Page 34 - Design Criteria.qxd

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35
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Welcome to the Next Generation of Sealing Technology
Lens Rings
In certain applications, the specification of a high integrity metallic seal has
usually lead to the selection of the Lens Ring concept, rather than the more
generally recognized ring type joint solution. The Lens Ring is covered sole-
ly by the DIN 2696 specification. However, ASME B16.5 and other flange
types can be modified to accept the Lens Ring.
The Lens Ring provides a metallic gasket design incorporating spher-
ical seating faces designed to suit specifically mating flange recesses, provid-
ing the user with a high integrity, high pressure/temperature metal to metal
seal.
As with all metallic gaskets, the Lens Ring material should be speci-
fied softer than the flange material, thus ensuring applied compressive load
leads to the elastic/plastic deformation of the lens ring and not the flange seal-
ing face. The distribution of high compressive loads leads to the spread of the
gasket facings, ensuring over stressing of the gasket is prevented.
In accordance with DIN 2696 general materials are limited to a range
of specified carbon steels and stainless steel grades, although alternative
grades are available upon request. Flexitallic requires a detailed drawing be
supplied when ordering non standard Lens Rings.
d
1
d
r
20°
S
DN
d
3
d
2
DIMENSIONS IN MILLIMETERS
NPS
d
d
2
middle
size
d1
S for d max contact
r
d3
x
DN
min
max
diameter
Nominal pressure PN64 - 400
10
10
14
21
7
17.1
25
18
5.7
15
14
18
28
8.5
22
32
27
6
25
20
29
43
11
34
50
39
6
40
34
43
62
14
48
70
55
8
50
46
55
78
16
60
88
68
9
65
62
70
102
20
76.6
112
85
13
80
72
82
116
22
88.2
129
97
13
100
94
108
143
26
116
170
127
15
125
116
135
180
29
149
218
157
22
150
139
158
210
33
171
250
183
26
Nominal Pressure PN64 and 100
(175)
176
183
243
31
202.5
296
218
28
200
198
206
276
35
225
329
243
27
250
246
257
332
37
277.7
406
298
25
300
295
305
385
40
323.5
473
345
26
350
330
348
425
41
368
538
394
23
400
385
395
475
42
417.2
610
445
24
Nominal pressure PN160 - 400
(175)
162
177
243
37
202.5
296
218
21
200
183
200
276
40
225
329
243
25
250
230
246
332
46
277.7
406
298
25
300
278
285
385
50
323.5
473
345
30
Avoid nominal pipe sizes in brackets.
d
3
d
1