INCLINED PLANAR FORMER FOR PRODUCING PAPER SHEET UNDER THE FELT FOR THE PRODUCTION OF MULTILAYER OR SINGLE-LAYER PAPER

Abstract: The equipment of the present invention serves to form a sheet of paper under the felt line, this sheet can be for monolayer or multilayer paper, the paper sheet so formed has superior characteristics to that of a sheet made in a fourdrinier manufacturing table. The fiber suspension is distributed through a head box over the forming table, allowing the fiber to freely orient according to the jet/fabric speeds rate, and to the hydraulic pattern generated by the forming activity lip. The effect generated by the activity lip is supplemented by the pulse forming roll allowing the fibers to orient freely or in a controlled fashion according to the roll speed. The water remaining in the fiber suspension is drained in a box divided in three vacuum compartments, to reach a fixed dryness to make contact with the prior unit sheet or with the felt in the case of being the first unit. The equipment comprises a forming table in which the tilt can be adjusted according to manufacturing requirements, this forming table comprises a fabric to form the paper sheet, a breast roll also serving as fabric stretcher, forming and dewatering foils, a pulse forming roll, flat boxes, a cylinder mold, a guide roll and control elements, support structures to support the former equipment, water collection trays, rails and rolls for maintenance of the former equipment, which allows the unit to be removed of service without halting production. The equipment also comprises a fiber distribution head box oriented towards the formation table, as well as a suction slider to extract water from the inner part of the felt. It also is provided with a rubber couch roll which presses the felt and the sheet in such a manner that the paper sheet adheres to the felt and can be transferred to the next formation unit. The couch roll is provided with a mechanism for setting position against the cylinder mold shaft, as well as with a bellows system to raise the cylinder mold or to apply pressure against said cylinder mold. The equipment comprises showers to keep clean the support roll, the fabric and the breast roll. A doctor blade is located in the breast roll, for keeping the roll clean and to divert the water drained in this zone to a tray. This unit has a system comprising two vertical structures and a lengthwise beam to provide rigidity thereto.

Description: TECHNICAL FIELD The present invention refers to a new type of under felt inclined flat former to produce multilayer or monolayer sheet of paper, to be advantageously used in the industry of paper manufacture. BACKGROUND OF THE INVENTION Currently there are several types of multilayer paper formation equipments among which the following can be mentioned: CYLINDER MACHINE, this machine forms the paper sheet draining the water through a mesh screen adhered to a cylinder. The formed sheet Is transferred directly to a felt for further joining the next layer. In this machine there is no control on the fiber orientation nor in the draining speed of the fiber suspension. FLAT FORMERS OVER FELT LINE, these formers have a flat table in the area of formation of the paper sheet, which once the paper sheet is formed, it is transferred to a felt completely surrounding the forming felt to thereafter pass under this formation unit and arrive to the next formation unit. US 3,357,880 discloses a portion of a paper machine where paper stock discharged from a head box is deposited on a web forming wire inclined upwardly from a breast roll toward a couch roll and having a suction box assembly mounted beneath the top strand of the wire with a suction box adjustably spaced from the breast roll. US 1,481,163 discloses a device for a Fourdrinier type paper machine for controlling the delivery of the pulp to the wire. In particular, a flow head box is used having lips forming a slot without segmentation whereby the slot is locally adjustable in width by screws over the lengths of the lips. DISCLOSURE OF THE INVENTION The object of the present invention, is to provide, a new equipment for the under felt paper formation, which overcomes all the defects of known equipments, since it allows to control the fibrous orientation in a formator under the felt line. It also allows to stop a formation unit and the complete removal thereof from the production line without shooting-down the production process. The equipment of the present invention serves to form a sheet of paper under the felt line, this sheet can be for monolayer or multilayer paper, the paper sheet so formed has superior characteristics to that of a sheet made in a fourdrinier manufacturing table. The fiber suspension is distributed through a head box over the forming table, allowing the fiber to freely orient according to the jet/fabric speeds rate, and to the hydraulic pattern generated by the forming activity lip. The effect generated by the activity lip is supplemented by the pulse forming roll allowing the fibers to orient freely or in a controlled fashion according to the roll speed. The water remaining in the fiber suspension is drained in a box divided in three vacuum compartments, to reach a fixed dryness to make contact with the prior unit sheet or with the felt in the case of being the first unit. The equipment comprises a forming table in which the tilt can be adjusted according to manufacturing requirements, this forming table comprises a fabric to form the paper sheet, a breast roll also serving as fabric stretcher, forming and dewatering foils, a pulse forming roll, flat boxes, a cylinder mold (support roll), a guide roll and control elements, support structures to support the former equipment, water collection trays, rails and rolls for maintenance of the former equipment, which allows the unit to be removed of service without halting production. The equipment also comprises a fiber distribution head box oriented towards the formation table, as well as a suction slider to extract water from the inner part of the felt. It also is provided with a rubber couch roll which presses the felt and the sheet in such a manner that the paper sheet adheres to the felt and can be transferred to the next formation unit. The couch roll is provided with a mechanism for setting position against the cylinder mold shaft, as well as with a bellows system to raise the cylinder mold or to apply pressure against said cylinder mold. The equipment comprises showers to keep clean the support roll, the fabric and the breast roll. A doctor blade is located in the breast roll, for keeping the roll clean and to divert the water drained in this zone to a tray. This unit has a system comprising two vertical structures and a lengthwise beam to provide rigidity thereto. DESCRIPTION OF THE DRAWINGS Figure 1 is an elevation view of the paper former showing all its constituents. Figure 2 is a detail of the couch roll with all the mechanisms thereof. Figure 3 shows a detail of the breast roll, the forming knife and the head box also with all their components. Figures 4a, 4b and 4c, illustrate the activity lip as well as all the components thereof. Figure 5 illustrates the water collecting trays and showers forming part of the formation unit. Figure 6 illustrates a side view of the forming roll; and Figure 7 illustrates a detail of the forming roll vane. SUMMARY OF THE INVENTION The equipment of the present invention comprises a vertical frame (1) anchored in its lower part by screws (4) and also comprises a second frame (3) anchored in the lower part to the floor by screws (7). A beam (2) is located in the top part of both frames, joining both frames by means of screws (5) and (6). In the second frame (3), at the exit side of the paper sheet, there is located a mechanism for applying pressure or for raising the couch roll (25), this mechanism comprises two supports (8) and (9), each of them have a corresponding rubber pneumatic bellows (10) and (11) joined thereto. The upper pneumatic bellows (10) is joined to the top part of the support (8) by screws (14) and to the lower part to an arm (12) that is attached to the couch roll by means of screws (15). The upper bellows (10) has as a function to raise the couch roll. The pneumatic lower bellows (11) is attached in the lower part to the support (9) by means of screws (17) and In the top part is attached to the arm (12) by means of screws (16). A support (13) is joined to the frame (3), said support (13) carries a bearing (30) in its central portion; said bearing houses a pin (31), that acts as a fulcrum for the arm (12) which fastens the couch roll by means of a support (18) that in turn is attached to a supporting block (19) through screws (20). The supporting block (19) has a threaded hole in the central part thereof. This block adjusts its position by means of a spindle (21) fixed to the arm (12) by means of dividers (28) and (29); the supporting block (19) is attached to the journal bearing (26) that supports the couch roll by means of rotating screws (23) and a separating block (22). The rotating screws (23) press the journal bearing of the couch screw by means of a nut (24) and rotate by means of a pin (27) fixed to the block (19). The equipment of the present invention also comprises a suction slider (134) that extracts the water from the sheet of paper and the felt when being pressed between the couch roll (25) and the support roll (32). This equipment also comprises a breast roll (97), a former roll (82) a flat box with three compartments (74), (75) and (76) having corresponding high density polyethylene covers (77), (78) and (79) in their upper part. It also has a cylinder mold (32) and a fabric lead roll (51), as well as a formation plastic fabric (72). The flat box with three compartments (74), (75) and (76) is attached to the main structure(35) by means of screws (80) and (81) that In turn allows alignment and leveling of the box. The flat box has a plate (130) which avoids that the water drained from the former equipment (82) adhere to the inner part of the flat box compartments. The cylinder mold (32) rotates on a bearing housed in a journal bearing (33). This journal bearing is attached to a main structure(35) by means of screws (34). The main structure(35) is supported by means of two blocks (37) and (60) which in tum are attached to the bases (39) and (61) of the former equipment. These bases are attached to the supports (43), (47), (65) and (68) by means of spacer blocks (41), (49), (63) and (70). A removable block (37) is attached to the base (39) and to the main structure(35) by means of two rotating screws (36) and (38). A second removable block (60) is attached to the structure and support (61) by means of rotating screws (58) and (59). The removable blocks (37) and (60) serve to keep the whole formation unit in such a way that when it is required to change the formation fabric (72), said blocks are merely removed while the whole unit remains in cantilever allowing to carry out set up of the new fabric in a minimum time. The support (39) which is located immediately below the support roll is attached to the bases (43) and (47) by means of spacers (41) and (49) held by screws (40) and (50), the support (61) which is immediately below the breast roll is attached to the bases (65) and (68) by means of spacers (63) and (70), these supports are held by means of screws (62) and (71). The equipment of the present invention has a rolls system (45), (46) and (66) which allows the unit to seat on rails (44) and (67) when the spacer blocks (63), (70), (49) and (41) are removed from the supporting position, this allows the unit to be completely removed from the machine without stopping production by merely pulling the former away from its operating position. This unit has a system for controlling the position of the formation plastic fabric (72) by means of a guide roll (51). The mechanism for operating this guide roll operates as follows: the guide roll (51) is supported by a journal bearing (57), this journal bearing is attached to a support plate (56), which is actuated by two pneumatic adjusting bellows (54) and (55). the support plate (56) is kept in position by the rolls (52) and (53), such rolls maintain the horizontal and vertical position of the support plate. The adjusting bellows (54) and (55) adjust the position of the guide roll (51) by changing the pneumatic pressure in each one of said bellows. This equipment comprises a former roll (82), attached to the main structure(35) by means of screws (101), which fix the journal bearing (83) about which the former roll rotates, to said structure. The former roll is built with a steel core (138) which is coated with a resin (82) whose surface is machined to provide thereto a streamline profile (139), which allows the generation of a positive pulse in the first contact with the fabric and a negative pulse at the time when this profile loses contact with the formation plastic fabric. The peripheral speed of the roll is lower to that of the formation fabric allowing injection of water from the lower part of the fabric to the upper part where the fiber suspension is, creating thus a rearrangement of the fibers. The breast roll (97) rotates over bearings located in a journal bearing (98), which is attached to the main structure(35) by means of screws (99) and (100). Adjustment of the position of the breast roll is carried out with a spindle (91) by means of nuts (95) and (96). The spindle (91) is attached to a structure (88) which also supports the base of the formation knives (86), this base is attached to the structure (88) by means of a screw (87). The position of the base of the formation knives against breast rolls is adjusted by means of a spindle (92) and retaining nuts (93) and (94). The structure (88) is attached to the main structure(35) by means of screws (89) and (90), the structure of the formation knives holds the formation knife (84) by means of T-shaped sliders (85). A plastic knife (103) is provided to keep clean the breast roll (97), the plastic knife (103) plays a cleaning role and at the same time deviates the water drained by the breast roll towards a collecting tray (128). The formation equipment comprises a flow head box, which comprises a conical manifold (121) whose function is to distribute uniformly the flow of the fiber suspension in a direction widthwise to the formation unit. Attached to this conical manifold by means of a throat (117), is a stepped diffuser (114) that is sealed in the lower and upper part by means of a plastic tube (118). To avoid flexing of the stepping diffuser, there is provided a plate (115) that covers completely the diffuser. The plate (115) is attached to the manifold and to the upper part of the head box by screws (119) and (120). The main role of the stepped diffuser is to maintain the fibers in a state of complete dispersion. The head box has a lower lip (109) and an upper activity lip (108). The upper lip sets its opening position to control the discharge flow by means of screws (122) located at the ends of the head box, the box profile is adjusted by screws (104) located in the internal part of the head box, in both cases the screws are adjusted by means of retaining nuts (106) and (104). Internal (104) and external (122) screws are attached to a bridge (105) allowing uniform movement of the lip. At the opposite end, the upper activity lip (108) has a universal joint (110) supported over a plate (112) and to a retaining unit (111). This allows the upper activity lip (108) to move freely without fiber suspension leaks. The discharge end of the upper activity lip has a profile designed to create activity in the fiber suspension and which is able to orient high concentration of fibers; it also allows obtaining a paper of lower density. This profile is comprised by a inclined part (136) and a straight part (135), that make a change in the speed in the flow of the fiber suspension, both horizontally and vertically. The activity profile is spaced widhtwise of the head box by means of sectors (137) keeping the same thickness of the upper activity lip, the upper activity lip internally generated hydraulic pattern produces crossed flows over the forming table at the time the fiber suspension leaves the head box. This makes the fiber orientation to be improved transversely, that Is the fiber orientation ratio in the machine direction to the transversal fiber orientation decreases. In this way, the values of the physical properties of the paper in the transversal sense tend to be similar to those in the machine sense. A shower (131) keeps the cylinder mold (32) clean. There is also a second shower (132) to keep the guide roll (51) clean. The formation fabric (72) is kept clean by means of a high pressure shower (133). To collect the drained water in the unit there are a series of trays (127), (128), (129) and (126) collecting such water and driving it to an independent tank.

Claims: An under felt inclined flat former to produce a multilayer or monolayer sheet of paper, said flat former including at least a first former unit comprising: a) support means including a first and a second vertical frame (1, 3) and a horizontal beam for supporting the unit; b) a forming table; c) a formation fabric (72); d) flow head box means for uniformly distributing suspension of fibers over a width of the forming table, said head box means comprising i) a conical manifold (121); ii) a stepped diffuser (114) for substantially completely dispersing fibers in the suspension flowing through the head box means; iii) activity lip means (108, 109) comprising upper and lower activity lips for controlling discharge of the suspension from the head box means, said upper activity lip (108) comprising flow control means for changing a speed and orientation of fiber flowing in the suspension through the head box means, said flow control means comprising an inclined portion and a straight portion, said inclined and straight portions providing the upper activity lip with a profile that causes the speed and orientation of the fibers flowing through the head box means to change in both a vertical and a horizontal direction, the activity profile of the upper activity lip being spaced widthwise of the head box by means of sectors keeping the same thickness of the upper activity lip, and means for controlling the activity lips; e) a former roll (83); f) a flat box (74, 75, 76) comprising three compartments and being supported by the forming table; g) a support roll (32); h) a couch roll (25); i) pressure-release means supported on the at least one vertical frame for releasably pressing the couch roll (25) against the support roll (32); j) a breast roll (97); said formation fabric (72), former roll (83) and flat box (74, 75, 76) being positioned between said support roll (32) and said breast roll (97); k) roll means which allows the support roll (32) and formation table to form a separable unit which can be completely removed from the flat former by pulling it away from its operating position; wherein stock is introduced onto the formation fabric (72) by the head box which, due to a rotation of the breast roll (97) and support roll (32), causes the formation fabric (72) to pass over the forming table, former roll (83) and flat box (74, 75, 76) causing activity and dispersion of stock and to pass over the flat box (74, 75, 76) which causes liquid drainage from the stock forming a sheet which is then transferred to a papermaking felt at a junction formed between the couch roll (25) and support roll (32). Underfelt inclined flat former according to claim 1, wherein the mechanism for applying pressure or for raising a couch roll (25) comprises an upper support (8) and a lower support (9), each of them having a corresponding rubber pneumatic bellows (10, 11) joined thereto; the upper pneumatic bellows (10) is joined to the top part of the upper support (8) by screws (14) and to the lower part to an arm (12) that is attached to the couch roll (25) by means of screws (15); the upper bellows (10) has as a function to raise the couch roll (25); the lower bellows (11) is attached in its lower part to a support (9) and in the top part is attached to the arm (12). Underfelt inclined flat former according to claim 1, wherein the position of the supporting block (19) Is adjusted by means of a spindle (21) fixed to the arm (12) by means of dividers (28, 29); the supporting block (19) is attached to the journal bearing (26) that supports the couch roll (25) by means of rotating screws (23) and a separating block (22). Underfelt inclined flat former according to claim 1, wherein the flat box with three compartments (74, 75, 76) is attached to the structure (35) by means of screws (80, 81) that in turn allows alignment and leveling of the box; said flat box has a plate (130) which avoids that the water drained from the former equipment (82) adhere to the inner part of the flat box compartments. Underfed inclined flat former according to claim 1, wherein the cylinder mold rotates on a bearing housed in a journal bearing (33); said journal bearing is attached to a main structure (35) by means of screws (34); said main structure is supported by means of two blocks (37, 60) which in turn are attached to the bases (39, 61) of the former equipment; said bases are attached to four base supports (43, 47, 65, 68) by means of several spacer blocks (41, 49, 63, 70); a base block (37) is attached to the base (39) of the main structure and to said main structure by means of two rotating screws (36, 38). Underfelt inclined flat former according to claim 1, further comprising two removable blocks (37, 60) that serve to keep the whole formation unit in such a way that when it is required to change the formation fabric (72), said blocks (37, 60) are merely removed while the whole unit remains In cantilever allowing to carry out set up of the new fabric in a minimum time. Underfelt inclined flat former according to claim 1, further comprising a rolls system (45, 46, 66) which allows the unit to seat on rails (44, 67) when the spacer blocks (63, 70, 49, 41) are removed from the supporting position, this allows the unit to be completely removed from the machine without stopping production by merely pulling the former away from its operating position. Underfelt inclined flat former according to claim 1, wherein the former roll is built with a steel core (1.38) which is coated with a resin whose surface Is machined to provide thereto a streamline profile (139), which allows the generation of a positive pulse in the first contact with the fabric and a negative pulse at the time when this profile loses contact with the formation plastic fabric (72); the peripheral speed of the roll is lower to that of the formation fabric allowing injection of water from the lower part of the fabric to the upper part where the fiber suspension is, creating thus a rearrangement of the fibers. Underfelt inclined flat former according to claim 1, wherein the breast roll (97) rotates over bearings located in a journal bearing (98) which is attached to the main structure (35) by means of screws (99, 100); adjustment of the position of the breast roll (97) is carried out with a spindle (91) attached to a structure (88) which also supports the base of formation knives (86); the position of the base of the formation knives against breast rolls is adjusted by means of a spindle (92) and retaining nuts (93, 94). Underfelt inclined flat former according to claim 1, comprising a shower (131) that keeps the cylinder mold (32) clean; there is also a second shower (132) to keep the guide roll (51) clean and a high pressure shower (133) to keep the formation fabric (72) clean. Underfelt inclined flat former according to claim 1, comprising a series of trays (127, 128, 129, 126) to collect the drained water in the unit, collecting such water and driving it to an independent tank.

Inventors: CABRERA Y LOPEZ CARAM LUIS FERNANDO, CABRERA Y LOPEZ CARAM, LUIS FERNANDO
Applicants: SMURFIT CARTON Y PAPEL DE MEXI, SMURFIT CARTON Y PAPEL DE MEXICO, S.A. DE C.V.
Application year: 1995
Main classification: D21F9
IPC codes: D21F11, D21F7, D21F9, D21F1