MATERIAL OF CONSTRUCTION OF
LINER
P.T.F.E. : Polytertrafluoroethylene (-20°C to
260°C) as per ASTM D 1457
PFA
: Perfluoro (Alkoxy alkane) (-20°C to 260°C) copolymer as
per ASTM D 3307
MFA
: Metafluoro (Alkoxy alkane) (-20°C to 240°C) copolymer as
per ASTM D 3307
FEP
: Perfluoro (Ethylene Propylene) (-20°C to 205°C)
copolymer as per ASTM D 2116
COEFFICIENT OF THERMAL
EXPANSION
For Steel
----- 1.1 x 10 -5
For P.T.F.E ----- 13 x 10
-5
Proper manufacturing parameters provide a lined pipe
with dimensional stability under Pressure and Thermal cycling
conditions, without which liner buckling and cracked flarings
could occur within operational limits.
LINER THICKNESS
Fluoropolymer lined pipes
and fittings are available in heavy duty as well as in
standard thickness. The heavy duty lining is desirable for
-
INDUSTRIAL APPLICATION
A.Chemical and
Petrochemical plants,
a. Chloro - Alkali Industries
b.
Pharmaceuticals
c. Pulp and Paper
d. Steel, Metal
pickling
e. Fertilizer, Agrochemicals and Pesticides
f. Petroleum and Plastics
g. Water treatment and
Wastewater management, Explosives
h. Nuclear Energy and
Power Generation etc.
PROCESS OF PTFE LINING
1) Batch
wise supply of resin is analyzed in the laboratory for
conformance to the applicable specifications.
2) The liner is extruded under controlled conditions at
pre-determined dimensional standards and visually inspected.
Programmed Sintering of the liners in a specially designed
oven, ensure quality liners.
3) The liner is drawn through a sizing die at a
controlled rate and installed in the steel shell precisely
fabricated as per standard specification.
4) A specially designed relaxing process is used to get
a liner snug fit into the shell, to avoid undesirable stresses
in the finished product.
5) Both ends of the spool piece are now flared in a
controlled manner to eliminate cracking at the neck of
flaring.
The finished product is then hydrostatically and / or
electro statically tested and visually inspected for any
defect.
The specially designed stress relieving process, gives
lined items a characteristic, by which expansion and
contraction of both liner and shell are nearly equal and hence
buckling and cracking of the liner is avoided.
LINING PROCESS OF PFA / MFA /
FEP
To avoid
thinning of the liner section at the strategic point of
branching and to get rid of one extra joint, fittings other
than Elbows can be supplied with liner made from PFA/MFA/FEP
as per service requirements.
PFA/MFA/FEP being a thermoplastic material with a
well-defined melting point can be processed using the
injection moulding process. This method enables precise wall
thickness to be maintained with tolerance of 0.5
mm.
PFA/MFA/FEP polymers have equivalent Thermal, Chemical
and Physical properties with
