Page 27 - FlexitallicCatalog2010

SEO Version

USEFUL TECHNICAL DATA
Gasket Style Selection
Ensure that the correct style of gasket has been selected for the appropriate application.
Note:
Flexitallic recommended Style CG Spiral Wound Gaskets up to and including Class 600 rating.
Style CGI Gaskets should be employed for pressure Classes 900 and above.
All PTFE filled Spiral Wound Gaskets for raised face and flat face flanges should utilize an inner and outer
guide ring.
When using Style ‘R’ Spiral Wound Gaskets ensure that a compression stop is incorporated into the flange
arrangement.
Required Gasket Compression
For optimum sealing performance Flexitallic Spiral Wound Gaskets should be compressed to the following
thicknesses:
Spiral Wound Gaskets with internal or external guide rings i.e. Style CG and CGI, should be fully compressed to
the guide ring. This will not damage the gasket or affect the sealing performance, since the rings are provided
as a compression limiting stop.
USEFUL ASSEMBLY TECHNIQUES
Flanges
Check that the flange faces are clean, in good condition and with a turned surface finish within the following
range Ra 3.2 to 6.3 micro metres (125 to 250 micro inches).
Bolting
Ensure that the correct bolting material is utilized to suit the operating conditions, taking into account the
limitation of low yield strength bolts.
Ensure that the use of bolt lubrication is employed. For torque tightening methods Flexitallic recommends
the use of molybdenum disulphide bolt lubrication or similar nickel based compound. Do not apply any lubricants
when using PTFE coated fasteners. Consult with the coating manufacturers for product specific friction coefficients.
Tightening Procedures
Controlled tightening procedures should be used when installing spiral wound gaskets. Flexitallic
recommends that the use of hydraulic tensioning equipment be considered where possible for bolt diameters
1
1
/
4
" and above.
Please refer to Flexitallic's Design Criteria for futher technical information.
INITIAL GASKET THICKNESS
RECOMMENDED COMPRESSED THICKNESS
1.6mm (0.0625in)
1.3/1.4mm (0.050in/0.055in)
2.5mm (0.100in)
1.9/2.Omm (0.075in/0.080in)
3.2mm (0.125in)
2.3/2.5mm (0.090in/0.100in)
4.5mm (0.175in)
3.2/3.4mm (0.125in/O.135in)
6.4mm (0.250in)
4.6/5.1mm (0.180in/0.200in)
7.2mm (0.285in)
5.1/5.6mm (0.200in/0.220in)
28