PSE 201 Final Exam Questions & Answers 2024/2025
What are the major categories of chemical additives used for papermaking? - ANSWERSretention aids, sizing agents, fillers, strength agents, alum
What is so special about "alkaline papermaking?" - ANSWERSIt allows the use of calcium carbonate ...
What are the major categories of chemical additives used for papermaking? - ANSWERSretention aids,
sizing agents, fillers, strength agents, alum
What is so special about "alkaline papermaking?" - ANSWERSIt allows the use of calcium carbonate as a
filler.
What are the three broad goals of the stock prep area? - ANSWERSAchieve desired product properties,
set/control sheet basis weight, increase sheet strength
How is the stock prep area set up? - ANSWERSA collection of tile-lined tanks called "chests." The dump
chest contains the raw pulp. The mix (or blend) chest receives from the dump chest and the furnish
components and feeds the refiners. The machine chest receives the refined stock and feeds the stuff
box.
Why do we refine? - ANSWERSIt decreases yield loss at lower-cost grades
What physical changes occur to a papermaking fiber when it goes through refining? What changes occur
to the stock? - ANSWERSThey collapse into flat ribbons, fibrillate, become more conformable, and can be
shortened.
Where do fines come from? - ANSWERSRefining
What things get better with refining? What things get worse? - ANSWERSTensile and burst strength,
formation, smoothness, and printability get better. Tear strength, freeness, yield, opacity, bulk, and air
porosity get worse.
What is the nature of the refining action? What type of equipment has been used to induce this action
into papermaking stock? - ANSWERSIt is a "rolling friction." Equipment that has been used to induce this
include the beater, Jordan, Claflin, and disk.
, What is freeness? How is it measured? - ANSWERSDescribes how freely water drains from a fiber slurry.
It is measured by the CSF test.
What relative refining energy level is required for various grades? - ANSWERStissue < linerboard base <
multiwall bag < bleached board < fine papers < linerboard top < glassine
Why are some grades NOT refined? - ANSWERSMarket pulp is normally not refined because the
customer will do it themselves.
What are the major goals of this area? - ANSWERSTo deliver the right amount of fiber to the paper
machine in order to meet basis weight specs, and to distribute that stock uniformly.
What is the role of the basis weight valve? - ANSWERSIt sets the average basis weight of the sheet by
metering thick stock to the fan pump.
Why is the stuff box important? - ANSWERSIt dampens pulsations from the thick stock pump that could
cause sheet barring.
How is thick stock converted to thin stock? - ANSWERSThe fan pump dilutes thick stock with white water
from the fourdrinier
What is the deculator? - ANSWERSIt is a vacuum header that removes air after centrifugal cleaning prior
to the headbox.
What is the headbox screen used for? - ANSWERSPulses stock against a screen to stop fiber flocs from
getting through
What does the headbox manifold do? - ANSWERSDeliver stock to the headbox with absolute even fiber
distribution across the machine width
Why is a headbox named that? - ANSWERSIt provides pressure, or "head"
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