here we go: Bed Depth VERY VERY IMPORTANT STUFF

It will determine if size of the vibrating screen by mathematic calculation needs to be adjusted.......to a BIGGER, WIDER OR LONGER MACHINE.

Before establing the size of the screen from the screen area calculations only, check that the teoretical bed depth is in accordance with good operating practice. (Excerpt from VSMA)

BED DEPTH FORMULA is as follows:

DBD = O x C = INCHES OF BED DEPTH



5 x T x W

FACTORS EQUAL:

DBD = DISCHARGE END BED DEPTH

O = OVERsize in STPH

C = CUBIC Feet per ton of material

5 = CONSTANT

T = Rate of Travel (nominal 75 fpm for inclined screen

at slope of 18-20 degree slope with directional flow

rotation and nominal 45 fpm for horizontal flat screen

W = Width of screening area in Feet

See next posting for more

George Baker MODERATOR ■

here we go: Bed Depth VERY VERY IMPORTANT STUFF

It will determine if size of the vibrating screen by mathematic calculation needs to be adjusted.......to a BIGGER, WIDER OR LONGER MACHINE.

Before establing the size of the screen from the screen area calculations only, check that the teoretical bed depth is in accordance with good operating practice. (Excerpt from VSMA)

BED DEPTH FORMULA is as follows:

DBD = O x C = INCHES OF BED DEPTH



5 x T x W

FACTORS EQUAL:

DBD = DISCHARGE END BED DEPTH

O = OVERsize in STPH

C = CUBIC Feet per ton of material

5 = CONSTANT

T = Rate of Travel (nominal 75 fpm for inclined screen

at slope of 18-20 degree slope with directional flow

rotation and nominal 45 fpm for horizontal flat screen

W = Width of screening area in Feet

See next posting for more

George Baker MODERATOR ■

BED DEPTH IMPORTANT IMPORTANT STUFF........to correctly picking a proper width and length of vibrating screen.

>>>>>The feed to a vibrating screen consists of a mass of material in different sizes. The oversize will retard passage of the undersize, and this temporary restriction results in a build up of material on the screen surface. The bed diminishes as the undersize passes the opening. However, the bed of material should never reach a depth where the undersize does not stratify before it discharges off the end of the screen. A rule of thumb is that the bed depth at the discharge end of ANY LENGTH of screen should NOT EXCEED (4) four times the size of the opening in the screening media OPENING, when separating material weighing 100 lbs per cu. ft. or a maximum of (3) three times for material weighing 50 lbs cu. ft.

THIS rule should be followed and is practical in most applications.

HOWEVER, it is based on volume only and many time the dimensions of the topsize pieces in the feed to the deck will exceed the calculated bed depth. This is not cause for alarm but it deserves consideration before selecting the screen size.

GEORGE BAKER MODERATOR ■