There are a number of rules of thumb.

One of mine is to consider a height equal to 3x the diagonal. Sometimes 2x the width can be used.

In the old days, prior to lots of people with BSc's, MSc's or even PhD's, you just built a large scale test rig, ideally full size, carried out tests, then from these tests deduced a suitable formula. Maybe you should revert back to to this method and deduce your own rules. ■

Does nobody run practical tests any more?

My formative days were before computers, before the internet, before discussion forums where the questions are "give me the formula for ------ " or "give me a program for ---- " (fill in the blanks yourself). You devised your own tests and deduced your own answers.

Is such basic engineering materials handling dead. (Answers on a postcard please ....... ) ■

Hi Gareth..

I always used 3 x max width as the head, and doubled that for the initial conditions.

Nowadays there are much cleverer people about who work these things out to 3 decimal places, using three different methods and get three different answers. They then select the worst one and make my life a misery by insisting I work to it.

Such people say the rule of thumb is rubbish, but then.. how come it has worked for me faithfully for many more years than Keira Knightly has been on this earth.

Cheers

LSL Tekpro ■

I've been reminded of a paper written by Harold Wright on the subject of downloads from hoppers onto belt feeders.

Maybe he would supply you with a copy.

he can be contacted here - http://www.drhwright.com/

One further point, no one has asked how to relate the material head/download to belt or chain pull of the feeder??? ■

Hello Designer..

To get the pulls, I multiply the vertical loads by 0.5

Regards

LSL Tekpro ■

0.5, that's an easy number to remember and use on the back of a fag packet. :-)) ■

Hi

I guess you cvan go to the feeder suppliers eg KRUPP, RCR etc etc and give them a performance spec. What they use may be rules of thumb or other formulas

The Uni in NSW must have some research bods there

Also, a guy called Rademacher in Holland came to Oz some year back - he has written papers on pull out forces etc

You may also find some more in textboook etc

Thanks

James ■

Gareth,

This may be of interest.

Attachments

20081013_155754_0257 (PDF)

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