Centrifugal-seal, Type CC and DS

Dust and water in bearings lead to early-life destruction. Therefore, protection methods against ingress are needed. This article introduces the CS centrifugal shaft seal design suited to contaminated conditions.

Why a CS-Seal?

Dusty, abrssieve  surroundings are one of the most difficult environments for bearings. In equipment handling powders or in processes generating dust, the protection of bearings against contamination by fine particles requires special consideration. Radial oil seal, while selected mainly for sealing the shaft to housing gap, is typically an unsatisfactory sealing in this suroundings. Over time, the rubber is attacked by dirt, water, sand and various other contamination. The pollution goes into the soft material of the rubber and the lip causes fretting corrosion of the shaft (the gouge seen under the lip when it slides off the shaft). Moisture on the shaft capillaries is drawn past the lip, and water sprayed directly at the lip seal blows past the seal and into the bearing.

Extreme Bearing has developed the CS seal to solve this problem!

Worn Bearing shaft by use normal lipseal

Triple barrier sealing

CS Seals are superior against sand and detergents

  1. Double lip centrifugal seal
  2. Grease-filled housing
  3. 2-RS bearing seal

 The Bearing housing is filled with grease to prevent contaminants from entering and damaging the bearing

CS-Seals specially developed to repel dirt and contaminants using centrifugal force generated by the shaft.

 

 

Sealing without creating wear on the shaft

The rubber of the CS-seal clamps around the shaft and is turning with the shaft vertically against the stator ring. Because the lips are positioned vertically against the stator ring, the dirt will be repelled by the centrifugal force from the sealing lips. The rotor ring can be moved eccentrically in relation to the stator ring. In this way, the centrifugal seal is able to absorb any misalignment of the shaft without creating wear on the rubber lips.

The grease passes the retaining edge through the lubrication channels under the stator ring and between the two sealing lips and stator ring. This makes sure that any dirt is flushed away. The clamping of the rubber rotor ring around the shaft means that the bearing can be assembled even on a shaft which has suffered light surface damage such as a groove.

 

Grease

Not only the small gap between the seal lip and the shaft that provides sealing against contaminants. The grease in the vicinity of the seal lip and grease in between two sealing lips also provide a sealing action.
The gaps between the lips and the stator of the seal must be greased to keep out dust and water. To improve bearing life for bearing shaft seals, recommended is to use an automatic lubricator or lubricate with some regularity. Only a small quantity is necessary when slowly flushed into the bearing cavity to force dust and moisture away from the elements.

 

 

 

 

 

 

 

 

Examples of grease diagram using  CS seals

If the contamination is only on one side of the bearing unit, a seal combination can be chosen so that by re-greasing the grease on this side will first leaving the bearing housing and the contamination with the grease shall flow away from the sealing lips. As example a AS-CS combination in this picture

CS-CS seal assembly

CS-VK seal assembly

CS-AS seal assembly

Centrifugal-seal

By applying the CS seal, it must be taken into account that it slightly expands

Ø

d1 t
20 32 3
25 40 3
30 46 3
35 50 3
40 60 3
45 60 3
50 70 3
55 70 3
60 80 3
65 100 5
70 100 5
75 110 5
80 110 5
90 110 5
100 110 5

DS Double seal

DS doubel seal is a a seal combination of a cs centrifugal seal in combination of a CC PTFE seal developed for bearing use in abrasive environmental.

The DS seal the combines the good of 2 seals with each other in 1 seal set. The CS seal means that the underlying CC seal is extra protected against abrasive parts. 

Grease 

Not only the small gap between the seal lip and the shaft that provides sealing against contaminants. The grease in the vicinity of the seal lip and grease in between two sealing lips also provide a sealing action.
The gaps between the lips and the stator of the seal must be greased to keep out dust and water. To improve bearing life for bearing shaft seals, recommended is to use an automatic lubricator or lubricate with some regularity. Only a small quantity is necessary when slowly flushed into the bearing cavity to force dust and moisture away from the elements.

Because that DS-seal has a larger built-in size, a spacer ring is needed on the cover side to provide this space. To be ensure that the grease does not choose the path of the least resistance, the spacer ring is also equipped with a grease nipple  to be sure that there is a grease flush occur, the dirt washed away and the seal remains in operation.

Gease diagrams using a CS seal

Seal assembly DSCC-DSCC

Seal assembly DSCC-CL

Seal assembly DSCC-VK