SYSTEM FOR SEPARATING SUSPENDED MATERIAL IN FLUIDS FROM A
FLUID THAT BRINGS MATERIAL PARTICLES TOGETHER WITH THE MATERIAL
FIELD OF THE INVENTION The present invention relates to a process for making products such as paper or tissue paper from pulp or other material containing fibers, and more particularly with a process for recovery and recirculation of usable fibers contained in water produced in that process. BACKGROUND OF THE INVENTION The manufacture of products such as paper and tissue paper uses fibrous material such as wood pulp, which is processed in a known manner to produce the desired final product. In a process of making paper or tissue paper, the pulp is applied to a papermaking screen or fabric of an entrance box, and water is extracted by pressing the pulp in a known manner to form paper or paper. silk, which dries and forms into a roll. The water that is extracted by pressure from the pulp is commonly known as white water, and typically includes small particles of fines and ash material which pass through the fabric along with the water. In addition, white waters inevitably include a quantity of usable fibers that pass through or around the fabric of
Ref .: 161337 paper manufacture, which are discarded if the white water is eliminated. This is a recognized problem in the tissue paper industry, and has resulted in the development of systems that recirculate the white water back into the pulp supply system to recirculate usable fibers. However, such systems also recirculate fines and ash material. This is acceptable in a paper-making process, in which fines and ash material can be incorporated into the paper. However, the presence of such material is very detrimental in a tissue paper manufacturing process, because small particles of material inhibit drainage. Consequently, simple recirculation systems are undesirable in a tissue paper manufacturing process, since fines and undesirable ashes are simply recirculated continuously in the process. Some sieve systems have been developed, which employ a stationary sieve, in an effort to separate usable fibers from fines and ashes. Typically, the fibers retained in the screen are intermittently scraped from the screen and recirculated in the pulp supply system. Because such systems necessarily use screens with small openings, there is a significant tendency for the screen openings to become clogged or "closed" due to the buildup of material in the openings. Consequently, many known systems do not work properly for this reason or require a large maintenance treatment to avoid plugging the screen openings. An object of the present invention is to provide an effective system for recovering usable fibers from white water in a papermaking system, in order to allow usable fibers to be recirculated in the system without recirculating undesirable unusable material such as fines. and ashes that are commonly found in white waters of papermaking. Another object of the invention is to provide such a system that involves small modifications to an existing papermaking circulation system, while permitting the recovery of usable fibers from white waters and recirculating the fibers usable for use. A further object of the invention is to provide such a system that requires little maintenance and which is relatively simple in its components, in its construction and operation, to allow the system to be installed and operated at a relatively low cost to justify recovery and the recirculation of usable fibers of white water. A further object of the invention is to replace existing ineffective recovery systems with a recovery system that provides a clean supply of material to the forming fabric to allow, a more efficient operation of the system. In accordance with the present invention, a fiber recovery system for a paper or tissue paper manufacturing process utilizes a filter or screen, on which white water from the process is directed at a downstream location of a waste collector. white water that is part of the paper manufacturing system. The screen is sized to allow water containing the undesirable or unusable components of white water, such as fines and ashes, to pass through the screen while retaining usable fibers on the screen. The water containing the undesirable or unusable material is directed to a waste water treatment plant, in a conventional manner, and then the cleaned water can be re-supplied to the system. The sieve, on which the white waters are directed, is formed of a flexible and foldable sieve material, which may be of the same type of material that is commonly used as the fabric in a tissue paper or fiber-making system. paper. The screen is supported in such a way that the screen remains relatively loose and flexible, for example, by suspending the screen of a frame. The screen is subject to movement when the white water is directed onto the screen, which results in the bending of the screen material, to provide a self-cleaning action of the screen which prevents plugging and closing of the screen openings. The invention contemplates several different arrangements for supporting and imparting movement to the screen, and for directing the white water on the screen. In all versions, the white water is applied to an interior area defined by the screen, and the usable fibers are collected on the internal surface of the screen. The screen is configured to direct the usable fibers to an open discharge area, where the usable fibers are discharged from the screen. The usable fibers are then returned to the system and incorporated into the fibrous material supplied to the entry box, for subsequent application to the tissue paper or papermaking fabric. Various other features, objects and advantages of the invention will be appreciated from the following description along with the figures. BRIEF DESCRIPTION OF THE FIGURES The figures illustrate the best mode currently contemplated for carrying out the invention. In the figures: Figure 1 is a side elevational view, partially in section, showing one embodiment of a fiber recovery system in accordance with the present invention; Figure 2 is a view of a partial section taken along line 2-2 of Figure 1, showing the sieve at rest; Figure 3 is a view similar to that of Figure 2, showing the operation of the system and the rotational movement of the screen; Figures 4 and 5 are views similar to those of Figure 3, showing alternative arrangements for directing the white waters on the screen; Fig. 6 is a view similar to that of Fig. 1, showing an alternative embodiment of the fiber recovery system of the present invention; Figure 7 is a sectional view taken along line 7-7 of Figure 6; Figure 8 is a partial side elevational view of the lower end of the screen incorporated in the fiber recovery system illustrated in Figure 6, with reference to line 8-8 of Figure 6; Figure 9 is an enlarged partial sectional view illustrating an alternative white water supply arrangement for the fiber recovery system illustrated in Figure 6; Figure 9A is a view similar to that of Figure 6, showing another alternative embodiment of the fiber recovery system of the present invention, incorporating the white water supply arrangement as illustrated in Figure 9; Figure 10 is an isometric view illustrating another embodiment of a fiber recovery system in accordance with the present invention; Figure 11 is a sectional view taken along line 11-11 of Figure 10; Figures 12A and 12B are sectional views similar to that of Figure 11, showing the screen being subject to movement for cleaning the screen and for unloading the collected fibers from the discharge area of the section; Figure 13 is a sectional view taken along line 13-13 of Figure 11, showing a mode for directing the white water over the screen; Figures 14-18 are views similar to those of Figure 13, showing alternative embodiments for directing the white water over the screen and for imparting movement to the screen; Figures 19 and 20 are partial side elevational views illustrating two different discharge arrangements for a screen configured as shown in Figure 11; Figure 21 is a view illustrating the discharge area of the supply conduit which directs the white water over the screen in a manner as illustrated in Figure 10; - | - Figure 22 is a view similar to that of Figure 21, showing a flow deflector in the discharge of the supply conduit; Figure 23 is a sectional view taken along line 23-23 of Figure 22; Figure 24A and 24B are views similar to that of Figure 21, showing alternative arrangements in the discharge of the supply conduit to alter the trajectory of the white waters as they are directed towards the screen; Figures 25-27 are views illustrating different configurations of openings for a supply conduit, for use in the direction of white waters towards the screen; Figure 28 is a schematic representation of a papermaking process incorporating the fiber recovery system of the present invention; Fig. 29 is an elevation view of the screen material used to form the screen incorporated in the fiber recovery system of the present invention; Figure 30 is a cross-sectional view of the screen material shown in Figure 29; Figure 31 is a view similar to that of Figure 30, showing the screen material in a deformed or arched configuration such as occurs when the white water is directed onto the screen in operation; Figure 32 is an enlarged cross-sectional view of a portion of the screen material as illustrated in Figure 30; and Figure 33 is an enlarged cross-sectional view of a portion of the screen material as illustrated in Figure 31. DETAILED DESCRIPTION OF THE INVENTION Figures 1-3 illustrate a first embodiment of a fiber recovery system., generally shown at 30, according to the present invention, which is particularly well suited for use in a tissue paper manufacturing process. Generally, the fiber recovery system 30 includes a screen 32 suspended from a frame 34 and configured to define a discharge opening 36, in combination with a white water supply system 38 which is operable to direct white water from a system of papermaking on a surface of the screen 32. The fiber recovery system 30 also includes an open fiber collection container or tank 40 located below the discharge opening 36 of the screen 32, and a collection container or tank. of waste water directed upwards 42. The screen 32 is formed of a flexible and foldable screen material and has a photonic shape. The screen material 32 can be of the same type used as the fabric in a tissue paper manufacturing process. Representatively, the material of the sieve 32 in a sieve material such as that available from Albany International, Appleton, Wire Division, Appleton, Wisconsin under Model No. Woven in M, Duraform, 7, -16, which is a five-shed tissue paper sieve material having a yarn count of 84 for every 2.54 cm (84 / inch) (MD), 78 for every 2.54 cm (78 / inch) (CD), a permeability of 1,240 m3 / h (730 CFM) and a caliber of 0.04 cm (0.016 inches). It is understood that this type of screen material is representative of various types of screen materials that can be employed, depending on the size of the fibers to be collected as well as various other operating parameters. For example, the thread size, counting and weaving pattern of the screen material may vary from the embodiment illustrated. The function of the flexibility and foldability of the screen 32 will be explained later. The upper end of the screen 32 is secured to the frame 34, such that the screen 32 is suspended from the frame 34. The frame 34 includes an outer peripheral frame member 44, which is generally circular, and to which the end is connected. upper of the strainer 32. The frame 34 further includes a series of radial spokes 46 extending between the outer frame member 44 and a hub 48. A mounting member. 50 is secured to any satisfactory upper support member 52, and includes a rotating shaft 54 to which the hub 48 is connected. In this form, the frame 34 and the screen 32 can rotate about a longitudinal axis of rotation defined by the longitudinal axis of the screen 32, which is coincident with the longitudinal axis of the shaft 54. The screen 32 is configured in such a way that its sides are oriented at an angle of approximately 30 ° from the vertical, in such a way that it defines an angle included approximately 60 °. Representatively, the screen 32 defines an upper diameter of approximately 121.9 centimeters (48 inches), wherein the screen 32 is connected to the outer frame member 44, and the discharge opening 36 has a diameter of approximately 17.78 centimeters (7 inches). The height of the screen 32 is approximately 104.14 centimeters (41 inches). It is believed that these dimensions provide a sufficient flow rate to accommodate the amount of white water generated in most tissue paper manufacturing operations. It is understood that these dimensions and angles are provided to illustrate a pattern of screen 32 and frame 34 which has been found to provide satisfactory results, and other dimensions and angles that function satisfactorily can also be found. For example, the size of the screen 32 can be increased to accommodate a greater volume of white water that can be generated in larger tissue paper manufacturing operations. The white water supply system 38 is operable to direct white water from a papermaking process on the inner surface of the strainer 32. As shown in Figures 1-3, the white water supply system 38 is in the form of a series of upwardly extending conduits 58, which are centered on a longitudinal axis coincident with the longitudinal axis of the screen 32. Each conduit 58 is provided with a series of openings spaced 60 along their length, and closed at their upper ends. Representatively, each conduit 58 has an internal diameter of 7.62 centimeters (3.0 inches), although it is understood that any other satisfactory conduit size can be employed. The conduits 58 extend through clamps 62, which function to maintain the position of the conduits 58 in relation to one another. The openings 60 in each conduit 58 are arranged in a linear fashion. The line of the openings 60 in each conduit 58 is radially oriented to face in a direction perpendicular to the direction of orientation of the line of openings 60 in the adjacent conduit 58. As shown in Figure 2, each line of openings 60 it is oriented in such a manner as to face in a direction parallel to and laterally offset from a radius of the screen 32. In this manner, each line of openings 60 functions to direct the white water on the inner surface of the screen 32 in a direction indicated generally by an arrow 64 (FIG. 2), in such a way that the white water colliding on the inner surface of the screen 32 simultaneously applies a radial force and a tangential force to the internal surface of the screen 32. Representatively, each opening 60 is of circular shape, and has a diameter of approximately 0.952 centimeters (0.375 inches), although it is understood that any other shape and dimension can be used transversal The conduits 58 extend through a lower wall 68 defined by a fiber collection tank 40, and through a lower wall 70 defined by the waste water collection tank 42. Openings are formed in the lower walls 68 and 70 of the wastewater. tank to accommodate the passage of the conduits 58 through them, and appropriate seals are provided between the conduits 58 and the lower walls 68, 70 of the tank. Alternatively, the conduits 58 can be directed outwardly between the discharge opening 36 and the fiber collection tank 40 to avoid difficulties and maintenance associated with the seal between the conduits 58 and the walls 68, 70. In operation, the recovery system of fibers 30 operates as follows to recover, usable fibers from the paper-making white waters, which are supplied through the conduits 58. The white waters are directed towards the internal surfaces of the sieve 32 by emission through the openings 60 of the conduits 58. Each line of openings 60 forms a series of linear white water jet streams, such that the white water is applied to the internal surfaces of the screen 32 generally in a pattern shown in FIG. 72. The tangential component of the force with which each jet of white water collides with the inner surface of the screen 32 functions to impart rotation to the screen 32 and n turn of its longitudinal axis, rotating the shaft 54 in relation to the mounting member 50. The rotation speed of the screen 32 is dependent on the amount of force applied by each jet of white water, which is proportional to the pressure of the white waters in the conduits 58, as well as the angle of the streams of white water jets. Representatively, it has been found that a satisfactory operation is obtained by maintaining a low pressure (for example 34.5 kPa (5 psi)) in the conduits 58 which functions to apply a force to the screen 32 which causes the sieve 32 to rotate at a speed of approximately 40 rpm. The openings in the screen 32 are dimensioned to retain usable fibers on the inner surface of the screen 32, and to allow the water and waste-contained material in the white waters, such as fines and ashes, pass through the openings of the strainer 32. The waste water passes through the strainer 32 to the outside of the strainer 32, and falls by gravity into the wastewater collector tank 42. The water The scrap can also be moved downwardly from the outer surfaces of the strainer 32. If desired, a jacket is provided at the lower end of the strainer 32 to direct the waste water outward into the waste water collection tank 42. The water The waste stream is then directed through a waste water outlet 74 of the waste water collection tank 42 to a waste water treatment system, where the solids are removed and the cleaned water can be recycled in the manufacturing process. of paper. The usable fibers contained in the white waters, which are retained on the internal surface of the screen 32, move downwards on the internal surface of the screen 32 towards the discharge opening 36, by gravity. The usable fiber layer collected on the inner surface of the screen 32 is representatively illustrated at 76. As the usable fiber layer 76 travels downwardly on the inner surface of the screen 32, the centrifugal forces due to the rotation of the screen 32 function to eject additional water and waste material through the openings of the screen 32 while the usable fibers advance towards the discharge opening 36. In this form, the usable fibers that are discharged through the discharge opening 36 are of a relatively consistent thick, with most of the water expelled from them. The usable fibers are collected in the fiber collection tank 40, and are directed through a fiber discharge outlet 78 of the collection tank 40 to a pump, which recirculates the usable fibers in the papermaking process. Alternatively, the fiber recovery system 30 can be installed on a receptacle level, such that gravity flow is employed instead of a pumping operation to recirculate usable fibers. The white waters can be applied to the screen 32 in various other ways, and examples are illustrated in Figures 4 and 5. As shown in Figure 4, two supply conductors 58 can be employed to apply the white water to the screen 32 in place of four ducts 58 as illustrated in Figures 2 and 3. Again, the openings 60 in the ducts 58 are arranged to be off center relative to the center of the screen 32 and in relation to the spokes of the screen 32, to apply the streams to the screen 32 with a tangential force to impart rotation to the screen 32. Figure 5 illustrates another embodiment, in which the white waters are supplied through a single, 80 conduit, with a series of elbows 82 that provide the offset of the jet to apply a tangential force to the screen 32 in such a way that rotation is imparted to the screen 32. While Figures 1-5 illustrate a certain embodiment of the invention, it is understood that variations to the to version and are contemplated as part of the scope of the present invention. For example, and without limitation, it is contemplated that the rotation of the screen 32 can be achieved by the use of a motor, to ensure that the screen 32 rotates at a desired speed. In a version such as this one, the white water jets are preferably applied to the screen in a radial form, so as to eliminate the tangential component of the force applied by the jet. Furthermore, although the screen 32 having a frusto-conical configuration of straight sides has been illustrated, it is also considered that the sides of the screen 32 can have a convex or concave configuration if desired. The white waters can also be applied to the inner surface of the screen at any location and in any way, and it is understood that the illustrated modes are simply representative of a variety of ways by which white water can be applied. Although the drawings illustrate the use of four jets to apply white water to the sieve, it is understood that any desired number and size of jets can be employed. . . . . .
The flexibility of the screen 32 allows the screen 32 to deform in its normal form during operation by directing the white water over the screen 32 and hitting it. As shown in Figure 3, the four jets applied to the screen 32 function to divert the portions of the screen outward where the white water jets are applied, to provide arcuate generally convex side areas between the outwardly deformed areas. This flexibility and foldability of the screen material provides a "self-cleaning" action of the screen, because the individual strands of the screen material flex and bend to prevent material accumulation in the corners of the screen openings, which may result in the plugging of the sieve openings and the "closing" of the sieve. The fiber recovery system 30 therefore requires very little maintenance, while at the same time providing an extremely effective and efficient system for the collection of usable fibers and the separation of unusable material. Figures 6-8 illustrate an alternative embodiment of a fiber recovery system generally shown at 30 ', which is generally similar to the fiber recovery system 30 as illustrated and described above. Similar reference characters will be used where possible to facilitate clarity. . . . .
In the fiber recovery system 30 ', the screen 32 is suspended from the frame 34 and has the same general configuration as described above. In the fiber recovery system 30 ', the white water supply system, shown generally at 38', differs to some extent from the white water supply system 38 because each conduit 58 'includes a lower section below the clamp 62, and an upper section 83 which is angled outward relative to the lower section. The upper sections 83 of the conduits 58 'diverge in an upward direction, and each upper section 83 is oriented substantially parallel to the side of the sieve 32 such that the currents of the white water discharged from the openings 60 are applied. in a direction substantially perpendicular to the strainer 32. This orientation of the upper sections of conduits 83 functions to provide a more efficient and direct application of the white waters to the interior of the surface of the strainer 32. In the case where the white waters are apply to the surface of the screen 32 to include a force component that is parallel to the plane of the screen 32, ie, in a non-perpendicular manner, the parallel force component of the white water has a tendency to deform the drainage channels of the 32 sieve material from a generally square or rectangular configuration to a losange configuration. This deformation of the drainage channels of the screen 32 further helps to provide the self-cleaning action of the screen 32 preventing the accumulation of material in the corner regions of the drainage channels. With reference to Figure 7, each upper section of conduit 83 has two lines of openings 60. One of the lines of openings 60 is oriented such that it applies a white water stream line Si which is directed outwardly. in a radial direction relative to the center of the screen 32. Each upper section of conduit 83 further includes an additional line of openings 60 that is angled relative to the radially oriented line of the openings 60. The second line of openings is placed in such a way to emit a series of S2 currents. Each stream S2 is oriented at an angle of approximately 45 ° relative to the currents Sx, and each stream S2 collides with the internal surface of the screen 32 in such a way that a force is applied which has at the same time a radial and a tangential component to the internal surface of the screen 32. Therefore the streams S2 function to impart rotation to the screen 32 due to the presence of the tangential force component. further, the emission of two separate streams from each upper section of duct 83 functions to apply white water through a significant part of the internal surface of the screen 32, to maximize the surface area of the screen 32 to which the white water is applied. . As shown in Figures 6 and 8, a lower section 85 is secured to the lower end of the screen 32 in the discharge opening 36. The lower section 85 is secured to the screen 32 by means of a skirt 87. The lower section 85 it works to increase the total surface area of the screen, and directs the usable fiber material inward to an outlet 89 at its lower end, which surrounds the conduits 58 '. At the outlet 89, the lower section 85 may include a series of fins 91 separated by slits 93. The usable fibers are discharged into the fiber collection tank 38 through the slits 93. In the operation, the fibers are collected on the inner surface of the lower section 85, and the skirt 87 functions to direct the waste water outwardly beyond the walls of the fiber collection tank 40, to prevent waste water from falling into the fiber collection tank 40. The Figure 9 illustrates an alternate system 38"of white water supply, which includes sections of upper conduits 83 at an angle as shown in Figures 6 and 7. In this embodiment, the white water supply system 38" includes a single supply conduit 95 which extends upwards in the lower area of the screen 32, and supplies white water to a distributor 97 secured to the upper end of the conduit 95. The sections of upper ducts 83 are connected in turn to the distributor 97, and receive white water from the distributor 97 for application through the openings 60 to the internal surface of the screen 32 in a manner as described above. In this embodiment, a single tube is required to supply white water to the recovery system, contrary to the multiple tubes illustrated in the previous modalities. With this construction, the funnel section 85 can be dimensioned such that the discharge 89 is formed relatively close to the exterior surface of the conduit 95, to further provide additional control for the discharge of usable fibers from the funnel section 85. FIG. 9? illustrates a cross-sectional view of a white water supply system 38"shown in Figure 9, and also illustrates an alternative system for supporting the screen 32. In the embodiment illustrated in Figure 9A, a vertical support in the form of a mast 99 is located inside the screen 32 to rotatably support the screen 32 from below instead of from above as illustrated in Figures 1 and 6. The mast 99 defines a lower end that is mounted to a oriented surface upwardly-defined by the distributor 97, in such a way that the screen 32 is supported from the distributor 97. A hub 101 is rotatably mounted to the upper end of the mast 99, and the frame 34 is interconnected with the hub 101 by means of With this construction, the fiber recovery system of the present invention is a generally self-contained system that does not require external support, to enable The system is produced off-site and then installed on the site by simply making appropriate plumbing connections with the white water, the white water recovery pipe and fibers from the paper or tissue paper manufacturing facility. Figures 10, 11, 12A and 12B illustrate an alternative fiber recovery system in accordance with the present invention, shown generally at 84. In this embodiment, a screen 86 is suspended from a frame 88 having an open discharge end. 90. A white water supply conduit 92 directs the white water over the screen 86. A fiber collection tank 94 is located below the discharge end 90 of the screen 86., and a white water collecting tank 96 is located below the remainder of the length of the screen 86. The frame 88 is generally rectangular in one plane, and includes a pair of frame end members 98 and a pair of side members of the frame. frame 100. The screen 86 is formed of the same type of material as the screen 32. The screen 86 has a channel or concave configuration, defining a closed end 102, and a pair of inclined side walls 104 converging in a grooved bottom 106. The screen 86 is oriented in such a manner that the fluted bottom 106 slopes downwards in a direction toward the discharge end 90. The white water supply conduit 92 defines an outlet 108 which directs white waters onto the internal surface of the screen 86 in the direction of an arrow shown at 110. The outlet 108 of the duct 92 is located in the direction of the discharge of the screen 86, and the pressure of the white water in the duct 92 is such that, upon discharge from the outlet 108, the white waters hit the internal surfaces of the screen 86 in its side wall 104 in close proximity to the closed end 102, and are deflected at the closed end 102 and the bottom 106. The frame 88 is supported in a way that allows the frame 88 and the screen 86 are movable. In the illustrated embodiment, the frame 88 is supported in a suspension-type shape using cables 112 and rings 114, which in turn are connected to suitable upper supports 116. As shown in Figures 12A and 12B, the frame 88 and the screen 86 is adapted to move in a longitudinal axial direction in a forward and backward manner, while the white water is applied to the internal surfaces of the screen 86 through the conduit 92. In the operation, the white water of manufacturing tissue paper or paper are applied to the internal surfaces of the screen 86 as shown in Figure 11, through the outlet 108 of the conduit 92. Again, the openings of the screen 86 are sized to retain usable material contained in the white waters on the internal surfaces of the sieve 86. The white waters, including the usable material such as fines and ashes, pass through the sieve 86 and are collected in the collecting tank. wastewater 96. Either intermittently or continuously, the screen 86 moves in an axial manner back and forth while the white water continues to be applied to the internal surfaces of the screen 86. The back and forth movement of the screen 86 is carried out in any satisfactory manner, preferably in an automated way by the operation of a motor with an intermittent impeller, such as a cam-type actuator or the like. To achieve this, the frame 96 is pushed back to a position as shown in Figure 12A, and subsequently it is left to swing forward due to its own weight, which includes the weight of the frame 88, the screen 86, and the material retained on the screen 86. This movement of the screen 86 achieves numerous functions. First, the usable fibers, which are collected in the screen channel 86 on the bottom of the screen 106 and the lower areas of the side walls 104, advance forward towards the discharge openings 90 when the screen 86 swings forward. as shown in Figure 12B. This causes the most extreme portion of the collected fibers, shown at 118, to pass through the discharge opening 90 for supply to the fiber collection tank 94. Furthermore, such movement of the screen 86 causes the screen material to bend and bending, which provides the self-cleaning action as described above. The movement of the sieve also varies the location in which the white waters hit the internal surfaces of the sieve 86, which again causes the sieve material to bend and flex locally, to self-clean the sieve. As the usable fibers advance towards the discharge opening 90, water and unwanted or unusable waste material contained in the white water continues to separate from the fibers and are discharged into the waste water collection tank 96. Again, the waste water is directed to a wastewater treatment facility for remove undesirable material, and recirculation of cleaned water, in the system. The usable fibers collected in the fiber collection tank 94 are recirculated back into the system through an outlet 120 associated with the fiber collection tank 94. Figure 13 illustrates a single conduit 92 arranged to direct white water towards a side wall 104. of the screen 86. As shown in Fig. 14, it is also contemplated that a pair of conduits 92 'may be arranged in a side-by-side, and spaced form of the linear openings formed in the conduits 92' in such a way that direct a stream of white water over the side walls 104 of the screen 86. Figure 15 illustrates the use of four white water supply conduits 92 'for directing white water jets on the side walls 104 of the screen 86. Figure 16 illustrates an arrangement similar to that of the figure
, but incorporating a pair of frame members 122 which assist in the formation of the fiber material collected in the bottom area of the screen 86. As shown in FIG. 17, it is also contemplated that the screen 86 can move in a side-by-side way to provide the same functions as previously established. Again, this is achieved by applying a lateral force to the frame 88, either continuously or intermittently, to impart movement to the screen 86. Such movement of the screen 86 'functions to wind the collected fibers to the bottom of the channel defined by the screen 86, so as to forming a roll or piece 122. The downward inclination of the bottom of the screen 106 functions to advance the roll or piece of fiber 122 towards the discharge outlet 90 as the screen 86 moves in a side-by-side manner. Figure 18 illustrates another alternative arrangement, in which the side walls 104 of the screen 86 are formed with extensions 124. The extensions of the side walls 124 extend and retract alternately, which results in an alternate elongation and shortening of the side walls 104 of the screen. In this form, the screen 88 is twisted about its longitudinal axis while the screen 86 moves to vary the location at which the white water hits the screen 86, to flex and self-clean the screen 86, and to advance the roll or piece of fibers 122 towards the discharge outlet of the screen 90. Figure 19 illustrates an arrangement in which a discharge conduit 126 is located at the discharge outlet 90 of the screen 86. Usable fibers that have advanced towards the discharge outlet 90 are directed to the entrance of the fiber discharge conduit 126, to eliminate the use of the fiber collection tank 94 and to direct the usable fibers directly back to the papermaking process. Figure 20 illustrates the use of a rigid frame member 126 located in the discharge outlet 90 of the screen 86. This arrangement works to create a fiber collection bag at the bottom end of the screen 86 adjacent to the discharge outlet 90, to form an accumulator on which the collected fiber material is discharged. Figure 21 shows a white water supply conduit 92 having an outlet 108 through which the white water stream is discharged for application to the internal surfaces of the screen 86. It is also contemplated that the location in which the waters White collide on the sieve 86 may vary varying the location of the flow instead of varying the position of the sieve; In this respect, as shown in 22, a flow deflector 130 can be mounted to the conduit 92, having a fin 132 located in the path of the white water flow. The fin 132 is configured to move in response to the impact of the white water on the fin 132, to move the flow of the white water as it is directed towards the screen 86. Figures 24A and 24B illustrate a flexible nozzle 134 mounted at the end of the conduit 92. The nozzle 134 is formed of a flexible material such as rubber, and has the function of moving up and down in response to the emission of the white water through its outlet in order to vary the location in wherein the white water collides on the internal surfaces of the screen 86. Figure 25 illustrates white water supply conduits such as 58 or 92 ', with openings 60 spaced apart to provide a jet of white water on the internal surfaces of a screen, such as 32 or 86. The openings 60 are illustrated as circular. As shown in Figure 26, the openings may also be in the form of straight transverse grooves 136, or, as shown in Figure 27, in the form of V-grooves 138, to provide different configurations of jets to apply the waters white to the sieve. It is understood that additional and alternative variations are possible for the system and details illustrated in Figures 11-27. For example, and without limitation, the particular shape and configuration of the screen may vary from the illustrated mode. The frame 88 can take any desired shape, and can be supported in any satisfactory way. White water can be applied to the screen using the various illustrated white water supply arrangements, or any other arrangement as desired. While the screen is shown and described as movable either axially or transversely, it is understood that a combination of axial and transverse movements can also be employed. Furthermore, it is understood that the present invention can be used to screen any type of particles suspended in fluids, and is not limited to use in a white water screening application for making paper or silk paper. Figure 28 illustrates a. representative tissue paper or papermaking system in which the fiber recovery system of the present invention, shown at 30 and 84, can be incorporated. As shown, the fiber recovery system 30, 84 is located current down the wire pit 152, which collects white water discharged through the fabric 154. The recovered fiber material is supplied to the machine receptacle 158 through an appropriate supply tube 160, which supplies the recovered fibers in the supply stream for the final supply to the inlet box 162 of the paper or tissue paper making machine. It is understood that any number of fiber recovery systems such as 30, 84 may be used in accordance with the size of the tissue paper or paper making system and with the volume of white water produced in the system, to recover all the Usable fibers contained in white water and to purge the system of small particles of material such as fines and ashes. Figures 29-33 illustrate a representative embodiment of the material used to construct the screens 32 and 86. As indicated above, the screen material may be a screen material for making a five-shed tissue paper, although it is understood that any other material-debris configuration can be employed. The screen material includes axial threads SA and transverse threads ST, which are woven together in a known manner and which cooperate to define generally rectangular drainage openings or channels C that extend through the thickness of the screen material. The screen material is selected in such a way that the dimensions of the C channels allow the fines and the ash material contained in the white waters to pass through the C channels, and to retain the usable fibers contained in the white waters above. the inner surface of the screen material in the fiber layer 76. As shown in Figures 31 and 33, the fiber layer 76 is formed on the internal surface of the screen material such that the area of the layer The fibers 76 covering each channel C extend partially into the channel C. This outward formation of the fiber layer 76 within the channels C has the function of anchoring the layer of fibers 76 on the screen material. When the area of the screen material is subjected to an outward pressure, such as when the area of the screen material passes through the area in which the white water jets are located, the pressure of the applied white water works to disrupt the individual fibers of the fiber layer 76 as well as the anchoring of the fiber layer 76 on the screen material, which allows the fiber layer 76 to move downwards on the screen material in the direction of the fiber area. At the same time, the outward pressure applied to the screen material functions to deflect or deform the screen material outwardly, as indicated above, to increase the degree of curvature of the screen material, such deflection or deformation towards the outside of the screen. sieve material causes the sieving action of the sieve as indicated above, which creates an alteration in the shape of the drainage channels C. This results in the self-cleaning function of the screen material, because the alteration of the shape of the drainage channels C prevents the accumulation of fines and material ash at the corners of the drainage channels C. Figures 32 and 33 illustrate this action. As shown in Figure 32, particles P of fines and ash material tend to be trapped between the strands of the screen material when the screen material is in a flat or slightly curved configuration, such as between areas where White water jets tend to be applied to the interior of the screen material. When the white water jets are applied to the screen material, the screen material is deflected outwardly to increase the curvature of the screen material and to simultaneously subject the inner surface of the screen material and the fiber layer 76 to the pressure of the spray applied. Such outward deflection of the screen material alters the surfaces of the wires defining the drainage channels C to loosen any particle P that can be trapped in the drainage channel C between adjacent wires. As shown in FIGS. 32 and 33, the strands of the screen material are normally separated by a space designated as A. When the screen material is flexed the internal threads move slightly together at a spacing shown in A-, and the External threads are separated slightly at a spacing shown in A +. Such movement of the joint and separation threads works to dislodge the particles from the corners of the drainage channels C, and the dislodged particles are subjected to pressure from the white water jet or to the pressure applied by the jet to the fibers incorporated in it. the fiber layer 76, to force the dislodged particles outwards to be discharged from the drainage channels C. This action prevents particles such as P from accumulating between the threads, to prevent clogging of the drainage channels C and thus eliminate downtime and additional equipment required to clean the sieve equipment as required by the past techniques. After the sieve material moves past the deflection location outwards, such as that caused by the application of the white water jets to the internal surface of the screen, the screen with the fiber layer 76 applied to the surface internal assumes a flat or less curved configuration. The fiber layer 76 tends to retain the greatest curvature due to the entanglement of the fibers at the time the fiber is formed, such that the flattening of the screen material then functions to dislodge the fiber layer 76 from the screen material. . In this form, the fiber layer 76 is able to move by gravity relative to the inner surface of the screen material towards the screen discharge area when the screen material is located between the jet application areas. If necessary, the screen can be washed occasionally as desired by reverse discharge of a fluid, such as by the application of air or water on the outside of the screen, in order to clean the screen as required. Various alternatives and modalities are contemplated as part of the scope of the following claims, particularly by pointing and distinctly claiming the subject considered as the invention. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.