Defibrator

Last updated

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]

Related Research Articles

<span class="mw-page-title-main">Pulp (paper)</span> Fibrous material used notably in papermaking

Pulp is a fibrous lignocellulosic material prepared by chemically, semi-chemically or mechanically producing cellulosic fibers from wood, fiber crops, waste paper, or rags. Mixed with water and other chemicals or plant-based additives, pulp is the major raw material used in papermaking and the industrial production of other paper products.

<span class="mw-page-title-main">Paper engineering</span>

Paper engineering is a branch of engineering that deals with the usage of physical science and life sciences in conjunction with mathematics as applied to the converting of raw materials into useful paper products and co-products. The field applies various principles in process engineering and unit operations to the manufacture of paper, chemicals, energy and related materials. The following timeline shows some of the key steps in the development of the science of chemical and bioprocess engineering:

<span class="mw-page-title-main">Medium-density fibreboard</span> Engineered wood product

Medium-density fibreboard (MDF) is an engineered wood product made by breaking down hardwood or softwood residuals into wood fibre, often in a defibrator, combining it with wax and a resin binder, and forming it into panels by applying high temperature and pressure. MDF is generally denser than plywood. It is made up of separated fibre but can be used as a building material similar in application to plywood. It is stronger and denser than particle board.

<span class="mw-page-title-main">Paperboard</span> Thick paper-based material

Paperboard is a thick paper-based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker than paper and has certain superior attributes such as foldability and rigidity. According to ISO standards, paperboard is a paper with a grammage above 250 g/m2, but there are exceptions. Paperboard can be single- or multi-ply.

<span class="mw-page-title-main">Pulpwood</span> Timber intended for processing into wood pulp for paper production

Pulpwood can be defined as timber that is ground and processed into a fibrous pulp. It is a versatile natural resource commonly used for paper-making but also made into low-grade wood and used for chips, energy, pellets, and engineered products.

<span class="mw-page-title-main">Paper machine</span> Industrial machine used in the pulp and paper industry

A paper machine is an industrial machine which is used in the pulp and paper industry to create paper in large quantities at high speed. Modern paper-making machines are based on the principles of the Fourdrinier Machine, which uses a moving woven mesh to create a continuous paper web by filtering out the fibres held in a paper stock and producing a continuously moving wet mat of fibre. This is dried in the machine to produce a strong paper web.

<span class="mw-page-title-main">Kraft process</span> Process of converting wood into wood pulp

The kraft process (also known as kraft pulping or sulfate process) is a process for conversion of wood into wood pulp, which consists of almost pure cellulose fibres, the main component of paper. The kraft process involves treatment of wood chips with a hot mixture of water, sodium hydroxide (NaOH), and sodium sulfide (Na2S), known as white liquor, that breaks the bonds that link lignin, hemicellulose, and cellulose. The technology entails several steps, both mechanical and chemical. It is the dominant method for producing paper. In some situations, the process has been controversial because kraft plants can release odorous products and in some situations produce substantial liquid wastes.

<span class="mw-page-title-main">Grinding wheel</span> Abrasive cutting tool for grinders

Grinding wheels are wheels that contain abrasive compounds for grinding and abrasive machining operations. Such wheels are also used in grinding machines.

Dr. Arne Asplund was a Swedish inventor. He invented the Defibrator pulping refiner and the defibrator-method for pulping wooden chips in 1930s. His invention resulted in the company AB Defibrator in Stockholm which was merged with Sunds AB to form Sunds Defibrator in 1979.

<span class="mw-page-title-main">Turning</span> Machining process

Turning is a machining process in which a cutting tool, typically a non-rotary tool bit, describes a helix toolpath by moving more or less linearly while the workpiece rotates.

<span class="mw-page-title-main">Olive oil extraction</span> Process of extracting oil from olives

Olive oil extraction is the process of extracting the olive oil present in olive drupes. Olive oil is produced in the mesocarp cells, and stored in a particular type of vacuole called a lipo vacuole, i.e., every cell contains a tiny olive oil droplet. Olive oil extraction is the process of separating the oil from the other fruit contents. It is possible to attain this separation by physical means alone, i.e., oil and water do not mix, so they are relatively easy to separate. This contrasts with other oils that are extracted with chemical solvents, generally hexane. The first operation when extracting olive oil is washing the olives, to reduce the presence of contaminants, especially soil which can create a particular flavor effect called "soil taste".

<span class="mw-page-title-main">Pulp mill</span> Facility which pulps wood or plant fibre

A pulp mill is a manufacturing facility that converts wood chips or other plant fiber sources into a thick fiber board which can be shipped to a paper mill for further processing. Pulp can be manufactured using mechanical, semi-chemical, or fully chemical methods. The finished product may be either bleached or non-bleached, depending on the customer requirements.

The Sartell Paper Mill, officially the Verso Paper Sartell Mill, was a paper mill located in the city of Sartell in the U.S. state of Minnesota, operating from 1905 until a disastrous explosion in 2012.

<span class="mw-page-title-main">Hollander beater</span> Dutch machine to produce paper pulp

A Hollander beater is a machine developed by the Dutch in 1680 to produce paper pulp from cellulose containing plant fibers. It replaced stamp mills for preparing pulp because the Hollander could produce in one day the same quantity of pulp it would take a stamp mill eight days to prepare.

<span class="mw-page-title-main">Woodchips</span> Small pieces of wood made when shredding larger pieces of wood

Woodchips are small- to medium-sized pieces of wood formed by cutting or chipping larger pieces of wood such as trees, branches, logging residues, stumps, roots, and wood waste.

<span class="mw-page-title-main">Paper</span> Material for writing, printing, etc.

Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses, or other vegetable sources in water, draining the water through a fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying. Although paper was originally made in single sheets by hand, almost all is now made on large machines—some making reels 10 metres wide, running at 2,000 metres per minute and up to 600,000 tonnes a year. It is a versatile material with many uses, including printing, painting, graphics, signage, design, packaging, decorating, writing, and cleaning. It may also be used as filter paper, wallpaper, book endpaper, conservation paper, laminated worktops, toilet tissue, currency, and security paper, or in a number of industrial and construction processes.

In manufacturing, threading is the process of creating a screw thread. More screw threads are produced each year than any other machine element. There are many methods of generating threads, including subtractive methods ; deformative or transformative methods ; additive methods ; or combinations thereof.

<span class="mw-page-title-main">Friedrich Gottlob Keller</span>

Friedrich Gottlob Keller was a German machinist and inventor, who invented the wood pulp process for use in papermaking. He is widely known for his wood-cut machine. Unlike Charles Fenerty, F.G. Keller took out a patent for his wood-cut invention.

Mechanical pulping is the process in which wood is separated or defibrated mechanically into pulp for the paper industry.

References

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