Paper Technology International 2020 - Journal - Page 71

PAPERTECHNOLOGYINTERNATIONAL
Correlating Sheet Moisture to Total Moisture in the Fabric/Sheet Matrix
Figure 6: Above shows various sheet weight trials and comparing total water mass, x-axis, to sheet water
weight. Note the high level of the coefficients of determination.
Machine configuration showing position of sensors
Figure 7: Side elevation.
CASE STUDY TWO: Elimination of Vacuum Pump and Reducing Overall Vacuum Levels
Water Content and Energy Consumption Over Time
Studies have established that
there is a fairly wide range of felt
moistures that will not affect sheet
moisture, whereas, above a certain
limit, it will. In daily mill operation,
the “more is better” theory often
applies to vacuum application at uhle
boxes, frequently resulting in excess
vacuum, higher press section drive
loads, and premature felt wear. At
this crescent former mill, we installed
3 fixed moisture measuring heads
(before the uhle boxes, between the 2
uhle boxes, and after the uhle boxes).
See (Figure. 8.) There was a liquid
ring pump supplying the pick-up roll
and the 2nd uhle box, while a blower
system supplied all other vacuum to
the machine.
Figure 8: Plot of energy and moisture vs. time showing erratic measurements during felt start up.
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