Abstract:
A headbox (20) has a tube bank (28) of tubes (26) arranged in machine direction rows. The tubes (26) extend from an outlet wall (30) of a header to the inlet of a nozzle (42). The upper and lower walls (44, 46) of the nozzle (42) converge toward the nozzle outlet (48), and planes extending from the walls (nozzle roof and apron) converge to define an imaginary centerline extending in the cross-machine direction. The rows of tubes (26) lie along radially extending planes defined with respect to the centerline. The injection ends of the tubes define a cylindrical surface (64) extending between the nozzle walls (44, 46). Stock from each tube (26) is directed radially toward the centerline along flow paths (47) of equal length. Trailing vanes (68) may be positioned between the rows of tubes (26) so that each flow experiences almost identical flow boundary conditions as it moves towards the nozzle outlet (48), hence contributing to more uniform fiber orientation in the resultant paper web (51).
Abstract:
The invention pertains to a core-insertion device for a winding machine with at least one support or carrier drum (21, 22) for winding of web-like material (1) to be wound, in particular paper or the like, with a means for feeding cores (10) to a take-up position running approximately parallel to the at least one support or carrier drum(s) (21, 22), with a displacement means (2) for holding, in a detachable way, and displacing the core(s) (10) from the take-up position to a winding position located at the surface of the at least one support or carrier drum(s) (21, 22). The displacement means comprises, firstly, an elongated core carrier (3) having a pivot joint (6) arranged above its center of mass and core-holding means (30) in its lower region, and secondly, an element which can be moved between the take-up position and the winding position for a free-swinging accommodation of the elongated core carrier (3) at its pivot joint (6) and for displacing the core carrier (3) including at least one core (10) from the take-up position to the winding position. Due to the invention, it is possible merely to move the winding cores (10) itself, but not its receiving recess (11), from the take-up position to the winding position on a predetermined path and at an unchanging angle with respect to the core axis, deeply into the winding bed (23), and then to release them there only when the winding cores (10) have come into contact with the support drums (21, 22).
Abstract:
An Extended Nip-type press (20) has a blanket (30) which passes over a shoe (22) which is urged against a backing roll (24) to form a press nip (56). A hydraulic system (70) and controller (94) provides for automatic continuous oscillation of the blanket (30) in the cross machine direction. The oscillation results in a region of high fatigue (58, 59) continuously moving over the blanket (30) surface so that the amount of time any particular region sees wear is minimized. Positioning of the heads (38, 42) to which the blanket (30) ends are mounted is controlled by hydraulic pistons (60, 62) mounted between a support beam (26) and the heads (38, 42). A controller (94) operates a valve (74) to reverse the direction of motion of the blanket (30) when sensors (92, 98) indicate one end of the blanket (30) has reached a stop (64, 80). A throttle valve (86) controls the rate at which hydraulic fluid is supplied to the cylinders (60, 62) which urge the head (38, 42) away from the shoe (22).
Abstract:
A calender employs an open-stack like arrangement with a single vertical beam (32) or support column on each end of the calender. In combination with the support beam (32), a special swing link (34) is used to support tension loads on the open side of the calender. The nip is thus straddled by structural members between the support column and the link. This combination has the ability to support high linear nip loads, as high as 2,500 PLI or higher. The link has pin connections (38, 44) at both ends so that when one pin is removed, the link can be swung open for roll removal or accessibility. Thus, the strength of the closed-stack calender is combined with the visibility and ease of access of the open-stack calender by the employment of tension links which replace one of the support columns utilized in a closed-stack calender.
Abstract:
An improved process is described for oxygen delignification of medium consistency pulp slurry which teaches control parameters and their resultant effect on final product characteristics. Specifically, a process is described wherein pulp slurries of from approximately eight percent to sixteen percent consistency, are heated to a temperature of at least 170 DEG F and impregnated with oxygen gas and alkali to bring the slurry to a pH of from approximately 11-12.5. The slurry is mixed in a high shear mixer, for agitating mixing therein, under pressure of from approximately 20-180 psig for a first reaction time of typically 5 minutes. Additional alkali is added to the slurry to return the pH to at least 11, preferably at least 12, and the residual alkali concentration to at least 4.0 gpl at the end of the first reaction time. The temperature of the slurry is raised to at least 170 DEG F followed by mixing for a second reaction time of typically 55 additional minutes.
Abstract:
A drive shaft is moved in a machine direction and a cross-machine direction to engage a spool on a winder. The drive shaft has an inner drive shaft which is elastically linked to an outer cylindrical shell, thereby allowing misalignment between the inner shaft and the outer shell and allows angular as well as horizontal and vertical displacement when the drive head engages the spool to provide centerwind assist to a roll of paper being formed thereon. The location of the drive shaft axis is determined at all times from geometric considerations and this data is used to position the drive shaft on the axis of the winding spool.
Abstract:
In a process and device for automated feed of winding cores in a reel cutter of the back-up roller type, the winding cores (33) are advanced to the feed device (60) individually and placed in their transfer position, where they are delivered to one of the conveyors for the two take-up stations (40, 50) such that only one winding core (33) is situated in the feed device (60) and the winding cores (44, 54) for the two take-up stations (40, 50) are raised or lowered together into the clamping position and are clamped in by the take-up devices (41, 51) of the take-up station (40, 50). For this purpose the conveyor comprises core support beams (70, 80) for the two take-up stations (40, 50), which can be raised and lowered and which are equipped with retention members (71, 81) for the winding cores (44, 54). The core support beams (70, 80) are fitted with means (62) which in the advance position form the gutter (61) for a winding core (44, 54) of the core support beams (70, 80) for the two take-up stations (40, 50), in conjunction with the corresponding means (62) of the other core support beams (70, 80). The means (62) are designed in such a way that a winding core (44, 54) situated in the gutter can be transferred to the retention members (71, 81) of one or the other core support beams (70, 80).
Abstract:
A method for reprocessing an ozone-containing gas present in a pulp bleaching plant comprising the steps of supplying the ozone-containing gas to a scrubber and reducing the ozone concentration of the gas as the gas flows through the scrubber. The step of reducing comprises the steps of supplying an alkaline medium to the scrubber and flowing the ozone-containing gas in countercurrent relationship with the alkaline medium within the scrubber so as to provide intimate contact between the ozone-containing gas and the alkaline medium, thereby converting the ozone-containing gas into a substantially ozone-free gas. The alkaline medium may comprise one of the following: a sodium hydroxide solution; white liquor; post oxygen stage filtrate; weak black liquor; or filtrate from an Eo stage of the pulp bleaching plant. The method further comprises the step of separately discharging the ozone-containing gas and the alkaline medium from the scrubber. The ozone-containing gas may comprise an off-gas, which has been partially reacted with a pulp within a pulp bleaching stage or alternatively may comprise fresh bleaching gas, having an ozone concentration ranging from about 6 % to about 14 % by weight within a carrier gas, with the fresh bleaching gas being supplied directly from an ozone generator to the scrubber.
Abstract:
A method and apparatus for bleaching hig consistency pulp with a gaseous bleaching reagent. The pulp is shredded and then fluffed in the presence of a contacting gas which includes the gaseous bleaching reagent within an upstream vessel (52) comprising a pin/foil contactor so as to suspend the pulp in the contacting gas and react the bleaching reagent with the pulp. The pulp is retained in the contactor for a predetermined time which is sufficient to consume about 75 % to about 90 % of a selected dose of the gaseous bleaching reagent which is required to delignify the high consistency pulp from an initial Kappa number to an intermediate Kappa number. The pulp and contacting gas are then separately supplied to a porous bed reactor where the reaction of the selected dose of the gaseous bleaching reagent with the pulp is substantially completed so as to further delignify the high consistency pulp from the intermediate Kappa number to a final Kappa number.
Abstract:
A winder in a papermaking machine has a frame (40) with horizontal rails (42) which are positioned above a rotatable reel support drum (34), which is fixedly mounted. As a relatively large diameter wound paper web reel, or jumbo, is formed on a spool riding on the rails, the surface of the jumbo remains tangent to the top of the support drum as the spool moves from a position vertically over the reel drum to a position laterally displaced horizontally along the rail. Centerwind drive(s) (36, 38) control spool torque. As the jumbo increases in size, it is moved linearly away from the initial position, while maintaining the paper web reel rotatively supported and in a nipping engagement with the support drum. Nip pressure between the support drum and the jumbo is controlled by the force of gravity and the horizontal positioning of the jumbo along the rails. The positioning of the jumbo along the rail may be controlled by a conventional pneumatic or hydraulic cylinder, or a screw mechanism. An alternative embodiment winder utilizes primary (121) and secondary arms (123) to position the jumbo and its spool along the reel rails.