PSE 322 Midterm Exam with all Correct & 100% Verified
Answers |Actual Complete Update |Already Graded A+
Pulp is purchased in the form of dry bales.
These mills utilize a pulper. ✔Correct Answer-Non-integrated mill
Slurries with consistency of 3-5%. ✔Correct Answer-Thick stock
An early technology of this mechanism is the Hollander beater, which is oval in shape.
Repeated passes through a beating operation tend to make the fibers more flexible and
comfortable. This increases the area of adhesion (RBA) between fibers. ✔Correct Answer-
Refining
The location in which papermakers combine different streams of stock into the system. Refining
of each type of fiber is done before this location. ✔Correct Answer-Blend chest
Acts as a buffer capacity in the system. Provides a reservoir of stock so that papermakers can
make quick adjustments in the rate at which stock is pumped towards the paper machine.
✔Correct Answer-Machine Chest
A measure of the rate at which water drains from fiber in the forming process. ✔Correct
Answer-Freeness
What is the purpose of separate refining? ✔Correct Answer-Allows papermakers to achieve a
better combo of strength properties at a given level of freeness.
By having one or more of these relatively late in the process, papermakers can make quick
adjustments and begin to see the results of such adjustments a few minutes later.
The refining plates and general design of these are often selected to give a relatively harsh,
cutting action.
Increase in load and decrease in space between refining plates = decrease in freeness and fiber
length. ✔Correct Answer-Tickle refiners
Provides a constant head so that the flow of thick-stock furnish to the paper machine can be
accurately controlled with a valve farther downstream. Excess furnish is recirculated back into
the machine chest. Often the last point where a chemical can be added as a stream coming out
of a simple hose at ambient pressure. ✔Correct Answer-Stuff box
A papermakers primary tool for adjusting the basis weight of paper. Controls the flow of thick
stock to the paper machine. ✔Correct Answer-Stock valve
,Steady, accurate control of thick stock flow requires 3 things: ✔Correct Answer-A constant
head
A steady, known value consistency
An accurate measurement of the total flow
Magnetic flow analyzer
Obtains an accurate measure of total flow ✔Correct Answer-Mag meter
When is the last chance to add a chemical? ✔Correct Answer-After screening. This point is
often positioned close enough after the pressure screens so that it can still take advantage of
the turbulent eddies generated by that operation.
Utilized to add chemical at four different points around the circumference of the stock line.
Often used for retention aid. ✔Correct Answer-Ring header
A type of pipe arrangement that discharges the additive near to the center of flow within the
stock line. ✔Correct Answer-Injection quill
Conveys the stock to the paper machine headbox, and at the same time, spread the flow so that
it matches the width of the paper machine. ✔Correct Answer-Approach Flow
Where the flow is spread to the width of the paper machine. On older paper machines this may
consist of a series of dividing pipes.
Now it consists of a tapering header with tubes coming off from it at a right angle. ✔Correct
Answer-Intake manifold
Why are showers placed within air-padded headboxes? ✔Correct Answer-To knock down
foam and prevent accumulation of deposits at the water line.
A moderate level of _______ tends to increase the rate of drainage and produce a less flocky
sheet. If it is too severe, blemishes can occur in the paper, sometimes leading to web breaks.
✔Correct Answer-Action
Water that is removed from the wet web in the forming section.
This includes water that is removed by gravity, by the action of hydrofoils, by blades or forming
rolls (in some twin wire systems), or vacuum.
There is the presence of fine material, such as fiber fines, mineral fillers, and bubbles of air.
Scatters light ✔Correct Answer-White water
A collection system for white water that drains by gravity or is removed by the hydrofoils.
Papermakers often test samples of white water from these sections to get an idea of how well
fine materials are being retained during the forming process. ✔Correct Answer-Tray
Very subtle, because it all happens in a tank.
, Provides a relatively air-free supply of white water for dilution of the stock. The diameter and
shape of this device is selected so that the downward flow is uniform and slow, allowing most
bubbles of air to rise and escape at the surface. The efficiency of bubble removal can be greatly
enhanced by use of a defoamer. ✔Correct Answer-Silo
A deaeration system.
This unit applies a partial vacuum to the furnish, causing release of dissolved gases.
Minimizes some of the problems caused by dissolved or entrained air. These problems can
include pinholes in the paper, circular marks on the paper surface, and a significant reduction in
drainage rate. ✔Correct Answer-Deculator
When excess white water leaves the primary circuit, the overflow stream is directed to this
device to avoid wasting all of the fine solids.
save - all . In modern paper mills it is common to find disc filters being used as these.
✔Correct Answer-Save-all
It is conventional practice to add a moderate level of pulp fibers as this to help filter the fine
material, and avoid its loss as effluent. Many paper machine systems employ broke stock for this
purpose. ✔Correct Answer-Sweetener
Defined as repulped furnish; it tends to vary in unpredictable ways due to paper breaks, grade
changes, coating operations, and the fact that it can be generated at different points in the
papermaking process. ✔Correct Answer-Broke
A change in velocity of fluid with distance, multiplied by a coefficient of viscosity.
One had to consider this variable when adding chemicals to a process. ✔Correct Answer-
Hydrodynamic shear
On a typical Fourdrinier, the pressure screens achieve some of the highest shear stress values.
Which of the following unit operations of a typical Fourdrinier paper machine with a
conventional air-pad headbox is least likely to reduce the molecular mass of a polymeric
additive that becomes exposed to that operation?
A. Fan pump
B. Hydrocylone cleaners
C. Pressure screen
D. Headbox ✔Correct Answer-D.
especially in the case of an air-padded headbox
But hydraulic headboxes usually can be expected to impart higher levels of hydrodynamic shear
than air-padded headboxes.
An additive is being injected into the center of flow, keeping it away from the walls. ✔Correct
Answer-Quill
Answers |Actual Complete Update |Already Graded A+
Pulp is purchased in the form of dry bales.
These mills utilize a pulper. ✔Correct Answer-Non-integrated mill
Slurries with consistency of 3-5%. ✔Correct Answer-Thick stock
An early technology of this mechanism is the Hollander beater, which is oval in shape.
Repeated passes through a beating operation tend to make the fibers more flexible and
comfortable. This increases the area of adhesion (RBA) between fibers. ✔Correct Answer-
Refining
The location in which papermakers combine different streams of stock into the system. Refining
of each type of fiber is done before this location. ✔Correct Answer-Blend chest
Acts as a buffer capacity in the system. Provides a reservoir of stock so that papermakers can
make quick adjustments in the rate at which stock is pumped towards the paper machine.
✔Correct Answer-Machine Chest
A measure of the rate at which water drains from fiber in the forming process. ✔Correct
Answer-Freeness
What is the purpose of separate refining? ✔Correct Answer-Allows papermakers to achieve a
better combo of strength properties at a given level of freeness.
By having one or more of these relatively late in the process, papermakers can make quick
adjustments and begin to see the results of such adjustments a few minutes later.
The refining plates and general design of these are often selected to give a relatively harsh,
cutting action.
Increase in load and decrease in space between refining plates = decrease in freeness and fiber
length. ✔Correct Answer-Tickle refiners
Provides a constant head so that the flow of thick-stock furnish to the paper machine can be
accurately controlled with a valve farther downstream. Excess furnish is recirculated back into
the machine chest. Often the last point where a chemical can be added as a stream coming out
of a simple hose at ambient pressure. ✔Correct Answer-Stuff box
A papermakers primary tool for adjusting the basis weight of paper. Controls the flow of thick
stock to the paper machine. ✔Correct Answer-Stock valve
,Steady, accurate control of thick stock flow requires 3 things: ✔Correct Answer-A constant
head
A steady, known value consistency
An accurate measurement of the total flow
Magnetic flow analyzer
Obtains an accurate measure of total flow ✔Correct Answer-Mag meter
When is the last chance to add a chemical? ✔Correct Answer-After screening. This point is
often positioned close enough after the pressure screens so that it can still take advantage of
the turbulent eddies generated by that operation.
Utilized to add chemical at four different points around the circumference of the stock line.
Often used for retention aid. ✔Correct Answer-Ring header
A type of pipe arrangement that discharges the additive near to the center of flow within the
stock line. ✔Correct Answer-Injection quill
Conveys the stock to the paper machine headbox, and at the same time, spread the flow so that
it matches the width of the paper machine. ✔Correct Answer-Approach Flow
Where the flow is spread to the width of the paper machine. On older paper machines this may
consist of a series of dividing pipes.
Now it consists of a tapering header with tubes coming off from it at a right angle. ✔Correct
Answer-Intake manifold
Why are showers placed within air-padded headboxes? ✔Correct Answer-To knock down
foam and prevent accumulation of deposits at the water line.
A moderate level of _______ tends to increase the rate of drainage and produce a less flocky
sheet. If it is too severe, blemishes can occur in the paper, sometimes leading to web breaks.
✔Correct Answer-Action
Water that is removed from the wet web in the forming section.
This includes water that is removed by gravity, by the action of hydrofoils, by blades or forming
rolls (in some twin wire systems), or vacuum.
There is the presence of fine material, such as fiber fines, mineral fillers, and bubbles of air.
Scatters light ✔Correct Answer-White water
A collection system for white water that drains by gravity or is removed by the hydrofoils.
Papermakers often test samples of white water from these sections to get an idea of how well
fine materials are being retained during the forming process. ✔Correct Answer-Tray
Very subtle, because it all happens in a tank.
, Provides a relatively air-free supply of white water for dilution of the stock. The diameter and
shape of this device is selected so that the downward flow is uniform and slow, allowing most
bubbles of air to rise and escape at the surface. The efficiency of bubble removal can be greatly
enhanced by use of a defoamer. ✔Correct Answer-Silo
A deaeration system.
This unit applies a partial vacuum to the furnish, causing release of dissolved gases.
Minimizes some of the problems caused by dissolved or entrained air. These problems can
include pinholes in the paper, circular marks on the paper surface, and a significant reduction in
drainage rate. ✔Correct Answer-Deculator
When excess white water leaves the primary circuit, the overflow stream is directed to this
device to avoid wasting all of the fine solids.
save - all . In modern paper mills it is common to find disc filters being used as these.
✔Correct Answer-Save-all
It is conventional practice to add a moderate level of pulp fibers as this to help filter the fine
material, and avoid its loss as effluent. Many paper machine systems employ broke stock for this
purpose. ✔Correct Answer-Sweetener
Defined as repulped furnish; it tends to vary in unpredictable ways due to paper breaks, grade
changes, coating operations, and the fact that it can be generated at different points in the
papermaking process. ✔Correct Answer-Broke
A change in velocity of fluid with distance, multiplied by a coefficient of viscosity.
One had to consider this variable when adding chemicals to a process. ✔Correct Answer-
Hydrodynamic shear
On a typical Fourdrinier, the pressure screens achieve some of the highest shear stress values.
Which of the following unit operations of a typical Fourdrinier paper machine with a
conventional air-pad headbox is least likely to reduce the molecular mass of a polymeric
additive that becomes exposed to that operation?
A. Fan pump
B. Hydrocylone cleaners
C. Pressure screen
D. Headbox ✔Correct Answer-D.
especially in the case of an air-padded headbox
But hydraulic headboxes usually can be expected to impart higher levels of hydrodynamic shear
than air-padded headboxes.
An additive is being injected into the center of flow, keeping it away from the walls. ✔Correct
Answer-Quill
