Lip seal TDMI series

wiperNBRpiston

The HUNGER TDMI tandem seal for multi-fluid inside sealing applications, is used to seal piston rods and plungers. It can be used with mineral oils and in modified form with water base fluids, fire resistant fluids and compressed air. The TDMI seal consists of two parts, an elastic ring of NBR and an internal slide ring as sealing ring. Prior to fitting, the sealing lips protrude beyond the nominal diameter of the seal and when fitted are pressed against the piston rod. Effective sealing is thereby provided even at zero pressure. The slide ring is surrounded by the elastic ring and moves axially in direct contact with the piston rod. With increasing pressure and compression of the sealing ring, it is the slide ring which is predominantly pressed against the piston rod. The inner sealing surface of the TDMI mainly comprises the slide ring which has excellent sliding properties. When combined with a surface finish of Ra 0.1 - 0.3 μm on the plunger or the piston rod, minimum friction levels are achieved with high sealing efficiency and long service life. There is no stiction, no unacceptable heat generation, and above all no stick-slip effect. The TDMI is recommended for use where different fluids on each side of the seal must be kept separate. It is also suitable for sealing grease chambers against the ingress of water or other fluids. Due to its good dry running properties, it can be used as a fluid seal on one side and simultaneously as a dirt wiper on the other side.