The tremendous energy required to convey the lime particles that you described would make dilute-phase a poor choice, not to mention the associated particle attrition and pipeline erosion.

The lime particles, assuming the particle size distribution is fairly narrow, are ideally suited to slow-motion dense-phase conveying.

Dense-phase can be accomplished with a blow tank, or with a high-pressure rotary valve which has its own unique advantages.

Dennis Hauch ■

Material with that sort of size - 3mm - may not be conveyable in dense phase at all. It depends on the size distribution. If it is narrow, dense phase may well work in which case you should look at both and compare the economics. The decision should be based on conveying trials at a reliable test house - don't trust anyone who tries to sell you a system (especially dense phase) without first doing thorough trials.

If the material has a wide size distribution then it probably won't be conveyable in dense phase. In this case a well designed lean phase system will be a better choice. Especially look at the use of a stepped bore pipeline, as it aids energy efficiency greatly.

If the material is likely to be at all variable, then dense phase is bad news because slight differences in size distribution alter the dense phase conveyability greatly. Again, lean phase is the only sensible choice then.

If you need further information email me at bm08@gre.ac.uk We have lots of publications and papers etc. which might help you find your way through this.

Mike. ■

Mike

Thank you, you are too kind!

Shall I send the beer in the post?

Mike. ■

Don't know when I'll next be in Tasie, but drop in here if you're ever in London!

I guess that invitation goes to anyone interested in Pneumatic Conveying, feel free to come and visit us at The Wolfson Centre if you're passing London UK way.

Mike. ■