Download - Fischer Connectors

13-11
Sealing Techniques
The degree of protection needed defines the sealing technique to use.
Technical Information
Sealed and Hermetic Connectors
There are various degrees of sealing protection available for connectors, these can be broadly classified into two groups :
■ External sealing, achieved through a protective device such as a flexible boot,
■ Internal sealing, utilizing some combination of o-rings or potting material.
External Sealing
Most applications requiring protection against only
dust or splashing liquid can use an unsealed
connector with a flexible protective boot.
When not in use, an unmated connector can be sealed
with a protective cap. Using protective caps and
boots is often a cost-effective solution to prevent mud,
dirt and other foreign matter from fouling, shorting
or otherwise damaging contacts and connector
locking mechanisms. In addition, mechanical damage
caused by impact on hard surfaces can be minimized
by using covers and boots. This is particularly
well appreciated in the broadcast industry, where
outdoor shooting conditions are very rough.
O-rings, here in green, are an efficient mechanical sealing method.
For the contacts of a panel mounted connector, the
sealing technique generally applied exploits potting
material, such as epoxy resin, rubber compounds, or
for the highest levels of impermeability, glass. Sealing
this area of the connector guarantees that no fluid
or other contaminant will enter an enclosure through
the connector, even when the connector is unmated.
These sealing methods can achieve reliable and
economical sealing performance for deep water
applications or ultra vacuum with leakage rates
below 10 -8 mbar l/s.
Caps, for receptacles, and flexible boots, for plugs, represent a cost-effective solution
to protect interconnections from environmental conditions.
Internal Sealing
Applications requiring exposure to environmental
factors like pressure, vacuum, liquids or steam demand
a greater degree of sealing than that provided by
covers and boots: the connector needs to be
intrinsically sealed.
Elastomer o-rings are one of the most common
mechanical gaskets used in connector technology.
Designed to be seated in a groove and compressed
between two parts – for example between two mating
connectors, between a connector and its mounting
surface (typically a chassis-panel), or between
a cable and its attached connector – o-rings
create a seal at the interface.
Close-up of the rear of a receptacle, in which potting material was injected.