Defibrator

Not to be confused with defibrillator.

The defibrator is a thermo mechanical pulping refiner in which the pulp material, such as wood chips, is ground in an environment of steam between a rotating grinding disc (rotor) and a stationary disc (stator) each with radial grooves that provides the grinding surface. Wood chips are fed into the centre and are broken down as the centrifugal force pushes them towards the circumference of the discs where the grooves are finer to produce wood fibre. The size of the refined fibres can to some extent be controlled by altering the distance between the discs where a closer distance produces finer fibres but also requires higher grinding force. The capacity per machine is largely determined by the size of the machine, as well as the motor speed 1500 rpm or 1800 rpm.

History

In 1931 the Swedish engineer Arne Asplund filed a patent on a method to defibrate wood chips.^[1] As opposed to the Masonite-method, the defibrator-method (also known as the Asplund-method) uses pressurised steam to soften the wood chips, then grinding discs to pull the wood fibres apart. This grinding unit is what Asplund called the defibrator. It became the key product of his company, AB Defibrator. The Defibrator trademark is now held by Valmet, the successor of AB Defibrator, for its line of refiners for the panelboard industry.^[2]

References

↑ US patent 2008892, Arne Johan Arthur Asplund, "Method of manufacture of pulp", issued 1935-07-23
↑ "Defibrator system". Valmet. Retrieved 6 April 2016.

Paper

History Manufacture/Papermaking

Types	Blotting Bond Construction Cotton Rag Crêpe Display Dó Asphalt Glassine India Korean Kraft Laid Manila Newsprint Oatmeal Onionskin Origami Baking Building Rice Rolling Security Seed Copy Tar Thermal Tissue Tracing Transfer Tree-free Wallpaper Washi Waterproof Wax Wood-free Wove Writing Xuan

Materials	Fiber crop Paper chemicals Papyrus Wood pulp Algal bloom (Shiro alga carta)

Specifications	Grammage Density Size Units of paper quantity Surface chemistry of paper Wet strength

Manufacture and process	Bleaching of wood pulp Calender Conical refiner Deinking Paper pollution Environmental impact of paper Hollander beater Kraft process Organosolv Paper cut Paper machine Paper recycling Soda pulping Sulfite process

Industry	Paper industry In Europe In Canada In India In Japan In the United States Paper mill List of paper mills

Category Commons

This article is issued from Wikipedia - version of the 4/5/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.