Lens gaskets0 pages

Lens gaskets
The proven high-pressure gaskets

Lens gaskets are reusable, as the sealing effect is generally achieved by elastic deformation of the surfaces.

We can also specially produce bellows lenses, lens blind
spectacle gaskets and half-lenses.

The projected sealing width bG is calculated in relation to the
angle a, which forms the sealing surface against the direction of the force (tubular axis) depending on the E modulus
EG and the surface pressure exerted by bG = 100 · σ / EG · r ·
sinα.

Lens blind spectacle gaskets are made of a sealing lens
and a lens blind, which are connected by a ligament. It is
also usual to use lens blinds on their own. In this case, it is
useful to weld on a small plate to render the lens blind distinguishable.

Gasket profiles

Profile

Profile A5BS
Specify DN, PN, size
a and d when ordering

Cross-section

06

A5

A5S

A5BS

Steel type
designation

Lens gaskets are impervious to overpressure. With increasing loads, the contact surface between the spherical lens
surface and the spherical flange groove increases, so that
the surface pressure only increases to a lesser extent.
A disadvantage with standard sealing lenses is that, at high
pressures and temperatures, the sealing lens can bulge
along the circumference and weaken the tension of the connection. Also, at greater nominal diameter, the flange can
become stuck in the area of the raised face diameter d5 and
lift up at the sealing diameter.

Material
number

For circulatory
temperatures

Code designation
on the outer edge

S235JRG2
P265GH
16Mo3
13CrMo4-5
10CrMo9-10
X6CrNiTi18-10
12CrMo19-5

1.0038
1.0425
1.5415
1.7335
1.7380
1.4541
1.7362

to 425 0C
to 425 0C
425 to 475
425 to 520
520 to 580
350 to 550
max. 650 0C

none
none
1 Punch mark
2 Punch marks
3 Punch marks
4 Punch marks
1 notch

X6CrNiMoTi17-12-2

1.4571

max. 550 0C 3 notches

Further technical data see section “Materials commonly used”.

Recommended max. roughness
of the flange surfaces

µm

Surface pressure
limits for 20 °C

N/mm2
N/mm2

E modulus at 20 °C
Surface pressure
limits for 300 °C

N/mm
N/mm2

E modulus at 300 °C

kN/mm2

Monel 2.4360

Steel 1.4541
silver-plated

Steel St 35
copper-plated

Stainless steel
1.4828

Stainless steel
1.4541

von
bis

3,2
6,3

3,2
6,3

3,2
6,3

1,6
3,2

1,6
3,2

3,2
6,3

6,3
12,5

3,2
6,3

3,2
6,3

σv
σϑ

235
525

300
675

400
900

335
750

400
900

135
600

100
750

135
300

260
660

210

210

210

200

200

210

200

128

178

235
315

300
585

400
730

335
630

400
750

135
390

100
630

135
150

260
650

185

185

190

186

186

185

186

114

175

kN/mm2
2

Heatresistant mild
steel 1.7362

Materials

Heat-resistant
mild steel
1.5415

A5, A5S, A5BS
Iron 1.1003

Profile

Copper 2.0090

Gasket limiting values

σv
σϑ

Kempchen Dichtungstechnik GmbH · Tel. +49 (0)208 8482 0 · Fax. +49 (0)208 8482 285 · info@kempchen.de · www.kempchen.de

Lens gaskets

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