MXPA01003275A - Bridge device for paper forming equipment and method - Google Patents

Abstract

A bridge (70) for a papermaking apparatus having a headbox (12), an apron lip (42) and a forming surface (16). The bridge spans a gap between the apron lip of the headbox and the forming surface to substantially eliminate a free jet of stock slurry as it leaves the headbox apron lip. This serves to maintain pressure from the headbox to the forming zone above the forming surface thereby eliminating the reduction in velocity of the stock slurry in the forming zone. In an aspect of the invention, the bridge generates micro-turbulent flow of stock slurry within the forming zone.

Description

DEVICE OF BRIDGE FOR METHOD AND PAPER FORMATION EQUIPMENT Background of the Invention The present invention generally relates to a paper making equipment. More particularly, the invention concerns paper making equipment that uses a stream of stored aqueous solution stream and a method for forming paper using such equipment.

Paper tissues can be manufactured using a variety of devices, such as suction chest roll formers, twin wire formers, arch formers, or the like. A common feature of these devices is to use a front head to provide a jet stream of stored aqueous solution which is deposited on a path forming surface. While the purpose of the paper forming equipment is generally to produce a uniform sheet in both the machine direction and the cross machine direction, each type of former has particular advantages and disadvantages.

A disadvantage usually associated with these devices and, in particular, with the suction chest roll formers is the great variability in tissue formation generated by changes in the location and operating parameters of the forward head. Generally speaking, suction chest roll formers operate well within a set of relatively narrow and specific conditions. Operating outside of these conditions results in less than optimal sheet formation. Typical defects in a tissue sheet produced with a suction chest roll former outside of its optimum operating conditions are intermittent flashes oriented in the machine direction of the sheet and lumps in the sheet.

These defects can become more significant as the speed of the paper machine increases beyond its original designed speed. Even though it may be possible to use a common water solution of low consistency (eg, an aqueous suspension of paper fibers) to compensate for the less optimal conditions, the supply and handling of the additional amount of water required is generally prohibitive.

Such operating variables present challenges to increase the production output of paper machines with suction chest roll formers without spending capital to replace the equipment. Additionally, such operating limitations appear to be a dead end in the evolution of tissue machines with a view to flexibility so that they can be adapted to make a variety of products on the same machine under different operating conditions. The ability of tissue machines to operate over a wide range of process conditions is becoming economically important.

Therefore, there is a need in the art for an improved jet-type forming equipment (eg, a suction chest roll former) which maintains consistent tissue formation over a wide range of operating conditions and at speeds higher than what is currently available. There is also a need for an improved jet-type forming equipment (eg, a suction chest roll former) which can easily be constructed as an improvement of the current trainers.

For example, in certain situations when the inward suction of the forming chest roller may be inadequate, either in terms of magnitude or coverage, the formation of the blade may be unacceptable. More particularly, in a typical suction chest roll former there is a separation between the platform and the moving cloth which creates a free jet of a watery solution stored upon exiting the edge of the platform. As a free jet, it is in an atmospheric environment from the moment it leaves the edge of the platform to the moment it makes contact with the moving fabric. The differential pressure needed to move the fiber to the forming surface (for example, the moving fabric) and to push the water out through the fabric to the forming roller for drainage is generated by the pressure above the fabric and the suction from below. If the suction is inadequate, the differential pressure is created by the pressure above the fabric which is converted from the speed of the stored water solution that moves according to Bernoulli's theorem. The large uncontrolled reduction resulting in velocity makes significant changes in the effectiveness of the jet (eg, the jet of watery substance) to form the wire speed ratio or wire / jet velocity difference) sufficient to place the operating conditions outside of the desirable range. These changes cause the formation of the sheet of paper to suffer.

Synthesis of the Invention The present invention addresses the needs described above by providing a bridge. The bridge spans a space between the platform edge of the head of a paper forming device and a forming surface (for example, the moving fabric). Eliminating the separation substantially eliminates a free jet of watery solution while leaving the edge of the platform of the front head.

This serves to maintain the head head pressure at the forming zone above the forming surface thereby preventing a substantial reduction in the velocity of the watery substance within the forming zone.

According to the invention, the bridge improves the conditions in the forming zone to generate a more uniform sheet formation and increase the strength of the sheet. In one aspect of the present invention, the bridge can be used to increase the speed and improve the formation of tissue over a wide range of operating conditions. Desirably, the invention can allow adequate formation over a wide range of consistencies (water to fiber ratio) that can be achieved without the use of the bridge.

According to another aspect of the invention, the bridge can be a flexible bridge.

In one embodiment, the present invention relates to an improved suction chest roll former. The suction chest forming roller includes a chest roller and a front head. The chest roll has a support surface defining openings therein that may or may not be operatively connected to a vacuum source. The front head is positioned in close proximity to the suction chest roll and is adapted to supply an aqueous suspension of papermaking fibers. The front head includes a slot roof and a platform that together define an opening slot of the front head. A forming roof which is generally rigid (but can be flexible) extends from the slot roof beyond the opening slot and, together with the forming fabric, defines between them the formation zone of the suction chest roll. trainer In a typical machine, there is a separation between the tip of the platform and the forming fabric. A feature of the present invention is a bridge that extends between the platform and the moving fabric. This bridge substantially eliminates the separation and the free jet of water solution present during the operation without the bridge.

For example, in a typical suction chest forming roller there is a separation between the platform and the moving fabric which generates or results in a free jet of watery solution during normal operation. As a free jet, it is usually in an atmospheric environment from the moment it leaves the edge end of the platform to the time it makes contact with the moving fabric. The differential pressure needed to move the fiber to the forming surface (for example, the moving fabric) and pushes the water out through the fabric to the forming roll for drainage is generated by the pressure above the fabric and the suction down. If the suction is inadequate, the differential pressure is created by the pressure above the fabric which is converted from the speed of the proper solution that moves according to Bernoulli's theorem. The large unchecked reduction resulting in velocity makes changes in the effectiveness of the jet (eg, the water solution) to form the wire speed ratio (or wire / jet velocity difference) sufficient to place the operating conditions outside the desirable range. The elimination of the separation and the free jet serves to transfer pressure from the current channel upwards to the formation zone which helps to avoid a substantial reduction in the speed of the diluted solution (for example, the aqueous suspension of fibers to make paper) within the formation zone. Even if the vacuum boxes are designed to extend through the length of the formation zone and / or the vacuum level is suitable for proper drainage, it may be desirable to have the bridge for at least the reasons described above. Additionally, large vacuum levels can adversely affect operation and reliability and can still create a speed difference.

Additionally, it is believed that air is introduced irregularly into the forming zone through the groove at the entrance of the jet and through the moving fabric. This can disrupt the formation of the sheet. It is believed that removing the slot prevents air from being introduced into the formation zone.

Desirably, the bridge is mechanically fastened to the edge of the platform. The clamping of the bridge by mechanical means protruding into the flow can be used to create a controlled turbulence in the jet in scale, intensity and depth, to promote improved sheet formation. The invention also encompasses providing texture or stiffness (e.g., ridges or dimples) on the surface of the bridge and / or on the platform and roof to generate such controlled turbulence to promote improved foil formation.

As used herein, the term "sheeting" or "forming" refers to the property which is determined by the degree of uniformity of distribution of the solid components of the sheet with particular reference to the fibers. It is usually when judged by the visual appearance of the sheet when observed by light transmission and can be determined using equipment such as, for example, a Microscanner Paprican Model LAD94 forming analyzer, available from Optest Equipment, Inc., of Haw esbury , Ontario, Canada. The formation of the leaf is an important property, not only because it has an influence on the appearance of the leaf, but because it influences the values and the uniformity of values of many other properties of the leaf.

The chest roll includes openings, such as holes, slots and other open areas, to keep the water away from the wet tissue until it can be discarded in a collector, for the water recycling process. The breast roller can be operatively connected to one or more vacuum bridges so that the vacuum is supplied to the openings, and corresponding to the formation zone. The areas just before and after the upper edge are provided with vacuum to remove the free water and therefore discard the water after the tip. The required differential pressure may come from the pressure alone or a combination of pressure and vacuum from a different source in the formation zone itself.

In one aspect of the present invention, the bridge can be used in conjunction with the suction chest roll forming equipment. As a result, the current forming suction chest rolls can be relatively easy and cheaply improved to improve conditions in the forming zone thereby generating more uniform sheet formation and an increase in sheet strength as well as extend the range of water handling capacity, increase speed and improve tissue formation over a wide range of operating conditions.

In the embodiment illustrated in Figure 1, the bridge is mechanically fastened to the edge of the platform. In an embodiment of the invention, the bridge can be flexible so that there is a controlled pressure against the fabric when there is a jet of water solution coming out of the slot. An additional feature is that the bridge can have sufficient flexibility so that it can bend during the passage of opposites or if the fabric overlaps. The bridge can be made as an integral part of the platform edge (for example, as an extension of the platform edge). Alternatively, the bridge can be attached to the edge of the platform in a variety of configurations. For example, the bridge can be butted to the edge of the platform or can be attached to the edge of the platform.

Suitable materials for forming the flexible bridge include Lexan (polycarbonate, from General Electric, Pittsfield, Massachusetts), epoxy resins reinforced with carbon fiber or glass, other polycarbonate materials, fiberglass or other compounds, stainless steel or similar, where the fiber or machining orientation can achieve the correct flexibility. Reinforced fiber resins can be constructed to be preferably folded in the machine direction, while maintaining rigidity in the cross machine direction.

The flexibility of the cross-machine direction of the flexible bridge is not generally desirable, therefore the flexible bridge can include a plurality of cross-machine direction stiffness elements. These stiffening elements, which are desirably placed on the surface of the flexible bridge facing away from the forming zone, can be formed of stainless steel, carbon fiber, fiberglass or other compounds, plastic compounds or the like. An alternative method is to produce a compound where the rigidity in the cross-machine direction is significantly greater than the rigidity in the machine direction. The bridge can be pre-tensioned in the direction transverse to the machine to eliminate any compressive conditions at the tip of the bridge.

In further embodiments of the invention, a different material surface may be held at the tip of the flexible bridge on the side of the fabric. The purpose of the different surface is to offer reduced wear of the bridge and the fabric. It can be made of a harder material such as a ceramic. It can be mechanically fastened, glued or molded into the bridge material.

In still other embodiments of the invention, a shower can be used to apply lubricant to the fabric moving upstream of the edge of the platform. The lubrication shower can be of conventional construction and has the purpose of reducing wear and improving the sealing between the bridge and the moving fabric.

It should be understood that the bridge device is used with paper making equipment to make paper tissue.

The wet paper fabric is formed into a moving forming fabric that moves through the forming zone between the suction ceiling roller and a rigid ceiling. The terms "forming fabric" and "moving fabric" refer to the wadding band adapted to drain water away from the fibers to make paper and provide support while the fabric is being formed. Suitable forming fabrics include synthetic fabrics and are available from fabric suppliers such as Lindsay Wire and Albany International.

One aspect of the invention relates to a method of forming paper web having improved forming characteristics using a paper making apparatus. In one embodiment, the method includes the steps of: 1) providing a paper making apparatus having a forming zone created between a forming surface and a leading head, the forming surface having a support surface which is operatively connected to a vacuum source and the front head has a slot roof and a platform defining between it a slotted opening, the front head further includes a bridge extending from the platform to a moving fabric supported by the forming surface; 2) configure the bridge to substantially eliminate the separation between the platform and the forming surface; 3) supplying an aqueous suspension of fibers to make paper to the front head under conditions to form a jet; and 4) depositing the aqueous suspension of fibers to make paper in the fabric moving under conditions that substantially eliminate the formation of a free jet and substantially maintain the pressure of the forward head to the formation zone above the forming surface so that a substantial reduction in the speed of the aqueous suspension of the fibers to make paper within the forming zone is avoided.

In one aspect of the invention, the step of depositing the aqueous suspension of the fibers to make paper on the forming surface includes introducing a controlled turbulence to the jet which may be, for example, microturbulence.

An embodiment of the invention relates to a method of forming a paper web having improved forming characteristics using a suction chest forming roller., in one embodiment, the method includes the steps of: 1) providing a suction chest forming roller having a forming zone created between a breast roller and a forward head, a breast roller having a supporting surface that defines openings therein that can be operatively connected to a vacuum source and the front head has a slot roof in a platform defining between it a slot opening, the front head further includes a flexible bridge extending from the platform to a moving fabric supported by the chest roller; 2) configure the flexible bridge to substantially eliminate the groove between the platform and the chest roller; 3) supplying an aqueous suspension of fibers to make paper to the front head under conditions to form a jet; and 4) depositing the aqueous suspension of paper fibers on the moving fabric under conditions substantially eliminating the formation of a free jet which substantially maintains pressure from the forward head to the forming zone above the forming surfaces which by thus avoids a substantial reduction in the speed of the aqueous suspension of the papermaking fibers (eg, water solution) within the forming zone.

The operating parameters of suction chest and front head roller such as throat opening, vacuum levels, and orientation of the front head and other operating parameters such as the speed of the ventilation pump can be adjusted as it can be recognized by those with great skill in the art in order to achieve the desired leaf properties. The type of fiber, the fiber consistency, and other factors may need to be taken into consideration but are less critical to the operation with the improved formation due to the incorporation of the bridge.

Many types of fiber may be used by the present invention which include hardwood or softwood, straw, flax, milkweed cottonwood, abaca, hemp, variety of hemp, bagasse, cotton, reed, and the like. All known papermaking fibers can be used, including unbleached and bleached fibers, fibers of natural origin (including wood fiber and other cellulose fibers, cellulose derivatives, and cross-linked or chemically rigid fibers) or synthetic fibers (synthetic paper fibers include certain forms of fibers made of polypropylene, acrylic, aramides, acetates, and the like), recycled or recovered and virgin fibers, hardwood and softwood, and fibers that have been mechanically made pulp (e.g., ground wood), chemically made pulp (which includes but is not limited to processes for making sulphate and kraft pulp), thermomechanical pulp, quimotermicomechanical pulp, and the like. Mixtures of any subset of fiber classes related or mentioned above can be used.

The fibers can be prepared in a multiplicity of ways known to be advantageous in the art. Useful methods of fiber preparation include dispersion for imparting curling and improved drying properties, as described in U.S. Patent Nos. 5,348,620 issued September 20, 1994 and number 5,501,768 issued on September 26, 1994. March 1996, both to MA Hermans et al. And U.S. Patent No. 5,656,132 issued August 12, 1997 to Farrington Jr. and others; which are incorporated herein by reference.

Once formed, the tissue paper can be processed using a wide variety of papermaking operations. For example, tissue paper can be formed into a tissue by drying without creping as described in U.S. Patent No. 5,667,363 issued September 16, 1997 to S.A. Engel and others; and U.S. Patent No. 5,607,551 issued March 4, 1997 to T.E. Farrington Jr. and others; which are incorporated herein by reference. The term "paper" is used herein to broadly include writing, printing, wrapping, toilets, and industrial papers, newsprint, liner, tissue, napkins, cleansers, towels, and the like.

Description of the Drawings The invention will now be described in greater detail with reference to Figure 1, which shows a simplified cross-sectional schematic view of a suction chest forming roller with an exemplary bridge device. Conventional papermaking apparatuses and operations (not shown) can be used with respect to solution preparation, forming fabrics, tissue transfers, creping, drying and the like.

Figure 1 shows a suction-forming breast roller 10 for making a paper tissue from an aqueous solution of papermaking fibers. The suction-forming breast roller includes a paper-making front head 12 placed in an operating relationship to a suction chest roller 14. The forward head 12 deposits the aqueous suspension of the fibers to make paper on the surface of a fabric forming machine 16 in a forming zone 18 of the suction chest forming roller. The forming fabric 18 forms an endless curl path between the front head 12 and the breast roller 14 in the direction of the arrow 100. The forming process allows partial drainage of the newly formed tissue paper. For example, the newly formed paper tissue can be partially dewatered to a consistency in the range of between about 7% and 15%. The aqueous suspension of the paper fibers is moved in the direction of the arrow 200.

The suction chest roller 14 includes a support surface 20 defining a plurality of openings 22. The openings 22 open to one or more vacuum boxes 24 located within the roller 14 at fixed radial locations around the circumference of the roller and operatively connected to a vacuum source (not shown). The specific size and / or location of these openings is conventional. While only a single vacuum box 24 is shown, one or more vacuum boxes 24 provide a controlled amount of vacuum in the forming zone. These vacuum boxes may be located under only a portion or the entire training zone as well as extend beyond the training zone. The vacuum level is conventional for the process described for making paper. The illustrated vacuum box may include section divisions (not shown) that divide the vacuum box into multiple sections.

The front head incorporates the slotted roof 40 and a platform 42 defining between the two a slotted opening 44. The platform 42 can be mounted on a flow spreader and the front head 12 can be positioned so that one end of the stream faces downwards. of the platform 42 is placed in close proximity to the fabric 16 to define a spacing 86 therebetween.

A forming roof 60 is coupled by a pivot assembly 62 to the end of the stream down a slotted roof 40. The distal end 64 of the forming roof 60 and the forming fabric 16 forms an upper edge space 46. The slotted opening 44 and the upper edge space 46 are adjustable through mechanisms not shown.

As shown in Figure 1, a bridge 70 is mechanically fastened to the platform 42 using small fasteners 72. Other mechanical or fastening means may be used. For example, the fastening means may be rivets, screws, clamps, staples, bolts, hooks, loops, welds, glues, adhesives and combinations thereof.

In an embodiment of the invention, the bridge 70 can be flexible and can touch the forming fabric 16 during operation. In accordance with aspects of the invention, the small fasteners 72 are strategically designed and placed to generate controlled turbulence. Alternatively and / or additionally, turbulence generating accessories such as, for example, dimples, hillocks, rods, protuberances, waves, grooves or the like may be used. The size, shape, spacing and number of turbulence generated may depend on the range of operating conditions required for the particular application of this invention. The invention also encompasses providing a texture or stiffness (e.g., hillocks and dimples) on one or more surfaces of the platform, the slotted roof and / or the forming roof to generate such controlled turbulence to promote improved sheeting.

Controlled turbulence is turbulence introduced in the front head of the paper making machine (for example, the suction chest forming roller). Such turbulence is desirably sustained during the operation of the paper making apparatus and may have a wavelength range which may vary during the different operating conditions. Desirably, controlled turbulence is microturbulence. As used herein, the term "microturbulence" refers to turbulence that has a wavelength that is relatively small relative to the dimensions of a jet of an aqueous suspension of papermaking fibers and is sufficient to prevent flocculation. desirable fiber to make paper. For example, the wavelength may be less than about 24 millimeters and desirably about 6 millimeters or less.

One or more vacuum boxes 24 provides a controlled amount of vacuum generally below the forming zone, and more particularly, in the area before and after the distal edge 64 of the forming roof 60. The required vacuum level can be adjusted as Those with an ability in art will be able to recognize it.

The above detailed description has been for the purpose of illustration. Therefore, a number of modifications and changes can be made without departing from the spirit and scope of the present invention. For example, optional or alternate features described as part of an embodiment may be used to access another embodiment. Additionally, two named components can represent parts of the same structure. In addition, several alternative processes and equipment arrangements can be employed, particularly with respect to the preparation of the solution and forming fabrics. Therefore, the invention should not be limited by the specific embodiments described, but only by the claims and all equivalents thereof.

For example, it is generally intended that the present invention be used in high speed papermaking processes. That is, processes for making paper operated where the moving fabric moves in proportions greater than 1,000 feet per minute. It is contemplated that the present invention may be used in operating ratios that are greater by a factor of three to six or even greater.

Although the present invention is shown on a conventional suction chest-forming roller, its application is not limited to such devices. Bridge devices can be used with other jet forming equipment, but not limited to, twin wire type formers, rising moon formers, and the like. In such configurations (for example, twin wire formers or rising moon formers) more than one bridge device can be used. For example, two bridge devices can be used.

Claims (22)

R E I V I N D I C A C I O N S
1. A papermaking apparatus having a forming zone created between a forming surface and a leading head comprising a groove ceiling and a platform edge defining a groove opening, the leading head further comprising at least one bridge extending from the platform edge to a moving fabric supported by the forming surface, whereby the bridge is adapted to substantially eliminate the space between the platform edge and the moving fabric to substantially eliminate the formation of a free jet of watery substance and maintaining the pressure from the front head to the forming zone above the forming surface thereby avoiding a substantial reduction in the speed of the watery substance within the forming zone.
2. 2. The apparatus for making paper as claimed in clause 1, characterized in that the bridge is a flexible bridge.
3. 3. The apparatus for making paper as claimed in clause 1, characterized in that the bridge comprises turbulence generating characteristics arranged on the surface of the bridge facing the forming surface.
4. 4. The apparatus for making paper as claimed in clause 1, characterized in that it comprises turbulence generation characteristics disposed on the surface of the slotted roof or the platform edge.
5. 5. The apparatus for making paper as claimed in clause 1, characterized in that the bridge is attached to the edge of the platform using mechanical fastening means.
6. 6. The apparatus for making paper as claimed in clause 5, characterized in that the mechanical fastening means are selected from rivets, screws, clamps, staples, bolts, hooks, loops, welds, adhesives and combinations thereof.
7. 7. The apparatus for making paper as claimed in clause 5, characterized in that the mechanical fastening means further comprise turbulence generating features disposed on a surface of the bridge facing the forming zone.
8. 8. The papermaking apparatus as claimed in clause 1, characterized in that the bridge comprises a first material adjacent to the edge of the platform and a second material adjacent to the moving fabric.
9. 9. The apparatus for making paper as claimed in clause 1, characterized in that it also comprises a shower to apply a lubricant to the fabric in movement upstream of the edge of the platform.
10. 10. A suction chest forming roller, comprising: a breast roller having a support surface defining openings therein that are operatively connected to a vacuum source; Y a front head positioned in close proximity to the suction chest roll and adapted to supply an aqueous suspension of fibers for making paper, the front head comprises a slot roof and a platform edge defining therein a slot opening, the The front head further comprises a bridge extending from the platform to a moving fabric supported by the forming surface, by which the bridge is adapted to substantially eliminate the separation between the edge of the platform and the moving fabric to substantially eliminate the formation of a free jet of the aqueous suspension of papermaking fibers and maintaining the pressure from the front head to the forming zone above the forming surface thereby avoiding a substantial reduction in the speed of the aqueous fiber suspension. make paper inside the forming area.
11. 11. The suction chest forming roller as claimed in clause 10, characterized in that the bridge is a flexible bridge.
12. 12. The suction chest forming roller as claimed in clause 10, characterized in that the bridge comprises turbulence generating features disposed on the surface of the bridge facing the forming surface.
13. 13. The suction chest forming roller as claimed in clause 10, characterized in that the bridge is fastened to the edge of the platform using mechanical fastening means.
14. 14. The suction chest forming roller as claimed in clause 13, characterized in that the mechanical fastening means are selected from rivets, clamps, staples, bolts, hooks, loops, welds, adhesives and combinations thereof.
15. 15. The suction chest forming roller as claimed in clause 13, characterized in that the mechanical fastening means further comprise turbulence generating features disposed on a surface, the flexible bridge facing the forming zone.
16. 16. The suction chest forming roller as claimed in clause 10, characterized in that the bridge comprises a first material adjacent to the edge of the platform and a second material adjacent to the moving fabric.
17. 17. A front head adapted to supply an aqueous suspension of fibers for making paper, the front head comprises: a slotted roof and a platform edge defining between them a slot opening; a bridge extending from the edge of the platform to a moving fabric supported by a forming surface, to which the bridge adapts to substantially eliminate the separation between the platform and the moving fabric to substantially eliminate the formation of a jet free and substantially eliminate the formation of a free jet of the aqueous suspension of fibers to make paper and maintain the pressure from the front head to a formation zone above the forming surface so that a substantial reduction in speed is avoided of the aqueous suspension of the fibers for making paper within the forming zone.
18. 18. A method for forming paper tissue, comprising: providing a paper making apparatus having a forming area created between a forming surface and a leading head, the forming surface having a support surface which can be operatively connected to a vacuum source and the front head having a ceiling groove and a platform edge defining between them a slot opening, the front head further includes a bridge extending from the platform edge to a moving fabric supported by the forming surface; configuring the bridge to substantially eliminate the space between the platform edge and the forming surface; supplying an aqueous suspension of fibers for making paper to the front head; Y depositing the aqueous suspension of fibers to make paper in the moving fabric under conditions that substantially eliminate the formation of a free jet and maintain the pressure from the forward head to the formation zone whereby a substantial reduction in the speed of the aqueous suspension of paper fibers within the formation zone.
19. 19. The method as claimed in clause 18, characterized in that the step of depositing the aqueous suspension of papermaking fibers on the forming surface further comprises introducing controlled turbulence into the aqueous suspension of papermaking fibers during deposition.
20. 20. The method as claimed in clause 19, characterized in that the controlled turbulence is microturbulence.
21. 21. The method as claimed in clause 19, characterized in that the bridge is a flexible bridge.
22. 22. A method for forming a paper web, comprising: providing a suction-forming suction chest roll has a formation zone created between a chest roll and a forward head, the chest roll has a support surface defining openings therein which can be operatively connected to a vacuum source and the front head has a slotted roof and a platform edge defining between them a slot opening, the front head further includes a bridge extending from the platform edge to the moving fabric supported by the chest roll; configuring the bridge to substantially eliminate the groove between the platform edge and the moving fabric; supplying an aqueous suspension of fibers for making paper to the front head; Y depositing the aqueous suspension of fibers to make paper in the moving fabric under conditions that substantially eliminate the formation of a free jet and maintain the pressure from the front head of the formation zone thereby avoiding a substantial reduction in the speed of the aqueous suspension of fibers to make paper within the formation zone. SUMMARY A bridge for a paper making apparatus having a front head, and a platform edge and a forming surface. The bridge extends to a spacing between the edge of the front head platform and the forming surface to substantially eliminate the free jet of watery substance while leaving the edge of the front head platform. This serves to maintain the pressure from the front head of the formation zone above the forming surface thereby eliminating the reduction in the velocity of the watery substance in the forming zone. In one aspect of the invention, the bridge generates a micro-turbulent flow of watery substance within the forming surface.