Spring design for screen

Posted in: , on 9. Mar. 2007 - 08:45

Dear All,

I would like to know the effect of spring mean diameter on the working of screen...we have heavy duty grizzly feeder with eccentic shaft circuler motion working principle....initially we had problem with spring wire touching each other at feeding point hence the springs were changed to bigger wire dia....now i have observed that the motion of screen at feed and discharge end is elliptical with both the ellipse is mirror image of each other...I have a doubt that the side wall plate may break in the centre...can anybody help me in solving this issue...is this normal in the operation of screens?

warm regards,

sujeet

Re: Spring Design For Screen

Posted on 9. Mar. 2007 - 08:13

Sujeet

The shape of your stroke seems to be correct - you have unbalanced shaft posioned above the CG of the feeder.

Your original springs were too soft and that was the reason that they were closing and I guess breaking often. By changing the wire you have changed the characteristics of the springs and they are much harder now - that should be calculated so you have maximum isolation from the structure. If you send the test cards I can possibly help you.

Ziggy Gregory www.vibfem.com.au

Re: Spring Design For Screen

Posted on 11. Mar. 2007 - 06:36

Dear Shri Sujeet Nadkarni,

The spring diameter and the wire diameter sizes are calculated to suit the particular application for the screen. One cannot change spring arbitrarily. You may refer to the supplier of the screen to check their design and supply you the right kind if screens. If you are modifying screen on your own due to change of capacity etc., then you have to design it yourself or you have to take help from the others. The only other option is trial and error but it is found to be expensive considering time, efforts and effect on the production.

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.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916