22
If a press has had extensive use in an abrasive application, the outer diameter of
the flights will be worn away at the discharge of the press. Radial wear of 1" to 4"
in larger presses will lead to serious jamming and, possibly, a burst screen.
When a press is operated in the reverse direction it is possible that solid in the
press will be forced against the A Plate. This can damage the shaft seal. For this
reason, care should be taken when running the press backwards.
Usually three or four revolutions of the screw are sufficient to clear a press. If running
the press backwards several cycles does not clear the jam, the screen should be
removed so that the cause of the jam can be determined. Look for a bent flight.
Before going to the trouble of removing the screen, shut down the press and try
clearing the end of the press with a long screwdriver.
Sometimes when a press is jammed, a flight on the shaft of the screw will fold.
This can happen if the press overloads on dry cake or if tramp metal is caught
between a flight and a resistor tooth. The weld at the shaft may tear. When this
happens flow through the press is greatly impeded.
FOLDED FLIGHTS
SCREEN BLINDING
A common problem is for the screen of the press to become blinded (covered
over). When this occurs, the flow of press liquor coming through the screen
diminishes. The level in the inlet hopper will fill up to where it overflows.
In some cases, the screen can be cleared by periodically reversing the direction of
rotation of the screw. This can be programmed with many VFD’s, so that the press
To Next Page
Loading...
Need help?
General