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Low Stress Spiral Wound Gasket

Style LS® & LSI®

+�� Style LS® spiral wound gasket has been engineered by Flexitallic to provide an

alternative to sheet gaskets in Class 150 and Class 300 service. Style LS® gaskets

have the inherent strength, resiliency and blowout resistance of spiral wound gaskets,

yet require low bolt load for seating. They are manufactured with high purity flexible

graphite, and PTFE filler for optimum sealability, and are available for the full range

of standard Class 150 and Class 300 flanges, as well as other non-standard low

pressure flanges. Consult Flexitallic Technical Department for availability of other

filler materials. PATENT NUMBERS 5161807 and 5275423.

The gasket allows designers to strictly adhere to ASME B and PV and ASME B31.3

codes requiring that bolt stresses do not exceed 25,000 psi. Where ASME flange

design calculations indicate that flanges will be over stressed if a standard Class 150

spiral wound gasket is used, the LS® gasket is designed to compress at significantly

lower bolt load than standard Class 150 spiral wound gaskets, thereby maintaining

flange stresses within allowable limits.

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LS® Gasket

����������� � ® GasketTypical gasket compression under

an applied gasket stress of 5000 psi

Gasket Stress – psi

6

5

4

3

2

1

0

Gasket Thickness – in.

LS 4” 150

����������� � ® GasketTypical gasket sealing profile

Seal Pressure – psi1400

0

0 1 2 3 4 5 6

Gasket Stress – Ksi

LS 4” 150

1200

1000

800

600

400

200

0.120.130.140.150.160.170.180.19

Filler Flush With Metal

Filler Protrudes Well Above Metal