First the easy question:

Melco South Africa build and test idler drag with caveates such as:

a) load variations

b) temperature range

c) test bias

d) grease types

e) speed range

f) accuracy needs

g) variation between rolls

h) isolation of seal, bearing and lubricant contributions

i) guaranteed drag values from above criteria

Contact them at: www.melco.co.za

Sandvik (Prok Australia) have a test facility: http://www.materialshandling.sandvik.com/au

Many academics and mfgs. around the world practice in measuring the idler drag for R&D purposes and to undestand the competition.

There are many test methods and noticable limitations on results. Some simple static and dynamics resistance procedures practiced are:

Static:

1. support idler on simple shaft rest and wrap string around shell center, add weights till breakaway - read weight and calc.

2. grab shell and read torque measurement on free shaft similar to point 1.

Dynamic:

3. grab shaft as in point 1, in a lathe and add rotating load with roller with pressure control onto shell while reading shaft torque resistance

There is a long list of the types and their biases. I would believe Bulk Solids library has some good input.

Lawrence Nordell

Conveyor Dynamics, Inc. ■