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84-519: The basic process is an industrialised version of the historical process of hand paper-making, which could not satisfy the demands of developing modern society for large quantities of a printing and writing substrate. The first modern paper machine was invented by Louis-Nicolas Robert in France in 1799, and an improved version patented in Britain by Henry and Sealy Fourdrinier in 1806. The same process

168-431: A sulphite process , but the kraft process is now predominant. Kraft pulp has superior strength to sulphite and mechanical pulps and kraft process spent pulping chemicals are easier to recover and regenerate. 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

252-490: 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

336-411: 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

420-401: A container of pulp slurry and either pouring it into a fabric sieve called a sheet mould or dipping and lifting the sheet mould from the vat. While still on the fabric in the sheet mould, the wet paper was pressed to remove excess water. The sheet was then lifted off to be hung over a rope or wooden rod to air dry. In 1799, Louis-Nicolas Robert of Essonnes , France, was granted a patent for

504-519: A continuous flow of stock and deliver an unbroken sheet of wet paper to a pair of squeeze rolls. As the continuous strip of wet paper came off the machine it was manually hung over a series of cables or bars to dry. With Didot's urging, Robert and Didot went to François de Neufchâteau , the Minister of the Interior and applied for a patent. In 1799, the patent (brevet d'invention) was granted by

588-541: A continuous paper making machine. At the time, Robert was working for Saint-Léger Didot , with whom he quarreled over the ownership of the invention. Didot believed that England was a better place to develop the machine but due to the turbulence 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

672-498: A few words I have set forth the advantages of my machine, which I have built at the home of Citizen Didot, manufacturer at Essonnes. It is here the place to say that in Citizen Didot I have found great help in the making of this machine. His workshop, his workers, even his purse, have been at my disposition; he shares generosity and confidence that one finds only in real friends of the arts. I solicit you, Citizen Minister, for

756-469: A forming roll. The web is pressed from the felt directly onto a large diameter dryer called a yankee . The paper sticks to the yankee dryer and is peeled off with a scraping blade called a doctor . Tissue machines operate at speeds of up to 2000 m/min. The second section of the paper machine is 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

840-564: A history dating back to 1355 and supplied paper to the Ministry of Finance for currency manufacture. Both Robert and Didot grew impatient with the quarrelling workers, vatmen, couchers, and laymen, so Robert was spurred to look for a mechanical solution to the manual labour of the paper-making process. In his book Papermaking: the History and Technique of an Ancient Craft , Dard Hunter reported that: [Louis-Nicolas Robert] declared that it

924-415: A less than optimum design. Older machines can be upgraded to include more appropriate forming sections. A second headbox may be added to a conventional fourdrinier to put a different fibre blend on top of a base layer. A secondary headbox is normally located at a point where the base sheet is completely drained. This is not considered a separate ply because the water action does a good job of intermixing

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1008-551: A machine capable of making paper from the vat; this machine forms paper of great width and of indefinite length. The machine makes paper of perfect quality in thickness and gives advantages that cannot be derived from ordinary methods of forming paper by hand, where each sheet is limited in size in comparison with those made on this machine. From all reports it is an entirely new invention and deserves every encouragement. The Conservatoire des Arts et Métiers paid Robert three thousand francs to build another model for permanent display at

1092-418: A means allowing air bubbles to escape. The consistency of the pulp slurry at the stuff box is in the 3% range. 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 is injected into the 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

1176-450: A more uniform distribution. Approaching the dry line on the table are located low vacuum boxes that are drained by a barometric leg under gravity pressure. After the dry line are the suction boxes with applied vacuum. Suction boxes extend up to the couch roll. At the couch the sheet consistency should be about 25%. The forming section type is usually based on the grade of paper or paperboard being produced; however, many older machines use

1260-506: A nearby flour mill. After a few months' rest from the paper factory, Didot encouraged Robert to reprise the paper machine, and put several mechanics at his disposal. The next model showed some improvement, and Didot therefore instructed Robert to make a full-size model, scaling-up to the popular 24 inch 'Colombier' width. This machine was a success and produced two sheets of "well felted" paper. Following Robert's successful model, built in 1798, Saint-Léger Didot insisted that Robert apply for

1344-543: A patent gratuitously. Robert De Neufchâteau authorised the Bureau of Arts and Trades (Bureau des Arts et Métiers) to send a draughtsman, Monsieur Beauvelot, to Essonnes to document and build an improved model. The minister also authorised a member of the Conservatoire National des Arts et Métiers to accompany him. The Bureau des Arts et Métiers then declared: Citizen Robert is the first to imagine

1428-414: A patent. Prior to 1798, paper was made one sheet at a time, by dipping a rectangular frame or mould with a screen bottom into a vat of pulp. The frame was removed from the vat, and the water was pressed out of the pulp. The remaining pulp was allowed to dry; the frame could not be re-used until the previous sheet of paper was removed from it. Robert's construction had a moving screen belt that would receive

1512-611: A series of meetings takes place for co-ordination and planning. These typically involve the various departments such as maintenance, power, engineering, safety and operating units. All work is done according to a carefully sequenced schedule that incorporates the various trades involved, such as pipe-fitters, millwrights, electricians, mechanics, laborers, etc., and the necessary equipment (cranes, mobile equipment, air compressors, welding machines, scaffolding, etc.) and all supplies (spare parts, steel, pipe, wiring, nuts and bolts) and provisions for power in case power will also be off as part of

1596-421: A sheet at higher consistency, which gives a more three dimensional fibre orientation than lower consistencies, resulting in higher caliper (thickness) and more stiffness in the machine direction (MD). High MD stiffness is useful in food packaging like cereal boxes and other boxes like dry laundry detergent. Tissue machines typically form the paper web between a wire and a special fabric (felt) as they wrap around

1680-618: 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. Because fibre and fillers are denser than water and tend to settle out quickly and also fibres are attracted together to form clumps called floc, low consistency pulp slurries are kept agitated in these chests by propeller like agitators near

1764-551: A simple civil contract, certified by a municipal officer. In 1790, having finished with his military career, Robert became an indentured clerk at one of the Didot family 's renowned Paris publishing houses. First working under Saint-Léger Didot as a clerk, he later switched to a position as "inspector of personnel" at Pierre-François Didot's paper-making factory in Corbeil-Essonnes . This well-respected establishment had

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1848-497: A top layer of bleached fibre to go over an unbleached layer. Another type forming section is the cylinder mould machine invented by John Dickinson in 1809, originally as a competitor to the Fourdrinier machine. This machine uses a mesh-covered rotating cylinder partially immersed in a tank of fibre slurry in the wet end to form a paper web, giving a more random distribution of the cellulose fibres. Cylinder machines can form

1932-560: A way that the paddles create a self-wiping action between themselves minimizing buildup of product except for the normal operating clearances of the moving parts. Barrels may also be heated or cooled to optimize the mixing cycle. Unlike an extruder, the Continuous Processor void volume mixing area is consistent the entire length of the barrel ensuring better mixing and little to no pressure build up. The Continuous Processor works by metering powders, granules, liquids, etc. into

2016-490: 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

2100-418: Is an impractical amount of water to handle. (Most paper machine run a higher headbox consistency than optimum because they have been sped up over time without replacing the fan pump and headbox. There is also an economic trade off with high pumping costs for lower consistency). The stock slurry, often called white water at this point, exits the head box through a rectangular opening of adjustable height called

2184-610: Is contrasted with batch production . Continuous usually means operating 24 hours per day, seven days per week with infrequent maintenance shutdowns, such as semi-annual or annual. Some chemical plants can operate for more than one to two years without a shutdown. Blast furnaces can run from four to ten years without stopping. Some common continuous processes are the following: Production workers in continuous production commonly work in rotating shifts . Processes are operated continuously for practical as well as economic reasons. Most of these industries are very capital intensive and

2268-523: Is credited with a paper-making invention that became the blueprint of the Fourdrinier machine . In 1799, Robert patented the first machine to produce 'continuous paper'. After a series of legal and financial quarrels with Saint-Léger Didot , Robert lost control of his patent. The machine was then shipped out of post- revolutionary France and further developed in England. Robert's invention became

2352-456: 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 of Bryan Donkin , a skilled and ingenious mechanic, an improved version of the Robert original was installed at Frogmore Paper Mill , Apsley, Hertfordshire , in 1803, followed by another in 1804. A third machine was installed at

2436-422: 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. (Note: 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

2520-417: Is located under the flow box, the jet being aimed to land on it at about the top centre. At the other end of the drainage table is the suction ( couch ) roll. The couch roll is a hollow shell, drilled with many thousands of precisely spaced holes of about 4 to 5 mm diameter. The hollow shell roll rotates over a stationary suction box, normally placed at the top centre or rotated just down machine. Vacuum

2604-402: Is not completely avoidable on Fourdrinier machines. On lower speed machines at 700 feet per minute, gravity and the height of the stock in the headbox creates sufficient pressure to form the jet through the opening of the slice. The height of the stock is the head, which gives the headbox its name. The speed of the jet compared to the speed of the wire is known as the jet-to-wire ratio . When

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2688-505: Is not now known where the original drawings can be seen. Continuous production Continuous production is a flow production method used to manufacture , produce, or process materials without interruption. Continuous production is called a continuous process or a continuous flow process because the materials, either dry bulk or fluids that are being processed are continuously in motion, undergoing chemical reactions or subject to mechanical or heat treatment. Continuous processing

2772-400: Is pulled on the suction box, which draws water from the web into the suction box. From the suction roll the sheet feeds into the press section. Down machine from the suction roll, and at a lower elevation, is the wire turning roll . This roll is driven and pulls the wire around the loop. The wire turning roll has a considerable angle of wrap in order to grip the wire. Supporting the wire in

2856-459: Is taken to insure that nothing will come through the pipes. Continuous Production can be supplemented using a Continuous Processor . Continuous Processors are designed to mix viscous products on a continuous basis by utilizing a combination of mixing and conveying action. The Paddles within the mixing chamber (barrel) are mounted on two co-rotating shafts that are responsible for mixing the material. The barrels and paddles are contoured in such

2940-544: Is the blast furnace for producing pig iron . The blast furnace is intermittently charged with ore, fuel and flux and intermittently tapped for molten pig iron and slag; however, the chemical reaction of reducing the iron and silicon and later oxidizing the silicon is continuous. Semi-continuous processes, such as machine manufacturing of cigarettes, were called "continuous" when they appeared. Many truly continuous processes of today were originally batch operations. The Cromford mill of 1771, designed by Richard Arkwright ,

3024-429: Is used to produce paperboard on a paperboard machine. Paper machines usually have at least five distinct operational sections: There can also be a coating section to modify the surface characteristics with coatings such as kaolin clay , alternatively known as china clay. This section can be on-line or off-line as well. Before the invention of continuous paper making, paper was made in individual sheets by stirring

3108-495: 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

3192-556: The Embargo of 1807 eventually persuaded Kinsey and his backers to change the mill's focus from paper to cotton and Kinsey's early papermaking successes were soon overlooked and forgotten. Gilpin's 1817 patent was similar to Kinsey's, as was the John Ames patent of 1822. The Ames patent was challenged by his competitors, asserting that Kinsey was the original inventor and Ames had been stealing other people's ideas, their evidence being

3276-547: The Musée des Arts et Métiers . In 1785, Christophe-Philippe Oberkampf invented the first machine for printing dyes on squares of wallpaper . The significance of Robert's invention was for more than mechanising a labour-intensive process, in also allowing continuous lengths of patterned and coloured paper to be produced for hanging. This offered the prospect of novel designs and nice tints to be printed and displayed in drawing rooms across Europe. Robert and Didot quarrelled over

3360-449: The slice , the white water stream being called the jet and it is pressurized on high speed machines so as to land gently on the moving fabric loop or wire at a speed typically between plus or minus 3% of the wire speed, called rush and drag respectively. Excessive rush or drag causes more orientation of fibres in the machine direction and gives differing physical properties in machine and cross directions; however, this phenomenon

3444-453: The 4 mm length typical of softwood fibres. 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

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3528-508: The Fourdriniers were awarded new patents. An example of the Fourdrinier machine was installed at Frogmore, Hertfordshire. In 1812, in poor health, having both sold and lost control of his invention and the patent, with further exploitation being concentrated in England, Robert retired from paper-making and left Corbeil-Essonnes . He moved to Vernouillet, Eure-et-Loir and opened a small school, Faubourg St Thibault. The French economy

3612-528: 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. Close to Frogmore Mill in Apsley, John Dickinson designed and built an alternate machine type; a Cylinder Mould Machine in 1809. Thomas Gilpin is most often credited for creating the first U.S. cylinder type papermaking machine at Brandywine Creek , Delaware in 1817. This machine

3696-551: The French Government, for which Robert paid 8,000 francs. The patent specification and application for the continuous paper-making machine is published in the second volume of the Brevets d'Inventions Expirés . On 9 September 1798 (23 Fructidor Year VI ) Robert wrote a letter applying for a patent : For several years I have been employed in one of the principal mills of France. It has been my dream to simplify

3780-458: The London patent application with brothers Sealy and Henry Fourdrinier , who ran a leading stationery house. Gamble was granted British patent 2487 on 20 October 1801 for an improved version of Robert's original machine. Thus the next development was financed by the London stationers. Gamble and Didot shipped the machine to London, and after 6 years and approximately £60,000 of development costs,

3864-560: The Metz Artillery regiment and was sent to Saint-Domingue , where he fought the English. He served in the military for 14 years (circa 1794), and rose to the rank of sergeant major . Another account of Robert's military career suggests that he left the army aged 28, in 1790. Robert married Charlotte Routier on 11 November 1794, in a civil ceremony. The ceremony was civil because of the post-Revolutionary decree that marriage be

3948-409: The continuous rolling of iron and later steel. Another early continuous processes was Oliver Evans 'es flour mill (ca. 1785), which was fully automated. Early chemical production and oil refining was done in batches until process control was sufficiently developed to allow remote control and automation for continuous processing. Processes began to operate continuously during the 19th century. By

4032-414: The core of the Fourdrinier machine, the basis for modern papermaking . He eventually became a school-teacher and died in penury. Louis-Nicolas Robert was born to aging parents on rue Neuve-Saint-Eustache, 1st arrondissement of Paris . As a child he was physically frail and self-conscious, but studious and ambitious. He received an excellent education with a strong focus on science and mathematics at

4116-408: The cotton boll. The fibres can range from 3 to 7 cm in length as they exist in the cotton field. 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

4200-412: The drainage table area are a number of drainage elements. In addition to supporting the wire and promoting drainage, the elements de-flocculate the sheet. On low speed machines these table elements are primarily table rolls . As speed increases the suction developed in the nip of a table roll increases and at high enough speed the wire snaps back after leaving the vacuum area and causes stock to jump off

4284-435: The early 20th century continuous processes were common. In addition to performing maintenance, shut downs are also when process modifications are performed. These include installing new equipment in the main process flow or tying-in or making provisions to tie-in sub-processes or equipment that can be installed while the process is operating. Shut-downs of complicated processes may take weeks or months of planning. Typically

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4368-428: 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

4452-544: The fibers of the top and bottom layer. Secondary headboxes are common on linerboard . A modification to the basic Fourdrinier table by adding a second wire on top of the drainage table is known as a top wire former . The bottom and top wires converge and some drainage is up through the top wire. A top wire improves formation and also gives more drainage, which is useful for machines that have been sped up. The Twin Wire Machine or Gap former uses two vertical wires in

4536-400: 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

4620-422: 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

4704-404: The forming section, thereby increasing the de-watering rate of the fibre slurry while also giving uniform two sidedness. There are also machines with entire Fourdrinier sections mounted above a traditional Fourdrinier. This allows making multi-layer paper with special characteristics. These are called top Fourdriniers and they make multi-ply paper or paperboard . Commonly this is used for making

4788-736: The hands of the religious order of the Minimes . He felt guilty for being a financial burden to his parents. At the age of 15, he tried to enlist in the army in order to support the American Revolution, but was rejected. He was accepted into the military four years later. On 23 April 1780 he joined the First Battalion of the Grenoble Artillery, and was subsequently stationed in Calais . In 1781 he transferred to

4872-554: The headbox is typically under 0.4% for most paper grades, with longer fibres requiring lower consistency than short fibres. Higher consistency causes more fibres to be oriented in the z direction, while lower consistency promotes fibre orientation in the x-y direction. Higher consistency promotes higher calliper (thickness) and stiffness, lower consistency promotes higher tensile and some other strength properties and also improves formation (uniformity). Many sheet properties continue to improve down to below 0.1% consistency; however, this

4956-447: The jet-to-wire ratio is less than unity, the fibres in the stock become drawn out in the machine direction. On slower machines where sufficient liquid remains in the stock before draining out, the wire can be driven back and forth with a process known as shake . This provides some measure of randomizing the direction of the fibres and gives the sheet more uniform strength in both the machine and cross-machine directions. On fast machines,

5040-467: 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

5124-478: 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)

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5208-625: The management is therefore very concerned about lost operating time. Shutting down and starting up many continuous processes typically results in off quality product that must be reprocessed or disposed of. Many tanks, vessels and pipes cannot be left full of materials because of unwanted chemical reactions, settling of suspended materials or crystallization or hardening of materials. Also, cycling temperatures and pressures from starting up and shutting down certain processes (line kilns, boilers, blast furnaces, pressure vessels, etc.) may cause metal fatigue or other wear from pressure or thermal cycling. In

5292-410: 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

5376-646: The more complex operations there are sequential shut down and start up procedures that must be carefully followed in order to protect personnel and equipment. Typically a start up or shut down will take several hours approximately. Continuous processes use process control to automate and control operational variables such as flow rates, tank levels, pressures, temperatures and machine speeds. Many processes such as assembly lines and light manufacturing that can be easily shut down and restarted are today considered semi-continuous. These can be operated for one or two shifts if necessary. The oldest continuous flow processes

5460-475: The motor starter, so that it cannot operate. It is common practice to put a padlock on the motor starter, which can only be unlocked by the person or persons who is or are endangered by performing the work. Other disconnect means include removing couplings between the motor and the equipment or by using mechanical means to keep the equipment from moving. Valves on pipes connected to vessels that workers will enter are chained and locked closed, unless some other means

5544-469: The operation of making paper by forming it with infinitely less expense, and, above all, in making sheets of extraordinary length without the help of any worker, using only mechanical means. Through diligent work, by experience, and with considerable expense, I have been successful and a machine has been made that fulfils my expectancy. The machine makes for economy of time and expense and extraordinary paper, being 12 to 15 metres in length, if one wishes. In

5628-549: The outage. Often one or more outside contractors perform some of the work, especially if new equipment is installed. Safety meetings are typically held before and during shutdowns. Other safety measures include providing adequate ventilation to hot areas or areas where oxygen may become depleted or toxic gases may be present and checking vessels and other enclosed areas for adequate levels of oxygen and ensure absence of toxic or explosive gases. Any machines that are going to be worked on must be electrically disconnected, usually through

5712-472: 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. Hardwood fibres are typically 1 mm long and smaller in diameter than

5796-538: The ownership of the invention. Robert eventually sold both the patent and the prototype machine to Didot for 25,000 francs. Didot defaulted on the payments to Robert, however, and he was forced to recover legal ownership of the patent on 23 June 1801. Didot wanted to develop and patent the machine in England, away from the distractions of the French Revolution , so he sent his English brother-in-law, John Gamble, to London. In March 1801, after demonstrating continuous rolls of paper from Essonne, John Gamble agreed to share

5880-406: The patent of my invention, which ought to assure me my property, and work for myself. My fortune does not permit me to pay the tax of this patent at once, which I desire to have for fifteen years, nor do my means permit me the cost of a model. This is why, Citizen Minister, I implore you to name a number of commissioners to examine my work, and in view of the immense usefulness of my discovery grant me

5964-403: The pulp into the basis 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

6048-415: 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 high density storage or from slusher/pulper the pulp is pumped to a low density storage chest (tank). From there it is typically diluted to about 4% consistency before being pumped to an unrefined stock chest. From

6132-407: The sheet and absorb the pressed water. The paper web consistency leaving the press section can be above 40%. Pressing is the second most efficient method of de-watering the sheet (behind free drainage in the forming section) as only mechanical action is required. Louis-Nicolas Robert Nicolas Louis Robert (2 December 1761 – 8 August 1828) was a French soldier and mechanical engineer , who

6216-429: The slurry across the width of the wire. Wood fibers have a tendency to attract one another, forming clumps, the effect being called flocculation. Flocculation is lessened by lowering consistency and or by agitating the slurry; however, de-flocculation becomes very difficult at much above 0.5% consistency. Minimizing the degree of flocculation when forming is important to physical properties of paper . The consistency in

6300-401: The stock does not remain on the wire in liquid form long enough and the long fibres line up with the machine. When the jet-to-wire ratio exceeds unity, the fibers tend to pile up in lumps. The resulting variation in paper density provides the antique or parchment paper look. Two large rolls typically form the ends of the drainage section, which is called the drainage table . The breast roll

6384-417: The unrefined stock chest stock is again pumped, with consistency control, through a refiner. Refining is an operation whereby the pulp slurry passes between a pair of discs, one of which is stationary and the other rotating at speeds of typically 1,000 or 1,200 RPM for 50 and 60 Hz AC, respectively. The discs have raised bars on their faces and pass each other with narrow clearance. This action unravels

6468-552: 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

6552-430: 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 oversized debris. The fan pump ultimately feeds the headbox, whether or not any centrifugal cleaners or screens are present. The purpose of the headbox is to create turbulence in order to keep the fibers from clumping together and to uniformly distribute

6636-424: The wire, disrupting the formation. To prevent this drainage foils are used. The foils are typically sloped between zero and two or three degrees and give a more gentle action. Where rolls and foils are used, rolls are used near the headbox and foils further down machine. Ultrasonic foils can also be used, creating millions of pressure pulses from imploding cavitation bubbles which keep the fibres apart, giving them

6720-634: Was a cylinder mould machine. The Fourdrinier machine wasn't introduced into the USA until 1827. Records show Charles Kinsey of Paterson, NJ had already patented a continuous process papermaking machine in 1807. Kinsey's machine was built locally by Daniel Sawn and by 1809 the Kinsey machine was successfully making paper at the Essex Mill in Paterson. Financial stress and potential opportunities created by

6804-402: Was introduced to the brothers Sealy and Henry Fourdrinier , stationers of London, who agreed to finance the project. Gamble was granted British patent 2487 on October 20, 1801. The Fourdrinier machine used a specially woven 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)

6888-475: Was the constant strife and quarrelling among the workers of the handmade papermakers' guild that drove him to the creation of the machine that would replace hand labour. Although Didot judged Robert's first plans to be "feeble", they showed enough promise to continue research, and Didot financed a small prototype model. This was completed by 1797, but it was also deemed a failure. Robert became discouraged, so Didot appointed him "superintendent of grain grinding" at

6972-549: Was the first factory to use a continuous process from raw material to finished product in a series of operations. The Fourdrinier paper machine , patented in 1799, was one of the earliest of the Industrial Revolution era continuous manufacturing processes. It produced a continuous web of paper that was formed, pressed, dried and reeled up in a roll. Previously paper had been made in individual sheets. The paper machine influenced other continuous processes such as

7056-492: Was very depressed after Napoleon's defeats, and Robert was very poorly paid. He continued teaching until his death on 8 August 1828. A statue of him stands in front of the church in Vernouillet, and the "Collège de Louis-Nicolas Robert" in the quartier des Grandes Vauvettes is named in his honour. In 1976, Leonard Schlosser discovered Robert's original drawings at auction and made facsimiles for scholars and friends. It

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