V- screen Capacity Data
The V-Screen is manufactured in one size only so a capacity formula is not used. Instead the capacity table based on field experience with various types of materials was established for one V-Screen.
Maximum feed size should be kept in line with the opening in the screen surface. For example separating at 20 mesh (.032″ space) a top-size of about 3/16″ is considered practical. As a guide it is desirable to keep maximum feed size to a ratio of not more than 5 to 6 times the opening used in the separation. The top-size and amount of same in the feed will have a definite bearing on cloth life. Below is a table listing recommended wire diameters for various screen cloth openings used on the SYMONS V-Screen.
NOTE: The MAXIMUM size piece fed to the V-Screen should be limited to about 1-1/2″.
The V-Screen capacity chart is based on material being relatively dry and weighing about 100 lbs. per cubic foot. It is also based on a split of about 50% oversize and 25% half the size of the opening.
For materials weighing less than 100 lbs. per cubic foot reduce the T.P.H. of feed on the capacity chart accordingly.
When the proportion of oversize and undersize is not 50% and the half size varies above or below 25% V-Screen capacity can be affected. Again feed rates listed in the chart should be adjusted accordingly.
Once the type of screen is selected is then becomes necessary to determine the size of screen. In some instances it may be necessary to figure a quantity of screens when a single size unit is not adequate for the duty.
There is no substitute for experience but some type of reference must be available to calculate theoretical screen area. This is the capacity chart which is a guide and must be used with discretion.
Factor A – TPH passing through a square foot of screen surface
Factor B – Percent oversize in feed to deck
Factor C – Percent halfsize in feed to deck
Factor D – Deck location
Factor E – Wet Screening
Factor F – Material weight
Factor G – Surface open area
Factor H – Shape of opening
From the above, a formula was developed to be applied to the opening conditions of the screen application being considered. This formula is as follows:
STPH through opening (undersize)
Theoretical Area Required = = Square Feet: A x B x C x D x E x F x G x H
The above formula is used in all the calculations. In multiple deck screens, each deck must be figured separately using changing conditions from one deck to another.
There is no substitute for experience. Practical experience or operators demand will often overrule the theoretical calculations arrived at when using a capacity chart. There are many hidden factors unaccountable in a formula and we make special mention of just a few.