: operation of valve by means of a manually controlled powered operator.Man- operated valves consist of manual valves.Auto- operated valves: checks valve, pres relief valve, rupture disc (non- reclosing type).

Ball valveGlobe valveGate- rising stemGate- non rising stem

Closing downA stopper-like closure member is moved to and from the seat in the direction of the seat axis

Slide valveA gate-like closure member is moved across the flow passage.

Rotary valveA plug or disc-like closure member is rotated within the flow passage, around an axis normal to the flow stream

Butterfly valve

Flex-body valveThe closure member flexes the valve bodyPinch valveDiaphragm valve

Pinch valve

Selection of valveStopping& starting flow: low flow resistance (straight through flow passage) including slide valve, rotary valve, flex-body valveControl of flow rate: closing down type (directly proportional relationship size seat opening+ travel of closure member)Diverting flow: plug or ball adapt readily, interlink may be acceptedSolid in suspension: closure slide across the seat with wiping motion

Multi-port configuration

Check valveRelief valveRupture disc

Check valve

Rupture disc

Scrap view of valve typesBall valve

Butterfly valve

Rising stem gate valve

Non-rising stem gate valve

Direction of flow

Globe valve, internal screw

Piston valve

Piston valve

Plug valve

Safety valve with separated bonnet

ANSI, API, ASMEStandard pertaining to valves