It increases the coefficient of friction to prevent slippage. Also to prevent wear on the drum. ■

Pulley Lagging does provide:

1. Improved drive/brake surface traction (friction)

2. Reduced pulley steel shell wear - bare steel has greatest belt-pulley sliding motion on pulley surface

3. Ability to grove pulley surface that removes water film on belt surface - eliminates or reduces likelyhood of hydroplaning

Ceramic and rubber lagging offer different behavior and benefits and must be differentiated according to their functions. ■

4. Sacrificial wear surface that can be replaced versus having to replace pulley ■

Dear Marcsua,

The other respondents have already given the information. This information in other words can be also mentioned as below:

1) Rubber lagging increases the frictional grip between belt and driving surface of the pulley. Therefore, for transmission of the tractive pull of particular value, resultant maximum tension in belt will be less when pulley is rubber lagged. So, it will have possibility of economical belt.

2) Rubber lagging when grooved, will have better result while dealing with wet or contaminated pulley surface. It will tend to eject out moisture and contamination while maintaining comparatively more value of friction coefficient.

3) Rubber lagging prevents the wear of the pulley rim and avoids the replacement of pulley drum (only rubber lagging needs to be redone when worn out).

4) Theoretically, conveyor design is possible without rubber lagging on pulley. Only thing is that it can have higher tensions, bigger pulleys, bigger bearings, stronger structure. But this can lead to uneconomical conveyor.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Author of Book : Belt Feeder Design and Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Pune, India.

Tel.: 0091 (0)20 25871916

Email: parimul@pn2.vsnl.net.in ■

Dear Mr.Marcsua,

I have seen the dozing conveyors or weigh feeders drive pulleys are not rubber lagged but with fine pitched grooves for better grip. Those conveyors are extremely slow in speed and the motors are of lower KW. If you could post your pulley's application and it's drive details, I think it would be more helpful in the discussion.

Regards, ■