Types Of Screens
CIRCLE THROW: basically is on a 20 deg incline downhill. can run directional. DOWNHILL.......or counterflow UPHILL.
DIRECTIONAL equals more TPH or less retention time on deck
UPHILL equals slower FPM travel or more efficient ( more retention time on deck)
WHY circle throw? GRAVITY or mother nature is free.....equals cheaper, less mtce problems, simple, NO gears........
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HORIZONTALS: usually needed when headroom to install a incline circle throw unit is NOT AVAILABLE. Vibration is accomplished by typically 2 shafts, driven by a big motor IE 50hp electric 1800 rpm 3/60hz for canadian standards.
very high mtce ON BREAKDOWNS vs inclined. 4 bearings, 2 shafts, gearset, 2 drive shafts, MORE COMPLEX, MORE TROUBLE when the bearings go.........ROLLERS GO through gearset and huge damage and typically spit chunks of metal through the drive COVERs. longer to fix.......and can actually SPRING the shafts if parts go thru the gear engagements.........NOW we are talking huge REPAIR BUCKS...........MEGA.
WHY do people use them? IF You speak to 10 people .....5 will say use horizontal........5 inclined.........and both RIGHT. It is preferance actually. Personal preference.
In actual fact, if tight for headroom go FLAT OR HORIZONTAL.
Screening on flat screen...material actually sees full opening in wirecloth.........vs inclined at 20 degrees for example.......IT DOES NOT SEE FULL OPENING.....ie 1" at 20 degree......material will actually only see about 15/16" opening........because of foreshortening of the opening due to angle of incline. STEEPER THE ANGLE......the smaller the opening that the material actually will see in fact. YES,,,,,,,,,,so you can cheat up on the opening and STILL STAY ON SPECIFICATION !!!
flat screens: XL on portable plants.........we have to go under bridges without hitting them...
KEEP SMILING.................GEORGE BAKER ■
Types and application of screens
I Want to know the different types of screens.Like Inclined horizontal and banana. Also i have noted that a circular drive is applied only to inclined screen. And sometimes its direction is set against the flow of material to improve screening. Why is it so.
Even in horizontal screens i have seen the drives set on the top either next to each other or sometimes in a 6 oClock 12 oClock Position and sometimes it only a single drive in the center of the drive beam.
Same is the case with banana screens also.
Can you tell me Why it is so. What difference it makes and what are the points taken into consideration while determining the type of screen with the type of motion to be used. ■