| Technical
>
Design
Guide >
Sealing
Sealing
Very
thin coatings of Xylan show little tendency to cold flow (migrate
under pressure), and thus are too hard to perform as conventional
sealing surfaces. Applied in thicker films, however, these coatings
will deform sufficiently under pressure to form a tight thread-to-thread
seal on pressure plugs, fittings, valve stems and other threaded
fluid power components. Tests of coated pressure plugs have shown
that they resist leaking even when surge-tested repeatedly to
950 kg per cm²/13,500 psi.
The other characteristics of
the coatings — low friction, corrosion resistance and
high-temperature stability — are beneficial in these applications
too. The low coefficient of friction results in lower seating
torques (as much as 60 percent). Because Xylan is stable up
to 290°C/ 550°F, it will not migrate from threads when
equipment is operated at high temperatures.
The
coatings can be used as dynamic seals too. For example: when
applied to the vanes of a powder metal rotor in an air-conditioning
compressor, Xylan seals the rotor/housing interface, preventing
leakage of the refrigerant past the rotor. To qualify for this
application, Xylan 1010 was tested for 150 million cycles at
8,000 rpm, at a temperature of 185°C/360°F.
Note:
Definitions of any technical terms used on this page
can be found in our
glossary.
|
