Product detailed description

The type 76.90H mechanical face seal (duo cone seal, floating seal, lifetime seal) is the most widely used design of face seals with O-rings. The set consists of two symmetrically tapered seal rings with a ground profile and two O-rings. It is interchangeable with the 76.97 design (cast profile).

Operating principle: the cast iron rings are preloaded by O-rings, and the axial force closes the gap between the sealing faces. The O-rings also transmit the friction torque to the housing and statically seal each ring in its seat, relative motion only occurs between the finely lapped faces. The rings open conically from the faces towards the centre – the lubricant reaches the faces by capillary action and centrifugal force, the faces are lubricated and cooled and the seal has a large wear reserve (the contact band moves towards the centre as it wears).

Material: seal rings made of high-speed ledeburitic cast iron with fine graphite (version C) – excellent tribological properties, low friction losses and sliding speed up to 12 m/s. O-rings made of NBR (standard).

Lubrication: lubrication is essential for operation. Gear oils SAE 80 and SAE 90, or engine oil 20W-20, are suitable, with the oil level between the axis and 2/3 of the seal diameter. At low sliding speeds a permanent grease fill can be used (consult us for speeds above 1 m/s). Do not fill an unvented seal cavity with a grease gun – the pressure may push out the O-rings.

Installation: during installation the O-rings are compressed between the conical surfaces of the ring and the housing – the specified installation gap A is decisive. The O-rings and housings must be clean and dry (free of oil and dirt), the O-rings must not be lubricated with oil or grease during installation. The rings are always installed in pairs.

Set dimensions (drawing H-20-C): ring inner diameter Di 163 mm, ring outer diameter Da 191.5 mm, set height H 38 mm. O-ring Ød1 166 x Ød2 12.7 mm. Housing: retaining lip diameter dh 196.5 mm, installation diameter de 195.5 mm, shoulder diameter df 178.5 mm, functional diameter dg 194.6 mm, shoulder depth t1 18 mm, total depth t2 min. 20.5 mm, cone angle 10°, gap A 3 mm.

Typical applications: axles and final drives of construction, agricultural and mining machinery, crawler undercarriages, screw conveyors, gearboxes, mixers.

Dimensions: 163x191.5x38, 163-191.5-38, 163/191.5/38, 163 x 191.5 x 38 mm.

Also searched as: face seal, mechanical face seal, metal face seal, duo cone seal, floating seal, lifetime seal, toric seal, heavy duty seal, Laufwerkdichtung, Gleitringdichtung, 76.90H, 76.97, H-20-C.