General Information
The O-Rings is toroidal, moulded seal with circular cross-section. It is manufactured
with great precision diametric and cross-sectional tolerance, plus with a high degree
of surface finish. We stock Orings in various materials like NBR, PTFE, Silicone,
EPDM, Neoprene and PU. We carry various Orings size in American Series Orings, Japanese
Series Orings, Metric Orings range.
Followings are some of the advantages of an O-Ring as a seal.
+ O-Rings are measured by its internal diameter I.D. and cross-section width C/S
and dimensions can be given in imperial or metric. See below figure.
+ O-Rings save space and they require less space than any other seal of comparable
efficiency.
O-Rings seal in both directions, thus simplifying design in many cases.
+
O-Rings are foolproof, i.e. they cannot be turned the wrong way when being installed.
Recessing requirements are simple and mounting errors are thus virtually eliminated,
even when an inexperienced person carries out the installation.
+ O-Rings come in
various materials and hardness. The hardness of any elastomer can be varied widely
by compounding. However, 70 Shore A hardness is by far the most commonly used in
the market and 90 Shore A hardness is used mainly in high pressure applications.
We offer precision O-Rings ranging from 50 to 98 Shore A hardness
Backup Rings for O-Rings
The higher the pressure used in a system, the greater the demand made on the O-Ring
When an O-Ring is subjected to a pressure, the rubber tends to flow into the clearance
between the adjacent machine parts. At low pressure, this tendency is a slight one,
but at around 10Mpa (100Bar) the extrusion can become excessive.
Therefore at pressure exceeding 10Mpa (100Bar), it is necessary to take special measures.
This is because extrusion can lead to permanent damage to the O-Ring thus resulting
in imperfect sealing.
We can resolve this by reducing the clearance between the metal surface to a minimum
and to use close tolerances, but this is an expensive way. Alternatively, we can
use higher hardness rubber material like 90 Shore A Duro, but that makes the seal
less elastic and flexible.
Therefore the most suitable solution is to use Backup Rings.
Backup Ring material are NBR 90 Shore A Duro, Polyurethane 90 Shore A Duro, YBPO,
PTFE etc.
Note:
Backup Rings intended for AS-568 O-Ring and Swedish / Japanese Standard O-Rings are
not listed. More information on them available on request.
For Metric and Special O-Ring sizes, please contact us.
