Valves for begginers, Lecture notes of Engineering

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Valves

Valve types & applications

Valve type by function



STOP VALVES– Closed or (wide) open to isolate

equipment or system, or route flow.



THROTTLE VALVES– may be partially opened to

control (throttle) flow.



CHECK VALVES– Permit flow in one direction only:

open when upstream pressure is greater than down-

stream, closed when downstream pressure is higher



STOP-CHECK VALVES– Act as stop valve when

closed, check valve when fully opened; may be

throttled to control flow (in one direction)

Valve type by function

STOP VALVES–

THROTTLE VALVES–

CHECK VALVES–

STOP-CHECK VALVES–

REGULATING VALVES–

RELIEF VALVES– (Automatically) open at a

predetermined level above the normal operating

pressure to protect system.



SAFETY VALVES– similar to relief valves, but reset

at a pressure below their “popping” level

GATE VALVES



Stop valve

function only

(closed or wide

open)

SEAT

DISC

BONNET

BODY

PACKING GLAND

STEM

HANDWHEEL

YOKE

BALL VALVES



Stop valve

function only

(closed or wide

open)



Suitable for high

pressure liquid

systems (S.W.

valves on

submarines)

BODY

PACKING GLAND

STEM

HANDLE

BALL VALVES



Open/close with only 90

o

rotation of handle



Valve open with handle in line with piping



Negligible opposition to flow when fully open

BUTTERFLY VALVES

GLOBE VALVES



Stop valve

or throttling

function

SEAT

DISC

BONNET

BODY

PACKING GLAND

STEM

HANDWHEEL

GLOBE VALVES



Numerous

construction

forms

CHECK VALVES



Swing Check



May be mounted

horizontally or vertically



Lift Check



Horizontal mounting only

VALVE SYSTEM NOMENCLATURE



Isolating Valves–

 Pumps: Suction & Discharge

 Heat Exchangers, metering &

control devices: inlet & outlet

 Root Valves

F.O. HTR

M

suction discharge (^) inlet

inlet

outlet

outlet

root V.

burner V.

P

VALVE SYSTEM NOMENCLATURE



Control Valves–

 Constant Pressure Regulator

F.O. HTR

M

suction discharge (^) inlet

inlet

outlet

outlet

outlet inlet

P

P

VALVE SYSTEM NOMENCLATURE



Control Valves–

 Constant Pressure Regulator

 F.O. Press Regulating Valve

F.O. HTR

M

suction discharge (^) inlet

inlet

outlet

outlet

outlet inlet

outlet inlet

Comb Contr (air) signal

REGULATING VALVES

 Air-Regulated

Downward

Seating

Upward

Seating

direct acting

indirect acting