How can you prevent grease from being flushed out of bearings?

How can you prevent grease from being flushed out of bearings?

How can grease be prevented from being flushed out of bearings?

The role and limitations of bearing seals

Bearing dust caps and seals act as vital barriers to protect the grease inside the bearing; they effectively prevent external particulates from entering whilst retaining the grease.

However, different types of seals vary in their protective effectiveness:

1. Non-contact dust seals:

This type of dust seal does not come into contact with the inner ring and therefore does not increase start-up or operating torque; however, its sealing performance is limited and it is not particularly effective at preventing lubricant washout.

2. Contact seals:

Contact seals made from nitrile rubber make close contact with the bearing inner ring, providing superior protection against contamination. However, it should be noted that these seals increase friction torque, which may affect the bearing’s operating efficiency; therefore, additional protective measures are required.

A compromise solution: non-contact seals

Non-contact seals represent a middle ground between dust caps and contact seals. They are also made from nitrile rubber but do not rub against the inner ring, and therefore do not affect torque or maximum speed. These seals offer better protection than metal shields and are suitable for most standard applications.

Expert advice on preventing lubricant washout

To achieve the best protection against washout, the following measures are worth considering:

1. Select the appropriate grease

Highly water-resistant grease: effectively resists water washout whilst maintaining lubrication performance

Food-grade grease: suitable for the food processing industry; withstands regular steam cleaning or chemical washing.

IPFPE grease: offers extremely high chemical resistance; suitable for harsh environments

3. Optimise the sealing system

In heavy-duty or highly contaminated environments, it is recommended to use double-lip contact seals and install protective devices:

Fit a protective cover over the bearing to reduce direct impact

Design drainage channels to prevent standing water from causing continuous scouring of the bearings

4. Regular Maintenance Checks:

Regularly inspect seals for wear

Monitor the condition of the grease and top up or replace it in a timely manner

By comprehensively applying these methods, the bearings’ resistance to scouring can be significantly improved, their service life extended, and the stable operation of the equipment ensured. For high-speed, light-load applications, consider combining non-contact and contact seals