Abstract: A pressurized screening device has two pairs of concentric cylindrical screenplates, one pair mounted coaxially above the other in a common housing. Each pair of screenplates has a separate rotary impeller mechanism, the impellers being mirror images of each other. The pair of screenplates share a common central feed chamber, common accepts chamber, and a common drive for the two rotary impellers. Each pair of screenplates is provided with a separate rejects collection chamber, one located at the base of the housing and the other located near the top of the housing. This arrangement permits both high capacity operation as well as efficient removal of heavy and light impurities from a feed stream.

Abstract: A brake control system for an unwinder measures the line speed of the moving web and the rpm of the roll and produces electrical output signals proportional to each, which signals are operated upon to produce a main brake control signal to apply a braking force proportional to the roll diameter as it is constantly decreasing, and a further output signal which is proportional to the energy in the roll based on the calculation of the cube of the diameter of the roll so that required braking force modification will occur during acceleration and deceleration of the web in order to maintain essentially constant web tension. An additional feedback from a web tension measuring device is also provided which adjusts the braking force to produce an actual tension equal to the desired tension which has been included in the main braking force output signal proportional to the roll diameter.

Abstract: In screening apparatus for paper making fiber incorporating a cylindrical screen member provided with screening perforations which are either cylindrical or slotted in section, the perforations are characterized by greater flow area on the inlet side of the cylinder than on the accepts side of the cylinder. More specifically, each of the screening perforations includes a generally funnel-shaped portion on the inlet side of the cylinder which leads to a short parallel sided portion on the accepts side of the cylinder.

Abstract: Waste paper containing materials, e.g. commercial "waste paper", are treated for recovery of reusable paper therefrom by slushing in a pulper from which two fractions are continuously extracted--a first fraction through small holes, e.g. 3/16 inch in diameter, and a second fraction through substantially larger holes, e.g. 1 inch in diameter. The second fraction is screened, preferably after a centrifugal cleaning operation, in a screen having small perforations sized to accept only substantially defibered paper, and the accepts flow is mixed directly with the first extracted fraction. The reject flow from this screen is conducted, with or without an intermediate deflaking operation, to a tailing screen from which the accepts are recycled to the pulper and the rejects are eliminated from the system.

Abstract: A rotary screening apparatus is provided for separating impurities in suspensions such as paper pulp or other slurries. The apparatus has a pressurized housing with a cylindrical screenplate separating the housing into an outer annular accepts chamber and an inner feed chamber. An impeller with one or more blades is mounted inside the feed chamber and imparts a rotary motion to the slurry. A series of horizontal baffles attached to the impeller divide the feed chamber into at least three sections. Piping is provided to inject dilution liquid into at least the lower two sections at separately controllable rates to compensate for the dewatering which occurs in the inlet section. The ability to treat and control individually each successive section of the screening device enables essentially complete separation of desirable fibers from impurities.

Abstract: A pressurized screen particularly adapted for screening paper making pulp includes a cylindrical screen plate mounted in a cylindrical casing and defining with it an annular chamber which receives unscreened pulp from which rejects are removed as the good pulp passes from the annular chamber through the screen plate. The axes of the screen plate and the casing are offset with respect to each other, forming an enlargement of the chamber which extends approximately from an inlet into the annular chamber to a rejects outlet which is diametrically opposite the inlet. A partition in the chamber extends parallel to the axes of the casing and screen plate from a position opposite the inlet to a position above the rejects outlet.

Abstract: Fibrous material is pre-steamed, impregnated with alkali liquor, refined, and then oxygen pulped at a low consistency (about 3 to 8 percent solids) using an alkali liquor which contains boron compounds. The pulping step of the process is carried out in stages with recycle of liquor to preceding stages after it has been reoxygenated. By recycling a major portion of the pulping liquor, the actual liquor to fibrous material ratio at each stage of the pulping step is maintained at a relatively high level (12/1 to 30/1) while the effective liquor to fibrous material ratio for the overall process is much lower (4/1 to 8/1). This results in a bright pulp of acceptable strength as well as a high solids content spent liquor which is economically recoverable.

Abstract: A method and apparatus are provided for forming a zero tail length splice between a new roll of web material (26) and an expiring roll (24) without interrupting continuous movement of the web (W).

Abstract: A dual blade fountain coater for simultaneously coating the opposite sides of a moving web of paper includes a pair of oppositely positioned, non-contacting fountains and a pair of oppositely positioned metering blade assemblies which are mounted for movement about a common transverse pivot axis, which pivot axis is substantially coincidental with the blade contacting region on the web. Each assembly is independently adjustable of the other for adjusting blade angle and each fountain is similarly independently adjustable for varying the coating contacting region and dwell time. Metering bars may be mounted on the blades.

Abstract: A brake control system for an unwinder is provided which measures the line speed of the moving web and the rpm of the roll and produces electrical output signals proportional to each which signals are operated upon to produce a main brake control signal to apply a braking force proportional to the roll diameter as it is constantly decreasing, and a further output signal which is proportional to the energy in the roll so that additional braking force modification will occur during acceleration and deceleration of the web in order to maintain essentially constant web tension. An additional feedback from a web tension measuring device is also provided which adjusts the braking force to produce an actual tension equal to the desired tension which has been included in the main braking force output signal proportional to the roll diameter.

Abstract: A dryer section of a web making or web processing machine comprises a plurality of drying cylinders disposed in spaced relationship so as to provide drying surfaces for alternately drying both sides of a web. The section comprises one or more sets of paired drying cylinders, each set being driven by a single drive coupled to each cylinder in the set by a gear reduction unit supported by the dryer journals. The gear reduction unit is so constructed and arranged as to accommodate a substantial range of spacings of the set of cylinders which it drives, and also a substantial amount of relative deflection of the journals.

Abstract: A disk refiner is provided with refiner plates having a working surface on each side thereof, and these plates are first mounted with one working surface in face to face engagement with the supporting face of the stator or rotor of the refiner. After the exposed working surfaces of the plates have been substantially worn away by use of the refiner, the plates are temporarily removed, their worn surfaces are ground into substantial parallellism with their unused working surfaces, and they are then replaced in the refiner with their ground surfaces engaging the faces of the stator and rotor.

Abstract: A rotating separator removes air coating from pigmented paper coating liquid stock. The separator employs a cylindrical tank which is mounted for rotation about a vertical axis. The separator is operated in a filled condition and an air laden or froth fraction is removed from a radially central region of the tank at the top of the tank, while a non-rotating pickup receives air free coating from a region adjacent the wall of the tank near the tank bottom. A method of treating and applying such a coating includes the steps of pumping an air laden coating into a centrifugal separator while maintaining the separator in a filled condition, removing an air froth from the separator for return to the supply tank, and delivering a substantially air free coating directly to the inlet of a control without the imposition of any intermediate pumping apparatus. The centrifugal pumping action of the separator supplements the pressure head on the coating material.

Abstract: In screening apparatus for paper fiber stock of the type wherein a cylindrical perforate screen member defines screening and accepts chamber on the inner and outer sides thereof in a closed housing, the inlet chamber for stock to be screened is located below the screening chamber, and the reject chamber for accumulating reject material is located above the screening chamber. Provision is made for retaining high specific gravity materials within the inlet chamber and for trapping and removing them therefrom without ever reaching the screen chamber. In addition, provision is made for developing centrifugal force effective to concentrate low specific gravity materials, such as bits of plastic foam, in the central part of the reject chamber, and a discharge outlet from the reject chamber located generally centrally of its top wall assures elimination of such light reject materials.

Abstract: A method and apparatus for treating a suspension of liquid, paper making fibers and undesirable rejects to remove a substantial portion of the rejects from the suspension. A cylindrical screen is utilized which has narrow slots on the order of 0.001 to 0.008 inch in width disposed normally with respect to the screen axis, and bars projecting from the inlet face of the screen and cooperating with rotating foils for creating a field of high intensity, fine scale turbulence adjacent the inlet face of the screen. This permits the paper making fibers to pass through the narrow screen openings but causes very small reject particles, which would pass through the larger openings of conventional paper making screens, to be removed without fractionation of the paper making stock or appreciable variation in the consistencies of the feed, accepts and rejects.

Abstract: A system and method for separating paper fibers from contaminants of lower specific gravities employ a reverse centrifugal cleaner wherein the inlet port is of substantially greater flow area than previously used or proposed for either normal or reverse centrifugal cleaning, each of the apex and base ports are of greater flow area than the inlet port, and the discharge flows are controlled to provide an accepts flow through the apex port which is less than the reject flow through the base port. The system provides substantial advantages over prior practice, particularly in the areas of both capital and operating costs, capacity, and cleaning efficiency in terms of the energy requirements for given tonnage of accepted fiber.

Abstract: Fabric changes at the forming section of non-cantilevered, fourdrinier, paper making machines are simplified through use of one or more C-shaped carriages which carry the new fabric and support the front framing of the machine to allow spacer blocks which normally support the front framing to be removed. This provides a gap extending the length of the forming section through which the new fabric may be moved into place and strung into operating position. Thereafter the spacer blocks are replaced and the carriages removed.

Abstract: Recovery of paper fiber for reuse from waste paper materials containing plastic sheet and film is facilitated by the combination of a pulper in which the waste paper materials are pulped in a pulper equipped with a junk remover connected with the bottom of the pulper tub by a chute and provided with a recycling circuit by which the plastic and other lightweight trash picked up by the conveyor buckets in the junk remover is removed from the pulping system, passed through a detrasher for removing bulky objects, then passed through a deflaking station, and then returned to the pulper tub for further defibering. This continuous withdrawal of liquid from the junk remover and its return to the tub act to maintain the hydrostatic head in the tub at a higher effective level than in the junk remover tower and thereby to promote transfer of the plastic and other lightweight trash to the junk remover for removal by the recycling circuit.

Abstract: In a vertical twin-wire paper machine, the initial forming zone is a wedge-shaped zone defined by a small number of deflectors arranged to bring the two wires into pressure engagement with the sheet therebetween and to remove the initial free or rapidly draining water from between the wires as quickly as possible, consistent with good sheet formation with the economical retention of formed components. The two wires and the sheet therebetween travel through a pressure zone which includes a convexly curved intermittent surface and guide rolls arranged to guide the wires from the wedge zone into wrapping engagement with the intermittent surface under tension causing pressure on the sheet and continued extrusion of liquid through one or both wires.

Abstract: A deflaker for use in defibering coarse paper making stock includes a rotor and stator having frusto-conical working faces, each of which has therein one or more circumferential rows of angularly spaced pockets separated by axially extending land areas and with a circumferential land between adjacent rows of pockets, the proportions and arrangement of the parts being such that the stock is forced to travel back and forth between rotor and stator pockets as it passes through the working zone.