This set of Pulp and Paper Multiple Choice Questions and Answers (MCQs) focuses on “The Heatbox”.
1. The inlet to the heatbox must confirm an odd fiber slurry consistency and pressure across the width of the heatbox to confirm cross direction non-uniformity of paper.
Explanation: The inlet to the heatbox must confirm an even fiber slurry consistency and pressure across the width of the heatbox to confirm cross direction uniformity of paper.
2. An even pressure around the heatbox’s maintained by controlling the rate of recirculation.
Explanation: By inc. the recirculation, i.e., by reducing the pressure at the narrow end of the tapered inlet, the pressure and, therefore, flow rate at the heatbox over the narrow part of the tapered inlet is decreasing.
3. The _________ is a pressurized device that releases a uniform pulp slurry on the wire through the slice.
b) Heat gear
c) Head gear
Explanation: The heatbox is a pressurized device that releases a uniform pulp slurry on the wire, throughout the slice, at nearly the identical velocity as that of the wire. Original heatboxes were open, un-pressurized, and utilized a hydrostatic head for the necessary pressure.
4. A _________ could be utilized part of the way down the table to give a top coat of best quality fiber relative to the rest of the sheet.
a) Primary heatbox
b) Secondary heatbox
c) Tertiary heatbox
d) Quaternary heatbox
Explanation: A secondary heatbox could be used as part of the way down the table to release a top coat of best quality fiber relative to the rest of the sheet. To produce a white printing surface upon linerboard or to put secondary fiber in the middle section layer of linerboard, where contaminants such as polymers and wax hide.
5. Paper machines functioning above 2500 ft/min use a special, high pressure heatbox called as _________
a) Hydraulic heatbox
b) Mechanical heatbox
c) Chemical heatbox
d) Secondary heatbox
Explanation: High pressure heatbox called as a hydraulic heatbox. These heatboxes don’t use rectifier rolls because the high turbulence that’s generated with these rolls causes formation problems beyond the heatbox.
6. The _________ is a rectangular space in the heatbox where the pulp slurry is applied to the wire.
Explanation: The slice is a rectangular space in the heatbox where the pulp slurry is applied to the wire. It consists of a lower, fixed apron and an upper, adjustable lip controlling the slice height.
7. The slice height’s variable across the width of the _________ to confirm uniformity of the paper across the width of the paper machine.
c) Heat box
d) Paper machine
Explanation: Paper machines now utilized velocity formation where the lower apron protrudes out of the heatbox to direct the slice outward. The slice height is variable across the width of the paper machine to confirm uniformity of the paper across the width of the paper machine.
8. The energy of the jet’s utilized to displace the air with the return fabric into the _________
Explanation: Accompanying the return fabric into the pans. As speeds inc. the energy of this air film inc. so the angle cannot be reduced. Therefore, the forming force inc. with advancing speed.
9. The eq., F = h sin (jS), for the forming force shows that the force will _________ with the speed unless the approach angle can be reduced then the sheet is “welded” to the wire.
Explanation: The eq. , F = h sin (j S), for the forming force shows that the force will increment with the speed. If the forming pressure reaches 34 kPa then the sheet’s “welded” to the wire, and never be removed. When beta = 8 degrees, this will occur at a speed of 4500 ft/min.
10. With _________ formation, the upper lip comes out beyond the apron and the jet’s directed toward the wire, which may cause poor formation, poor retention, and wire mark.
Explanation: With pressure formation, the upper lip protrudes beyond the apron as a result of the development of water removal equipment, it’s no longer sufficient to use pressure forming except for tissue grades.
Sanfoundry Global Education & Learning Series – Pulp and Paper.
To practice all areas of Pulp and Paper, here is complete set of 1000+ Multiple Choice Questions and Answers.
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