MATERIALS HANDLING
Suppliers are starting to
integrate more functionality in belt cleaner designs
cleaner installation; there must be access to the far side for adjustment; the guide mechanisms are subject to fouling from dust and corrosion; and changing from bottom adjustment to top adjustment or providing for adjustment from one side complicates the tensioner design.
ROTARY TENSIONERS Rotary tensioners using an actuator are principally designed using a lever arm or an elastomeric element that is concentric with the belt cleaner support shaft. Tey apply a blade-to-belt contact surface determined by the actuating force and linkage geometry. Te energy source delivers a force to the lever arm which rotates the shaft and forces the belt cleaner blade(s) against the belt surface. Rotary designs tend to be compact and, in most cases, the actuator(s) can be mounted at any orientation, which provides options for installing the belt cleaner in the optimum position.
COUNTERWEIGHT TENSIONER
At one time the most common rotary tensioner was a counterweighted lever arm, with its position adjusted to apply the design cleaning force to a blade or blades that contact the belt. A counterweight can be mounted on one end of the shaft or both. Usually, the initial installation would have the arm angle set so that at the midpoint of the blade wear the arm would be horizontal, thus roughly averaging the design cleaning force over the life of the blade. Te primary advantage of the
counterweight design is that it is self- adjusting by gravity. Te disadvantages of the counterweight design include the lack of damping which allows the blade and
CEMA-defined cleaning positions
therefore the weight to bounce when struck by a splice, strongly adhered material, like ice or a defect in the belt. Te unexpected movement of the counterweight can represent a safety hazard and uncontrolled bouncing can result in belt top cover damage. Also, the counterweight tensioner takes a significant amount of space and,
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