TYPES OF NOZZLES FLANGES USED IN PRESSURE VESSELS
A nozzle is a device used to control the direction of
fluid flow in exit & enter in enclosed chamber or pipe.
WNRF FLANGES :-
Pic01
Above picture is WNRF FLANGE having 3 inch 300# (300 rating/class), ASTM B16.5, SCH.160 (Schedule 150), UT/DP OK (Dye penetration testing/ ultrasonic testing found ok), MONOGRAM (logo of manufacturer) and HEAT NO/GROUP NO. 3341P low stressed hard punched by manufacturer.
WNRF means Weld Neck Raised Face flanges
having raised face. Large variety of & different types of flanges used as
per requirement. Generally, TDS (Technical Data Sheet) is received from client
to manufacturing vendor for appropriate requirement of client. Generally different
types of and size of flanges available.
The size
and dimensions of WNRF flanges as per ASME CODES. The main parameter is diameter,
hole PCD (Pitch Circle Diameter) of holes, thickness, no of holes, specifications,
rating, schedule & class, this is checked by appropriate QC department.
The flanges having size 24 inch and above is
checked as per B16.47 & below 24 inch as per B16.5. The tolerance for each dimension
is mentioned and also done as per codes.
Material Test Certificate (MTC) is
supplied by vendor that consisting chemical as well as mechanical properties
also any other additional supplementary requirement is fulfill by manufacturer.
Weld neck flanges can be differentiated
from all other variety of flanges by their long-tapered hub. For ordinary case ASTM
A105 flanges used & for special requirement ASTM A350 LF2 CLASSES.
Specially for man-ways openings in
vessels the WNRF flanges provided with BLIND FLANGES, blind flanges also have
specific thickness, O.D. specification and sizes also that type of flanges have
material test certificate include all tastings done by manufacturer as per client
requirements.
Pic02
Pic02
Above picture is set up of WNRF flange with pipe butt welded and employed setup (fit-up) on blind flange.
LWNRF NOZZLES:-
LWNRF NOZZLES
(FLANGES) means Long Weld Neck Flanges generally used where we avoid use of
WNRF FLANGES & pipe assembly.
Generally, LWNRF
FLANGES having straight hub different length as per requirement by client
Material used for manufacturing of such flanges is ASTM A105 OF CS & ASTM A182, A240 for SS, dimension, size as per B16.5.
Such type of flanges
in which the inside diameter of neck shall not be less than nominal size of the
neck. Different sizes of such flanges available as per rating and schedule. The
dimensions i.e. O.D. of flange, length of straight hub, inside diameter of
flange neck, raised face, pitch circle diameter of holes dia of holes etc. must
required to fulfill the requirement as per code & also material test
certificate also reflect major parameter such as MOC (material), standard, rating.,
I.D. LENGTH, chemical as well as mechanical properties, supplementary
requirement as per client requirement.
The LWNRF
FLANGES is directly welded on main shell. One think is noted that neck of the
flanges becomes the nozzle neck & attachment joint (nozzle neck to shell)
is termed as ‘D’ category as per ASME codes.
If we find difference between the WNRF flanges & LWNRF flanges,
LWNRF flanges consisting straight hub but in case of WNRF flanges the separate
pipe is require to joint to WNRF flanges as butt weld.
Same as previous the hard punched by
manufacturer on given flanges much required material grade, heat no., manufacturer
logo, rating thk. & length.
In pressure vessels generally LWNRF flanges used for the level
transmitter, inlet/outlet of pipping, liquid inlet/outlet or vent. Raised face
& surface finishing in AARH is also specify except client additional
requirements.
S.R. NECK NOZZLES :-
In pressure vessels there is large variety of flanges used as per requirement
as per pressure, design temperature etc, that’s why the selection of flanges is
plays major role during selection. Different type of materials used for the
flanges, S.R. NECK FLANGES is one of this.
S.R, NECK flanges is self-reinforced it means not required any
reinforcement pad separately. Self-reinforcement flanges (nozzles) holds more important
in quality and strength, generally S.R. NECK nozzles used where pressure vessels
is operating at high pressure.
Material
used for S.R. NECK is vary as per requirement.
Pic03
Above picture of S.R. NECK made of of material ASME SA 266
GR. 4, it means the chemical analysis and mechanical properties of given S.R.
NECK should fulfill as per given code. Test certificate of given S.R. NECK is containing
chemical as well as mechanical properties of given material, also the UT
(ultrasonic testing) & DPT (Die Penetration Testing) done on given S.R.
NECK & also mentioned in material test certificate.
Size and dimensions of S.R. NECK is checked by appropriate
vendors QC DEPARTMENT. The size & dimensions are as per B. 16.5 mentioned in
NB (Nominal Bore) and in term of SCH (Schedule), thickness is also mentioned on
material. The tastings MOC (Material), Heat No, Batch No., Thickness is must be
mentioned on actual S.R. NECK.
Pic04
+
Above picture is set-up of S.R. NECK nozzle on shell of
pressure vessel, the joint (welding joint) is generally named as LEAP JOINT.
One think is noted that no any joint
permissible during fabrication of S.R. NECK. Should be made in single piece & no repair
allowed.
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