Machine paper (or paper making machine ) is an industrial machine used in the Pulp and paper industry to make large quantities of paper at high speed. The modern paper-making machine is based on the principles of the Fourdrinier Machine, which uses a web of moving webs to create a continuous paper net by filtering the fibers stored in paper stock and producing wet mats that keep moving from the fibers. It is dried in the machine to produce a strong paper net.
The basic process is an industrial version of the historical process of papermaking, which can not meet the demands of modern society's development for a large number of printing and writing substrates. The first modern paper machine was invented in England by Henry and Sealy Fourdrinier, and patented in 1806.
The same process is used to produce paperboard on paperboard machines.
Video Paper machine
Bagian proses
Paper machines usually have at least four different operational sections:
- The forming section, commonly called the wet tip, is where the fiber slurry filters the liquid from the continuous fabric loop to form a wet fiber net.
- Press the part where the wet fiber web passes between large rolls loaded under high pressure to squeeze as much water as possible.
- The drying section, in which the pressed sheet passes partially, by means of serpentine, a series of steam-heated drying cylinders. Drying eliminates water content to a level of about 6%, where it will remain in typical indoor atmospheric conditions. The infra-red dryer is also used to complete the cylinder drying if necessary.
- The calendar section where the dry paper is smoothed with load and high pressure. Only one nip is required to hold the sheet, which shrinks through the drying section and is held in the tension between the tap (or the cracking pile if used) and the calendar. The extra nips provide more alignment but at the expense of paper power.
There can also be a coating section to modify the surface characteristics with coatings such as china clay.
Maps Paper machine
History
Prior to the invention of continuous paper making, the paper is prepared in individual sheets by stirring the pulp slurry container and pouring it into a fabric screen called sheeting or dipping and lifting the molded sheet from the barrel. While still on the fabric in the sheet mold, the wet paper is pressed to remove the excess water and then the sheet is lifted to hang on a rope or log to dry the air.
Fourdrinier Machine
In 1799, Louis-Nicolas Robert of Essonnes, France, was granted a patent for a paper-making machine continuously. At that time Robert worked for Saint-LÃÆ' Â © ger Dido, with whom he had a fight about the ownership of this discovery. Didot thinks that England is a better place to develop engines. But during the difficult times of the French Revolution, he could not go there alone, so he sent his brother-in-law, John Gamble, an Englishman who lived in Paris. Through a chain of acquaintances, Gamble was introduced to the Sealy brothers and Henry Fourdrinier, the London stationer, who agreed to finance the project. Gamble was granted British patent 2487 on October 20, 1801. The Fourdrinier machine used a special woven plastic mesh conveyor belt (known as a wire , as it had been knitted from bronze) in the molding section, in which the fiber slurry (usually wood or other vegetable fibers) are dried to make a continuous paper web. The original Fourdrinier builder section uses a horizontal drainage area, called the drainage table .
With the help of mainly Bryan Donkin, a skilled and ingenious mechanic, an improved version of the original Robert was installed at Frogmore Mill, Apsley, Hertfordshire, in 1803, followed by another in 1804. The third machine was installed in Fourdriniers' own mill in Two Waters. Fourdriniers also purchased mills at St Neots who intend to install two machines there and the process and machinery continues to grow.
Thomas Gilpin is most often credited for inventing the first US cylinder paper making machine in Brandywine Creek, Delaware in 1817. This machine was also developed in England, but it is a cylinder mold machine. Fourdrinier machines were not introduced to the United States until 1827.
Similar design
Note showing Charles Kinsey of Paterson, NJ had patented a continuous paper-making process in 1807. Kinsey's machine was built locally by Daniel Sawn and in 1809 the Kinsey machine succeeded in making paper at Essex Mill in Paterson. The financial pressures and potential opportunities created by Embargo 1807 finally convince Kinsey and his supporters to turn the paper mill's focus into cotton and Kinsey's rapidly forgetting and forgotten paper-making success.
Gilpin's 1817 patent is similar to Kinsey, like the 1822 patent of John Ames. Patent Ames is challenged by its competitors, asserting that Kinsey is the original inventor and Ames has stolen someone else's ideas, their proof being the work of Daniel Sawn working on his machine.
Related discovery
The continuous production methods demonstrated by the paper machine affect the development of continuous iron milling and then steel and other sustainable production processes.
Type of slurry and preparation
Plant fibers used for pulp consist mostly of cellulose and hemi-cellulose, which have a tendency to form molecular relationships between fibers in the presence of water. After the water evaporates the fibers remain attached. There is no need to add an additional binder for most paper values, although wet and dry strength additives may be added.
Cotton and linen fabrics are the main source of pulp before pulp. Currently almost all pulp is wood fiber. Cotton fibers are used in special classes, usually in printed paper for things like resumes and currencies.
Fabric sources often appear as waste from other manufactures such as denim cuts or glove cuts. Fiber from clothing comes from cotton boll. The fibers can range from 3 to 7 cm in length because they are in the cotton field. Bleach and other chemicals remove the color of the fabric in the cooking process, usually with steam. Fabric fragments mechanically blur into fibers, and the fibers are shortened to the appropriate length for paper making by cutting process. Rags and water dump into a trough that forms a closed loop. Cylinders with sharp edges, or knives, and knife beds are part of the loop. The rotating cylinder pushes the contents of the trough around repeatedly. Because it decreases slowly for several hours, it damages the fabric into fibers, and cuts the fiber to the desired length. The cutting process ends when the mixture has passed through the cylinder quite a lot on the programmable final cleansing of the knife and bed.
Another source of cotton fiber comes from the cotton ginning process. The seed is fixed, surrounded by a short fiber known as linter because of its short length and resemblance to the fibers. Linters are too short for successful use in fabric. Linters removed from cotton seeds are available as first and second pieces. The first cut is longer.
The two main classifications of pulp are chemical and mechanical. The chemical pulp previously used the sulfite process, but the kraft process is now dominant. Kraft pulp has superior strength for sulfite and mechanical pulp. Both chemical pulp and mechanical pulp can be bleached to high brightness.
Pulping chemically dissolves lignin that binds fibers to each other, and binds the outer fibrils that make up individual fibers to the fiber core. Lignin, like most other substances that can separate the fibers from each other, acts as a debonding agent, lowering its strength. Strength also depends on maintaining a long chain of cellulosic molecules. The kraft process, due to the alkaline and sulfur compounds used, tends to minimize attacks on cellulose and non-crystalline hemicellulose, which increase bonding, while dissolving lignin. The acid stripping process shortens the cellulose chain.
Kraft Porridge makes superior linerboard and excellent printing and papers.
Groundwood, the main ingredient used in newsprint and the main component of a magazine paper (layered publications), is a groundwood produced by grinders. Therefore, it contains many lignin, which decreases its strength. The burrs produce very short fibers that flow slowly.
Thermomechanical pulp (TMP) is a variation of groundwood in which the fibers are mechanically separated while at a sufficiently high temperature to soften the lignin.
Between chemical and mechanical pulp there is a semi-chemical pulp that uses mild chemical treatment followed by distillation. Semi-chemical pulp is often used for corrugating media.
Recycled paper bales (usually old corrugated containers) for unbleached packaging (brown) may only be crushed, filtered and cleaned. Recycling for making white paper is usually done in an ink removal plant, which uses filtering, cleaning, washing, bleaching and flotation. Deinked pulp is used for printing and writing paper and tissues, napkins and tissues. It is often mixed with virgin porridge.
In integrated pulp and paper mills, pulp is usually stored in towers of high density before being pumped into stock preparation. Unintegrated plants using dry or wet pulp (pressed), usually received in bales. Balul porridge darkened in the pulper [back].
Preparation of stock (porridge)
Stock preparation is an area where the slurry is usually distilled, mixed with the proportion of hardwood, softwood or recycled fiber proper, and diluted to be uniform and constant as consistent as possible. The pH is controlled and various fillers, such as bleach, wet size or strength or dry strength are added if necessary. Additional fillers such as clay, calcium carbonate and titanium dioxide increase opacity so that printing on the back side of the sheet will not distract from the content on the outer side of the sheet. Fillers also improve print quality.
Pulp is pumped through a tank sequence commonly called crates , which can be round or more often rectangular. Historically this is made of special ceramic tiles facing reinforced concrete, but mild steel and stainless are also used. The slurry of low consistency pulp is kept restless in this chest by a propeller-like agitator near the suction pump at the bottom of the chest.
In the following process, different types of pulp, if used, are usually treated in separate but similar to mixed-up pathways in a mixed chest:
From high density storage or from slusher/pulper, the slurry is pumped to a low-density storage tank (tank). From there it is usually diluted to about 4% consistency before being pumped into an unrefined crate. From unimproved stock chest stock is pumped again, with consistency control, through refiner. Purification is an operation where the slurry slurry passes through a pair of discs, one of which is stationary and the other rotates at a speed of usually 1,000 or 1,200 RPM for 50 and 60 Hz AC, respectively. The disks have lifted the bars on their faces and passed each other at narrow distances. This action outlines the outer layers of the fibers, causing fibrils from the fibers to partially discharge and expand outward, increasing the surface area to encourage bonding. The distillation thus increases the tensile strength. For example, tissue paper is relatively unrefined while the wrapping paper is smoother. Refined stock from the refiner then goes into purified stock chest, or blend chest, if used as such.
Wood fibers are usually 1 mm in diameter and less than 4 mm long in softwood fiber. Purification can cause the softwood fiber tube to shrink so as to produce undesirable properties in the sheet.
From an enhanced stock, or a chest mixture, re-stock the consistency that is controlled as it is pumped into the machine. These can be refined or additives can be added on the way to the engine chest.
The engine chest is basically a leveling of chest consistency having about 15 minutes of retention. This is a sufficient retention time to allow any variation in the consistency of entering the crate to be leveled by the action of the base weight valve receiving feedback from the online weight measurement scanner. (Note: Many paper machines incorrectly control the consistency that comes out of the engine chest, disrupting the basic weight control.)
Operation
There are four main parts on this paper machine. The shaping part makes the slurry the base for the sheet along the wire. The press section, which removes much of the remaining water through the nips system formed by the roll presses against each other assisted by a press fitting that supports the sheet and absorbs pressed water. The dryer part of the paper machine, as the name implies, dries the paper through a series of internally heated cylinders that evaporate moisture. Calendars are used to make the paper surface extra smooth and shiny. In practice, the calendar rolls are usually placed vertically in the stack.
Forming section or wet end
From the stock the chest machine is pumped into the head tank, commonly called a "head tank" or stuff box , whose purpose is to keep the head constant (pressure) on the fiber slurry or stock because the feed base weight valve. The goods box also provides a means that allows air bubbles to escape. The consistency of pulp pulp in the goods box is in the range of 3%. The flow from the goods box is by gravity and is controlled by the base weight valve on its way to the suction pump fan where it is injected into the main stream of water to the fan pump. The main stream of water pumped by the fan pump comes from the whitewater chest or tank that collects all the water that is drained from the paper-forming part of the machine. Before the fiber stream from the goods box is introduced, the whitewater is very low in fiber content. The whitewater is constantly recirculated by the fan pump through the headbox and recalled from the wire hole and various other tanks and crates receiving drainage from the forming wire and the vacuum-assisted drainage from the suction box and the wet fiber web hand reel. On the way to the pulp slurry head box can pass centrifugal cleansers, which remove heavy contaminants such as sand, and screens, which break down the clump fibers and remove large debris. The fan pump finally feeds the headbox, whether there is a cleanser or a centrifugal screen or not.
The goal of the headbox is to create turbulence to keep the fibers from clumping together and to distribute the slurry evenly across the width of the wire. Wood fibers have a tendency to attract each other, forming clots, an effect called flocculation. Flocculation is reduced by decreasing consistency and or by stirring the slurry; However, de-flocculation becomes very difficult with a consistency above 0.5%. Minimizing the level of flocculation when forming is important for the physical properties of the paper.
Consistency in headboxes is typically below 0.4% for most paper grades, with longer fibers requiring less consistency than short fibers. Higher consistency leads to more fiber oriented in the direction of z , while lower consistency increases the fiber orientation in the direction of x-y . Higher consistency will increase calliper (thickness) and higher rigidity, lower consistency increase higher tensile and some other strength properties and also improve formation (uniformity). Many sheet properties continue to increase to below 0.1% consistency; However, this is the amount of water that is not practical to handle. (Most paper machines run consistently higher headboxes than optimal because they have been accelerated over time without replacing the fan pump and headbox There is also a trade off economy with high pumping costs for lower consistency).
The stock slurry, often called water at this point, comes out of the head box by opening a rectangle of adjustable height called slice , a water stream called > jet and this is pressurized to high-speed engines so that they land gently on a moving moving circle or wire at a speed usually between plus or minus 3% of the wire speed, called the rush and drag respectively. Excessive hurry or drag causes more fiber orientation in the machine direction and provides different physical properties in the machine and cross direction; However, this phenomenon can not be completely avoided on Fourdrinier machines.
At a low speed engine at 700 feet per minute, the gravity and height of stock in the head box create enough pressure to form the jet through the opening of the cut. The stock height is the head, which names the headbox. The jet velocity compared to the wire speed is known as the jet-to-wire ratio. When the jet-to-wire ratio is less than one, the fibers in the stock become pulled out in the machine direction. On slower machines where sufficient fluid remains in stock before disposal, the wire can be pushed back and forth by a process known as shake . It provides several measures of randomness of the fiber direction and provides a more uniform power sheet in both the engine and the cross-machine direction. On a fast machine, the stock does not stay on the wire in liquid form long enough and the long fibers are parallel to the engine. When the jet-to-wire ratio exceeds unity, fiber tends to accumulate in clumps. Variations generated in paper density give the appearance of antique or parchment paper.
Two large rolls usually form the ends of the drainage section, called the drainage table . The breast rolls are located beneath the flow box, a jet aimed at landing around the top center. At the other end of the drainage table is a roll of suction ( sofa ). The sofa roll is a hollow shell, drilled with thousands of holes spaced just about 4 to 5 mm in diameter. Hollow skin rolls rotate above the stationary suction box, usually placed in the top center or rotated down the machine. Vacuum is drawn on the suction box, which draws water from the web into the suction box. From the suction roll, the sheet is inserted into the press section.
The engine down from the suction winding, and at lower altitudes, is the wire turning wire. This roll is pushed and pulls the wire around the loop. The wire turns have enough wrapping angle to hold the wire.
Supports wire in the drainage table area are a number of drainage elements. In addition to supporting the wire and increasing drainage, the elements de-flocculate sheet. In low-speed machines, the element of this table is table roll . As speed increases, the suction developed at the nip roll table increases and at a fairly high speed, the wire is locked back after leaving the vacuum area and causing the stock to jump from the wire, disrupting the formation. To prevent this drainage foil is used. The foil usually tilts between zero and two or three degrees and gives a softer action. Where the coils and foils are used, the rolls are used near the headbox and slide further down the machine.
Approaching the dry line on the table lies a low vacuum box drained by barometric feet under gravitational pressure. After the dry line is a suction box with vacuum application. The suction box extends down to the sofa roll. On the sofa, the consistency of the sheet should be about 25%.
Variations of Fourdrinier formers
The type of molding member is usually based on the level of paper or paperboard produced; However, many older machines use a less than optimal design. Older engines can be upgraded to include a more precise forming part.
A second box can be added to a conventional fourdrinier to place a different fiber mix above the base layer. A secondary headbox usually lies at the point where the base sheet is completely drained. This is not considered a separate ply because the action of water does a good job of intermixing the fibers from the top and bottom layers. Secondary headboxes are commonly used on linerboards.
Modify it into the basic fourdrinier table by adding a second wire above the drainage table known as over the used wire . Cable down and top meet and some drainage rises through the top wire. The top wire improves formation and also provides more drainage, which is useful for accelerated machines.
Twin Wire Machine or The previous slit uses two vertical wires in the forming section, thus increasing the blurring rate of the slurry fibers while also providing two uniform sides.
There is also a machine with all the Fourdrinier parts mounted on top of the traditional Fourdrinier. This enables the creation of multi-layer paper with special characteristics. These are called Fourdriniers over and they make multi-ply paper or paperboard. Usually this is used to make the top layer of bleach fiber to pass through the unbleached layer.
The other type of forming part is a cylinder mold machine using a mesh-coated rotating cylinder partially immersed in a fiber slurry tank on a wet tip to form a paper web, providing a more random distribution of cellulosic fibers.. The cylinder engine can form sheets at a higher consistency, which provides more three-dimensional fiber orientation than low consistency, resulting in higher calliper (thickness) and more stiffness in the machine direction (MD). High MD stiffness is useful in food packaging such as cereal boxes and other boxes such as laundry detergents.
Machine wipes usually form a paper network between wire and special fabric (felt) as they wrap the forming coil. The web is pressed from direct to a large diameter dryer called yankee . The paper sticks to the yankee dryer and is peeled with a knife called the doctor . The tissue machine operates at speeds up to 2000 m/min.
Press the
sectionThe second part of the paper machine is the press section, which removes much of the remaining water through a nips system formed by rolls pressing against each other assisted by pressure presses supporting the sheet and absorbing suppressed water. The consistency of web paper leaving the press section could be above 40%.
Pressing is the most efficient method of removing water because it only takes mechanical action. Wrap presses are historically made of wool. However, today they are almost 100% synthetic. They are made of polyamide woven fabrics with thick batts applied in a special design to maximize water absorption.
Pressing can be single or double perceived. One felt press on one side and smooth roll on the other side. A double felted press has both sides of the sheet in contact with the felt press. Single felted nips are useful when mated with a smooth roll (usually in the top position), which adds two sides - making the top side look smoother than the bottom. Double felted nips give roughness on both sides of the sheet. Double press is felt to be desired for the first press part of thick paperboard.
Simple press rolls can be rolled with a perforated or drilled surface. The more sophisticated press rolls are the suction scrolls. It is a roll with shell and a hollow cover. Metal-shelled shells like bronze stainless steel covered with rubber or synthetic materials. Shells and covers were drilled across the surface. The stationary suction box is installed in the core of the suction winding to support the pressed shell. The final facial mechanical seal is used to interface between the inner surface of the shell and the suction box. For smooth rolls, they are usually made of granite rolls. Granite rolls can be up to 30 feet (9.1 m) in diameter and 6 feet (1.8 m) in diameter.
Press the conventional roll configured with one of the press rolls in a fixed position, with the pair coil being loaded on this fixed roll. Kempa runs through the thinness of the press roll and continues around the perceived run, usually consisting of several rollers. During the stay time in the nip, the moisture from the sheets is transferred to the felt press. When the press feels out of the nip and continues, the vacuum box known as the Uhle Box uses a vacuum (typically -60 kPa) to the felt press to remove moisture so that when the flavor returns to the nip in the next cycle, it does not add moisture to the sheet.
Several levels of paper using suction take rolls that use vacuum to move sheets from sofa to tin felt in the first press or between parts of the press. Pickup roll presses usually have a vacuum box that has two vacuum zones (low vacuum and high vacuum). The roll has a large number of holes drilled in the cover to allow the vacuum to pass from the stationary vacuum box through a rotating roll cover. The low vacuum zone takes sheets and transfers, while the high vacuum zones try to remove moisture. Unfortunately, in high-speed centrifugal force high enough to remove the water emptied, making this less effective for dewatering. Pickup presses also have a standard feel runs with Uhle boxes. However, the pickup press design is very different, because air movement is important for pickup and dewatering aspects of its role.
Crown Controlled Rolls (also known as CC Rolls) is usually a marriage roll in a press arrangement. They have a hydraulic cylinder in a press roll that ensures that the roll does not bend. The cylinder is connected to a shoe or some shoe to keep the knob on a flat reel, to fight the natural "turn" in the form of a roll as it imposes the load to the edge.
Extended Nip Presses (or ENP) is a relatively modern alternative for compressing conventional rolls. The top roll is usually a standard winding, while the bottom roll is actually a large CC roll with the curved extended shoe to form the top roll, surrounded by a rotating rubber belt rather than the standard roll cover. The purpose of the ENP is to extend the residence time of the sheet between the two rolls so as to maximize de-watering. Compared to standard roll presses that reach up to 35% solids after being pressed, ENP brings this up to 45% and higher - providing significant steam savings or increased speed. ENP compresses the sheet, thereby increasing the tensile strength and some other physical properties.
Dryer section
The dryer part of the paper machine, as the name implies, dries the paper through a series of internally heated cylinders that evaporate moisture. Vapor pressure can reach 160 psig. The vapor enters the tip of the dryer head (cylinder cover) through the vapor connection and exits the condensate through siphon that flows from the internal shell to the central pipe. From the center pipe, the condensate exits through the joint at the dryer head. The wide engine needs a lot of siphon. In centrifugal force the fast machine holds the condensate layer still against the shell and the turbulence generating bar is typically used to stir the condensate layer and increase heat transfer.
This sheet is usually held against the dryer with the long loop felt at the top and bottom of each part of the dryer. Quake greatly increases heat transfer. The foil dryer is made of rough yarn and has a very open, almost transparent fabric. It is common to have the first undeclared bottom dryer section to break down the basement floor during sheet breaks or when sheets sheets.
Paper dryers are usually arranged in groups called sections so they can be run at a slightly slower speed to compensate for the sheets depreciation when the paper dries. Distance between sections is called drawing .
The drying section is usually closed to save heat. Hot air is usually supplied to bags where the sheet breaks out with the dryer. This increases the rate of drying. Ventilated ventilation tubes have slots along the entire length that face into the pocket. The dryer hood usually runs out with a series of exhaust hood fans mounted on the roof on the dryer.
Sizer
Additional adhesives, including resins, glue, or starch, may be added to the web to change their characteristics. Sizing increases paper water resistance, reduces its ability to fuzz, reduces abrasives, and improves printing properties and surface bond strength. It can be applied to wet (internal size) or on dry tip (surface size), or both. At dry end size is usually applied with press size . The size of the press may be an applicator roll (nip flooded) or a Nozzle applicator. Usually placed before the last dryer. Some paper machines also use 'coating' to apply a filler layer such as calcium carbonate or china clay which is usually suspended in a cooked starch binder and styrene-butadiene rubber. The coating produces a very smooth and bright surface with the highest print quality.
Calendar Section
The calendar consists of two or more scrolls, in which pressure is applied to the passing paper. Calendars are used to make the paper surface extra smooth and shiny. It also gives him a more uniform thickness. The pressure applied to the web by the rollers determines the end of the paper.
After calendering, the web has a water content of about 6% (depending on the furniture). This is a roll called tambour or reel , and is stored for cutting and final delivery. The hardness of the roll shall be inspected, obtained, and adjusted to ensure that the hardness of the roll is within an acceptable range for the product.
Glossary
broke : used paper, whether made during a sheet or decoration. It is collected and put into the repulper to be recycled back into the process.
consistency : percent dry fiber in pulp pulp.
sofa : French which means to lie . After roll the sofa sheet is lifted from the wire and transferred to the press section.
dandy cuts : closed hollow rolls that are piled over Fourdrinier. This breaks down the fiber of the clumps to increase sheet formations and can also be used to create traces, such as by putting the paper. See also watermarks.
fan pump : a large pump that circulates water from the water chest to the headbox. Pumps are a special low-pulse design that minimizes the effect of vane pulses that will cause uneven paper bottom weight in machine direction known as restrictions . The flow from the fan pump can be through the screen and cleaner, if used. On a large paper machine fan machine can be rated in tens of thousands of gallons per minute.
feels : a circle of fabric or synthetic material between the press roll and serves as a place for receiving pressed water. Kempa also supports wet paper web and guide through the press section. The quake is also used in the dryer section to keep the sheet in close contact with the dryer and increase heat transfer.
fillers : finely divided substances added to paper in the forming process. The filler improves print quality, brightness and opacity. The most common fillers are clay and calcium carbonate. Titanium dioxide is a filler but also increases brightness and opacity. The use of a calcium carbonate filler is a process called alkaline measurement and uses a chemical different from the size of the acid. Alkaline paper has superior aging properties.
formation : the degree of uniformity of fiber distribution in finished paper, which is easily seen by holding the paper to light.
headbox : the pressure chamber where turbulence is applied to break the clump fibers in the slurry. The main job of the headbox is to distribute the fiber slurries evenly across the cable.
nip : the contact area where two opposite scrolls meet, such as on a media or calendar
pH : the acidity or alkalinity of a solution. Alkaline paper has a very long life. Acid paper worsens over time, leading to libraries either taking conservation measures or replacing many older books.
size : chemicals (previously rosin derived but now different chemicals) or starch, applied to paper to slow down the rate of water penetration. Size prevents bleeding ink while printing, improves sharpening of printing.
slice : adjustable rectangular orifice, usually at the bottom of the headbox, where the jets of clear water flow into the wire. The slice opening and water pressure together determine the amount and speed of the whitewater flow through the slice. The slice usually has some form of adjustment mechanism to flatten the paper weight profile across the machine (CD profile), although newer methods are to inject water into the water across the headbox slice area, thereby using local consistency to control the CD weight profile.
stock : processed pulp slurry in stock preparation area with necessary additives, purification and pH setting and ready to make paper
web : continuous flow of non-dried fibers from the couch rolls under the paper machine
white water : filtrate from the drainage table. Water from the table is usually stored in white water pumped by the fan pump to the headbox.
wire : fabric woven loop fabric used to drain the slurry slurry from the headbox. Until the 1970s bronze wire was used but now they are woven from synthetic rough mono-filaments similar to fishing rods but very stiff.
Materials
Stainless steels are widely used in the Pulp and Paper industry for two main reasons, to avoid the iron contamination of the product and its resistance to corrosion against the various chemicals used in the paper making process. Type 316 stainless steel is a material commonly used in paper machines.
See also
- Paper chemicals
- Continuous production
- Cutting stock issues
References
External links
- Patents for Louis-Nicolas Robert
- Technical Association of Pulp and Paper Industry
- Institute of Materials Science and Technology at Georgia Tech
- Description of the Fourdrinier machine from Paper Manufacturing in the United States, 1916
- Henry Fourdrinier's Biography of National Biography Dictionary, 1889
- The British paper historian association
- Video: Frogmore Mill at Apsley; Victorian Fourdrinier era machine
- QCS Quality Control System
Source of the article : Wikipedia
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