Abstract: A screen cylinder, screen, method of manufacture of the screen cylinder, and method of use of the screen cylinder, allow screen capacity to be maximized without sacrificing screen cylinder strength, and while achieving a clean accepts flow. A screen cylinder is constructed in a conventional manner except that at least one reinforcing ring is permanently fastened (typically by continuous or spot laser or electric beam welding, or direct resistance welding) to at least a majority of (and typically essentially all of) the land areas which separate grooves in a row from each other, at the outlet surface of the cylinder, or at least one spiral ring is applied. In this way effective slot length of screen cylinders may be about 65-90% of the total screen length, compared to only about 45-55% for conventional screen cylinders. The screen cylinders are particularly effective in screening cellulose pulps from the pulp and paper industry.

Abstract: A screen cylinder, screen, method of manufacture of the screen cylinder, and method of use of the screen cylinder, allow screen capacity to be maximized without sacrificing screen cylinder strength, and while achieving a clean accepts flow. A screen cylinder is constructed in a conventional manner except that at least one reinforcing ring is permanently fastened (typically by continuous or spot laser or electric beam welding, or direct resistance welding) to at least a majority of (and typically essentially all of) the land areas which separate grooves in a row from each other, at the outlet surface of the cylinder. The welds each typically have a width of about 1 to 3 mm (that is they are very small), but that width is typically at least about 75% of the width of a land area in which it is formed, and the weld has a length of at least about 50% of the width of the reinforcing ring at the weld.

Abstract: A screen cylinder or plate has a screening surface and accepts surface on opposite faces, and screens pulp flowing in a flow direction to separate accepts from rejects. A number of substantially parallel macro grooves are formed in the screening surface generally transverse to the flow direction, and a number of parallel micro grooves are formed in the screening surface within each macro groove also generally transverse to the flow direction. The macro grooves induce shear stress in the reject material flowing in the flow direction to keep it in constant motion and to prevent it from forming a mat on the screening surface. The micro grooves induce micro turbulence into the pulp at the immediate area of screening openings extending from each micro groove to the accepts surface, to fluidize the pulp so that accepts readily pass through the screening openings toward the accepts surface. Each micro groove within a macro groove is located further away from the accepts surface moving in the flow direction.

Abstract: The screen cylinder includes a screening plate having contoured grooves along an inflow side and a backing cylinder having a plurality of openings therethrough and disposed on the outflow side of the screening cylinder. The contoured grooves are elongated in the axial direction and are closely circumferentially spaced one from the other about the screen cylinder. In one embodiment, circumferentially extending grooves are formed along the outflow side of the screening cylinder whereby pulp flows through the contoured grooves into the recesses and then through the openings of the backing cylinder. In another embodiment, the recesses are formed on the inflow side of the backing cylinder, the screening cylinder being provided with elongated slots along its outflow side in registry with the contoured slots. In this manner, increased flow capacity is provided. Additionally, the screening cylinder is removable when worn for replacement by a fresh screening cylinder which may then be secured to the backing cylinder.

Abstract: A plurality of blind openings (e.g. holes or slots) are formed through a first face of a steel plate and extend a predetermined distance short of the opposite face. Larger size openings are formed through the first face using the blind openings as pilot openings. The larger size openings extend into the plate short of the terminations of the blind openings. Metal is machined from the opposite face in parallel rows defining grooves and to a depth to uncover the terminations of the blind openings in the plate body thereby providing through-extending screen openings in the plate. The ridges (bars) between the grooves may be quadrate in cross-section, or a side face sloped (angled) by machining. A screen cylinder with bars of the invention has a maximum screen area (compared to prior art screens with bars).