Volume 1, Number 4
Oct 1988

Glossary

Wet end of a fourdrinier paper machine.

AKD

Alkyl ketene dimer - a synthetic sizing agent introduced in the 1950s and used in the form of an emulsion. An AKD with the trade name of Aquapel was used in the first commercial sized alkaline paper, manufactured by the Standard Paper Co. in 1959 for William J. Barrow. It is effective at pH levels above 6 or 6.5.

ASA - Alkenyl succinic anhydride - a synthetic sizing agent; more reactive than AKD, must be emulsified shortly before use & develops its full sizing level more quickly. Effective at pH levels > 5 and used in alkaline papermaking.

Biological control - Use of biocides, housekeeping measures and good plant design to minimize formation of microbiological deposits (usually slim) in machine system. In alkaline system the micro-organisms are usually bacteria rather than fungi.

Boilout - The use of hot chemicals (caustic, acids, solvents, penetrants, dispersents, etc.) circulating through the paper machine and its piping system to dissolve and disperse deposits.

Broke - Paper discarded in the process of manufacture, and usually returned to the repulsing unit for reprocessing.

Chests - Mechanically agitated storage tanks for pulp slurries, usually constructed of vitreous tile.

Dandy roll - A roll or cylinder of wire cloth that rides on the wet web of paper and may mark it with a watermark, laid pattern or other design; or which assists in sheet formation.

Dual polymer program - The simultaneous use of two retention aids, one cationic and the other anionic, to flocculate fiber, filler and fines and improve retention and drainage.

Fines - Very short pulp fibers or fiber fragments and ray cells.

First pass retention - The ratio of the suspended solids in the tray water to the percent suspended solids in the headbox, subtracted from one. A measure of how well fillers and fines are being retained in the sheet.

Foil boxes (usually referred to as "foils") - Drainage-inducing elements placed under the fourdrinier wire in the drainage section to assist in removing water from the sheet. The active element is an airfoil shaped scraper blade.

Grade - A type of paper with specific known properties.

P.M. - Paper machine. The paper machines in all of the Simpson Paper Company's mills are numbered in the same sequence. The Plainwell mill has only P.M.s No. 16, 17 and 18.

Pigment - Any inorganic, insoluble material of fine particle size added to the wet end of a paper machine or used as a surface treatment. Generally used for economy, color, brightness and opacity characteristics.

Pitch - A troublesome material originating from the resins in the wood used to make the pulp, which sometimes accumulates on the fourdrinier wire or the press section.

Slice walkway - A platform across the fourdrinier headbox which allows inspection of the table.

Soda ash - Sodium carbonate (Na₂CO₃), an alkaline compound.

Table - The portion of a fourdrinier section where drainage of water from the stock and consolidation of the sheet takes place.

Titanium dioxide - TiO₂, a white pigment used as a filler and in coatings. With its high index of refraction, it is the most effective and expensive opacifying agent available, on a pound-for-pound basis.

Vacuum boxes - Drainage elements in the table which remove water with an externally generated vacuum.

Wet end - Another name for the general fourdrinier section of a paper machine, but extending back to include the piping and equipment of the stock delivery system; that part of a paper machine where the stock is "wet."

Wire - An endless belt woven of plastic or metal for use an the fourdrinier machine; forming fabric.