|
General Engineering Menu | O-Rings Suppliers
Molded Orings Services
1. A
stretch greater than 5% on the O-ring I.D. is not recommended because it can lead to a loss of seal compression.
2. A Groove depth is the machined depth into one
surface, whereas a Gland depth consist of the groove depth plus diametrical clearance and is used to calculate seal compression.
3. To create seal compression the groove depth must
be less than the seal cross section. To compensate for this compression, the groove width must be greater than the seal cross section.
4. Static applications are more tolerant of material
and design limitations than dynamic applications.
5. The maximum volume of the O-ring should never
surpass the minimum volume of the gland.
6. For reciprocating seals passing O-rings over
ports is not recommended. Nibbling and premature wear and seal failure will result.
7. The closer the application is to room
temperature, the longer an O-ring can be expected to effectively seal.
8. Avoid using graphite-loaded compounds with
stainless steel, as they tend to pit the stainless steel surface over time.
9. Before installation, make sure the lightly coat
the O-ring with a lubricant that is compatible with the O-ring material, as well as with system chemicals.
10. When using only one back-up ring, be sure to
install it on the low pressure side of the O-ring.
11. Static seal cross-sections are generally
compressed from 10% to 40%, whereas Dynamic seals are from 10% to only 30%.
12. When it is said that an elastomer is good for an
application it is meant that some compounds which include that material are acceptable. Not All. For instance, some compounds of EP are good for brake fluid applications, but most are not
acceptable.
13. Material cost does not correlate with
performance, it depends on the application.
14. You must test all seals in their actual
environment because every application is unique.
15. DO NOT use a lubricant composed of the same
material as the O-ring. For example, a silicone lubricant should NOT be used with a silicone O-ring.
16. Resistance of elastomers to chemical attack is
greatly reduced at elevated temperatures.
|
