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Glands
Introduction
Hardware design is an essential
element in the success of any
fluid-sealing product. When designing
hardware, it is important to consider
gland type, mating-surface hardness
and surface finish in order to properly
design the right seal for a given
application. The information in this
section applies to the design of new
hardware as well as modifying existing
hardware to improve seal performance
in terms of wear life, leakage rate,
friction, etc.
The main objective in selecting a gland
type is to be able to install the seals
without damaging or misaligning them.
This section addresses the basic gland
types and installation procedures.
Split Gland
The split gland entails hardware that is
"split" into two or more separate
pieces. This is the recommended
gland type when designing hardware
because it allows for easy installation
without damaging the seal.
Stepped Gland
A stepped gland has a small step,
which serves as a retaining wall and
retains the seal. The step height is
generally small so that the seal can be
pushed past it easily. Once installed,
the step holds the seal in place. In most
cases, no special tooling or installation
procedures are required. Consult the
factory for specific step dimensions.
Basic Gland Types
Basic Gland Types
There are three basic gland types to be
considered. These are stepped, split
and solid glands (see illustration). The
gland required for a radial AccuSeal is
similar to an o-ring gland with one major
difference. An o-ring gland is typically
solid (one-piece) with a full gland wall
on each side. Since o-rings are typically
elastomeric in nature, they can be easily
stretched to fit into a solid gland.
Conversely, the AccuSeal is made from
polymeric compounds, which do not
stretch like elastomers. Therefore,
installation into such solid glands can
be difficult, if not impossible. To install
the AccuSeal easily requires either a
split (preferable) or stepped gland. This
enables installation without stretching or
otherwise deforming the seal and
risking damage or misalignment.
Solid Gland
Because the AccuSeal does not
stretch like an elastomeric o-ring, it is
difficult to install in a solid radial gland.
In some cases, it is possible to retrofit
an AccuSeal into an existing solid
gland as long as the ratio of seal
diameter to cross-section is sufficiently
large.
Face Seal Glands
Face seal glands are typically the
same as o-ring glands. There are
typically no special considerations
when installing face seals.
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Introduction |
