HNBR O-Rings

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O-Ring Sizes for Industrial Applications From
machine design to applications in household
appliances, the use of the o-ring is practically
indispensable. Availability of o-rings comes in
the form of metric as well as inch
sizes. Industrial applications of o-rings A
precisely engineered mechanical mounting is
essential for the successful use of o-rings in
joint design. Such a mounting must take into
consideration the deformation of the o-ring. The
amount of stress, which is mechanical in nature,
should be of a precisely calculated amount at the
o-ring contacting surface with the mounting. In
principle, the fluid pressure that is been
contained must not be greater than the stress
that is imposed on the o-ring. As such, leakage
in the component will not happen. And because
the o-ring material is virtually incompressible,
the pressure of the fluid that is being contained
is transferred and the pressure at the interface
increases as the operating pressure goes up. The
specification of o-ring sizes is by means of the
inner diameter as well as the thickness,
otherwise known as the cross section diameter.
As long as the o-ring does not fail in a
mechanical way, the sealing of high pressure
fluid can be done effectively. The usual mode of
sealing failure is at the interface of the
adjoining parts. The design of the seal is such
that a contact exist between the sealing
surfaces, that is between the o- ring and the
mounting surfaces. This method of sealing allows
for the containment of high pressure fluids.
This can be achieved within the failure stress
limits of the o-ring. Imperfections are common in
the contact surfaces of the mounting parts, and
o-ring material which is highly flexible in
nature, effectively fills out and accommodates
all uneven surfaces. Nevertheless, an excellent
surface finish is imperative for all the parts
that comes into contact, meaning that there
should be as little imperfections as possible on
the surfaces between o-ring as well as the
contact surfaces of the mounting. This is
especially critical in low temperature
applications because the material of the sealing
compound is at its glass transition temperature
threshold, making it more crystalline in its
properties. The same principle would apply to
applications of o-ring sealing in dynamic
environments. An exceedingly rough finish to the
surface of the contact parts will cause abrasion
to the surface of the o-ring. On the other hand,
the sealing would not be sufficiently lubricated
by fluid film in the situation that the surfaces
that come into contact are exceedingly
smooth. In conclusion, the correct choice of
o-rings in terms of sizes and material would have
to take into consideration its nature of
application and the environment, including that
of physical and chemical resistance. O-rings are
available in a number of materials that include
Viton, nitrile, FFKM, FKM, silicone, epdm and
more.