AN APPARATUS FOR CUTTING A TAIL FROM A WEB

Abstract: An apparatus is disclosed for cutting a tail from a web (WA) extending from a single tier dryer section (15A) to a further single tier dryer section (16A). The apparatus includes a last dryer (18) of the dryer section (15A) and a dryer felt (F) extending around the last dryer (18) such that the web (WA) is disposed between the dryer felt (F) and the last dryer (18) for drying a second side (20) of the web (WA). A last felt roll (22) is disposed downstream relative to the last dryer (18) such that the felt (F) extends around the last felt roll (22). A first dryer (24) of the further dryer section (16A) is disposed downstream relative to the last dryer (18) and a first felt roll (26) is disposed between the last dryer (18) and the first dryer (24). A further felt (FF) extends around the first felt roll (26) and the first dryer (24) such that the web (WA) extends in open draw (28) between the last dryer (18) and the first dryer (24) and thereafter around the first dryer (24) between the further felt (FF) and the first dryer (24) for drying a first side (30) of the web (WA). A tail cutter (32) is disposed adjacent of the web (WA) for cutting a tail from the web (WA) in the open draw (28).

Description: TITLE OF THE INVENTION: AN APPARATUS FOR CUTTING A TAIL FROM A WEB £B21£_:£III^I £I_Σ£_ Iϊ- ϊI5_A ZΪιi C A T I O N The present invention is a con t inu t ion - i n -pa of co-pending application Serial No. 014,569 filed February 13, 1987. All of the subject matter of Serial No. 014,569 is incorporated herein by reference. BACKGROUND_OF_THE_INVENTION III_ . £_£I_Ϊ2]!__INIINT I ON This invention relates to an apparatus and method for cutting a tail from a web. More particularly, this invention relates to a tail cutting apparatus and method for cutting a tail from a web extending between a single tier dryer section to a further single tier dryer section. INFORMATION_DISCLOSURE_STATEME T In co-pending patent application Serial No. 014,569 filed February 13, 1987, a Total BelRun dryer section is disclosed which includes a plurality of alternate top and bottom felted single tier dryer sections which alternately and successively dry alternate sides of the web as the web progresses through the dryer. Total BelRun is a Registered Trademark of Beloit Corporation. Several advantages are presented by the aforementioned Total BelRun configuration. First, the long open draw between dryers within each dryer section is eliminated. The elimination of such open draw improves the runnability of the web. Second, the vacuum rolls between dryers maintain the sheet shrinkage restraint resulting in more uniform cross-machine directional sheet properties. However, with the aforementioned Total BelRun configuration, a problem exists in that there is no open draw between the last dryers of the final dryer section and such an open draw is essential for the installation of a tail cutter. Although the aforementioned problem could be overcome by the provision of a conventional two-felt dryer section in the final dryer section, such two-felted dryer section would greatly reduce the cro s s - d irec iona1 sheet shrinkage restraint and this reduced shrinkage restraint would be in a critical portion of the drying cycle. The present invention overcomes the a orementioned problem by providing an open draw transfer between the last two Total BelRun dryer sections and the installation of a tail cutter adjacent to such open draw transfer. T e advantages provided by the provision of a Total BelRun confi uration throughout the dryer is primarily that the drying restraint is extended to the end of the dryer whereas in the conventional two-felt dryer section, the sheet tension between the dryers within a dryer section are to a large extent unco trolled. Additionally, some web slack may develop in the area where the tail cutter is located . However, in the configura ion according to the present invention, the sheet tension in the open draw is controlled directly by adjusting the relative speeds of the final dryer section with respect to the immediate upstream dryer sect on. In generally cut just prior to the last one or two dryers. Although the sheet has nearly developed its full strength at this stage, the sheet at this point is also often very dry, particularly in dryer sections w ch precede a size press. The aforementioned dry sheet can be very abrasive on a cutting knife and the blade life thereof is relatively short. Typically, the knife or blade has to be replaced b a special saw which may result in dusting problems. However, in the present invention, the web still contains enough moisture to allow a knife to be used as a tail cutter. Such knife not only inhibits the generation of sawdust but also permits the use of a simple tail cutter and minimizes the number of blade changes. The length of the open draw in which the tail is cut on a conventional machine is often dictated by the specific dryer geometry which is required for runnability, roll and doctor mounting and for ventilation. However, in the present invention, the open draw length can be independen ly adjusted by adjusting the horizontal and/or vertical space between the dryers adjacent to the transfer draw. Such draw is then set to the. minimum required for mounting a tail cutter. The aforementioned arrangement permits the draw length to be as short as possible. In the present invention, in the event of sheet breakage in the last BelRun dryer section, and if such a break occurs during a tail cutting operation, the tail cutting is unaffected. This is because the sheet is unable to snap back between the dryers and the felt to reach the tail cutter knife when there are more than one or two dryers following the knife. Therefore, it is a primar object of the present invention to provide an apparatus for cutting a tail from a web extending between a single tier dryer section to a further single tier dryer section. Other objects and advantages of the present invention will be apparent to those skilled in the art by a consideration of the detailed description contained hereinafter taken in conjunction with the annexed drawings and as defined by the appended claims. SUMMARY_OF_THE_INVENTION The present invention relates to an apparatus and method for cutting a tail from a web extending between a single tier dryer section to a further single tier dryer section. The apparatus includes a last dryer of the dryer section and a dryer felt which extends around the last dryer such that the web is disposed between the dryer felt and the last dryer for drying a first side of the web. A last felt roll is disposed downstream relative to the last dryer such that the felt extends around the last felt roll . A first dryer of the further dryer section is disposed downstream relative to the last dryer. A first felt roll is disposed between the last dryer and the first dryer and a further felt extends around the first felt roll and the first dryer such that the web extends in open draw between the last dryer and the first dryer and thereafter around the first dryer between the further felt and the first dryer for drying a second side of the web. A tail cutter is disposed adjacent to the open draw for cutting a tail in the web. More particularly, the last dryer is bottom felted and the last felt roll is a vacuum roll connected to a source of partial vacuum. The vacuum roll has a variable partial vacuum for removing boundary air from the first dryer and for controlling and stabilizing release of the web from the dryer fel . Furthermore, the first dryer is top felted and the first felt roll is a vacuum roll connected to a source of partial pressure for generating a variable partial vacuum for removing boundary air from the further felt and for inhibiting air currents in the vicinity of the web in the open dra . In an alternative embodiment of the present invention, the first felt roll is adjustable from a first position in which the tail cutting means is movable from an inoperative to an operative tail cutting disposition thereof, the first felt roll being movable to a second position for reducing the open dra . In either of the aforementioned embodiments, the tail cutting means includes alternately , a stationary single blade and an adjacent plate disposed parallel to the web in the open draw when in the operative disposition relative to the web or the tail cutting means includes a rotatable circular saw . In one embodiment of the present invention, the tail cutting means includes air nozzle means secured to the plate for generating a cushion of air between the plate and the web and for stabilizing the web relative to the plate. The tail cutting means in one embodiment is disposed on the first side of the web and in a further embodiment of the present invention the tail cutting means is disposed on the second side of the web. Many modi ications and variations of the present invention will be apparent to those skilled in the art by considera ion of the detailed description contained hereinafter. However, such variations and modific tions fall within the spirit and scope of the present invention as defined by the appended claims. £_ . I__I_£I ££IIII£N_£I_THE_DRAWINGS Figure 1 is a s ide - e 1e at i ona1 view of a Total BelRun dryer section similar to the arrangement disclosed in co-pending patent application 014,569 filed February 13, 1987 ; Figure 2 is an enlarged elevational view of the single tier dryer section and a further final single tier dryer section according to the present invention showing an open draw between the respective dryer sections and a circular saw-type tail cutter disposed in an operative tail cutting disposition adjacent to the open drawj Figure 3 is a s ide - e1evat iona1 view of a further embodiment of the present invention showing the tail cutter including a rotatable cutting saw in an inoperative disposition and a first felt roll in a first position; Figure 4 is a s ide - e1evat iona 1 view of the embodiment shown in figure 3 with the cutter in an operative disposition adjacent to the web; Figure 5 is a s id e - e 1 evat iona 1 view of the embodiment shown in figure 3. However, the first felt roll is shown in a second position thereof for reducing the open draw; Figure 6 is a s ide - e1evat iona1 view of another embodiment of the present invention in which the circular saw-type tail cutter is replaced by a single blade-type tail cutter; Figure 7 is an enlarged elevational view of the tail cutting means showing the blade and the plate; and Figure 8 is an enlarged s ide - e 1evat iona1 view of the tail cutter with the tail cutter disposed ' on the opposite side of the web. Similar reference characters refer to similar parts throughout the various embodiments of the present invention. £I__^ItI____lI_i£_-I-l_:I£ _£l__ S£_£5: uIE £ Figure 1 is a s id e- elev tiona1 view of a Total BelRun dryer section generally designated 10 similar to the type of dryer section disclosed in co-pending patent application 014,569 filed February 13, 1987. The dryer 10 includes dryer sections 12, 13, 14, 15 and 16. Of the dryer sections 12 to 16, dryer sections 12, 14 and 16 are top felted drying sections and dryer sections 13 and 15 are bottom felted. As shown in figure 1, a first side of the web is dried during passage of the web through dryer sections 12, 14 and 16 whereas a second side of the web is dried during movement of the web through dryer sections 13 and 15. Figure 2 is a s ide-elevational view of an apparatus generally designated 10A according to the present invention for cutting a tail from a web WA extending between a single tier dryei section generally designated 15A to a further single tier dryer section generally designated 16A. The apparatus 10A includes a last dryer 18 of the dryer section 15A. A dryer felt F extends around the last dryer 18 such that the web WA is disposed between the dryer felt F and the last dryer 18 for drying a second side 20 of the web WA. A last felt roll 22 is disposed downstream relative to the last dryer 18 such that the dryer felt F extends around the last felt roll 22. A first dryer 24 of the further dryer section 16A is disposed downstream relative to the last dryer 18. A first felt roll 26 is disposed between the last dryer 18 and the first dryer 24. A further felt FF extends around the first felt roll 26 and the first dryer 24 such that the web WA extends in open draw 28 between the last dryer 18 and the first dryer 24 and thereafter around the first dryer 24 between the further felt FF and the first dryer 24 for drying a first side 30 of the web W . A tail cutting means generally designated 32 is disposed adjacent to the open draw 28 for cutting a tail from the web WA. More specifically, the last dryer 18 is bottom felted as shown in figure 2 and the last felt roll is a vacuum roll and is connected to a source of partial vacuum P for generating a variable partial vacuum within the vacuum roll 22 for removing boundary air as indicated by the arrow 34 from the first dryer 24 and for controlling and stabilizing the release of the web WA from the dryer felt F. As shown in figure 2, the first dryer 24 is top felted and the first felt roll 26 is a vacuum roll which is connected to a source of partial pressure P for generating a variable partial vacuum within the first felt roll 26. Such variable partial vacuum removes boundary air as indicated by the arrow 36 from the further felt F and assists in inhibiting air currents as indicated by the arrow 38 in the vicinity of the web WA in the open draw 28. Figure 3 is a s ide -e 1evational view of an alternative embodiment of the present invention in which the first felt roll 26B of the apparatus 10B is adjustable from a first position as shown in figure 3 in which the tail cutting means 32B is movable from an inoperative disposition as shown in figure 3 to an operative disposition thereof shown in figure 4. The first felt roll 26B is movable to a second position as shown in figure 5 for reducing the open draw 28B when the cutting means 32B is the inoperative disposition. Figure 6 shows a further alternative embodiment of the present invention in which an apparatus IOC includes cutting means 32C having a stationary single blade 40 and a plate 42 disposed parallel to the web WC in the open draw 28C when the cutting means 32C is operatively disposed as shown in figure 6 relative to the web WC . Figure 7 is an enlarged elevational view of the open draw 28C and shows the tail cutting means 32C having an air nozzle means 44 secured to the plate 42 for generating a cushion of air indicated by the arrows 46 and 48 between the plate 42 and the web WC after stabilizing the web WC relative to the plate 42. In all of the embodiments shown in figures 2 to 7, the tail cutting means is disposed on the second side of the web. However, in an alternative arrangement shown in figure 8, the tail cutting means 32D is disposed on the first side 30D of the web WD . In operation of the apparatus according to the present invention, the tail cutting means is moved from an inoperative position to an operative position adjacent to the open draw of the web for cutting a tail in the web and thereafter moving in a cros s -mach ine direction for widening the tail to the full width of the web. Such tail cutting operation facilitates the threading of the further papermachine . In the embodiment shown in figures 3-5, when the tail cutting operation has been completed, the first felt roll 26B is moved towards the last dryer 18B for decreasing the open draw thereby increasing web stab lization. The present invention provides a simple means for the inclusion of a tail cutter in a Total BelRun configura ion while maintaining sheet restraint throughout the entire dryer section.

Claims: What is claimed is: 1. An apparatus for cutting a tail from a web extending from a single tier dryer section (15A) to a further single tier dryer section (16A), said apparatus comprising: a last dryer (18) of the dryer section (15A); a dryer felt (F) extending around said last dryer (18) such that the web (WA) is disposed between said dryer felt (F) and said last dryer (18) for drying a second side (20) of the web (WA); a last felt roll (22) disposed downstream relative to said last dryer (18) such that said felt (F) extends around said felt roll (22); a first dryer (24) of the further dryer section (16A), said first dryer (24) being disposed downstream relative to said last dryer (18); a first felt roll (26) disposed between said last dryer (18) and said first dryer (24); a further felt (FF) extending around said first felt roll (26) and said first dryer (24) such that the web (WA) extends in open draw (28) and thereafter around said first dryer (24) between said further felt (FF) and said first dryer (24) for drying a first side (30) of the web (WA); and tail cutter means (32) disposed adjacent to said open draw (28) for cutting the tail for assisting threading of the further dryer section (16A). 2. An apparatus as set forth in claim 1 wherein said last dryer (18) is bottom felted. 3. An apparatus as set forth in claim 1 wherein said last felt roll (22) is a vacuum roll, said vacuum roll being connected to a source of partial vacuum (P) such that a variable partial vacuum is generated within said last felt roll (22) for removing a boundary layer of air (34) following the surface of said first dryer (24), said variable partial vacuum also controlling and stabilizing the release of the web (WA) from said dryer felt (F). 4. An apparatus as set forth in claim 1 wherein said first dryer (24) is top felted. 5. An apparatus as set forth in claim 1 wherein said first felt roll (26) is a vacuum roll, said vacuum roll being connected to a source of partial vacuum (P) such that a variable partial vacuum is generated within said first felt roll (26) for removing a boundary layer of air (36) traveling with said further felt (FF), said variable partial vacuum inhibiting air currents (38) disposed in the vicinity of said open draw (28) from disturbing the web (WA) disposed in said open draw (28). 6. An apparatus as set forth in claim 5 wherein said first felt roll (26B) is adjustable such that in a first position thereof, said tail cutting means (32B) is movable from an inoperative to an operative tail cutting disposition thereof, said first felt roll (26B) being adjustable to a second position thereof for reducing said open draw (28B). 7. An apparatus as set forth in claim 1 wherein said tail cutting means (32G) includes: a stationary single blade (40); a plate (42) disposed adjacent to said blade (40), said plate (42) being disposed parallel to the web (WC) in said open draw (28C) when said tail cutting means (32G) is disposed in an operative disposition relative to the web (WC). 8. An apparatus as set forth in claim 7 wherein said tail cutting means (32C) further includes; air nozzle means (44) secured to said plate (42) for generating a cushion of air (46,48) between said plate (42) and the web (WC) for stabilizing the web (WC) relative to said plate (42). 9. An apparatus as set forth in claim 1 wherein said tail cutting means includes a rotatable circular saw. 10. An apparatus as set forth in claim 1 wherein said tail cutting means (32D) is disposed on said first side (30D) of the web (WD). 11. An apparatus as set forth in claim 1 wherein said tail cutting means (32,32B,32C) is disposed on said second side (20,20C) of the web (W,WB,WC). 12. A method for cutting a tail from a web extending from a single tier dryer section (15A) to a further single tier dryer section (16A), said method comprising the steps of: guiding a dryer felt (F) around a last dryer (18) of the dryer section (15A) such that the web (WA) is disposed between the dryer felt (F) and the last dryer (18) for drying a second side (20) of the web (WA); guiding the felt (F) around a last felt roll (22) disposed downstream relative to the last dryer (18); guiding a further felt (FF) around a first felt roll (26) and thereafter around a first dryer (24) of the further dryer section (16A); guiding the web (WA) in open draw (28) between the last dryer (18) and the first dryer (24) and thereafter around the first dryer (24) between the further felt (FF) and the first dryer (24) such that a second side (20) of the web (WA) is dried as the web (WA) extends around the last dryer (18) and a first side (30) of the web (WA) is dried when the web (WA) extends around the first dryer (24); and moving a tail cutter (32) to a position adjacent to the web (WA) in the open draw (28) for cutting the tail for assisting threading of the further dryer section (16A). 13. A method as set forth in claim 12 including the further step of: moving the first felt roll (26) towards the last dryer (18) when the tail cutting step is completed so that the open draw (28) of the web (WA) between the dryers (24,18) is reduced.

Inventors: WEDEL GREGORY L, WEDEL, GREGORY, L.
Applicants: BELOIT CORP, BELOIT CORPORATION
Application year: 1989
Main classification: D21G9
IPC codes: D21F5, D21F7, D21F9, D21G9