CA2046588C - A forming apparatus - Google Patents
A forming apparatusInfo
- Publication number
- CA2046588C CA2046588C CA002046588A CA2046588A CA2046588C CA 2046588 C CA2046588 C CA 2046588C CA 002046588 A CA002046588 A CA 002046588A CA 2046588 A CA2046588 A CA 2046588A CA 2046588 C CA2046588 C CA 2046588C
- Authority
- CA
- Canada
- Prior art keywords
- wire
- stock
- disposed
- endless loop
- water
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F1/00—Wet end of machines for making continuous webs of paper
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F9/00—Complete machines for making continuous webs of paper
- D21F9/003—Complete machines for making continuous webs of paper of the twin-wire type
Landscapes
- Paper (AREA)
- Containers And Plastic Fillers For Packaging (AREA)
- Replacement Of Web Rolls (AREA)
Abstract
A forming apparatus (10) is disclosed for forming a web (W) from stock (S) ejected through a slice lip (12) of a headbox (14). The apparatus (10) includes a first wire (16) which extends in an endless loop (18) past the slice lip (12) such that the stock (S) is ejected through the slice lip (12) onto the first wire (16). A second wire (20) extends in a further endless loop (22) with the second wire (20) cooperating with the first wire (16) for defining therebetween a forming section (24) having a first and a second end (26, 28) such that the web (W) is formed during passage of the stock (S) through the forming section (24). A first and a second turning bar (30, 32) are disposed respectively within the endless loop (18) and the further endless loop (22) adjacent to the first end (26) of the forming section (24) such that the slice lip (12) is disposed in close proximity to the first end (26) of the forming section (24). The apparatus (10) also includes a curved drainage device (34), a first slot (36), a box (38), a second slot (42) and a further curved drainage device (44). The curvature of the curved drainage device (34) and the box (38) is opposite to the curvature of the further curved drainage device (44) such that the stock (S) is progressively drained through both wires (16, 20) during pas-sage through the forming section (24) from the first (26) towards the second end (28) thereof.
Description
WO ~/09~ (1) PCT/US90/00213 ' 2 ~
PATENT APPLICATION
A FORMING APPARATUS FOR FORMING A WEB FROM STOCK
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
This invention relates to a forming apparatus for forming a web from stock. More particularly, the present invention relates to a forming apparatus for forming a web from stock ejected through a slice lip of a headbox into a forming section defined between a first and a second wire.
INFORMATION DISCLOSURE STATEMENT
In some of the earlier paper-forming machines, a headbox was disposed at the upstream end of a moving fourdrinier wire and stock was ejected from the slice lip of the headbox onto the forming wire such that water drained through the wire leaving a formed web on the top surface of the wire.
Subse~uent proposals included the provision of a top wire disposed downstream relative to the headbox such that water was drained from the stock not only downwardly through the fourdrinier wire but also upwardly through the top wire thereby improving the two-sidedness of the resultant web.
With the aforementioned twin-wire formers, certain problems existed in that the web was already partially formed prior to extending through the twin-wire formation section. Furthermore, the top surface of the stock supported on the fourdrinier wire was subjected to vibration which caused nonuniform characteristics to the upper surface of the resultant web.
More recently, proposals have been made particularly in US Patent No. 4,830,709 in which the headbox is disposed ;mm~; ately adjacent to the upstream end of the forming section defined between cooperating twin wires. Such true WO90/09~1 (2) PCT/US90/00213 ~ h5~ ~n gap formers ave improved the two-sidedness of the resul t web because the slice lip ejects stock almost immediately between the gap formed between the cooperating forming wires.
However, although the aforementioned gap formers have proved very successful in the formation of lightweight grades such as newsprint, problems have been experienced using such forming apparatus for forming heavier grades.
In the formation of heavier grades, the speed of the former is considerably less than the speed of the former when forming lightweight grades because more time is required in draining the water from the larger quantity of stock used in the production of heavier grade webs.
Because of the lower wire speed and the correspondingly slower rate of ejection of stock through the slice lip, it is essential that the slice lip be disposed as close as possible to the upstream end of the forming section. If the headbox is disposed at a relatively considerable distance from the upstream end of the forming section, there exists a tendency for the trajectory of the jet of stock to be excessively curved and the angle of impingement of the stock relative to the lower wire to be increased to an unacceptable angle.
Ideally, the impingement angle relative to the lower wire should be as small as possible so that as the jet impinges on the wire, m;n;mum disturbance to the stock occurs and the stock impinges on the lower wire at a speed which is the same as that of the lower wire.
The present invention attains the aforementioned objective by substituting turning bars for the breast rolls disclosed in the aforementioned proposal as taught in US
Patent No. 4,830,709.
WO ~/09~1 (3) ~ 20465~8 Therefore, it is a primary object of the present invention to provide a high capacity forming apparatus which overcomes the aforementioned inade~uacies of the prior art proposals and which provides a significant contribution to the art of forming a web from stock.
Another object of the present invention is the provision of a twin-wire forming apparatus including a first and a second turning bar which permit the headbox slice lip to be disposed in close proximity to the first or upstream end of the forming section defined by the wires.
Another object of the present invention is the provision of a forming apparatus which includes at least two auto slices with means for adjusting the vacuum slots of the auto slices relative to the second wire for varying the amount of water removed from the second wire.
Another object of the present invention is the prov:ision of a forming apparatus in which the forming sect:ion is disposed substantially horizontally.
Another object of the present invention is the provision of a forming apparatus in which the forming section follows a generally sinusoidal path from the first to the second end thereof.
Another object of the present invention is the provlsion of a vacuum box disposed between the first and the second vacuum slots and on the opposite side of the wires relal:ive to the vacuum slots, the vacuum box having a curved surface which permits removal of water downwardly through the first wire and upward removal of water centrifugally throllgh the second wire.
Another object of the present invention is the prov~sion of a forming apparatus which includes at least one further vacuum slot disposed between the first and the WO90/09~1 (4) PCT/US90/00213 - 20~65~8 ~
second vac~ for upward removal of water through the second wire.
Other objects and advantages of the present invention will be apparent from a consideration of the detailed description of various embodiments of the invention as described hereinafter and as shown in the annexed drawings.
SUMMARY OF THE INVENTION
The present invention relates to a forming apparatus and method for forming a web from stock. More particularly, the present invention relates to a forming apparatus and method for forming a web from stock ejected through a slice lip of a headbox. The apparatus includes a first wire which extends in an endless loop past the slice lip such that the stock is ejected through the slice lip onto the first wire.
A second wire extends in a further endless loop with the second wire cooperating with the first wire for defining therebetween a forming section having a first and a second end such that the web is formed during passage of the stock through the forming section. A first turning bar is disposed within the endless loop and adjacent to the first end of the forming section such that the first wire is sandwiched between the stock and the first turning bar. A
second turning bar is disposed within the further endless loop and adjacent to the first end of the forming section such that the stock is disposed between the wires, the wires being disposed between the turning bars permitting the slice lip to be disposed in close proximity to the first end of the forming section. A curved drainage means is disposed within the endless loop immediately downstream relative to the first turning bar for removing a first portion of water from the stock through the first wire and for removing a second portion of water centrifugally through the second wire during passage of the stock through the forming section and past the curved draining means. A first vacuum slot is disposed within the further endless loop and extends in a cross-machine direction ; mmeA; ately downstream relative to the curved drainage means for removing a third portion of WO ~/09~1 (5) 20~65~8 ~ ~ ~
water from the stock through the second wlre. A vacuum box is disposed within the endless loop ;mme~;ately downstream relative to the vacuum slot with the vacuum box defining a curved surface for removing a fourth portion of water from the stock through the first wire. A second vacuum slot is disposed within the further endless loop and extends in a cross-machine direction downstream relative to the vacuum box for removing further water from the stock through the second wire. Additionally, a further curved drainage means is disposed within the further endless loop and immediately downstream relative to the second vacuum slot for removing water from the stock through the second wire. The curvature of the curved drainage means and the vacuum box is opposite to the curvature of the further curved drainage means such that the stock is progressively drained through both wires during passage through the forming section from the first towards the second end thereof.
More specifically, the first wire is disposed relative to the slice lip such that the stock impinges on the first wire before contacting the second wire.
In a preferred embodiment of the present invention, the forming section is disposed substantially horizontally and the forming section follows a generally sinusoidal path.
In one embodiment of the present invention, the turning bars are of ceramic material and the curved drainage means also includes a plurality of drainage slots which are connected to a source of partial vacuum.
The curved drainage ~e~n~ defines a face having a radius of curvature which is greater than the radius of curvature of the curved surface of the vacuum box.
In the preferred embodiment of the present invention, the first vacuum slot is a first auto slice which includes adjusting means for adjusting the vertical and/or the angular position of the first vacuum slot relative to the wo go/og~l 2 0 ~ 6 ~ 8 ~ ( 6) PCT/US90/00213 second wire. The adjusting means also permits movement o~
the first vacuum slot between the curved drainage means and the vacuum box.
In one embodiment of the present invention, the curved surface of the vacuum box permits centrifugal removal of a fifth portion of water from the stock through the second wire.
In another embodiment of the present invention, the forming apparatus includes an adjustable foil which is disposed within the endless loop between the vacuum box and the second vacuum slot for assisting removal of further water through the second vacuum slot.
In an alternative embodiment to the present invention, the forming apparatus also includes a further vacuum slot which is disposed within the further endless loop and disposed between the first and second vacuum slots for removing water from the stock through the second wire.
In another embodiment of the present invention, the second vacuum slot is a second auto slice which includes further adjusting means for adjusting the second vacuum slot relative to the second wire for sk;mm; ng the further water removed from the stock through the second wire.
In the preferred embodiment of the present invention, the further curved drainage means also includes a plurality of cross-machine direction shoes defining therebetween a plurality of openings connected to a source of partial vacuum for removing water from the stock through the second wire.
The present invention also includes a method of forming a web from stock ejected through a slice lip of a headbox.
The method comprises the steps of moving a first wire, which extends in an endless loop, past the slice lip and then ejecting the stock through the slice lip onto the first WO ~/09~1 (7) 20465~8 wire. The arrangement is such that the stock contacts the firt;t wire at a m;nim~l angle of impingement due to the first wire extending around a first turning bar disposed adjacent to the point of impingement of the stock onto the first wire.
Additionally, the method includes the step of moving a second wire, which extends in a further endless loop, around a second turning bar such that the second turning bar is disposed adjacent to the first turning bar so that the slice lip is disposed in close proximity to a first end of the forming section defined between the wires.
Also, the method includes the step of forming the web from the stock during passage of the stock through the forming section by progressively removing water from the stoc:k through both wires.
More specifically, the step of forming the web from stock during passage of the stock through the forming section includes removing a portion of water from the stock through a curved vacuum box disposed downstream and on the opposite side of the wires relative to a vacuum slot.
Although specific embodiments of the present invention are described hereinafter in the detailed description and are shown in the annexed drawings, it will be apparent to those skilled in the art that many variations and modifications of the present invention may be made without departing from the spirit and scope of the present invention as defined by the appended claims.
Included among such modifications and variants would be the provision of a gap former having a forming section disposed substantially vertically.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a side-elevational view of a forming apparatus according to the present invention;
WO90/09~1 - (8) PCT/US90/00213 5~ ~
Figure 2 is an enlarged fragmentary view of the drainage means;
Figure 3 is an enlarged fragmentary view of the curved inverted vacuum box; and Figure 4 is a side-elevational view of an alternative embodiment of the present invention showing a further vacuum slot disposed between the first and the second vacuum slots.
Similar reference characters refer to similar parts throughout the various embodiments of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
Figure 1 is a side-elevational view of a forming apparatus generally designated 10 according to a preferred embodiment of the present invention.
The forming apparatus 10 forms a web W from stock S
ejected through a slice lip 12 of a headbox generally designated 14.
The apparatus 10 includes a first wire 16 which extends in an endless loop generally designated 18 past the slice lip 12 such that the stock S is ejected through the slice lip 12 onto the first wire 16.
A second wire 20 extends in a further endless loop generally designated 22. The second wire 20 cooperates with the first wire 16 for defining therebetween a forming section generally designated 24 having a first and a second end 26 and 28, respectively, such that the web W is formed during passage of the stock S through the forming section 24.
A first turning bar 30 is disposed within the endless loop 18 and adjacent to the first end 26 of the forming WO 90/09~1 ( 9 ~ 8 ~PCT/US90/00213 sect.ion 24 such that the first wire 16 is sandwiched between the stock S and the first turning bar 30.
A second turning bar 32 is disposed within the further endless loop 22 and adjacent to the first end 26 of the forming section 24 such that the stock S is disposed between the wires 16 and 20. The wires 16 and 20 respectively are disposed between the turning bars 30 and 32 respectively thereby permitting the slice lip 12 to be disposed in close proximity to the first end 26 of the forming section 24.
A curved drainage means generally designated 34 is disposed within the endless loop 18 immediately downstream relative to the first turning bar 30. The drainage means 34 removes a first portion of water from the stock S through the first wire 16 and removes a second portion of water centrifugally through the second wire 20 during passage of the stock S through the forming section 24 and past the curved drainage means 34.
A first vacuum slot generally designated 36 is disposed within the further endless loop 22 and extends in a cross-machine direction immediately downstream relative to the curved drainage means 34 for removing a third portion of water from the stock S through the second wire 20.
A vacuum box 38 is disposed within the endless loop 18 immediately downstream relative to the vacuum slot 36. The vacuum box 38 defines a curved surface 40 for removing a fourth portion of water from the stock S through the first wire 16 and removes another portion of water centrifugally through the second wire 20 during passage of the stock S
through the forming section.
A second vacuum slot generally designated 42 is disposed within the further endless loop 22 and extends in a cros.s-machine direction downstream relative to the vacuum box 38 for removing further water from the stock S through the second wire 20.
WO90/09~1 ~ (10) PCT/US90/00213 A further curved drainage means generally designated 44 is disposed within the further endless loop and immediately downstream relative to the second vacuum slot 42 for removing water from the stock S through the second wire 20.
The curvature of the curved drainage means 34 and the vacuum box 38 are opposite to the curvature of the further curved drainage means 44 such that the stock S is progressively drained through both wires 16 and 20 respectively during passage through the forming section 24 from the first end 26 towards the second end 28 thereof.
More specifically, as shown in figure 1, the forming apparatus 10 is arranged such that the first wire 16 is disposed relative to the slice lip 12 so that the stock S
impinges on the first wire 16 before contacting the second wire 22.
As shown in figure 1, the forming section 10 is disposed substantially horizontally and the forming section 24 follows a generally sinusoidal path.
In one embodiment of the present invention, the turning bars 30 and 32 are of ceramic material. Figure 2 is an enlarged fragmentary view of the drainage means 34 in which the curved drainage means 34 further includes a plurality of support foils 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62 and 63 which define therebetween a plurality of drainage slots 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80 and 81.
The plurality of drainage slots 64 to 81 are connected to a source of partial vacuum 82.
The curved drainage means 34 defines a face 84 having a radius of curvature which is greater than the radius of curvature of the curved surface 40 of the vacuum box 38.
~4~58~
WO ~/09~1 (11) PCT/US90/00213 -~ As shown in figure 2, the first vacuum slot 36 is a first auto slice 86 which includes adjusting means 88 for adjusting the angular and vertical position of the first vacuum slot 36 relative to the second wire 20.
Additionally, the adjusting means 88 permits movement of the first vacuum slot 36 between the curved drainage means 34 and the vacuum box 38.
The curved surface 40 of the vacuum box 38 also permits cent:rifugal removal of a fifth portion of water from the stock S through the second wire 20.
Figure 3 is an enlarged fragmentary view showing the further curved drainage means or curved inverted vacuum boxes 44. As shown in figure 3, the forming apparatus 10 also includes an adjustable vacuum foil 90 which is disposed within the endless loop 18 between the vacuum box 38 and the second vacuum slot 42 for assisting removal of the further water through the second vacuum slot 42.
Figure 3 also shows the second vacuum slot 42 as a second auto slice 92 with the second auto slice 92 further including further adjusting means 94 for adjusting the second vacuum slot 42 relative to the second wire 20 for sk; mm; ng the further water removed from the stock S through the second wire 20.
Figure 3 shows the further curved drainage means 44 as incl.uding a plurality of cross-machine direction shoes 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113 and 114 which define therebetween a plurality of openings 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131 and 132 connected to a source of partial vacuum (not shown) for removing water from the stock through the second wire 20.
In an alternative embodiment to the present invention as shown in figure 4, a forming apparatus generally WO90/09~1 ~ (12) PCT/US90/00213 5~ ~
designated lOA further includes a further vacuum slot 13 which is disposed wïthin a further endless loop 18A and disposed between the first and the second vacuum slots 36A
and 42A respectively for removing water from the stock through the second wire 2OA.
In operation of the apparatus according to the preferred embodiment of the present invention, high consistency stock S is ejected from the headbox 14 through the slice lip 12 such that the angle of impingement of the jet of stock relative to the first wire 16 is very small.
Furthermore, the slice lip 12 is able to be disposed in very close proximity to the first end 26 of the forming section 24 due to the provision of the turning bars 30 and 32 respectively. Therefore, according to the present invention, when ejecting high consistency stock at relatively low machine speeds, the stock is deposited on the lower wire 16 with mi n; m~ 1 disturbance of the stock.
Subsequently, a first portion of water is removed downwardly through the curved drainage means 34 and a second portion of water is removed upwardly through the second wire 20 due to the centrifugal force applied to the stock during passage of the stock through the forming section 24 around the curved drainage means 34.
Thereafter, a third portion of water is removed by means of the first vacuum slot 36, and a fourth portion of water is removed downwardly through the vacuum box 38.
The vacuum box 38 having a curved surface 40 results in a fifth portion of water being removed upwardly through the second wire 20. The first wire 16 then passes over the foil 90 which assists the removal of a further portion of water through the second vacuum slot 42.
The wires then proceed to extend around at least one curved inverted vacuum box or further curved drainage means 44 for removing water through the second wire 20.
WO90/09~1 (13) ,PCT/US90/00213 ~ . . . ?
20465~8 The curved drainage means 34 and vacuum box 38 have a radius of curvature which is opposite to the radius of curvature of the further curved drainage means 44 so that the forming section 24 follows a generally sinusoidal configuration from the first end 26 to the second end 28 of the forming section 24.
The operation of the apparatus shown in figure 4 is similar to the operation of the apparatus shown in figures 1-3 except in that a further auto slice 134 is used for assisting withdrawal of water upwardly through the wire 20A.
The aforementioned arrangement not only permits prog~essive drainage through both wires during passage through the forming section but also permits the high consistency stock to be ejected into the forming section with a m;n;mum trajectory thereby improving formation and the two-sidedness of the resultant web.
PATENT APPLICATION
A FORMING APPARATUS FOR FORMING A WEB FROM STOCK
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
This invention relates to a forming apparatus for forming a web from stock. More particularly, the present invention relates to a forming apparatus for forming a web from stock ejected through a slice lip of a headbox into a forming section defined between a first and a second wire.
INFORMATION DISCLOSURE STATEMENT
In some of the earlier paper-forming machines, a headbox was disposed at the upstream end of a moving fourdrinier wire and stock was ejected from the slice lip of the headbox onto the forming wire such that water drained through the wire leaving a formed web on the top surface of the wire.
Subse~uent proposals included the provision of a top wire disposed downstream relative to the headbox such that water was drained from the stock not only downwardly through the fourdrinier wire but also upwardly through the top wire thereby improving the two-sidedness of the resultant web.
With the aforementioned twin-wire formers, certain problems existed in that the web was already partially formed prior to extending through the twin-wire formation section. Furthermore, the top surface of the stock supported on the fourdrinier wire was subjected to vibration which caused nonuniform characteristics to the upper surface of the resultant web.
More recently, proposals have been made particularly in US Patent No. 4,830,709 in which the headbox is disposed ;mm~; ately adjacent to the upstream end of the forming section defined between cooperating twin wires. Such true WO90/09~1 (2) PCT/US90/00213 ~ h5~ ~n gap formers ave improved the two-sidedness of the resul t web because the slice lip ejects stock almost immediately between the gap formed between the cooperating forming wires.
However, although the aforementioned gap formers have proved very successful in the formation of lightweight grades such as newsprint, problems have been experienced using such forming apparatus for forming heavier grades.
In the formation of heavier grades, the speed of the former is considerably less than the speed of the former when forming lightweight grades because more time is required in draining the water from the larger quantity of stock used in the production of heavier grade webs.
Because of the lower wire speed and the correspondingly slower rate of ejection of stock through the slice lip, it is essential that the slice lip be disposed as close as possible to the upstream end of the forming section. If the headbox is disposed at a relatively considerable distance from the upstream end of the forming section, there exists a tendency for the trajectory of the jet of stock to be excessively curved and the angle of impingement of the stock relative to the lower wire to be increased to an unacceptable angle.
Ideally, the impingement angle relative to the lower wire should be as small as possible so that as the jet impinges on the wire, m;n;mum disturbance to the stock occurs and the stock impinges on the lower wire at a speed which is the same as that of the lower wire.
The present invention attains the aforementioned objective by substituting turning bars for the breast rolls disclosed in the aforementioned proposal as taught in US
Patent No. 4,830,709.
WO ~/09~1 (3) ~ 20465~8 Therefore, it is a primary object of the present invention to provide a high capacity forming apparatus which overcomes the aforementioned inade~uacies of the prior art proposals and which provides a significant contribution to the art of forming a web from stock.
Another object of the present invention is the provision of a twin-wire forming apparatus including a first and a second turning bar which permit the headbox slice lip to be disposed in close proximity to the first or upstream end of the forming section defined by the wires.
Another object of the present invention is the provision of a forming apparatus which includes at least two auto slices with means for adjusting the vacuum slots of the auto slices relative to the second wire for varying the amount of water removed from the second wire.
Another object of the present invention is the prov:ision of a forming apparatus in which the forming sect:ion is disposed substantially horizontally.
Another object of the present invention is the provision of a forming apparatus in which the forming section follows a generally sinusoidal path from the first to the second end thereof.
Another object of the present invention is the provlsion of a vacuum box disposed between the first and the second vacuum slots and on the opposite side of the wires relal:ive to the vacuum slots, the vacuum box having a curved surface which permits removal of water downwardly through the first wire and upward removal of water centrifugally throllgh the second wire.
Another object of the present invention is the prov~sion of a forming apparatus which includes at least one further vacuum slot disposed between the first and the WO90/09~1 (4) PCT/US90/00213 - 20~65~8 ~
second vac~ for upward removal of water through the second wire.
Other objects and advantages of the present invention will be apparent from a consideration of the detailed description of various embodiments of the invention as described hereinafter and as shown in the annexed drawings.
SUMMARY OF THE INVENTION
The present invention relates to a forming apparatus and method for forming a web from stock. More particularly, the present invention relates to a forming apparatus and method for forming a web from stock ejected through a slice lip of a headbox. The apparatus includes a first wire which extends in an endless loop past the slice lip such that the stock is ejected through the slice lip onto the first wire.
A second wire extends in a further endless loop with the second wire cooperating with the first wire for defining therebetween a forming section having a first and a second end such that the web is formed during passage of the stock through the forming section. A first turning bar is disposed within the endless loop and adjacent to the first end of the forming section such that the first wire is sandwiched between the stock and the first turning bar. A
second turning bar is disposed within the further endless loop and adjacent to the first end of the forming section such that the stock is disposed between the wires, the wires being disposed between the turning bars permitting the slice lip to be disposed in close proximity to the first end of the forming section. A curved drainage means is disposed within the endless loop immediately downstream relative to the first turning bar for removing a first portion of water from the stock through the first wire and for removing a second portion of water centrifugally through the second wire during passage of the stock through the forming section and past the curved draining means. A first vacuum slot is disposed within the further endless loop and extends in a cross-machine direction ; mmeA; ately downstream relative to the curved drainage means for removing a third portion of WO ~/09~1 (5) 20~65~8 ~ ~ ~
water from the stock through the second wlre. A vacuum box is disposed within the endless loop ;mme~;ately downstream relative to the vacuum slot with the vacuum box defining a curved surface for removing a fourth portion of water from the stock through the first wire. A second vacuum slot is disposed within the further endless loop and extends in a cross-machine direction downstream relative to the vacuum box for removing further water from the stock through the second wire. Additionally, a further curved drainage means is disposed within the further endless loop and immediately downstream relative to the second vacuum slot for removing water from the stock through the second wire. The curvature of the curved drainage means and the vacuum box is opposite to the curvature of the further curved drainage means such that the stock is progressively drained through both wires during passage through the forming section from the first towards the second end thereof.
More specifically, the first wire is disposed relative to the slice lip such that the stock impinges on the first wire before contacting the second wire.
In a preferred embodiment of the present invention, the forming section is disposed substantially horizontally and the forming section follows a generally sinusoidal path.
In one embodiment of the present invention, the turning bars are of ceramic material and the curved drainage means also includes a plurality of drainage slots which are connected to a source of partial vacuum.
The curved drainage ~e~n~ defines a face having a radius of curvature which is greater than the radius of curvature of the curved surface of the vacuum box.
In the preferred embodiment of the present invention, the first vacuum slot is a first auto slice which includes adjusting means for adjusting the vertical and/or the angular position of the first vacuum slot relative to the wo go/og~l 2 0 ~ 6 ~ 8 ~ ( 6) PCT/US90/00213 second wire. The adjusting means also permits movement o~
the first vacuum slot between the curved drainage means and the vacuum box.
In one embodiment of the present invention, the curved surface of the vacuum box permits centrifugal removal of a fifth portion of water from the stock through the second wire.
In another embodiment of the present invention, the forming apparatus includes an adjustable foil which is disposed within the endless loop between the vacuum box and the second vacuum slot for assisting removal of further water through the second vacuum slot.
In an alternative embodiment to the present invention, the forming apparatus also includes a further vacuum slot which is disposed within the further endless loop and disposed between the first and second vacuum slots for removing water from the stock through the second wire.
In another embodiment of the present invention, the second vacuum slot is a second auto slice which includes further adjusting means for adjusting the second vacuum slot relative to the second wire for sk;mm; ng the further water removed from the stock through the second wire.
In the preferred embodiment of the present invention, the further curved drainage means also includes a plurality of cross-machine direction shoes defining therebetween a plurality of openings connected to a source of partial vacuum for removing water from the stock through the second wire.
The present invention also includes a method of forming a web from stock ejected through a slice lip of a headbox.
The method comprises the steps of moving a first wire, which extends in an endless loop, past the slice lip and then ejecting the stock through the slice lip onto the first WO ~/09~1 (7) 20465~8 wire. The arrangement is such that the stock contacts the firt;t wire at a m;nim~l angle of impingement due to the first wire extending around a first turning bar disposed adjacent to the point of impingement of the stock onto the first wire.
Additionally, the method includes the step of moving a second wire, which extends in a further endless loop, around a second turning bar such that the second turning bar is disposed adjacent to the first turning bar so that the slice lip is disposed in close proximity to a first end of the forming section defined between the wires.
Also, the method includes the step of forming the web from the stock during passage of the stock through the forming section by progressively removing water from the stoc:k through both wires.
More specifically, the step of forming the web from stock during passage of the stock through the forming section includes removing a portion of water from the stock through a curved vacuum box disposed downstream and on the opposite side of the wires relative to a vacuum slot.
Although specific embodiments of the present invention are described hereinafter in the detailed description and are shown in the annexed drawings, it will be apparent to those skilled in the art that many variations and modifications of the present invention may be made without departing from the spirit and scope of the present invention as defined by the appended claims.
Included among such modifications and variants would be the provision of a gap former having a forming section disposed substantially vertically.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a side-elevational view of a forming apparatus according to the present invention;
WO90/09~1 - (8) PCT/US90/00213 5~ ~
Figure 2 is an enlarged fragmentary view of the drainage means;
Figure 3 is an enlarged fragmentary view of the curved inverted vacuum box; and Figure 4 is a side-elevational view of an alternative embodiment of the present invention showing a further vacuum slot disposed between the first and the second vacuum slots.
Similar reference characters refer to similar parts throughout the various embodiments of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
Figure 1 is a side-elevational view of a forming apparatus generally designated 10 according to a preferred embodiment of the present invention.
The forming apparatus 10 forms a web W from stock S
ejected through a slice lip 12 of a headbox generally designated 14.
The apparatus 10 includes a first wire 16 which extends in an endless loop generally designated 18 past the slice lip 12 such that the stock S is ejected through the slice lip 12 onto the first wire 16.
A second wire 20 extends in a further endless loop generally designated 22. The second wire 20 cooperates with the first wire 16 for defining therebetween a forming section generally designated 24 having a first and a second end 26 and 28, respectively, such that the web W is formed during passage of the stock S through the forming section 24.
A first turning bar 30 is disposed within the endless loop 18 and adjacent to the first end 26 of the forming WO 90/09~1 ( 9 ~ 8 ~PCT/US90/00213 sect.ion 24 such that the first wire 16 is sandwiched between the stock S and the first turning bar 30.
A second turning bar 32 is disposed within the further endless loop 22 and adjacent to the first end 26 of the forming section 24 such that the stock S is disposed between the wires 16 and 20. The wires 16 and 20 respectively are disposed between the turning bars 30 and 32 respectively thereby permitting the slice lip 12 to be disposed in close proximity to the first end 26 of the forming section 24.
A curved drainage means generally designated 34 is disposed within the endless loop 18 immediately downstream relative to the first turning bar 30. The drainage means 34 removes a first portion of water from the stock S through the first wire 16 and removes a second portion of water centrifugally through the second wire 20 during passage of the stock S through the forming section 24 and past the curved drainage means 34.
A first vacuum slot generally designated 36 is disposed within the further endless loop 22 and extends in a cross-machine direction immediately downstream relative to the curved drainage means 34 for removing a third portion of water from the stock S through the second wire 20.
A vacuum box 38 is disposed within the endless loop 18 immediately downstream relative to the vacuum slot 36. The vacuum box 38 defines a curved surface 40 for removing a fourth portion of water from the stock S through the first wire 16 and removes another portion of water centrifugally through the second wire 20 during passage of the stock S
through the forming section.
A second vacuum slot generally designated 42 is disposed within the further endless loop 22 and extends in a cros.s-machine direction downstream relative to the vacuum box 38 for removing further water from the stock S through the second wire 20.
WO90/09~1 ~ (10) PCT/US90/00213 A further curved drainage means generally designated 44 is disposed within the further endless loop and immediately downstream relative to the second vacuum slot 42 for removing water from the stock S through the second wire 20.
The curvature of the curved drainage means 34 and the vacuum box 38 are opposite to the curvature of the further curved drainage means 44 such that the stock S is progressively drained through both wires 16 and 20 respectively during passage through the forming section 24 from the first end 26 towards the second end 28 thereof.
More specifically, as shown in figure 1, the forming apparatus 10 is arranged such that the first wire 16 is disposed relative to the slice lip 12 so that the stock S
impinges on the first wire 16 before contacting the second wire 22.
As shown in figure 1, the forming section 10 is disposed substantially horizontally and the forming section 24 follows a generally sinusoidal path.
In one embodiment of the present invention, the turning bars 30 and 32 are of ceramic material. Figure 2 is an enlarged fragmentary view of the drainage means 34 in which the curved drainage means 34 further includes a plurality of support foils 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62 and 63 which define therebetween a plurality of drainage slots 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80 and 81.
The plurality of drainage slots 64 to 81 are connected to a source of partial vacuum 82.
The curved drainage means 34 defines a face 84 having a radius of curvature which is greater than the radius of curvature of the curved surface 40 of the vacuum box 38.
~4~58~
WO ~/09~1 (11) PCT/US90/00213 -~ As shown in figure 2, the first vacuum slot 36 is a first auto slice 86 which includes adjusting means 88 for adjusting the angular and vertical position of the first vacuum slot 36 relative to the second wire 20.
Additionally, the adjusting means 88 permits movement of the first vacuum slot 36 between the curved drainage means 34 and the vacuum box 38.
The curved surface 40 of the vacuum box 38 also permits cent:rifugal removal of a fifth portion of water from the stock S through the second wire 20.
Figure 3 is an enlarged fragmentary view showing the further curved drainage means or curved inverted vacuum boxes 44. As shown in figure 3, the forming apparatus 10 also includes an adjustable vacuum foil 90 which is disposed within the endless loop 18 between the vacuum box 38 and the second vacuum slot 42 for assisting removal of the further water through the second vacuum slot 42.
Figure 3 also shows the second vacuum slot 42 as a second auto slice 92 with the second auto slice 92 further including further adjusting means 94 for adjusting the second vacuum slot 42 relative to the second wire 20 for sk; mm; ng the further water removed from the stock S through the second wire 20.
Figure 3 shows the further curved drainage means 44 as incl.uding a plurality of cross-machine direction shoes 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113 and 114 which define therebetween a plurality of openings 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131 and 132 connected to a source of partial vacuum (not shown) for removing water from the stock through the second wire 20.
In an alternative embodiment to the present invention as shown in figure 4, a forming apparatus generally WO90/09~1 ~ (12) PCT/US90/00213 5~ ~
designated lOA further includes a further vacuum slot 13 which is disposed wïthin a further endless loop 18A and disposed between the first and the second vacuum slots 36A
and 42A respectively for removing water from the stock through the second wire 2OA.
In operation of the apparatus according to the preferred embodiment of the present invention, high consistency stock S is ejected from the headbox 14 through the slice lip 12 such that the angle of impingement of the jet of stock relative to the first wire 16 is very small.
Furthermore, the slice lip 12 is able to be disposed in very close proximity to the first end 26 of the forming section 24 due to the provision of the turning bars 30 and 32 respectively. Therefore, according to the present invention, when ejecting high consistency stock at relatively low machine speeds, the stock is deposited on the lower wire 16 with mi n; m~ 1 disturbance of the stock.
Subsequently, a first portion of water is removed downwardly through the curved drainage means 34 and a second portion of water is removed upwardly through the second wire 20 due to the centrifugal force applied to the stock during passage of the stock through the forming section 24 around the curved drainage means 34.
Thereafter, a third portion of water is removed by means of the first vacuum slot 36, and a fourth portion of water is removed downwardly through the vacuum box 38.
The vacuum box 38 having a curved surface 40 results in a fifth portion of water being removed upwardly through the second wire 20. The first wire 16 then passes over the foil 90 which assists the removal of a further portion of water through the second vacuum slot 42.
The wires then proceed to extend around at least one curved inverted vacuum box or further curved drainage means 44 for removing water through the second wire 20.
WO90/09~1 (13) ,PCT/US90/00213 ~ . . . ?
20465~8 The curved drainage means 34 and vacuum box 38 have a radius of curvature which is opposite to the radius of curvature of the further curved drainage means 44 so that the forming section 24 follows a generally sinusoidal configuration from the first end 26 to the second end 28 of the forming section 24.
The operation of the apparatus shown in figure 4 is similar to the operation of the apparatus shown in figures 1-3 except in that a further auto slice 134 is used for assisting withdrawal of water upwardly through the wire 20A.
The aforementioned arrangement not only permits prog~essive drainage through both wires during passage through the forming section but also permits the high consistency stock to be ejected into the forming section with a m;n;mum trajectory thereby improving formation and the two-sidedness of the resultant web.
Claims (18)
1. A forming apparatus (10) for forming a web (W) from stock (S) ejected through a slice lip (12) of a headbox (14), said apparatus comprising:
a first wire (16) extending in an endless loop (18) past the slice lip (12) such that the stock (S) is ejected through the slice lip (12) onto said first wire (16);
a second wire (20) extending in a further endless loop (22), said second wire (20) cooperating with said first wire (16) for defining therebetween a forming section (24) having a first and a second end (26,28) such that the web (W) is formed during passage of the stock (S) through said forming section (24);
a first turning bar (30) disposed within said endless loop (18) and adjacent to said first end (26) of said forming section (24) such that said first wire (16) is sandwiched between the stock (S) and said first turning bar (30);
a second turning bar (32) disposed within said further endless loop (22) and adjacent to said first end (26) of said forming section (24) such that the stock (S) is disposed between said wires (16,20), said wires (16,20) being disposed between said turning bars (30,32) permitting the slice lip (12) to be disposed in close proximity to said first end (26) of said forming section (24);
a curved drainage means (34) disposed within said endless loop (18) immediately downstream relative to said first turning bar (30) for removing a first portion of water from the stock (S) through said first wire (16) and for removing a second portion of water centrifugally through said second wire (20) during passage of the stock (S) through said forming section (24) and past said curved drainage means (34);
(15) a first slot (36) disposed within said further endless loop (22) and extending in a cross-machine direction immediately downstream relative to said curved drainage means (34) for removing a third portion of water from the stock (S) through said second wire (20);
a box (38) disposed within said endless loop (18) immediately downstream relative to said slot (36), said box (38) defining a curved surface (40) for removing a fourth portion of water from the stock (S) through said first wire (16);
a second slot (42) disposed within said further endless loop (22) and extending in a cross-machine direction downstream relative to said box (38) for removing further water from the stock (S) through said second wire (20); and a further curved drainage means (44) disposed within said further endless loop (22) and immediately downstream relative to said second slot (42), for removing water from the stock (S) through said second wire (20), said curvature of said curved drainage means (34) and said box (38) being opposite to the curvature of said further curved drainage means (44) such that the stock (S) is progressively drained through both wires (16,20) during passage through said forming section (24) from said first (26) towards said second end (28) thereof.
a first wire (16) extending in an endless loop (18) past the slice lip (12) such that the stock (S) is ejected through the slice lip (12) onto said first wire (16);
a second wire (20) extending in a further endless loop (22), said second wire (20) cooperating with said first wire (16) for defining therebetween a forming section (24) having a first and a second end (26,28) such that the web (W) is formed during passage of the stock (S) through said forming section (24);
a first turning bar (30) disposed within said endless loop (18) and adjacent to said first end (26) of said forming section (24) such that said first wire (16) is sandwiched between the stock (S) and said first turning bar (30);
a second turning bar (32) disposed within said further endless loop (22) and adjacent to said first end (26) of said forming section (24) such that the stock (S) is disposed between said wires (16,20), said wires (16,20) being disposed between said turning bars (30,32) permitting the slice lip (12) to be disposed in close proximity to said first end (26) of said forming section (24);
a curved drainage means (34) disposed within said endless loop (18) immediately downstream relative to said first turning bar (30) for removing a first portion of water from the stock (S) through said first wire (16) and for removing a second portion of water centrifugally through said second wire (20) during passage of the stock (S) through said forming section (24) and past said curved drainage means (34);
(15) a first slot (36) disposed within said further endless loop (22) and extending in a cross-machine direction immediately downstream relative to said curved drainage means (34) for removing a third portion of water from the stock (S) through said second wire (20);
a box (38) disposed within said endless loop (18) immediately downstream relative to said slot (36), said box (38) defining a curved surface (40) for removing a fourth portion of water from the stock (S) through said first wire (16);
a second slot (42) disposed within said further endless loop (22) and extending in a cross-machine direction downstream relative to said box (38) for removing further water from the stock (S) through said second wire (20); and a further curved drainage means (44) disposed within said further endless loop (22) and immediately downstream relative to said second slot (42), for removing water from the stock (S) through said second wire (20), said curvature of said curved drainage means (34) and said box (38) being opposite to the curvature of said further curved drainage means (44) such that the stock (S) is progressively drained through both wires (16,20) during passage through said forming section (24) from said first (26) towards said second end (28) thereof.
2. A forming apparatus (10) as set forth in claim 1 wherein said first wire (16) is disposed relative to the slice lip (12) such that the stock (S) impinges on said first wire (16) before contacting said second wire (20).
3. A forming apparatus (10) as set forth in claim 1 wherein said forming section (24) is disposed substantially horizontally.
(16)
(16)
4. A forming apparatus (10) as set forth in claim 1 wherein said forming section (24) follows a generally sinusoidal path.
5. A forming apparatus (10) as set forth in claim 1 wherein said turning bars (30,32) are of ceramic material.
6. A forming apparatus (10) as set forth in claim 1 wherein said curved drainage means (34) further includes:
a plurality of support foils (46-63) defining therebetween a plurality of drainage slots (64-81).
a plurality of support foils (46-63) defining therebetween a plurality of drainage slots (64-81).
7. A forming apparatus (10) as set forth in claim 6 wherein said plurality of drainage slots (64-81) are connected to a source of partial vacuum (82).
8. A forming apparatus (10) as set forth in claim 1 wherein said curved drainage means (34) defines a face (84) having a radius of curvature greater than the radius of curvature of said curved surface (40) of said box (38).
9. A forming apparatus (10) as set forth in claim 1 wherein said first slot (36) is a first auto slice (86) including:
adjusting means (88) for adjusting the angular or vertical position of said first slot (36) relative to said second wire (20).
adjusting means (88) for adjusting the angular or vertical position of said first slot (36) relative to said second wire (20).
10. A forming apparatus (10) as set forth in claim 9 wherein said adjusting means (88) permits movement of said first slot (36) between said curved drainage means (34) and said box (38).
11. A forming apparatus (10) as set forth in claim 1 wherein said curved surface (40) of said box (38) permits centrifugal removal of a fifth portion of water from the stock (S) through said second wire (20), said box (38) being connected to a source of partial pressure.
(17)
(17)
12. A forming apparatus (10) as set forth in claim 1 further including:
an adjustable vacuum foil (90) disposed within said endless loop (18) between said box (38) and said second slot (42) for assisting removal of said further water through said second slot (42).
an adjustable vacuum foil (90) disposed within said endless loop (18) between said box (38) and said second slot (42) for assisting removal of said further water through said second slot (42).
13. A forming apparatus (10A) as set forth in claim 1 further including:
a further slot (134) disposed within said further endless loop (18A) and disposed between said first and second slots (36A,42A) for removing water from the stock through said second wire (20A).
a further slot (134) disposed within said further endless loop (18A) and disposed between said first and second slots (36A,42A) for removing water from the stock through said second wire (20A).
14. A forming apparatus (10) as set forth in claim 1 wherein said second slot (42) is a second auto slice (92), said second auto slice (92) further including:
further adjusting means (94) for adjusting said second slot (42) relative to said second wire (20) for skimming said further water removed from the stock (S) through said second wire (20).
further adjusting means (94) for adjusting said second slot (42) relative to said second wire (20) for skimming said further water removed from the stock (S) through said second wire (20).
15. A forming apparatus (10) as set forth in claim 1 wherein said further curved drainage means (44) further includes:
a plurality of cross-machine direction shoes (96-114) defining therebetween a plurality of openings (115-132) connected to a source of partial vacuum (not shown) for removing water from the stock (S) through said second wire (20).
a plurality of cross-machine direction shoes (96-114) defining therebetween a plurality of openings (115-132) connected to a source of partial vacuum (not shown) for removing water from the stock (S) through said second wire (20).
16. A forming apparatus (10) for forming a web (W) from stock (S) ejected through a slice lip (12) of a headbox (14), said apparatus comprising:
a first wire (16) extending in an endless loop (18) past the slice lip (12) such that the stock (S) is ejected through the slice lip (12) onto said first wire (16);
(18) a second wire (20) extending in a further endless loop (22), said second wire (20) cooperating with said first wire (16) for defining therebetween a forming section (24) having a first and a second end (26,28) such that the web (W) is formed during passage of the stock (S) through said forming section (24);
a first turning bar (30) disposed within said endless loop (18) and adjacent to said first end (26) of said forming section (24) such that said first wire (16) is sandwiched between the stock (S) and said first turning bar (30);
a second turning bar (32) disposed within said further endless loop (22) and adjacent to said first end (26) of said forming section (24) such that the stock (S) is disposed between said wires (16,20), said wires (16,20) being disposed between said turning bars (30,32) permitting the slice lip (12) to be disposed in close proximity to said first end (26) of said forming section (24);
a curved drainage means (34) disposed within said endless loop (18) immediately downstream relative to said first turning bar (30) for removing a first portion of water from the stock (S) through said first wire (16) and for removing a second portion of water centrifugally through said second wire (20) during passage of the stock (S) through said forming section (24) and past said curved drainage means (34);
a first vacuum slot (36) disposed within said further endless loop (22) and extending in a cross-machine direction immediately downstream relative to said curved drainage means (34) for removing a third portion of water from the stock (S) through said second wire (20);
a vacuum box (38) disposed within said endless loop (18) immediately downstream relative to said vacuum slot (36), said vacuum box (38) defining a curved surface (40) for removing a fourth portion (19) of water from the stock (S) through said first wire (16), a second vacuum slot (42) disposed within said further endless loop (22) and extending in a cross-machine direction downstream relative to said vacuum box (38) for removing further water from the stock (S) through said second wire (20); and a further curved drainage means (44) disposed within said further endless loop (22) and immediately downstream relative to said second vacuum slot (42), for removing water from the stock (S) through said second wire (20), said curvature of said curved drainage means (34) and said vacuum box (38) being opposite to the curvature of said further curved drainage means (44) such that the stock (S) is progressively drained through both wires (16,20) during passage through said forming section (24) from said first (26) towards said second end (28) thereof.
a first wire (16) extending in an endless loop (18) past the slice lip (12) such that the stock (S) is ejected through the slice lip (12) onto said first wire (16);
(18) a second wire (20) extending in a further endless loop (22), said second wire (20) cooperating with said first wire (16) for defining therebetween a forming section (24) having a first and a second end (26,28) such that the web (W) is formed during passage of the stock (S) through said forming section (24);
a first turning bar (30) disposed within said endless loop (18) and adjacent to said first end (26) of said forming section (24) such that said first wire (16) is sandwiched between the stock (S) and said first turning bar (30);
a second turning bar (32) disposed within said further endless loop (22) and adjacent to said first end (26) of said forming section (24) such that the stock (S) is disposed between said wires (16,20), said wires (16,20) being disposed between said turning bars (30,32) permitting the slice lip (12) to be disposed in close proximity to said first end (26) of said forming section (24);
a curved drainage means (34) disposed within said endless loop (18) immediately downstream relative to said first turning bar (30) for removing a first portion of water from the stock (S) through said first wire (16) and for removing a second portion of water centrifugally through said second wire (20) during passage of the stock (S) through said forming section (24) and past said curved drainage means (34);
a first vacuum slot (36) disposed within said further endless loop (22) and extending in a cross-machine direction immediately downstream relative to said curved drainage means (34) for removing a third portion of water from the stock (S) through said second wire (20);
a vacuum box (38) disposed within said endless loop (18) immediately downstream relative to said vacuum slot (36), said vacuum box (38) defining a curved surface (40) for removing a fourth portion (19) of water from the stock (S) through said first wire (16), a second vacuum slot (42) disposed within said further endless loop (22) and extending in a cross-machine direction downstream relative to said vacuum box (38) for removing further water from the stock (S) through said second wire (20); and a further curved drainage means (44) disposed within said further endless loop (22) and immediately downstream relative to said second vacuum slot (42), for removing water from the stock (S) through said second wire (20), said curvature of said curved drainage means (34) and said vacuum box (38) being opposite to the curvature of said further curved drainage means (44) such that the stock (S) is progressively drained through both wires (16,20) during passage through said forming section (24) from said first (26) towards said second end (28) thereof.
17. A method of forming a web (W) from high consistency stock (S) ejected through a slice lip (12) of a headbox (14), said method comprising the steps of:
moving a first wire (16) extending in an endless loop (18) past the slice lip (12);
ejecting the stock (S) through the slice lip (12) onto the first wire (16) such that the stock (S) contacts the first wire (16) at a minimal angle of impingement due to the first wire (16) extending around a turning bar (30) disposed adjacent to the impingement of the stock (S) onto the first wire (16);
moving a second wire (20) extending in a further endless loop (22) around a second turning bar (32) such that the second turning bar (32) is disposed adjacent to the first turning bar (30) so that the slice lip (12) is disposed in close proximity to a first end (26) of a forming section (24) defined between the wires (16,20); and (20) forming the web (W) from the stock (S) during passage of the stock (S) through the forming section (24) by progressively removing water from the stock (S) through both wires (16,20).
moving a first wire (16) extending in an endless loop (18) past the slice lip (12);
ejecting the stock (S) through the slice lip (12) onto the first wire (16) such that the stock (S) contacts the first wire (16) at a minimal angle of impingement due to the first wire (16) extending around a turning bar (30) disposed adjacent to the impingement of the stock (S) onto the first wire (16);
moving a second wire (20) extending in a further endless loop (22) around a second turning bar (32) such that the second turning bar (32) is disposed adjacent to the first turning bar (30) so that the slice lip (12) is disposed in close proximity to a first end (26) of a forming section (24) defined between the wires (16,20); and (20) forming the web (W) from the stock (S) during passage of the stock (S) through the forming section (24) by progressively removing water from the stock (S) through both wires (16,20).
18. A method of forming a web (W) as set forth in claim 17 wherein the step of forming the web (W) from the stock (S) during passage of the stock (S) through the forming section (24) includes:
removing a portion of water from the stock (S) through a curved vacuum box (38) disposed downstream and on the opposite side of the wires (16,20) relative to a first vacuum slot (36).
removing a portion of water from the stock (S) through a curved vacuum box (38) disposed downstream and on the opposite side of the wires (16,20) relative to a first vacuum slot (36).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8903517-4 | 1989-02-16 | ||
| GB898903517A GB8903517D0 (en) | 1989-02-16 | 1989-02-16 | A forming apparatus for forming a web from stock |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2046588A1 CA2046588A1 (en) | 1990-08-17 |
| CA2046588C true CA2046588C (en) | 1996-04-02 |
Family
ID=10651789
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002046588A Expired - Lifetime CA2046588C (en) | 1989-02-16 | 1990-01-17 | A forming apparatus |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0458799B1 (en) |
| JP (1) | JPH0726354B2 (en) |
| KR (1) | KR0153748B1 (en) |
| AU (1) | AU629901B2 (en) |
| BR (1) | BR9007120A (en) |
| CA (1) | CA2046588C (en) |
| FI (1) | FI913867A0 (en) |
| GB (1) | GB8903517D0 (en) |
| WO (1) | WO1990009481A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5084138A (en) * | 1990-11-13 | 1992-01-28 | Beloit Corporation | Deflection compensated forming wire turning bar |
| DE4037017C2 (en) * | 1990-11-20 | 1994-12-08 | Escher Wyss Gmbh | Wet part of a twin wire paper machine |
| JPH04194093A (en) * | 1990-11-28 | 1992-07-14 | Mitsubishi Heavy Ind Ltd | Twin wire former of paper-making machine |
| US5201999A (en) * | 1991-06-10 | 1993-04-13 | Beloit Technologies, Inc. | Twin wire forming apparatus |
| PL171439B1 (en) * | 1992-08-19 | 1997-04-30 | Beloit Technologies Inc | Apparatus for making a multiple-layer web |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5856593B2 (en) * | 1980-09-08 | 1983-12-15 | 工業技術院長 | low expansion adhesive |
| DE3128156C2 (en) * | 1981-07-16 | 1985-01-24 | J.M. Voith Gmbh, 7920 Heidenheim | Wire section of a paper machine |
| GB8710428D0 (en) * | 1987-05-01 | 1987-06-03 | Beloit Corp | Multi-ply web forming apparatus |
-
1989
- 1989-02-16 GB GB898903517A patent/GB8903517D0/en active Pending
-
1990
- 1990-01-17 JP JP2502150A patent/JPH0726354B2/en not_active Expired - Lifetime
- 1990-01-17 BR BR909007120A patent/BR9007120A/en not_active Application Discontinuation
- 1990-01-17 EP EP90902035A patent/EP0458799B1/en not_active Expired - Lifetime
- 1990-01-17 KR KR1019910700900A patent/KR0153748B1/en not_active IP Right Cessation
- 1990-01-17 AU AU49439/90A patent/AU629901B2/en not_active Ceased
- 1990-01-17 CA CA002046588A patent/CA2046588C/en not_active Expired - Lifetime
- 1990-01-17 WO PCT/US1990/000213 patent/WO1990009481A1/en active IP Right Grant
-
1991
- 1991-08-15 FI FI913867A patent/FI913867A0/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| FI913867A0 (en) | 1991-08-15 |
| JPH0726354B2 (en) | 1995-03-22 |
| JPH03505352A (en) | 1991-11-21 |
| BR9007120A (en) | 1991-11-12 |
| KR0153748B1 (en) | 1998-12-01 |
| KR920701567A (en) | 1992-08-12 |
| GB8903517D0 (en) | 1989-04-05 |
| WO1990009481A1 (en) | 1990-08-23 |
| EP0458799B1 (en) | 1993-06-09 |
| AU4943990A (en) | 1990-09-05 |
| AU629901B2 (en) | 1992-10-15 |
| CA2046588A1 (en) | 1990-08-17 |
| EP0458799A1 (en) | 1991-12-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed | ||
| MKEC | Expiry (correction) |
Effective date: 20121202 |