While still on the fabric in the sheet mould, the wet paper is pressed to remove excess water and then the sheet is lifted off to be hung over a rope or wooden rod to air dry. In , Louis-Nicolas Robert of Essonnes , France, was granted a patent for a continuous paper making machine.
Didot thought that England was a better place to develop the machine. But during the troubled times of the French Revolution , he could not go there himself, so he sent his brother-in-law, John Gamble, an Englishman living in Paris. Through a chain of acquaintances, Gamble was introduced to the brothers Sealy and Henry Fourdrinier , stationers of London, who agreed to finance the project.
Gamble was granted British patent on 20 October The Fourdrinier machine used a specially woven plastic fabric mesh conveyor belt known as a wire, as it was once woven from bronze in the forming section, where a slurry of fibre usually wood or other vegetable fibres is drained to create a continuous paper web. The original Fourdrinier forming section used a horizontal drainage area, referred to as the drainage table.
With the help particularly of Bryan Donkin , a skilled and ingenious mechanic, an improved version of the Robert original was installed at Frogmore Paper Mill , Apsley, Hertfordshire , in , followed by another in A third machine was installed at the Fourdriniers' own mill at Two Waters.
The Fourdriniers also bought a mill at St Neots intending to install two machines there and the process and machines continued to develop. Thomas Gilpin is most often credited for creating the first U.
S cylinder type papermaking machine at Brandywine Creek , Delaware in This machine was also developed in England, but it was a cylinder mould machine.
The Fourdrinier machine wasn't introduced into the USA until Records show Charles Kinsey of Paterson, NJ had already patented a continuous process papermaking machine in Gilpin's patent was similar to Kinsey's, as was the John Ames patent of The Ames patent was challenged by his competitors, asserting that Kinsey was the original inventor and Ames had been pilfering other peoples' ideas, their evidence being the employment of Daniel Sawn to work on his machine.
The method of continuous production demonstrated by the paper machine influenced the development of continuous rolling of iron and later steel and other continuous production processes. The plant fibres used for pulp are composed mostly of cellulose and hemi-cellulose, which have a tendency to form molecular linkages between fibres in the presence of water.
After the water evaporates the fibres remain bonded. It is not necessary to add additional binders for most paper grades, although both wet and dry strength additives may be added. Rags of cotton and linen were the major source of pulp for paper before wood pulp. Today almost all pulp is of wood fibre.
Cotton fibre is used in speciality grades, usually in printing paper for such things as resumes and currency. Sources of rags often appear as waste from other manufacturing such as denim fragments or glove cuts.
Fibres from clothing come from the cotton boll. Bleach and other chemicals remove the colour from the fabric in a process of cooking, usually with steam. The cloth fragments mechanically abrade into fibres, and the fibres get shortened to a length appropriate for manufacturing paper with a cutting process. Rags and water dump into a trough forming a closed loop. A cylinder with cutting edges, or knives, and a knife bed is part of the loop. The spinning cylinder pushes the contents of the trough around repeatedly.
As it lowers slowly over a period of hours, it breaks the rags up into fibres, and cuts the fibres to the desired length.
The cutting process terminates when the mix has passed the cylinder enough times at the programmed final clearance of the knives and bed. Another source of cotton fibre comes from the cotton ginning process. The seeds remain, surrounded by short fibres known as linters for their short length and resemblance to lint. Linters are too short for successful use in fabric. Linters removed from the cotton seeds are available as first and second cuts. The first cuts are longer.
The two major classifications of pulp are chemical and mechanical. Chemical pulps formerly used a sulphite process , but the kraft process is now predominant. Kraft pulp has superior strength to sulphite and mechanical pulps. Both chemical pulps and mechanical pulps may be bleached to a high brightness. Chemical pulping dissolves the lignin that bonds fibres to one another, and binds the outer fibrils that compose individual fibres to the fibre core. Lignin, like most other substances that can separate fibres from one another, acts as a debonding agent, lowering strength.
Strength also depends on maintaining long cellulose molecule chains. The kraft process, due to the alkali and sulphur compounds used, tends to minimize attack on the cellulose and the non-crystalline hemicellulose , which promotes bonding, while dissolving the lignin.
Acidic pulping processes shorten the cellulose chains. Kraft pulp makes superior linerboard and excellent printing and writing papers. Groundwood, the main ingredient used in newsprint and a principal component of magazine papers coated publications , is literally ground wood produced by a grinder. Therefore, it contains a lot of lignin, which lowers its strength. The grinding produces very short fibres that drain slowly.
Thermomechanical pulp TMP is a variation of groundwood where fibres are separated mechanically while at high enough temperatures to soften the lignin. Between chemical and mechanical pulps there are semi-chemical pulps that use a mild chemical treatment followed by refining.
Semi-chemical pulp is often used for corrugating medium. Bales of recycled paper normally old corrugated containers for unbleached brown packaging grades may be simply pulped, screened and cleaned. Recycling to make white papers is usually done in a deinking plant, which employs screening, cleaning, washing, bleaching and flotation.
Deinked pulp is used in printing and writing papers and in tissue , napkins and paper towels. It is often blended with virgin pulp. At integrated pulp and paper mills, pulp is usually stored in high density towers before being pumped to stock preparation. Non integrated mills use either dry pulp or wet lap pressed pulp, usually received in bales. The pulp bales are slushed in a [re]pulper. Stock preparation is the area where pulp is usually refined, blended to the appropriate proportion of hardwood , softwood or recycled fibre, and diluted to as uniform and constant as possible consistency.
The pH is controlled and various fillers, such as whitening agents, size and wet strength or dry strength are added if necessary.
Additional fillers such as clay , calcium carbonate and titanium dioxide increase opacity so printing on reverse side of a sheet will not distract from content on the obverse side of the sheet.
Fillers also improve printing quality. Pulp is pumped through a sequence of tanks that are commonly called chests , which may be either round or more commonly rectangular.
Historically these were made of special ceramic tile faced reinforced concrete, but mild and stainless steels are also used. Low consistency pulp slurries are kept agitated in these chests by propeller like agitators near the pump suction at the chest bottom.
In the following process, different types of pulp, if used, are normally treated in separate but similar process lines until combined at a blend chest:. From the unrefined stock chest stock is again pumped, with consistency control, through a refiner. The discs have raised bars on their faces and pass each other with narrow clearance. This action unravels the outer layer of the fibres, causing the fibrils of the fibres to partially detach and bloom outward, increasing the surface area to promoting bonding.
Refining thus increases tensile strength. For example, tissue paper is relatively unrefined whereas packaging paper is more highly refined. Refined stock from the refiner then goes to a refined stock chest, or blend chest, if used as such. Refining can cause the softwood fibre tube to collapse resulting in undesirable properties in the sheet.
From the refined stock, or blend chest, stock is again consistency controlled as it is being pumped to a machine chest. It may be refined or additives may be added en route to the machine chest.
The machine chest is basically a consistency levelling chest having about 15 minutes retention. This is enough retention time to allow any variations in consistency entering the chest to be levelled out by the action of the basis weight valve receiving feedback from the on line basis weight measuring scanner. Many paper machines mistakenly control consistency coming out of the machine chest, interfering with basis weight control. There are four main sections on this paper machine.
The forming section makes the pulp into the basis of for sheets along the wire. The press section, which removes much of the remaining water via a system of nips formed by rolls pressing against each other aided by press felts that support the sheet and absorb the pressed water.
The dryer section of the paper machine, as its name suggests, dries the paper by way of a series of internally steam -heated cylinders that evaporate the moisture. Calenders are used to make the paper surface extra smooth and glossy. In practice calender rolls are normally placed vertically in a stack. From the machine chest stock is pumped to a head tank, commonly called a "head tank" or stuff box , whose purpose is to maintain a constant head pressure on the fiber slurry or stock as it feeds the basis weight valve.
The stuff box also provides a means allowing air bubbles to escape. Flow from the stuff box is by gravity and is controlled by the basis weight valve on its way to the fan pump suction where it injected into main flow of water to the fan pump. The main flow of water pumped by the fan pump is from a whitewater chest or tank that collects all the water drained from the forming section of the paper machine.
Before the fiber stream from the stuff box is introduced, the whitewater is very low in fiber content. The whitewater is constantly recirculated by the fan pump through the headbox and recollected from the wire pit and various other tanks and chests that receive drainage from the forming wire and vacuum assisted drainage from suction boxes and wet fiber web handling rolls.
On the way to the head box the pulp slurry may pass through centrifugal cleaners, which remove heavy contaminants like sand, and screens, which break up fibre clumps and remove over-sized debris.
The fan pump ultimately feeds the headbox, whether or not any centrifugal cleaners or screens are present. Newspapers offset used printing machine. Quality newspaper printing machine price With Promotional Price. About product and suppliers: A wide variety of newspaper printing machine options are available to you, such as bill printer, paper printer, and card printer.
You can also choose from new, used. As well as from automatic, semi-automatic. And whether newspaper printing machine is two colors, multicolor, or single color. There are 1, newspaper printing machine suppliers, mainly located in Asia. Newspaper vending machines have been criticized for occasionally failing to distribute a newspaper after it has been paid for.
Due to their design, one could insert the requisite amount and remove more than one copy of the newspaper. However, a second copy of a newspaper normally represents little value to the thief, as the information contained within the copies is identical; thus, the potential lost revenue due to stolen copies is mitigated by the low value that the average person places on a second copy of a newspaper.
However, the potential for theft of additional copies is obviously problematic when a copy of the newspaper in question has potential future value, such as on the day after an election, sports event, or major world occurrence. From Wikipedia, the free encyclopedia.
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A newspaper vending machine or newspaper rack is a vending machine designed to distribute newspapers. Newspaper vending machines are used worldwide, and they are often one of the main distribution methods for newspaper publishers.
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A paper machine (or paper-making machine) is an industrial machine 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. Used Newspaper machines for sale - choose between all the brands - Goss, Hantscho, Harris, Heidelberg/Harris, KBA, MAN, Manroland, Solna, they are all .