Page 21 - Design Criteria.qxd

22 ® Welcome to the Next Generation of Sealing Technology
Spiral Wound Gaskets
STYLE R
Basic construction, inner and outer diameters are reinforced with several plies of metal without filler to
give greater stability and better compression characteristics. Suitable for tongue and groove or male and
female or groove to flat face flange assemblies.
STYLE RIR
Solid inner metal ring acts as a compression stop and fills the annular space between flange bore and the
inside diameter of the gasket. Designed to prevent accumulation of solids, reduce turbulent flow of
process fluids and minimize erosion of flange faces. Suitable for male and female pipe flanges.
STYLE CG
Utilizes an external ring which accurately centers gasket on flange face; provides additional radial
strength to prevent gasket blowout and acts as a compression stop. A general purpose gasket suitable for
use with flat face and raised face flanges.
STYLE CGI
Suitable for use with flat face and raised face flanges and specified for high pressure/temperature serv-
ice or where corrosive or toxic media are present.
Note on use of inner rings: ASME B16.20, which covers spiral wound gaskets, requires the use
of solid metal inner rings in:
• Pressure Class 900, nominal pipe sizes 24” and larger
• Pressure Class 1500, nominal pipe sizes 12” and larger
• Pressure Class 2500, nominal pipe sizes 4” and larger
• All PTFE filled gaskets.
ASME B16.20 recommends the use of inner rings if the user’s experience has shown inward buck-
ling of the gasket.
Flexitallic also recommends the use of inner rings for the following applications:
• Vacuum service or suction side of rotary equipment such as pumps and compressors
• Aggressive media, high pressure or temperature
• Surface finishes smoother than 125 micro-inch
• If over compression of the gasket is a concern.
It is customary to select inner ring material to be the same as the metal winding.
MULTI-CLASS
One gasket accommodates both Class 150 and 300 flanges. Multi-Class Gasket features are as follows:
• One gasket accommodates both Class 150 and 300 flanges, available pipe size 1/2” - 24”
(Class 150 to 600 in NPS 1/2 through NPS 3)
• Low Stress (Style LS) gasket for Class 150 and 300 Flanges
• Reduces inventory requirements
• Easy to install . . . Less than half the studs need to be removed to change the gasket.
STYLE HE
Style HE gaskets are used for heat exchangers where pass bars may be required. The outer portion is of
standard spiral wound construction, whereas the rib partition is normally of single or double jacketed
style, securely fastened to the I.D. of the spiral wound portion.
STYLE HE-CG
This style is identical to the Style HE, except that it is fitted with an outer guide ring. Note: Style HE
and Style HE-CG gaskets have a primary seal of spiral wound construction with its inherent resiliency and excellent sealing quality. It
is necessary that dimensional drawings locating the pass ribs and the configurations be submitted for all inquiries and orders for these
style gaskets.
Multi-Class
Style R
Style RIR
Style CG
Style CGI
Style HE
Style HE-CG