Abstract: The dryer section in a papermaking machine has a single tier of all top felted dryer rolls six to nine feet in diameter. Air caps are employed over the dryer rolls to simultaneously dry both sides of the web to prevent curl and to increase drying rates. The air caps employ blown air at a temperature of 250-900 degrees Fahrenheit and air speeds of 8,000-40,000 feet per minute. The dryer fabric employed is foraminous with a permeability of between 300-1,200 cubic feet per minute per square foot and is designed to withstand peak temperatures of up to 900 degrees Fahrenheit and average temperatures of between 500-600 degrees Fahrenheit. A single transfer roll, or more advantageously, two grooved vacuum rolls in a vacuum box are disposed between the dryer rolls to maximize the circumferential wrap of the web and, at the same time, support and transport the web between dryer rolls.

Abstract: The dryer section in a papermaking machine has a single tier of all top felted dryer rolls six to nine feet in diameter. Air caps are employed over the dryer rolls to simultaneously dry both sides of the web to prevent curl and to increase drying rates. The air caps employ blown air at a temperature of 250-900 degrees Fahrenheit and air speeds of 8,000-40,000 feet per minute. The dryer fabric employed is foraminous with a permeability of between 300-1,200 cubic feet per minute per square foot and is designed to withstand peak temperatures of up to 900 degrees Fahrenheit and average temperatures of between 500-600 degrees Fahrenheit. A single transfer roll, or more advantageously, two grooved vacuum rolls in a vacuum box are disposed between the dryer rolls to maximize the circumferential wrap of the web and, at the same time, support and transport the web between dryer rolls.

Abstract: The centrifugal cleaner of this invention is of the type having an inverted cylindrical cone, with a tangential inlet at the top and an outlet at the bottom. The improvement consists of placing a ring or flow smoothing means on the inside surface of the cylindrical cone about one-half the diameter of the base of the cone down from the inlet. The ring forces the stock injected into the centrifugal cleaner to flow towards the axis of the cone away from the inside cone wall. Once the stock passes over the dam it once again flows to the inner wall of the cone. The stock, in being forced to flow over the ring, is made uniform, eliminating spiraling of the flow which has been found to decrease the efficiency with which separation within the cleaner is accomplished.

Abstract: A drying section in a papermaking machine has a first section with a series of single-tiered drying cylinders having vacuum transfer rolls with external vacuum chambers therebetween for improving web runnability, and a second dryer section with a series of single-tiered drying cylinders having movable vacuum transfer rolls disposed therebetween for providing improved cross-directional web shrinkage restraint.

Abstract: A controlled deflection roll for a papermaking machine. The roll includes a roll shaft having a longitudinal axis, a roll shell surrounding the shaft, and a bearing pad assembly supported on the shaft to supportingly engage the shell and move the shell translationally relative to the shaft in a plane including the axis. In one embodiment, the bearing pad assembly includes a plurality of bearing pads. Each bearing pad is spaced apart in the cross-machine direction and has a contact surface engageable with the inner surface of the shell. The contact surface is in the shape of a parallelogram and defines therein at least one recess. The side edges of adjacent bearing pads are straight and parallel to each other and define gaps therebetween. The gaps do not extend along a plane which is perpendicular to the axis. In another embodiment, the bearing pad assembly includes at least one bearing pad having a contact surface and opposite edges. The contact surface has a contact surface portion engageable with the shell.

Abstract: A lapping assembly is described wherein a lapping process is performed to provide a flat headbox apron floor. The lapping assembly includes an eight-legged fly-style plate and a spring loaded floating driver. The lapping assembly and operation consists of attaching a spring loaded floating driver to a machine spindle of a milling machine. A lapping fly wheel is attached to the spring loaded floating driver. A coated abrasive strip with desired grit size to achieve the desired finished results is clamped in place on the lapping fly wheel. The machine spindle is rotated, thereby rotating the spring loaded floating driver and the lapping fly wheel, and the grinding and lapping of the apron floor can begin.

Abstract: A winding machine for winding up webs, possibly longitudinally divided webs, and preferably paper webs. The winding machine comprises two support rollers which support, in a winding bed, the roll to be produced. During the winding process, the web running through the spacer gap between the two support rollers partially wraps around one of the two support rollers. The winding machine further comprises a space delimited by the two support rollers, the partly formed roll, and this space has sealed closures on its ends and a sealed closure below the spacer gap between the two support rollers. Finally, the winding machine generates excess pressure in this space in order to balance the inherent weight of the roll. The sealed closure below the spacer gap comprises a pivotable side wall which extends substantially over the entire maximum web width of the roll to be produced and whose pivot axis extends approximately parallel to the support rollers axes.

Abstract: A dryer section employs top-felted and bottom-felted dryer sections each comprised of a single steam-heated drying cylinder with a diameter of about 12 feet. The web is transferred between drying cylinders by a two vacuum roll transfer without an open draw. The dryer fabric wrap on the large dryer cylinders is over 270 degrees resulting in large drying capability per dryer roll. Because each large dryer is followed by another large dryer roll which dries the opposite side of the web, uniformity of drying is maintained. Each dryer cylinder may have its own dryer fabric stretcher and guides. Alternatively, individual dryer fabrics service multiple top-felted dryers and bottom-felted dryers respectively. The web is constrained approximately 96 percent of the time as it passes through the is dryer section. The dryer section can achieve 2.9 inches of dryer surface in the machine direction for every inch of dryer section.

Abstract: A cleaning apparatus is disclosed for cleaning and removing contaminants from a forming wire of a paper machine. The apparatus includes a shower which is disposed adjacent to the wire for supplying a cleaning fluid onto one side of the forming wire. A leading blade is disposed downstream relative to the shower. The leading blade contacts the wire on the one side of the wire and extends in a cross-machine direction across the wire. A trailing blade is disposed downstream relative to the leading blade. The arrangement being such that the leading blade and the trailing blade defined therebetween a cross-machine directional slot. The slot is connected to a source of pressurized air so that the pressurized air flows through the slot and through the wire for removing the cleaning fluid and the contaminants from the wire. Furthermore, the trailing blade and the wire define therebetween a wedge shaped gap which converges in a direction from the slot and away from the leading blade.

Abstract: The invention described a method of oxygen delignification of medium consistency pulp slurry, which includes the steps of providing a pulp slurry of from approximately ten percent to sixteen percent consistency, at a temperature of from approximately 170-240.degree. F., preferably from 190 to 220.degree. F., thoroughly impregnating the slurry with oxygen gas, and with alkali to bring the slurry to a pH of at least 11, more preferably 12, introducing the slurry to oxygen gas in a high shear mixer, for agitating mixing therein, reacting the slurry in a first pressurized reactor for between 5 to 10 minutes, returning the pH of the slurry to at least 11, more preferably 12, with a residual alkali concentration of at least 1.25 gpl, thoroughly impregnating the slurry with H.sub.2 O.sub.2 and oxygen gas, and reacting the slurry in a second reactor for between 30 to 180 minutes.

Abstract: A control system for the vacuum cut-off valve of a rotating disc or drum filter is provided. The control system includes an actuator that is connected to the vacuum cut-off valve for adjusting the rotation of the vacuum cut-off valve with respect to the core. The actuator is linked to a controller which receives communications from a vacuum sensor that senses the level of vacuum inside the vacuum box. The controller sends signals to the actuator to either move the vacuum cut-off valve forward (or to a higher position) or rearward (or to a lower position) in response to the vacuum or pressure level inside the vacuum box.

Abstract: A clamping bar assembly for a bar screen with a plurality of screen bars and in which at least one leg extends downwardly from each bar and a bar support beam extends below the bars. The bar of this invention includes a plurality of spacers positioned on the support beam between neighboring bar legs. The spacers are clamped together with the bar legs by a first flange which is fixed to the support beam and which has an upwardly extending portion, and a portion which extends inwardly above the beam to engage the spacers. A second flange, removably fixed to the beam, has an upwardly extending portion, and a portion which extends inwardly above the beam toward the first flange so that the clamped spacers and bars are restricted from vertical displacement by the first and second flanges.

Abstract: A blanket passes over a concave shoe which is urged against a backing roll to form a press nip. The ends of the blanket are attached to circular heads. The transition from the nip-imposed cardioid shaped to the circular shape maintained by the heads results in a region of the blanket subject to fatigue. The heads are mounted on journals for motion between inboard stops and outboard stops which are spaced apart approximately 4 inches in the cross machine direction. Positioning of the heads on the journals is controlled by four hydraulic pistons mounted between the support beam and each head. Multiple hydraulic systems are controlled to extend the life of the blanket by alternating between holding the back head fixed and letting the front head float and fixing the front head and letting the back head float.

Abstract: An extended nip press having a concave shoe which is supported on a hydraulic actuator which urges the shoe against a backing roll. A pair of opposed profile control hydraulic actuators apply a pure couple about the load support line formed by a bearing pin which transmits the support load from the hydraulic actuator to the shoe. A leading hydraulic actuator is positioned in front of the load support line and pulls down on the shoe. A trailing hydraulic actuator is positioned behind the load support line and pushes up on the shoe. The leading hydraulic actuator and trailing hydraulic actuator are equally spaced from the load support line and have equal hydraulic actuator area and are connected to the same hydraulic reservoir. Thus the hydraulic actuators exactly balance each other out except for the couple or torque which they apply about the load support line.

Abstract: A web support foil positioned adjacent to a Yankee dryer above a creping doctor. The foil supports the web as it leaves the dryer. Mounted to the top of the foil is an adjustable air deflector which is positioned tangent to the Yankee dryer. The air deflector blocks air moving along the web. A slotted opening draws air from a leading-edge pocket collecting fibers which are broken loose during the creping action. The web is held against the bottom side of the foil by one or more air jets which are directed over the bottom surface on the foil. The jets of air function as coanda air jets and prevent the web from sticking to the bottom surface of the foil while creating a Bernoulli effect which holds the web against the bottom of the foil.

Abstract: A press section is provided for a papermaking machine having an Extended Nip press before a conventional press section such as a Beloit Corporation Tri-Nip or Twinver press. A Beloit Corporation Extended Nip.RTM. press or similar type press, preferably of the closed blanket type, is installed before a conventional two or three nip press and thus reduces the problem of the web sticking to the center roll in the conventional press. The use of an Extended Nip press in front of a conventional pressing section can also increase the bulk of the web being formed. The pressing section of this invention is particularly useful for pressing webs formed of 100 percent tropical hardwood fibers which contain resinous particles which can cause problems in sticking to the center roll.

Abstract: For distributing stock evenly across the face of a tube bank in a papermaking machine, the stock supply header has an increasing change in cross-sectional area per unit width traveling from the inlet end to the recirculation end of the header. The header top wall converges toward the bottom wall, while the rear wall converges toward the front wall. The change in cross-sectional area down the header from the inlet end to the recirculation end is thus closely matched to an ideally parabolic shape.

Abstract: A dryer section in a papermaking machine has two reversing rolls to form a pocket between each pair of dryers in a dryer tier. The first reversing roll is a vacuum roll and the second reversing roll is a grooved roll. A blow box is disposed between the two rolls, the blow box provides suction for the grooved roll and provides vacuum which restrains a web on the dryer fabric as it travels between the first and the second rolls. The blow box also provides a supply of make-up air which extends in a cross machine direction along the pocket formed by the two reversing rolls. The blow box also supports a pivoting foil which is positioned against the dryer fabric as it moves from a first dryer, towards the first reversing roll. The foil defines a region of low pressure which restrains the web as it travels between the first dryer and the first reversing roll.

Abstract: A soft nip calender employing a compliant roll constructed of circumferentially superpositioned layers of compliant material which are progressively less compliant as the layers approach an underlying steel roll.

Abstract: The invention is a paper making machine and a method of making paper. The machine includes a section for forming a wet paper web having first and second sides and a dryer for drying the wet paper web. At least a first portion of the dryer is capable of preferentially drying the first side of the wet paper web to a dryness level of at least about 70% solids. In a variation of the paper making machine, the first portion of the dryer is capable of preferentially drying the first side of the wet paper web to a dryness level of at least about M, as represented by the formula:M=101-0.246 (WRV)in which WRV is the water retention value of the web. The method for drying a web of paper includes a forming step and a drying step. The forming step is carried out by forming a wet paper web having first and second sides.