The Hunger TDI tandem seal for inside sealing is a
piston rod seal.
It can be used with mineral oils and in modifi ed form
with water base fl uids, fi re resistant fl uids and compressed
The TDI seal consists of 2 parts, an external elastic
ring of PUR with a sealing lip and an internal slide ring
of abrasion resistant PTFE-Bronze compound with a
sealing edge. Prior to fi tting, the sealing lip protrudes
beyond the nominal diameter of the seal and when
fi tted is pressed against the piston rod. Effective sealing
is thereby provided at zero pressure.
The slide ring is surrounded by the elastic ring and
seals axially in direct contact with the piston rod. Under
increasing pressure and compression of the sealing
ring, it is the slide ring which is predominantly pressed
against the piston rod. The slide ring produces an
annular cavity where any seepage oil that has passed
the elastomer lip is collected.
The seepage cul is held back by the sealig edge such that
the emerging piston rod romains dry Di.nng the retum stroke.
the cdected oél is lorced back into the cylinder
The internai sealng surface ot the seal pnmahly comprises
the internai skde ring wtùch possoss excellent sldng propeiîies
When combeied wth a surface foish o»R„0.1 0.3 pm on tho piston rod.
minimum friction levels are acheved with hlghty efficient sealng
and long service life There is no stiction. no unacceptable heat
geoeraton and above ali no stck-slip eftect