Industrial Seals

• Radial Shaft Seals
• Mechanical Seals
• V-Ring Seals
• Hydraulic Seals
• Static Seals

Radial Shaft Seal

• Radial shaft seals are used between rotating and non-rotating machine components. They are made up of
- a cylindrical outer covering of sheet steel (shell) or elastomer which seals statically against the housing bore and enables the requisite interference fit of the seal in the housing bore to be obtained as well as facilitating proper installation;
- the sealing lip of elastomer which provides dynamic and static sealing against the shaft. The lip has a sealing edge which is formed by pressing, cutting or grinding and is normally pressed against the counterface on the shaft with a defined radial force by a garter spring. The edge of the sealing lip and the shaft counterface form the most important functional area of a radial shaft seal. The sealing effect of the lip can be enhanced by providing the contact area of the lip with hydrodynamic aids which may be designed for single direction operation, or for alternating directions of shaft rotation.

• Mechanical seals are designed for use under severe service conditions at relatively low peripheral speeds. They offer reliable protection against solid and liquid contaminants as well as leak-proof retention of lubricant. The seals were originally developed for off-road and tracked vehicles but have been found to be equally suitable for a range of other applications where effective protection is required against sand, soil, mud, water etc. These applications include
- all types of mixers,
- sand treatment equipment,
- conveyors and other construction equipment,
- agricultural machinery,
- washing equipment,
- grinding mills and other comminution equipment,
- ore dressing equipment, and
- mining equipment.
The mechanical seals from CR, of the HDDF design, consist of two identical sealing rings and two similar nitrile rubber Belleville washers. The sealing rings are of wear and corrosion resistant steel and have finely finished sliding and sealing surfaces. Sealing is assured even against thin oils, such as SAE 10W40 oils. The Belleville washers (cup springs) of nitrile rubber provide the necessary uniform face loading and positive sealing at the bore and outside diameters. The outside diameter of the washers adapts to the form of the bore in which they are mounted and there are no special demands in respect of surface finish.
CR mechanical seals are supplied as ready-to-mount cartridge units. A special retainer ring holds the two sealing ring faces together. This not only facilitates mounting but also protects the seal against damage. The retainer is left in position after mounting and provides extra protection for the sliding surfaces during the initial stages of operation. It slowly wears away.

Installation
No special tools are required to mount the mechanical seals. To ease installation it is recommended that the housing bore should have a lead-in or chamfer.

• V-ring seals are mounted on shafts and their thin, tapered lip seals against a surface (counterface) at right angles to the shaft. No special demands are placed on the surface finish of the shaft seating and the V-rings act as flingers since they have an interference fit on the shaft and rotate with it. Misalignment of the shaft with respect to the counterface can be tolerated and V-rings also provide reliable sealing if the shaft is out-of-round or rotates eccentrically. It should be remembered when using V-rings that the amount by which the shaft can be displaced axially is governed by the permissible displacement of the V-ring relative to its counterface.

V-rings are made entirely of elastomer without fabric or sheet metal reinforcement. They are, therefore, particularly easy to install. They can be stretched and, depending on size, can be pushed over other components of the arrangement, e.g. flanges, pulleys or even housings. This is a very valuable characteristic, expecially in the case of repairs.