By

• R.SIVAKUMAR
 VALVES
• Function of valves
• Type of valves
• Material of construction
• Standards
• Valve actuators
• Special requirements
• Valve specification
FUNCTION OF VALVES
Valves shall be used in the following
services in process piping systems.
1 .OPEN /CLOSE SERVICE
2. FLOW REGULATION
3. NON RETURN SERVICE
4. TO CHANGE FLOW DIRECTION
 TYPE OF VALVE
Most commonly used valves in process
system are
• GATE VALVE
• GLOBE VALVE
• BALL VALVE
• CHECK VALVE
• BUTTERFLY VALVE
 GATE VALVE
Gate valves are widely used valves in process industries.It
is normally used for on-off service. It has a bi-directional
sealing capacity and there fore can be installed in the line
in either direction.
Gate valve has following parts Body, Bonnet,Wedge
(gate),Gland, Stem packing, Trim ( stem, body seat ring,
gate seat ring), Hand wheel.
Types of bonnet
1. Bolted bonnet
2.Welded bonnet
3.Pressure seal bonnet
Types of wedges
1. Flexible wedge
The flexible wedge is cast or machined steel with groove to
allow seat ring to move independently and adjust to
movement of body seats. It is used where line load or thermal
expansion of the system is likely to distort the seat.
2. Solid Wedge
The solid wedge is simplest and most economical of various
wedge types. The disadvantage of this wedge does not self
compensating to seat distortion caused by thermal expansion.
Types stem sealing
1. Stem packing
2. Bellow seal
 GATE VALVE
PARTS
• BODY
• BONNET
• GATE
• STEM
• GLAND
• PACKING
• HAND WHEEL
 GLOBE VALVE

Globe valves are used for flow regulation. Globe valve has
bi-directional sealing capacity however it is preferable to
flow from under the disc.
Globe valve has following parts Body, Bonnet,Disc,Gland,
Stem packing, Trim ( stem, body seat, Disc seat), Hand
wheel.
It can be used for size upto 6” to 8” . As the diameter
become larger disc vibration will be high, Since the disc is
not supported at periphery when the valves in open
position.Guided discs are some time used to avoid vibration.
 GLOBE VALVE
PARTS
• BODY
• BONNET
• DISC
• STEM
• GLAND
• PACKING
• HAND WHEEL
 BALL VALVE
Ball valves are used for tight shut off service.Soft seat
(PTFE) gives tight sealing capacity for ball valve. It can also
be used for quick on-off service. Ball valve can not be used
for more than 200 deg C because of pr. Temp. limitation of
soft seat.
Ball has the following parts Body, Ball,Stem , Stem seal and
wrench.
Types of ball valves
Based on port size
1. Reduced port
2. Full port
Based on ball type
1.Floating ball valve
2. Trunnion mounted ball valve
Float ball valve shall be used for small bore and low pr valves.
In float ball valves during the closed state ball is pushed
against the soft seat by the upstream pressure. This force may
cause damage to seat in case of big bore and high pr valve.
Hence trunnion mounted valves are used for big bore valves.
Based on seat
1. Soft seat valve
2. Metal seat valve
Based on body construction
1. One piece construction (Top entry and end entry)
2.Spilt construction (2 piece and 3 piece construction)
 BALL VALVE

PARTS
• BODY
• BALL
• SEAT
• STEM
• LEVER
BALL VALVE
 CHECK VALVE
Check valve are unidirectional. It open automatically by
fluid pressure and close when flow reverse or stop.
Types of check valves
Swing check valve, Lift check valve, Dual plate check
valve.

PARTS
• BODY
• DISC
• BONNET
• HINGE
 BUTTERFLY VALVE
Butterfly valves shall be used for flow regulation service in
big bore lines. It shall not be used for high pressure service

Type
• Wafer type
• Lug type
• Flanged valves
PARTS
• BODY
• DISC
• SEAT
• HANDLE
 MATERIAL OF CONSTRUCTION
Material for process wetted parts of valve shall be suitable
for service fluid.ASTM specification for various material
used for valve body material are as follow.
• CABON STEEL
– A 105
– A 216 GrWCB
• LOW TEMP CARBON STEEL
– A 350 GrLF2
– A352 Gr LCC/ LCB
• STAINLESS STEEL
– A 182 Gr 316/ 304
– A 351 Gr CF8M / CF8
• ALLOY STEEL 1.25 Cr-0.5 Mo
- A182 Gr F11 cl 2
- A217 Gr WC6
• ALLOY STEEL 2.25 Cr-1 Mo
-A182 Gr F22 cl 3
-A217 Gr WC9

TRIM
The most commonly used trim are
• 13 Cr - 182 F6a / A 217 CA 15
• HARDFACED - STELLITE
• 13 Cr & HARDFACED - A182 F6a & STELLITE
• 18Cr – 8 Ni (SS 316)- A 182 F316
 STANDARDS
DESIGN STANDARDS

Valves shall be designed according to ASME

B16.34 . Class rating(pressure temperature rating )
of valve shall be selected according to this
standard.Design temperature and pressure of valve
should be with in the limit of pressure -temp
cruve of concern class rating.
For example
Gate valve, A 105, design temp- 100 deg F
design pressure - 200 psig
Class rating shall be 150 lbs
 PPRESSURE TEMP CURVE FOR CS 150 CLASS RATING ASME B16.34
A 105, A 216 WCB, A 515 70

Temp F -20 100 200 300 400 500 600 650 700 750 800 850 900 950 1000
pressure
(psig) 285 285 260 230 200 170 140 125 110 95 80 65 50 35 20

class 150

300
Working pressure (psig)

250
200
150 class 150
100
50
0
-20

200
300

500
600
650
700
750
800

900
950
100

400

850

Temperature in F 1000
In addition to ASME B 16.34 the requirement of
following STD shall be complied as applicable
• API 600 - API STD for steel gate valves
• API 602 - API STD for compact steel gate valves
• BS 1873 - BS STD for globe valves
• BS 5351 - BS STD for steel ball valves
• API 594 -API STD for check valves
• API 609-API STD for butterfly valves
 DIMENSION STANDARDS
• FACE TO FACE
– Face to face and end to end dimension of valves shall be
according to ASME B 16.10
• VALVE END
Valve end dimensions shall be acc. To the following standards
as applicable
– FLANGED END ASME B 16.5
– SOCKET WELDED END ASME B 16.11
– SCREWED END ASME B 16.11
– BUTT WELDED END ASME B16.25

VALVE TESTING STANDARD

• Valve shall be tested and inspected according to
API 598
 VALVE OPERATOR
• HAND WHEEL OPERATED
- Shall be used for small bore valves
• GEAR OPERATED
- Shall be used for big bore valves. Gear operated valve shall
be provided for the following size range acc. to TP std.
Type of valve Rating Diameter
Gate Valve 150 / 300 lbs 14 " and over
600 lbs 12 "and over
900 lbs 8" and over
1500 / 2500 lbs 6" and over
Globe valve 150 / 300 lbs 8" and over
600 / 900lbs 6" and over
1500 / 2500 lbs 4" and over

• When specified power operator has to be provided

(motor / Pneumatic operated)
 SPECIAL REQUIREMENT
• HIGH PR. STEAM SERVICE
Valve shall be provided with pressure seal bonnet and seat shall be
hard faced.
• CRYOGENIC SERVICE
Valves shall be made entirely of SS material and shall be provided
with extended bonnet so that temp at packing should be near atm.
• SOUR SERVICE
Valve material used in sour service shall meet the requirement of
NACE MR 01 75
• VOLATILE AND TOXIC
Valves shall be provide with bellow seal.
• FIRE SAFE DESIGN
Soft seat shall be backed by steel ring so that in case of fire steel
ring can seal the fluid.
 VALVE SPECIFICATION
To specify the valve at least the following parameters has
to be defined
• Valve type : Gate / Globe / Ball ...
• Valve size :Diameter
• Pressure rating: 150#, 300 #...
• Material of body and trim : ASTM spec...
• Material for packing: Graphite ...
• Design std : ASME B 16.34, API 600, ...
• Type of bonnet: Welded, Bolted, Pressure seal
• Vale operator: Hand wheel, Gear operator
• Valve end type : SW, FE,Screwed End, ..
• Special requirement:NACE, Fire safe..
 EXAMPLE
• Valve type : GATE VALVE
• Valve size : 6 “
• Pressure rating: 150#
• Material of body and trim : BODY A 105 & TRIM SS316
• Material for packing: Graphite
• Design std : ASME B 16.34
• Type of bonnet: BOLTED
• Vale operator: HAND WHEEL OPERATED
• Valve end type : FLANGED END RF acc . ASME B 16.5
• Special requirement:---