Dictionary

Search for glossary terms (regular expression allowed)
Begin with Contains Exact term
Term Definition
Cull

Unsaleable off-grade paper.

Curl

(1) The tendency of paper to bend to one side of the sheet under humidity changes due to uneven evaporation of absorption of water from side to side of the sheet. (2) Tendency of a sheet of paper to coil or roll up at the edges. Usually caused by changes in weather or faulty drying on the paper machine.

Curltech

Steamshower to control on-line curl in both cross and machine direction.

Cutter

A machine which cuts rolls of paper into predetermined sheet sizes. The sheets are then cut to final size on a guillotine trimmer.

Cv Factor

"CV factor denotes the flow characteristics of control valves in terms of the flow coefficient Cv. The flow coefficient Cv is based on the imperial units system and is defined as: ""the flow of water through a valve at 60 °F in US gallon/minute at a pressure drop of 1 lb/in²"". The flow coefficient Cv is commonly used in the US."

Cylinder Machine

One of the principal types of papermaking machines, characterized by the use of wire-covered cylinders or molds on which a web is formed. These cylinders are partially immersed and rotated in vats containing a dilute stock suspension. The pulp fibers are formed into a sheet on the mold as the water drains through and passes out at the ends of the cylinders. The wet sheet is couched off the cylinder onto a felt, which is held against the cylinder by a couch roll. A cylinder machine may consist of one or several cylinders, each supplied with the same or different kinds of stock. In the case of a multi-cylinder machine, the webs are successively couched one upon the other before entering the press section. This permits wide variation in thickness or weight of the finished sheet, as well as a variation in the kind of stock used for the different layers of the sheet. The press section and the dry end of the machine are essentially the same as those of other types of machines.

D-Bar

A bar located on the underside of the winder. Used for sheet spreading to keep rolls from running together on the winder. Common name is spreader bar.

D.C. Motor

Motor driven by direct current.

Damp Streaks

Crushed or blackened streaks running in the machine direction. They are the result of crushing caused during pressing or calendering a sheet of paper having high moisture content areas.

Dandy "Pick"

A defect in paper caused by the dandy roll picking up fibers from the sheet or otherwise disturbing the sheet formation to leave thin spots or other imperfections.

Dandy Roll

(1) A roll placed on the fourdrinier to help reduce two sidedness of the sheet. (2) A skeleton cylinder covered with a woven wire cloth, or with an arrangement of fine longitudinal wires, crossed at close intervals by heavier circumferential wires. The former structure produces wove and the latter laid paper. The dandy roll is one method of applying watermarks to paper while wet. It is positioned on the top of the wire in front of the couch roll.

Data Processing

The accumulation and storage of mill data in the mill's computer system.

Deckle

(1) A term indicating the width of the web formed on the paper machine. (2) The straps (deckle ruler) on the wet end of a paper machine which prevent the fibers from flowing over the sides and which determine the width of the web of paper which can be run on any given machine.

Decor Paper

Special papers for laminating chipboard surfaces in the furniture and construction industry. Décor paper is rotogravure color printed with a wide range of imitation wood graining, masonry textures or other patterns. Later the paper is impregnated with resin and pressed onto the chipboard surface.

Defoamer

A surface-active chemical used to inhibit the production of and to kill foam.

Demineralizer

A vessel which utilizes an ion exchange resin to chemically remove scale and sludge forming material from boiler feed water.

Density

The weight per unit volume of a material, i.e., water has a weight of 8.33 Ibs./gallon, etc.

Department

The units of division within the mill. Each is the responsibility of the designated department head.

Desuperheating Water

Water introduced into a steam line to lower the superheat temperature and which reduces steam pressure.

Differential

The difference in pressure between the inlet dryer steam pressure and the outlet condensate pressure, or the difference in pressure from the top dryers to the bottom dryers.