CONFIGURATIONS OF ECCENTRIC SHAFTS WITH BALANCE WEIGHTS FOR FOUR BEARING SINGLE SHAFT SCREENS:

TYPE ONE: Machine balanced weight (Offsets machined into shaft design)

TYPE TWO: Shaft with bolt on blance weights

TYPE THREE: Shaft with flat bolt on balance weights

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Screen balance considerations:

DEFINITION OF BALANCE:

Screen balance is a subject frequently MISUNDERSTOOD....Balance, as related to vibrating screens , is the equating of the machine moment and the balance moment. This blancing can only be accomplished on four bearing, single shaft screens.

All vibrating screens consist of a body to which are attached screen decks and one or more shafts with unbalance weight. This unbalanced weight produces the exciting force when it revolves resulting in SCREEN VIBRATION.

On four bearing screens, the unbalanced weight is a COUNTER WEIGHT or balance weight which offsets the machine imbalance. Vibration is accomplished (multiple shaft) through a machined shaft offset.

ON TWO BEARING and HORIZONTAL MULTIPLE SHAFT SCREENS vibration is produced by unbalanced weight on a rotating shaft, therefore, these types of screns work on an unbalanced principle

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From VSMA handbook.................MOre later.....

George ■