Page 33 - FlexitallicCatalog2010

STYLE LS™ & LSI LOW STRESS RANGE OF SPIRAL WOUND GASKETS
The LS gasket offers the same high integrity seal associated with the
spiral wound gasket however, the LS and LSI has been designed in
such a way that compression and sealing requirements are achieved
under very low seating stresses. These gaskets are intended for use
on class 150 and 300 applications, where customers traditionally
do not use spiral wound gaskets due to concerns about exceeding
allowable design stresses.
The traditional spiral wound gasket has its steel windings protruding
above the compression stop; this requires a significant loading
stress to compress the gasket to its optimum operating thickness.
The LS and LSI gaskets have only sof t Flexicarb or PTFE filler
protruding above metal windings and guide ring; therefore as
the gasket is compressed, the Flexicarb®, Thermiculite™ 836, or PTFE
filler is readily compressed thus producing the sealing mechanism
at an earlier stage as compared to the conventionally manufactured
spiral-wound gasket.
The “LSI” gasket retains more of its initial stress or tightness, even
when subjected to high temperatures, unlike PTFE sheet gaskets.
AVAILABLE IN A VARIETY OF METALS,
ENGINEERED TO SUIT SPECIFIC APPLICATIONS.
PTFE Filler provides excellent
chemical resistance. Also
available with Thermiculite™
or a combination of both.
Low Stress construction
seals at sheet
gasket torques
Metallic centering ring
provides blowout resistance
and compression stop
Color coded and stamped
centering ring for easy
product identification
Spiral wound design
significantly reduces
gasket creep
Metallic inner ring
contains and protects
sealing elements
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Patent #5161807/5275423
5000
4000
3000
2000
1000
700
600
500
400
300
200
100
0.5 1.0 1.5 2.0 2.5 3.0
Elapsed Test Time (hours)
3.5 4.0 4.5
0
0 0
Gasket Stress (psi ) Temperature (
°F )
Temperature
“LSI” Gasket
FLEXITALLIC “LSI” vs. PTFE Sheet
1/16" PTFE Sheet
++ + ++++++
+++
+++
+++++++
+++
++++++ + + ++
+
Flexitallic recommended minimum bolt torque figures
for use with the “LSI” gasket on ASME/B16.5 flanges.*
Note: Minimum required torques may be even lower
depending on gasket size and bolt material. Please
contact Flexitallic’s Technical Services Department
for more information.
*Above torque values are for class 150 ASME flanges
LOWER BOLT STRESS-REDUCED FUGITIVE EMISSIONS
NPS (Ins) TORQUE FT. LBS.
1/2
3/4
1
1 1/4
1 1/2
2
2 1/2
3
3 1/2
4
25
25
25
25
25
50
50
50
50
50
5
6
8
10
12
14
16
18
20
24
83
83
83
133
133
204
204
296
296
417
NPS (Ins) TORQUE FT. LBS.
Traditional Spiral Wound Gasket with Inner Ring
“LSI” Gasket
TRADITIONAL VS. “LSI” and “LS”
“LS” Gasket
34
TORQUE VALVES FOR 300 # AVAILABLE ON REQUEST.