Tonnage per hour desired is the rule

Go to the vibrating screen manufacturers web site and or cema.org

you have answered your question pretty well as the tonnage per hour is what rules everything and screen opening size, number of screeens per screener and work load desired per screen-tons per hour and gradation to the final desired product size is the ruling factor.

The square foot of the screen deck is key and not overloading it is very important as it will flood and reduce screening of oversize. ■

Check out this website: SELF EXPLANATORY.

Basically, You decide what sizes you want to screen at and apply this formula to get the vibrating screen size needed.

www.wovenwire.com/reference/screenarea.htm

"Sizing up the situation" happy holidays..... ■

You will see the same thing at start up of a screener- the reason it is not visible during operation is simply the human eye can not follow it fast enough-thus the optical illusion of smooth operation. ■

This is because at some rpm , it matches the natural frequency of the system suspended on the springs. This is known as resonance.

The force applied to a suspended system at it's natural frequency accumulates and goes on accumulating, till the system breaks down.

Thankfully, the rpm while closing or starting remain at the natural frequency for a very short time.

George, please correct me if I am wrong. ■

The reason this occurs it quite simple:

1. STARTUP: we have a slight erractic bouncing of the screen but, quickly disappears after the screen has turned the shaft over the twelve oclock position and now the unit is off and running up to operating RPM.....whatever that might actually be.

2. SHUTDOWN: Here we have the reverse osmosis ...... the power is cut, the shaft is still turning full RPM and decelerating over the course of say 1 to 1.5 minutues or whatever. If you hit stop and time it.....you will clearly see the erratic action TIMING as it gets slower and slower.......the VIBRATION to all gets WORSE.

In the last 10-15 seconds we get REALLY BOUNCY ERRATIC. Here what is actually occuring is the SHAFT is now trying to SLOW to a STOP and it eventually gets slow enough to barely make it over the twelve oclock position for the last time, then when it does....IT ROCKS erractically back and forth til it come PEACEFULLY to a nice DEAD STOP REST. In that shutdown mode we end up passing thru the nature frequency of the structure and shake the handrails, flooring and the operator.....no big deal.

PS: can you use reverse motor setup to cut the shutdown erractic-NESS to absolute minimal. XL especially if you are way up HIGH in a structure.

Wishing you calm vibrations. ....and Happy 2007. ■