Velocity of material which the pipes are holding.
Velocity
of the gases and air =15 to 20 m/s
Velocity
of steam = 40 m/s
Pressure drop should be minimized to get better
efficiency of machine.
Generally we allow 1% of pressure drop in
100mt.length.
Pressure drop is inversely proportional to Dia. of the
pipe.
Pressure drop is directly proportional to square of
velocity.
Headloss (hl) = flv2/2gd,
Where
f = friction factor.
L = equivalent length.
Equivalent
length for elbow = 1.5d
For tee = 2d
For valve = 5d.
MATERIAL USED
IN BHEL:
For Pipes:
CS
Material is SA106Gr.B
SS
Material is A312TP321
For Fittings:
CS Material is
A234WPB
SS
Material is A403WP321
For Flanges:
CS
Material is A105 Gr2
SS
Material is A182F321
For Gaskets:
Permanent Gaskets.
For ‘O’ Rings:
Soft
Iron, Stain less steel (AISI 304)
For Studnuts:
ASA193B7
(Stud material)
ASA1942H
(Nut Material)
For Valves:
CS-Cast
Steel Body.
SS-Internals.
MATERIAL
SELECTION:
·
Up to 415 deg. We use Carbonsteel Material.
·
More than 415deg. & Less than
520 deg. W e use SS Material.
·
More than 520 deg. We use Alloysteel
Material.
·
Below –20 deg. We use Low
Carbonsteel material
COMMONLY USED PIPE JOINTS:
1)
Screwed
Joints
2)
Welded
Joints
3)
Flanged
Joint
TYPES
OF SUPPORTS:
1) Spring Hanger
2) Spring Supports
2.1) Guiding Supports
2.2) Pedestal Spring Support.
3) Sliding Supports
4) Rigid Supports (Anchors)
TYPES OF WELDING:
1)
Socket
Welding
2)
Butt
Welding
3)
Lap
Welding
- Socket Welding is used for not more than 2” pipes.
- Butt Welding is used for larger diameters. Butt Welding efficiency is 100%
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