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The actual as produced seal diameter shall be as close as possible to the groove diameter.
By compressing the seal in the groove, the seal outside diameter for internal pressure seals will try to grow and the seal inside diameter for external pressure will try to shrink.
This phenomena is covered by the DC or diametrical clearance. The DC will give allowance for this increase or decrease of the seal diameter.
The seal tolerance and also groove tolerance shall be kept as small as possible. It is better for the seal performance to keep the DC in compressed condition as small as possible.
Ideally, once compressed the seal outer diameter should slightly touch the groove outer diameter or for an external pressure seal the inner seal diameter should slightly touch the groove ID.
|
Internal Pressure Groove OD Tolerance |
External
Pressure Groove ID Tolerance |
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|
Type ----- Cross section |
O Ring |
C Ring & Oysterseal |
CS Ring |
Type ----- Cross section |
O Ring |
C Ring & Oysterseal |
CS Ring | |
|
0.79 |
+ 0.05 |
+ 0.05 | --- |
0.79 |
- 0.05 |
- 0.05 | --- | |
|
0.89 |
+ 0.10 |
+ 0.05 | --- |
0.89 |
- 0.10 |
- 0.05 | --- | |
|
1.19 |
+ 0.10 |
+ 0.08 | --- |
1.19 |
- 0.10 |
- 0.08 | --- | |
|
1.57 |
+ 0.10 |
+ 0.08 | + 0.10 |
1.57 |
- 0.10 |
- 0.08 | - 0.10 | |
|
2.39 |
+ 0.15 |
+ 0.10 | + 0.10 |
2.39 |
- 0.15 |
- 0.10 | - 0.10 | |
|
3.18 |
+ 0.15 |
+ 0.10 | + 0.13 |
3.18 |
- 0.15 |
- 0.10 | - 0.13 | |
|
3.96 |
+ 0.15 |
+ 0.13 | + 0.15 |
3.96 |
- 0.15 |
- 0.13 | - 0.15 | |
|
4.78 |
+ 0.20 |
+ 0.15 | + 0.15 |
4.78 |
- 0.20 |
- 0.15 | - 0.15 | |
|
6.35 |
+ 0.20 |
+ 0.20 | + 0.20 |
6.35 |
- 0.20 |
- 0.20 | - 0.20 | |
|
7.9 |
+ 0.20 |
+ 0.20 | + 0.20 |
7.9 |
- 0.20 |
- 0.20 | - 0.20 | |
|
9.53 |
+ 0.25 |
+ 0.25 | + 0.25 |
9.53 |
- 0.25 |
- 0.25 | - 0.25 | |
|
12.7 |
+ 0.25 |
+ 0.25 | + 0.25 |
12.7 |
- 0.25 |
- 0.25 | - 0.25 | |
Groove tolerances for face type seals
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Copyright ©2005 HTMS |
Disclaimer |
Resilient metal seals from High
Tech Metal Seals NV are used in the most extreme environmental conditions.
Spring Energised Metal C Rings are used under extreme conditions where
temperature can range from cryogenic up to extreme high temperatures, such
as 800°C.
To serve the harsh conditions in today’s Oil and Gas exploration, High Tech
Metal Seals NV designs and manufactures resilient metals seals which comply
and exceed the ISO 15848 leakage requirements for valves intended for
application with volatile air pollutants and hazardous fluids. High Tech
Metals Seals are manufactured from high alloy materials so that the finished
product complies with NACE MR0175 requirements. Silver plated Metal O rings
or Metal C Rings, because of ductile layer are successfully used in high
vacuum applications. Silver plated or PTFE coated spring energised C Rings
and Metal C Rings comply and exceed the ISO 15848 leakage requirements, from
cryogenic temperatures up to extreme high temperatures and pressures. In
nuclear applications, particle research, and other radiation application,
typically high load resilient metal seals, such as spring energized metal C
Rings or Metal O Rings, with a ductile layer of silver are successfully
used. High Tech Metal Seals NV, seals for extreme environmental conditions
are particularly suited for high pressure. The system pressure assist in
maintaining intimate contact with the mating flanges.