You may want to contact www.zeppelin-industry.de

I was involved with a large helical screw agitator that Zeppelin design/fabricated.

A helix is generated by a point moving around and along the surface of a cylinder or cone with a uniform angular velocity about the axis, and with a uniform linear velocity in the direction of the axis.

A cylindrical helix is generally known simply as a "helix". The distance measured parallel to the axis traversed by the point in one revolution is called the "lead".

The helix finds many applications in industry, as in screw threads, worm gears, conveyors, "spiral" stairways, and so on. The stripes of a barber pole are helical in form.

Thanks for the immediate response.But my requirement is for getting the calculations for thickness of the helical screw flight.I have searched the sight you have given me, could't get the required data.Some conveyor manufacturers have given in their catalogues flight thk, dia,hp etc,.in tabular form but not the calculations. I require this for a project to be completed for an interview