CA1182319A - Method and apparatus for trimming and removing an edge of the web formed on a papermaking machine - Google Patents

Method and apparatus for trimming and removing an edge of the web formed on a papermaking machine

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Publication number
CA1182319A
CA1182319A CA000415010A CA415010A CA1182319A CA 1182319 A CA1182319 A CA 1182319A CA 000415010 A CA000415010 A CA 000415010A CA 415010 A CA415010 A CA 415010A CA 1182319 A CA1182319 A CA 1182319A
Authority
CA
Canada
Prior art keywords
edge
layer
stock
blade
headbox
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
Application number
CA000415010A
Other languages
French (fr)
Inventor
Umberto F. Bollani
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Beloit Corp
Original Assignee
Beloit Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Beloit Corp filed Critical Beloit Corp
Priority to CA000415010A priority Critical patent/CA1182319A/en
Application granted granted Critical
Publication of CA1182319A publication Critical patent/CA1182319A/en
Expired legal-status Critical Current

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Abstract

ABSTRACT OF THE DISCLOSURE
A method and mechanism of removing an edge of a paper web formed on a traveling foraminous wire from stock issuing from the slice of a headbox including a blade positioned parallel to the machine direction and located to separate the edge from the flow of stock issuing from the slice opening before it engages the traveling wire and collecting the edge material separated and conveying it away so that the material can be used.

Description

3 ~ ~

BACKGR~UND OF THE INVENTION
_ _ _ The present invention relates to improvements in papermaking machines, and more particularly to a method and device for separating the marginal edge of a paper web formed on a traveling wire wherein the web is ~ingle layer or multiple layered~
In a papermaking machine, the sheet or web is formed by depositing one or more layers of stock which is fibers in an aqueous suspension onto a traveling wire~ The stock is normally derived from wood or other vegetable fibers/ and the suspension of stock is delivered onto the traveling wire by h~adboxes having slice openings and positioned along the wire. The layers of stock which are formed in this manner have longitudinal ed~es which are not perfectly even or regu-lar, both from the standpoint of their geometry and their dimension, an~ these edges must therefore be made even and regular after the headboxes have deposited the web on the wire.
This is frequently done by means o devices which employ wa~er jets which are directed onto the edges of the layers on the wire in order to separate the most irregulclr marginal portions from the web. The scrap which is generated by this separation arrangement is collected by ducts, and the material of the scrap is used for additional stock.
Methods and devices used heretoEore or trimming or forming the edge of a traveling web have encountered disad-vantages. First, they do not allow complete and useful re-covery of the scrap material which is derived from the separated edge. This is because the usual edge forming device which is located a considerable distance downstream of the headbox separates the marginal portions of the single layer e ~23~9 or the multi-layered web in a single operation, and when multiple layers are used, each of the layers normally comprises fibers of a different type and quality. That is~ ~here multipl~
layer paper is made, one layer may be made of Eibers that has unique tear strength, and another layer made o fibers has unique softness. I~ the edge from the multiple layers is separated, this mixes the fibers so that ~hey cannot be used ~o make either layer. It is almost impossible to separate the fibers of the various layers after they have been intermixed and their subsequent use is considerably limited.
Accordingly, an object of the invention is to provide a method and a mechanism for adjusting and ~rimming the edge of one or more continuous layers of paper delivered by head-boxes, and which enables the marginal portions of the edges of these layers to be separated while at the same time making it possible to completely reuse the fibers of the scrap stock separated from the edge of the web.
A further object of the invention is to provide a device for trimming the edge o~ a traveling paper web being ~ormed which can be associated with the headbox and provides for separation at an early stage of the ~ormation.
The concepts of the invention provide a method for adjusting the edge of one or more overlying layers of paper web deposited on an endless traveling wire of a papermaking machine wherein each o the layers is delivered through the slice opening of individual headboxes and where a blade separ-ates the marginal portions of each edge of a~ least one of the layers from the remainder of ~he layers as it leaves the slice opening, and a stage is provided in which the scrap genera~ed by separating the marginal portions is conveyed in~o a collector.

1 ~2~19 The invention also provides a device for adjust.ing the width or edge of at least one layer of a ibrous web deposited on a traveling wire of a papermaking machine wherein the layer is delivered through the slice of a headbox and the mechanism is characterized by a blade mounted on the headbox and positioned along the emerging stock jet with the blade located in a position to separate the marginal portion of at least one edge of one layer from the remainder of the layer and conveyiny means is provided by which the scrap generated by separating the edge is conveyed into a collector.
Other objects, advantages and eatures of the invention will become more apparent with the teaching of the concepts ancl principles of the invention in connection with the disclosure of the preferred embodimen~s thereof, in which:
DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a diagrammatic side view o-E a dev.ice con-structed and operated in accordance with the principles of the present invention;
FIGURE 2 is a plan view of the mechanism of Figure l;
FIGURE 3 is a more detailed view of the device of Figure 1 showing a portion of the mechanism substantially en~
larged; and FIGURE 4 is a diagrammatic representation of a part oE
a papermaking machine wherein a multi-layered web is formed and one of the layers is trimmed.
DESCRIPTION OF T~E MECHANISM
.
In a continuous paper web manufacturing mechanism, a continuous foraminous wire 1~ Figures 1 and 2, is provided for orming the web and is positioned to receive one or more layers of stock which is fibers in an aqueous suspension, normally 3 ~ 9 wood fibers. Each layer is delivered through the slice opening
2 of a corresponding headbox 3 to which a suitable quantity of the stock is delivered for continuous flow of stock through the slice opening. The slice opening 2 is positioned above the wire so that the stock leaving the slice opening spouts at a predetermined flow rate and forms a layer 4 of predetermined thickness on the wire, as may be seen in Figure 3, The mechanism accordiny to the invention includes at least one flat blade 5 disposed in a plane perpendicular to the plane of the wire and in a plane extending in the machine direction which is also essentially perpendicular to the plane of the layer of stock leaving the slice opening. The blade has a sharp front edge 6 which is configured so that it makes contact with the front edges 7 of the slice opening, Figure 3, touching both the upper and lower slice lip and the blade may be configured at its leading edge so that it actually projects into the slice opening.
As the layer of stock leaves the slice opening ~, the blade is located in a predetermined position relative to the width of the web so as to be able to separate the margina:L ~dge portion of at least one edge of the layer 4 from the remainder of the web. Two blades 5 will norrnally be disposed with one on each side of the slice opening 2 in order to separate both lateral marginal portions of the edges of the layer 4 from the remainder of the web.
The mechanism also includes means for conveying the separated marginal portions into suitable containexs or to scrap utilization devices. These means can comprise an assembly of walls arranged to define actual conduits indicated overall by 8I Figures 1 and 2. These can comprise, for example, upper ~ ~23:~9 and side walls 11, 12 and 13 respectively, Figure 3, which define a conduit of rectangular cross-section with the lower wall receiving the marginal portiorl 14 of the layer 4 when these are separated from the remainder of ~he web.
The blade 5 is conveniently fixed to one of the side walls 13 of the conduit as is illustrated.
The conduit formed in this manner can open into a collection hopper 15, Figures 1 and 2, arranged to convey the scrap generated as a result of the separation, into a predetermined 20ne.
The device also comprises means for transversely adjusting the position of the blade in a cross-machine direction in order to adjust the width of the marginal portion of the edge which is separated from the web, These means can comprise a flat guide 16, Figure 3, fixed to the frame of the headbox
3, and a slide 17 slidable on said guide and to which the assembly of walls 11, 12, 13 and the blade 5 are fixed. The slide 17 can be provided with slots 18 through which the shank of locking capscrews 19 are inserted. In addition, the wall assembly can be connected to a plate 20, Figure ~, which can be fixed in a predetermined position relatively to a bar 21 by capscrews 22 inserted through slots 23.
In operation, one or more headboxes, shown as 2 and indicated by the refarence numerals 30 and 31, can be disposed along a traveling wire such that, as shown in Figure 4, there is delivered fiber suspension layers 32 and 35 xespectively of which the first is deposited direc~ly on the wire 1, and the second is deposited onto the top of the preceding layer.
According to the concepts of the invention t the edge separating mechanism is located at 3~ and is arranged to 3 ~ 3 ~ ~

separate the edge from the second layer. This device is connected to the headbox 31, and a similar device can also be associated with the other headbox 30, or alternately a de~ice may be provided for the headbox 30 and not for the headbox 31. Production lines may be employed comprising more than two headbDxes for generating multi-layer sheets and separating mechanisms such as the device 34 associated with vne or more of the headboxes.
In the instance of the example illustrated in Figure
4, the layer 35 is deposited by the headbox 31 on top of the layer 32 which is deposited by the headbox 30, As soon as the layer 35 leaves its slice opening, the edges are separated by the actions of blades S of the device 34. The edges are shown as the lateral strips 14, Figure 3, leaving the main web in the center. The edges comprise irregular marginal portions and the centraJ web has remaining edges which are straight and regular. The removed strips are conveyed through conduits 8 defined by the walls 11, 12 and 13 to a reutili2ation zone and the web is deposited onto the previously formed layer 32.
The web compxisiny the two layers formed in this manner can pass through a zone 36 in which suitably di~ected water jets 37 are directed to separate the marginal portiolls of the first layer in a conventional manner~ Thus, if the two layers are formed of different fibers~ the trimmed edges of fibers arP
maintained separate so that they can be reutilized. The re-maining multi-layered web has uniform straight edges.
If the first headbox 30 were also provided with a s~parator device 34, the web comprising the layers 32 and 35, which is formed downstream of the second headbox 31, would already be perfectly regular at its edges, and thus it would ~ ~\

3 ~ ~

not be necessary to use the conventional device including the jets 37.
In accordance with the invention, it is not only possi-ble to obtain perfect regularity of the edge of the resultant web whatever the number of layers which make up the web, but also the fibers of each of the layers, which normally are of different type or collected separately from the others with the advàntage of being able to reuse them in the most suitable manner taking account of their physical and chemical character-istics.
It is intended to cover equivalent methods and struc-tures within the spirit and scope of the invention.

Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. The method of controlling the edge of a paper web formed on a traveling foraminous wire from stock issuing from the slice of a headbox comprising the steps of:
separating the marginal edge of a layer of stock as it leaves the slice opening by placing a blade in contact with the slice in the stock flow from the slice opening;
collecting the material of said marginal edge by conveying it into a collector; and the blade being located in a predetermined position and being adjusted along the emerging width of the layer leaving the slice opening in accordance with the width of the edge to be removed.
2. A device for controlling the edge of a paper web formed on a traveling foraminous wire from stock issuing from a slice opening of a headbox comprising in combination with said headbox:
a thin blade in contact with the slice and positioned along the path traveled by the stock as it leaves a slice opening of a headbox with a blade extending parallel to the flow of stock and in a position to intersect the flow of stock and separate one edge from the layer of stock;
conveying means positioned adjacent the blade location recei-ving the material of the edge which is separated by the blade; and means for adjusting the blade relative to the slice opening while maintaining the blade in a predetermined cross-machine direction.
3. A device for controlling the edge of a paper web formed on a traveling foraminous wire of a papermaking machine from stock issuing from a slice opening of a headbox of said machine compri-sing in combination with said headbox:
a thin blade positioned along the path traveled by the stock as it leaves a slice opening of a headbox with a blade extending parallel to the flow of stock and in a position to intersect the flow of stock and separate one edge from the layer of stock;
conveying means positioned adjacent the blade location receiving the material of the edge which is separated by the blade; and the blade having a shape such that it is in contact with the front surface of the slice lip defining said slice opening.
4. A device for controlling the edge of a paper web formed on a traveling foraminous wire from stock issuing from a slice opening of a headbox comprising in combination with said headbox:
a blade means in contact with the slice and positioned to intersect the path of travel of the stock as it leaves the slice opening to be deposited on a traveling foraminous wire and separate an edge from the flow of stock;
means for subsequently removing the separated edge material; and means for adjusting the cross-machine direction of the blade to change the width of edge removed from the web to be formed on the wire.
5. The method of controlling the edge of a multi-ply paper web formed on a traveling foraminous wire from stock issuing from the slice openings of first and second headboxes comprising the steps:
depositing a first layer from the first headbox on the trave-ling wire;
depositing a second layer on top of the first layer from the second headbox; and positioning a blade adjacent the edge of the second layer at the exit of the slice opening of the second headbox before the second layer is deposited on the first layer to intersect the flow of stock and separate one edge from the layer of stock, thereby making the second layer narrower than said first layer and removing the stock separated by the blade so that the separated stock is maintained integral and separate from the stock of the first headbox for reuse.
6. The method of controlling the edge of a multi-ply paper web in accordance with the steps of claim 5:
including applying an edge separating jet to the first layer after the second layer has been deposited thereon at substantially the location of the edge of the second layer to complete the trimming of the multi-ply web.
7. A device for controlling the edge of a multi-ply paper web formed on a traveling foraminous wire of a papermaking machine from stock issuing from the slice openings of first and second headboxes of said machine comprising in combination with said second headbox:
a thin blade positioned at the exit from the slice opening of the second headbox adjacent the edge thereof for separating the edge of the flow of stock from the centre portion so that the second layer is narrower than the first layer; and conveying means positioned adjacent the blade for receiving the separated edge so that the material is maintained separate from the first layer and the trimmed second layer is deposited on the first layer.
8. A device for controlling the edge of a multi-ply paper web formed on a traveling foraminous wire from stock issuing from first and second headboxes constructed in accordance with claim 7:
including a jet positioned downstream from the second headbox directed at the edge of the first layer substantially coincident with the edge of the second layer for trimming the first layer.
CA000415010A 1982-11-05 1982-11-05 Method and apparatus for trimming and removing an edge of the web formed on a papermaking machine Expired CA1182319A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA000415010A CA1182319A (en) 1982-11-05 1982-11-05 Method and apparatus for trimming and removing an edge of the web formed on a papermaking machine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA000415010A CA1182319A (en) 1982-11-05 1982-11-05 Method and apparatus for trimming and removing an edge of the web formed on a papermaking machine

Publications (1)

Publication Number Publication Date
CA1182319A true CA1182319A (en) 1985-02-12

Family

ID=4123893

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000415010A Expired CA1182319A (en) 1982-11-05 1982-11-05 Method and apparatus for trimming and removing an edge of the web formed on a papermaking machine

Country Status (1)

Country Link
CA (1) CA1182319A (en)

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