Abstract:
A chamber (22) has an outlet (24) which opens downwardly to the atmosphere and an upwardly opening air return plenum (28). A duct (38) is inclined upwardly at approximately sixty degrees to the horizontal, and a fan (32) mounted therein directs moving air (36) into the chamber (22). An upwardly inclined ramp (40) is positioned within the duct (38), and communicates between the chamber (22) and a downwardly opening discharge opening (46) in the duct (38). A metered supply of wood chips (52) is fed down a sixty degree incline (56) onto the ramp (40) through the air stream (36) which is moving through the duct (38). Lightweight chips (55) become entrained in the air (36) and are separated from the rocks, tramp metal and knots (50) which slide down the inclined surface (40) and exit through the opening (46) in the duct (38). The entrained wood chips (55), together with the air (36) from the fan (32), are directed into a baffle (58) spaced within the chamber (22). By forcing the air (36) and chips (55) to move in a curved path, the baffle (58) separates the chips (55) from the air stream (36). As the air stream (36) expands into the chamber (22), its velocity drops then passes through the chip stream (52) up to the air return plenum (28). The chips (55), under the force of gravity, continue their downward flight, and exit the chamber (22) through the outlet (24). An inclined ramp (40) with a slowly moving conveyor (168) may be used to avoid a build-up of material (50) on the inclined ramp (40).
Abstract:
A controlled deflection roll (1) has a roll shell (2) which is hydrostatically radially supported by internally disposed hydrostatic shoes (3, 9). In order to axially position the roll shell (2), a mechanical locating link (23) is provided which is disposed externally of the roll shell (2). The link is coupled at one end to an element attached to the roll shell (2), and is coupled at an opposite end to a fixed support, such as a floor stand (7). The end of the roll at which the locating link (23) is disposed is thus axially fixed, while the opposite end of the roll remains free to float. The locating link (23) can be connected to an oscillator to oscillate the roll shell (2) axially during operation so as to distribute any non-uniformities in the roll shell (2) and thus to mitigate their effect on the sheet.
Abstract:
A disk (28) especially suitable for a papermaking wood chip and pulp refiner (20) has an array of refiner bars (50) which protrude outwardly from a base member (52). Grooves (56, 60) are formed between adjacent bars (50) which may change in depth toward the outer diameter (33) of the disk (28). Alternating grooves (56, 60) are of greater depth, to increase the open area of the disk (28) to facilitate steam evacuation without significantly reducing the bar stiffness and hence resistance to breakage and deflection of individual bars (50).
Abstract:
A method for improving pulp brightness utilizes a combination of a distributed total white liquor charge during the warm fill, hot fill and cooking stages of a batch cooking process and low cooking temperatures during the cooking stage. The high total white liquor charge ranges between 15 % AA &tilde& 35 % AA, while the cooking temperatures range between 150 &tilde& 168 DEG C._________________________
Abstract:
A dryer section apparatus (10) as disclosed for drying a web of paper (W). The apparatus (10) includes a plurality of dryer groups (12, 14, 16) disposed successively relative to one another, such that the web (W) is progressively dried during movement thereof through the dryer groups (12, 14, 16). The plurality of groups (12, 14, 16) include a first single-tier group (12) for drying the first side (18) of the web (W), and a second two-tier group (14) disposed downstream relative to the first group (12). A second single-tier group (16) is disposed downstream relative to the two-tier group (14) for restraining the web (W) against cross-machine directional shrinkage.
Abstract:
A doctor blade structural support (24) has the form of a hollow structural member of roughly triangular cross section, one side of the triangular cross section being substantially tangent to the surface of the dryer roll (22). A quantity of water is disposed within the hollow structural member and resides on the inside surface of the structural member adjacent to the heated dryer roll surface (50). The interior of the doctor support structure (24) is sealed from the atmosphere and is evacuated so that the interior of the structure contains only water and water vapor. Heat radiating from the dryer roll surface (50) to the doctor support structure (24) causes water disposed on the inside surface adjacent to the dryer roll to evaporate, thus raising the internal vapor pressure in the sealed interior of the doctor support structure. The water vapor continuously condenses on the inside surfaces of the support structure which are not exposed to radiant heating from the dryer roll (22). This evaporation and condensation of water within the interior hollow support structure maintains relative temperature uniformity from top to bottom of the support structure. The temperature uniformity in turn leads to a minimizing of thermal distortion caused by the heat transfer between the doctor support structure (24) and the dryer roll (22).
Abstract:
Two webs of paper (68, 84), without the necessity of a glue or starch shower, are joined together to form multi-ply linerboard (112). Two surfaces of two sheets having the same freeness and furnish are brought together and thus readily bonded together without a binder. To form multi-ply linerboard one of the webs is formed as a multi-ply web, one exterior ply of the multi-ply web matches the freeness and furnish of the other web and so bonds readily to it.
Abstract:
A wood chip cracking device (20) for use in papermaking employs closely spaced, oppositely rotating rolls (24, 26) which have pyramid-shaped projections (38) on the roll surfaces (32, 34). This chip destructuring apparatus (20) is rendered readily serviceable with minimal downtime by constructing the roll surface (32, 34) of removable segments (25) which are bolted to a central rotatable shaft (46). The segments (25) are sized so they can be lifted by a service man. As damage to the roll surface (32, 34), such as by exposure to tramp metal, is typically limited to a single segment, service and repair of the roll (24, 26) is expedited by permitting removal of a single damaged segment without removing the remaining undamaged segments (25). Each segment is bored for twelve bolts (72) and is affixed to the inner shell by twelve recessed bolts (72). The surface segments (25) allow the surface to be replaced without removing the rolls (24, 26) from the frame (30) of the wood chip cracking device (20).
Abstract:
A dryer for drying material carried along and dried by hot gases including a hollow rotatable drying drum (10) with an inlet (15) and a discharge end, means (12, 13, 14) for driving the drum in rotation and a group of flights projecting into the gas flow stream to break up the material and retard the speed of flow of the material with the flowing gases with the flights arranged in one group at the outer periphery inside the drum and the other supported on a central axially extending shaft (18) and arranged on the ends of arms (19, 20) projecting radially from the shaft to provide satellite groups (40, 41) which are adjustable in a radial rotational and axial directions to change their location relative to the gas flow.
Abstract:
A basis weight control apparatus (10) is disclosed for controlling the cross-machine direction basis weight of a stream of stock (S) ejected from a headbox (12) onto a forming wire (14). The apparatus includes a plurality of conduits (18-22) with each conduit defining an outlet nozzle (24-28) disposed adjacent to a slice lip (30) of the headbox (12) and spaced relative to each adjacent nozzle in a cross-machine direction (CD). The conduits (18-22) are connected to a source of pressurized air (32). A plurality of control valves (34-38) are arranged with each valve (34-38) cooperating with a corresponding conduit (18-22) for controlling a flow of pressurized air (40) to each nozzle. A control device (42) is connected to the valves (34-38) for controlling the valves such that a flow of air to each of the nozzles (24-28) is permitted for controlling the cross-machine basis weight of the stream of stock (S). The arrangement is such that when the flow of air (40) through one of the nozzles is increased, the basis weight of the stream of stock (S) in the vicinity of the one nozzle is correspondingly reduced so that the basis weight of the stream of stock in a cross-machine direction is selectively controlled.