US3255074A - Headbox for paper-making machine - Google Patents

Description

June 7, 1966 s. M. SALOMON ETAL 3,255,074

HEADBOX FOR PAPER-MAKING MACHINE Filed April 5, 1964 6 Sheets-Sheet l EI 7/ q AI m 5/ J/d z IN VEN TORG 4 @01220/2 1% 6ala%a12 BY M $4A%ATTORNEYS June 7, 1966 Filed April 5, 1964 s. M. SALOMON ETAL 3,255,074

HEADBOX FOR PAPER-MAKING MACHINE 6 Sheets-Sheet 2 By X,

I XVEN TORS 6240/ /01/ /./6240M0/1/ 442 J /z/sras' #ATTORNEYS s. M. SALOMON ETAL 3,255,074

HEADBOX FOR PAPER-MAKING MACHINE June 7, 1966 6 Sheets-Sheet 5 Filed April 5, 1964 @4/ d dzz iae' BY i M%IAZMWATTORNEYS June 7, 1966 5. M SALOMON ETAL HEADBOX FOR PAPER-MAKING MACHINE 6 Sheets-Sheet 4 Filed April 5, 1964 M a m INVENTORii fi e/012204 ZSQZGMQ/Z Zafyw (f dz'zazw Bi w ATTORNEYS June 7, 1966 s. M. SALOMON ETAL 3,

HEADBOX FOR PAPER-MAKING MACHINE Filed April 5, 1964 6 Sheets-Sheet 5 IN VENTORL) 6&(0122912 ZZ 62/04/220 Z afya/ z/ wizza BY ATTORNEYS June 7, 1966 s. M. SALOMON ETAL 3,255,074

HEADBOX FOR PAPER-MAKING MACHINE 6 Sheets-Sheet 6 INVENTOKS a/amazz 1 /azzzazz Zafya/ d wezae' 12 z w ATTORNEYS United States Patent 3,255,074 HEADBOX FOR PAPER-MAKING MACHINE Salomon M. Salomon and Edgar I; Justus, Beioit, Wis.,

assignors to Beloit Corporation, Beloit, Wis, acorporation of Wisconsin Filed Apr. 3, 1964, Ser. No. 357,171 8 Claims. (Cl. 162-338) This is a continuation-in-part of our applications Serial Nos. 140,350, filed September 25, 1961 and 141,270, filed September 26, 1961, said applications now having been abandoned.

This invention relates to papermaking and like processes, and is more particularly directed to improved methods and means for minimizing flocculating of furnish immediately prior to its discharge from a flow chamber or headbox.

In the prior art, it is generally recognized that the condition of the furnish or stock as it flows through the slice onto the forming surface of a papermaking machine is a critical factor in the determination of the characteristics of the forming web and the formed paper product.

Heretofore, many attempts have been made to condition the furnish prior to its delivery from the outlet onto the forming wire by rotary rolls and the like through which the stock passes for enhancing fiber distribution and minimizing fioccing in the headbox. However, rotary rectifier rolls or holey rolls are expensive, must be maintained in smooth, unscarred and uncorroded condition; otherwise they will fail to perform their function or produce even greater flocs, strings or lumps which may be released with the flow from the slice.

With the present invention, we substantially overcome the problems and difiiculties of the prior art and provide eflicient means which are self-cleaning for dispersing fibers adjacent the outlet of a flow channel or headboX.

It is therefore an object of the present invention to minimize floccing of papermaking stock and the like.

It is another object of the present invention to provide improved means for dispersing fibers in paperrnaking stock or furnish and the like.

Still another object of the present invention is to provide improved means which are self-cleaning for minimizing fioccing of papermaking stock adjacent the outlet of the flow channel or headbox.

A further object of the present invention is to provide a hydrofoil and screen arrangement for dispersing fibers in papermaking stock and the like prior to delivery of the furnish to the forming surface of a papermaking machine.

Yet another object of the present invention is to provide improved method for dispersing fibers and minimizing fioccing thereof adjacent the outlet of a flow channel or headbox prior to delivery of the stock to the forming surface of a papermaking machine.

These and other objects, features, and advantages of the present invention will become readily apparent to those skilled in the art from a consideration of the following detailed description when considered in conjunction with the accompanying drawings illustrating preferred embodiments of the present invention and wherein like reference numerals and characters refer to like and corresponding parts throughout the several views.

On the drawings:

FIGURE 1 is a view in vertical section of a headbox arrangement constructed in accordance with the principles of the present invention.

FIGURE 1-A is a top view in section of an alternative reject discharge channel which may be positioned in the region designated A of FIGURE 1.

FIGURE 2 is a view in vertical section illustrating an alternate embodiment of the invention wherein an adjustable nozzle is employed in a headbox consrtucted in accordance with the principles of the present invention.

FIGURE 3 is a view in vertical section of a headbox wherein the furnish is supplied to the screen through a curved flow channel.

FIGURE 4 is a view wherein stock is supplied to the flow channel parallel to the outlet thereof.

FIGURE 5 is a top view in elevation of a flow channel arrangement.

FIGURE 6 is a view in vertical section taken along line XIV-XIV of FIG. 5.

FIGURE 7 is a view in vertical section of a dual flow headbox wherein the furnish is supplied to the screen I FIGURE 11 illustrates averticalsection of a flow channel employing an adjustable screen having diiferent size apertures.

FIGURE 12 is a view in vertical section of the device of FIGURE 11 illustrating a solid plate section.

As shown on the drawings:

Briefly stated, the present invention involves employment of a screen member positioned in a headbox or flow channel adjacent the outlet thereof through which the stock furnish flows onto a forming surface; On the inlet side of the screen, a hydrofoil arrangement carries bars of generally aerodynamic configuration which cooperate with the supply side of the screen plate to deliver the furnish through apertures formed in the plate thereby dispersing the fibers immediately prior to their delivery to the forming surface and thereby minimizing fioccing thereof. Secondarily, the rotor bars tend to maintain the supply side of the screen free and prevent lumps or agglomerations from building up on the screen and clogging the apertures in the screen.

Important aspects of the invention include generally a tangential stock inlet to the interior screen system (as in the case of FIGURES 1 through 8) and/ or generally tangential outlet therefrom, (usually through a suitable screen member which affords cross flow and precludes rejects from entering into the stock being fed to the forming surface, as in FIGURES 9 and 10).

As appears in FIGURE 1, the general arrangement of a headboX or flow box assembly 1B is shown for delivering stock fed through an inlet 2 to an outlet 3 positioned over a conventional breast roll 5 carrying a forming surface, such as a Fourdrinier wire 4. The outlet 3 may be provided with a conventional adjustable slice 3a.

The headbox or flow channel assembly 1 includes a front wall 6, rear wall 7, an open or closed top 8, side walls 9, one of which appears in FIGURE 1, and a bottom wall 10. The bottom wall 10 may carry an apron 11 and with the tapered wall 12 define a converging flow path to the outlet 3.

The stock in the headbox has a free surface level L, maintained by a level control Set. With a pressure type headbox this would be an orifice permitting a balanced escape of liquid and air. With an open type headbox this would be a conventional overflow. Conventional showers 8b suppress foam and assist in maintaining a clean surface.

Positioned in the headbox adjacent the outlet 3 is a hydrofoil arrangement including a rotor 13 carried by a shaft 14 which is rotatable counterclockwise by means (now shown) which may vary the speed at which the rotor 13 is rotated. It will be noted in FIGURE 1 that the rotor is completely submerged below the furnish surface level L.

The rotor appearing in FIGURE 1 carries four more radially extending arms 154%. Carried at the end of each arm -18 and preferably at an equal distance from the rotor 13 is a head or foil bar 19-122 of generally aerodynamic configuration in cross-section. v

A curved screen plate 23 extends the full width of the headbox and is connected to the wall 12 as at and the bottom wall 10 as at 26. The screen 23 is concave as seen from the rotor 13 and is provided with a plurality of apertures 24 through which the furnish is supplied to the outlet 3. The bars 12-22 are preferably of a length sufficient to sweep adjacent the transverse width of the plate 23 for the effective flow of the furnish to the apertures 24.

Each bar 19-22. is provided with a leading edge and a trailing edge and a portion of the outer surface of, the bar adjacent the supply side of the screen 23 is curved concave in section as seen from the rotor 13.

The outer surface of each bar 19-22 is positioned inwardly from the supply side of the screen 23 a small distance so that as each bar passes around adjacent the inner surface of the screen its leading edge creates a positive pressure wave tending to force the furnish in the space between the screen 23 and outer surface of the bar 1922 through the apertures 24 of the screen and to the outlet 3 of the flow channel or headbox 1.

The trailing edge of each bar 19-22 develops between the supply side of the screen 23 and the outer surface of the trailing edge of each bar a wave of reduced pressure, when compared with the pressure condition created between the leading edge of each bar and the screen, which tends to draw away from the surface of the screen large lumps, particles or fibers which would otherwise tend to remain in place and clog the screen. The rotation of the hydrofoil arrangement causes these large size lumps to be drawn downwardly and tangentially outward through a flow channel A defined by an arcuate baffie plate and the end wall 10. A distributor roll 27 of the conventional perforated type having apertures 28 therein is provided for further enhancing fiber distribution and dispersion in the flowing slurry.

A plurality of showers 8b are disposed above the level L of the furnish and a level control outlet 8a is also provided.

In the embodiment appearing in FIGURE 1, the approach of the flow of furnish to the plate 23 is tangentially from the top of the chamber through an inlet 36 defined by the screen 23 and an end of an arcuate plate 37. A plate 37a joins with plate 37 to assure streamline flow channel into the chamber 7a. Once the furnish is introduced into the chamber defined by the hydrofoil and screen plate and arcuate plate 37, and furnish is supplied through the apertures of the screen plate and tailings are exhausted through the outlet A.

FIGURE 1A is a top view in section depicting a preferred alternate construction of a reject/recirculation outlet 40a of FIGURE 1 (which may be used in FIG- URE l at substantially the mouth or peripheral location, indicated at A, of the tangentially aligned outlet slot between the inlet fioor 10 and the wall 30 for flow control). Struts or abutments 40b serve to stiffen upper wall 30 and to limit and control flow of exiting stock through the spaces 46a defined thereby. Similar structure is preferred for reject outlets shown in other modifications herein.

In the arrangement appearing in FIGURE 3 the headbox is constructed so that the flow channel 66 is defined by an outer wall member 67, a generally hemicylindrical screen plate 68 and a formed wall member 69. The wall 69 is preferably attached at the screen plate 68 terminus so that the wall 69 is curved rather than abrupt. The desired curve may be approximated by an involute developed on the cylinder 68. This is found advantageous to across the full width of the chamber.

maintain a square velocity profile, i.e., where instantaneous velocities are everywhere equal through a plane perpendicular to the general direction of flow in the: channels while in a highly turbulent condition. In this embodiment, the flow of stock is directed upwardly through the inlet 2 and the hydrofoil bars 19 tend to carry the slurry upwardly and around through the apertures formed in the plate 68. Rejects are removed tangentially through the reject outlet 58a which may comprise a plurality of pipes coextensive with the headbox width and, thus, functionally comparable to the embodiment of FIG- URE 1A. One of the advantages of this particular atrangement is that the main flow component is nowhere subjected to abrupt change of direction.

In FIGURE 4, the furnish is supplied tangentially into the top of the chamber defined by the hydrofoil and screen plate 68 and rejects are taken off tangentially through the outlet 58a having a lateral leg 58b. The screened slurry flows through a converging flow channel 70 which also has an insert 6 9 as previously described, to the outlet 5 thereof and to, the forming wire 4.

It will be observed that the furnish is introduced in one direction and supplied to the forming wire in a diametrically opposite direction, without abrupt change of direction. This modification is particularly useful for the well known secondary headbox on Fourdrinier paper machines.

In FIGURE 2, there is shown an arcuate delloccing chamber 71 to which the furnish is supplied tangentially through a channel 72 defined by the top guiding wall 73 and an arcuate solid plate member 74 which extends The furnish is supplied through a screen member 75 into a converging flow channel 76 defined by a top wall 77 and a bottom wall 78. The flow channel 76 extends the full width of the forming wire 4 and the deflocced furnish flows through the outlet 79 onto the forming wire. To vary the height of the outlet, the top wall 77 is pivoted at 80 to the top wall 73.

The tailings and rejects are removed tangentially through an opening 81 into a chamber 31a feeding into a cross flow conduit 81b indicated diagrammatically as feeding to a downwardly directed outlet 40a. The chamber is defined by the bottom wall 10 land a section 74a of the curved wall 74. A side wall 83 cooperates with the end wall 73 to define the flow path 72.

In the embodiment appearing in FIGURE 5 a compact drum type flow vessel, generally indicated by the numeralis disclosed, which can be made to pivot around the horizontal axis (FIGURE 6), which is also the axis of the rotating hydrofoil assembly. The combination of the translatory movements (laterally and vertically, means not shown) with the rotary movement permits the exact positioning of the issuing jet on the forming wire. The flow vessel '95 consists of a central chamber '96 containing a hydrofoil arrangement therein which includes an enlarged rotor supported in the bearing housings. Means (not shown) are provided for driving the axle of rotor 97 and means are provided for pivoting the flow vessel 95 about the horizontal axis. This arrangement is of particular advantage for pressure forming devices where the nozzel direction requires very exacting adjustments.

The rotor 97 carries the hydrofoil arms 15 and bars 19 which by means of pulsation permit the movement of furnish through the apertures 24 in the screen plate 23. From the channel 106, the defiocculated furnish flows immediately through the outlet 3 onto the forming wire 5.

The furnish is introduced int-o the top portion of the chamber 96 through a flow channel 1tl7 which is sized to the chamber 96. The furnish is introduced into the channel 107 from an annular chamber 1&8 which may be considered similar to the cross flow distributor of well known construction. The chamber 108 is defined by hemicylindrical housing 109 and a generally concentric inner pipe 110 which communicates with an inlet conduit 111 and extends preferably the full width of the housin 109.

The conduit or tubing 110 is provided with a plurality of apertures 112, one of which is shown in FIGURE 6. These are so designed to provide an even pressure distribution in the annular chamber 108. It will be observed that the apertures 112 are formed in the pipe 110 on the side thereof opposite the flow channel 107. In this man,- ner the force of the jets issuing from the perforations is dampened and most of the energy reconverted into pressure. The fibers are distributed to some extent with the furnish flowing through the apertures 112 and passing as indicated by the arrows, for How in two directions. Thus, the furnish is separated into two flow paths and recombines or merges in the channel 107 thereby further enhancing fiber distribution in the slurry prior to delivery thereof to chamber 96.

In the FIGURE 7 is illustrated a dual flow headbox assembly that includes two sections 115 and 116 which receive stock from a plurality of inlet lines 117 and 118, respectively, and deliver the stock to a double slice lip or nozzle 119. Each of the sections 115 and 116 includes two solid arcuate wall sections 120 and 121 which form the two lips 122 and 123 at one end and are in open communication with the inlet lines from a suitable distributor at their other ends 124 and 125.

Within the headbox assembly are fixed two solid arcuate members 126 and 127 which join at the center to form a common wall 128. Two arcuate extensions 129 and 130 of the two members 126 and 127, respectively, converge at the point 133 and form, with the arcuate outer members 120 and 121, two flow channels 131 and 132. A plurality of braces 134 are fastened to the members 126, 127, 129 and 130 for support.

Mounted with the two sections 115 and 116 are two hemicylindrical screen plates 135 and 136 which have a plurality of apertures 137 and 138 formed in them. Concentrically mounted within each of the two screen plates 135 and 136 are rotors 139 and 140 which are carried by two shafts 141 and 142, respectively. Each of the rotors 139 and 140 carries radially extending arms 143 and 144, respectively, which support a plurality of heads or foil bars 145 and 146. Again, the "bars 145 and 146 are. mounted at equal distances from the rotors 139 and 140 and sweep adjacent the transverse width of the plates 13.; and 136 in order to induce the flow of the stock through the apertures 137 and 138.

The rejects or tailings are removed from the two sections 115 and 116 through a plurality of reject lines 147 and 148.

The combinations possible with this type of arrange-- ment are numerous. The following are some of the improvements that are obtainable over present head boxes: Better formation, better strength in cross-section, better drainage control at high speeds, and lower loss of fillers in the whitewater.

The principle incorporated is based on the non-mixing of streams when flowing through a converging section. The forming of the sheet takes place in the short section available at the discharge of the orifice or nozzle. The following are some of the jet combinations that are possible:

(1) upper jet with short average fiber distribution and lower jet with long fibers; (2) upper jet with low consistency and lower jet with high consistency; (3) upper jet of higher grade stock (liner) and lower jet of lower grade stock; (4) upper jet at wire speed or slower and lower jet at wire speed; and (5) upper jet with filler and lower jet without additives.

A further possible application of the double jet prin ciple lies in the double wire forming of paper.

In FIGURE 8 is illustrated an alternate type of dual nozzle for this apparatus. This apparatus includes an upper slice lip 150' that is fastened to a pivotally mounted shaft 151 and a lower slice lip 152' that is fastened to a pivotally mounted shaft 153. These two lips 150' and 152' are connected to two actuator rods 154' and 155' which vary the vertical position of the two lips 150' and 152'. These two rods 154' and 155 may-be connected to a suitable motor (not shown) such as an air or hydraulic motor. 7

A member 155 is mounted between the two lips 150 and 152' on a rotatable shaft 156'. This member converges to a point at 157' which extends between the two lips 150' and 152. the member 155' through which water can be injected for lubrication purposes.

It is apparent that by moving the rods 154 and 155', the two lips and 152' can be made to pivot around the axes of the shafts 151' and 153 in order to vary the width of the stock outlet 159' or to change the angle at which the stock is discharged. Further, the position of the member can be varied in order to give a different percentage of the stock coming from the two sections.

With the apparatus of the present invention, an even flow in the transverse and longitudinal directions of the furnish are created by maintaining average velocities essentially the same in the flow of furnish and the elimination of cross flows whether of transient or periodic origin.

The type of headbox or flow vessel employed is not considered critical. The operating features of the hydrofoil screen arrangement should be such that the hydrofoil rotates at speeds, for example within the range from about 30 to about 60 fps. to provide the intensity of pulses required to maintain the plates open and the frequency of operation will depend largely upon the type of screen perforations and the consistency of the stock. Excellent results are obtained where the frequency is not less than 20 c.p.s. at machine speeds of 1,000 f.p.m. In this manner, 'the longitudinal basis weight variations are minimized. In addition, the distance or clearance of the hydrofoil bars from the screen may be varied depending upon the intensity of the pulses required. Excellent results are obtained where the clearance between the hydrofoil bar and screen is within the range of from about .060" to about 1.00" anda clearance of about A" has produced satisfactory results. The hydrofoil bar should also be designed to oifer a rounded surface of a thickness not less than /2" on the leading edge adjacent the screen. The channel between the screen and bar created by the hydrofoil and the screen plates should be established in such a manner that the angle of attack of the hydrofoil leading edge does not exceed a critical divergence angle formed by the trailing edge of the bar and the curvature of the plate. Experimentation indicates that this angle should be less than 14.

Preferably the furnish entering the chamber inwhich the hydrofoil bars are located should be introduced preferably in a direction of rotation of the hydrofoil bars to minimize the possibility of creation of large turbulence and the dissipation of energy into heat. The power required for the assembly will be reduced substantially if the furnish is fed tangentially into the chamber in which the hydrofoil bars are rotating at velocities within the range of from about 10 to about 15 feet per second. Experimentation has indicated that the power requirements to rotate the hydrofoil bars in the same direction as introduction of the flow of furnish will be approximately 50% less than in the case where the hydrofoil bars are rotating in a direction opposite to the direction of flow of the furnish into the chamber.

It will be appreciated that the intensity of pulsation and frequency of the bar and screen arrangement will depend largely upon the consistency of the furnish being defiocced. The higher the stock consistency, the greater the amount of energy required to obtain the same flow through the screen plate, other conditions being identical. The power required to drive the rotating hydrofoil members will depend greatly on the type of structural supports assigned to carry the hydrofoil structures. In addition,

At least two slots 158' are formed in- Reynolds number, N within the range of from about X10 to about 5x10 The Reynolds number is a dimensionless ratio equal to a characteristic length L, in this case the chord of the hydrofoil, multiplied by the linear velocity of V of the foil, divided by the viscosity '1 of the fluid The screen plate perforation size will depend upon the type of fibers in the furnish and the consistency of the furnish. It will be observed, however, that perforations to times smaller than the perforations in the present rectifier rolls will be possible.

A thin plate may be employed and the type of mechanical construction and support for such plate will depend upon factors such as furnish velocity and consistency. Thus, the sizeof the plate or cross-sectional thickness may be determined in conventional manner.

The actual configuration of the hydrofoil bar in crosssection may be any configuration so long as the pulsation effect is created adjacent the screen and the leading edge supplied the furnish through the screen and the trailing edge cleans the supply side of the screen.

Thus, the hydrofoil bar in crosssection may have any aerodynamic configuration, the velocity of the foils and the number of the foils employed will depend upon intensity of pulsation required, which in turn depends upon the type of furnish, number of apertures in the screen plate, size of the apertures and the like. The velocity of the foil bars is independent of the entering velocity of furnish and the exit velocity through the apertures of the screen plate depend upon the number of apertures, size of the apertures and the like. The position of the bars relative to the screen depends upon these factors also, but in general, it will be observed that the bars located relative to the screen to create a pressure on the leading edge of the bar to force the furnish through the apertures and a reduced pressure at the trailing edge of the bar to clean the screen.

Vibrating means (not shown) may also be employed for vibrating the screen to assist in the cleaning effect. The hydrofoils operate preferably completely submerged in the slurry and the apertures in the screen may be slots, perforations and the like.

It will be noted that one characteristic of the views of FIGURES 1 through 8 is that these views show the stock feed to the interior screen as being generally tangential in character. In contrast it will be seen hereinafter that the stock feed to the embodiments of FIGURES 9 and 10 involve cross-machine stock feed; but all of these embodiments involve withdrawal of rejects along a generally tangential slot (or its equivalent) from the screen, at an open portion thereof along a generally tangential region.

=Briefiy stated, the present invention of FIGURES 9 and 10 involves employment of a screen cylinder positioned in a headbox or flow channel adjacent the outlet thereof through which stock furnish flows onto a forming surface of a papermaking machine. On the inlet side of the screen, a hydrofoil arrangement carries bars of generally aerodynamic configuration which cooperate with the supply side of the screen cylinder to deliver the furnish flowing centrally in a cross-machine direction through apertures formed in the cylinder thereby dispersing the fibers immediately prior to their delivery to the forming surface and thereby minimizing floccing thereof. secondarily, the rotor bars tend to maintain the supply side of the screen free from lumps and also prevents lumps or agglomerations and the like from building up on the screen cylinder and clogging the apertures thereof.

As appears in FIGURE 9, the general arrangement of a headbox or flow assembly, generally indicated by the numeral 114 is shown for delivering slurry of furnish fed through cross-machine inlet 115 to an opposite crossmachine outlet 116 positioned over a conventional breast roll 117 carrying a forming surface, such as a Fourdrinier wire 118. The outlet 116 may be provided with a conventional adjustable slice' (not shown), but is equipped for cross-machine recirculation of the stock.

The headbox or flow channel assembly 11d includes a downwardly directed top wall 1119 which converges with the bottom wall v116 to define the outlet 116. The assembly 114 is provided with an arcuate end wall portion 111 which joins the bottom wall 110. A generally tangential cross-machine slot i also provided between the walls 141 and 14-2 which slot 143 receives rejects and withdraws the same in a cross-machine direction via a cross-machine header 144 at the forward end thereof. To complete the headbox assembly, two side walls .112, one of which is shown in FIGURE 10, run parallel to each other on each side of the walls 109 and .110. The headbox assembly is in a cross-machine direction size-d to the effective forming surface of the wire 11% and the bottom wall may carry an apron (not shown) adjacent the outlet.

Positioned in the headbox is a hydrofoil arrangement including a rotor 113 carried by a shaft 124 which is rotatable by means on bearings 114a which may also vary the speed at which the rotor 13 is rotated. The rotor 113 carries radial arms 119a, etc., 113a, etc. Carried at the end of each of the arms 113a, etc., and preferably these arms or foils 119a, etc. are at equal distances from the rotor 113. Each such bar 119a is a head or hydrofoil bar 119a, etc. of general aerodynamic configuration cross-section which extends lengthwise of a cylindrical housing 111.

The cylindrical housing 111 is provided with a peripheral screen portion 151 within the periphery of a portion of the housing '111,and 110 and is supported in the assembly 114 by the side walls 112. With the slotted rotor 113, the concentric slotted stationary cylinder 53 define a cross-machine cylindrical stock channel from 115416. The chamber or channel -116 may be of any crosssectional width depending upon the size and configuration of the slotted rotor 113 and stationary member 153, which has slots 154 in registry with the smaller elongated slots 155 in non-rotary cylinder 153.

The bars 119a, etc. are preferably of a length sufficient to sweep adjacent the transverse width of the cylindrical housingjll for effective flow of the furnish through the screened apertures 151 therein.

Each of the bars 119a, etc. has a leading edge, atrailing edge, and an outer surface (all as hereinbefore shown). This outer surface is disposed closely adjacent the inner surface of the cylinder 111 and its screen 151 and a small space .127 is defined between the inner surface of the cylinder 11-1 and its screen 151 and the outer surface of each of the bars 119a, etc.

When the rotor 113 and the eight bars 11%, etc. are rotating at proper speeds, each bar creates a momentary pressure variation or pulse in the furnish. A pressure wave travels around the screen 151 at the speed of travel of the bars 119a, etc., and each point of the cylinder screen is effected by each pressure wave only instantaneously.

The type, intensity and duration of the pressure waves obtained depends on the position of the foils in relation to the cylinder, the length of the foils, and their linear speed. In general they consist of an increase above the average pressure in the chamber as the leading edge of a foil approaches a reference point on the cylinder and a decrease in pressure starting at'the point of minimum clearance between the surface (indicated at 126 for the foil 11%) and the cylinder screen 151. This results in a very effective and localized pulse which, by reversing the direction of flow, permits the dislodging of fibrous lumps or other undesirable particles which, otherwise, may remain lodged in the apertures of the screen portion 151 and clog the screen cylinder.

The rotation, clockwise or counterclockwise, of the bars 110a, etc. causes the undesirable lumps or particles to be drawn downwardly and out of the head-box through a generally tangential outlet opening 143 between the walls 141 and 142. The outlet opening 143 communicates with the cross-machine chamber 144 and carries these large size lumps and other particles through such a discharge conduit 144 in a cross-machine direction.

The entire headbox system is maintained under pressure during operation and is filled with stock. The stock afiter passing through the screen apertures in the screen portion 131 flows in a generally tangential direction toward the outlet 116 between the walls 109 and 110.

It will thus be appreciated that the rejects are removed generally tangentially at the forward end of the rotating foils and the refined, screened stock is also processed through a screen (e.g. 151, 23, etc.) in a generally radial direction initially but in the case of the unit of FIG- URES 9 and this refined stock flow is ultimately converted into a generally tangential flow (with respect to the rotating foils of the unit).

It will be understood that modifications and variations may be efiected without departing from the scope of the novel concepts of the present invention.

Referring to FIGURES L1 and 12, it will be seen that these figures correspond respectively to FIGURES 5 and 6 of our aforesaid previous application Serial No. 141,270 (now abandoned) although the reference numerals used herein are the same as those previously usedexcept that they are in the 200 series. In the headbox flow channel arrangement 201D appearing in FIGURE 11, the screen plate 223 is provided with an extension 245 of smaller cross sectional thickness than the section 223 with apertures 245a of smaller dimension than the apertures 224. The screen sections 223 and 245 are rotatable clockwise to the position shown by the dotted lines for positioning the screen section 245 adjacent the outlet 203 of the flow channel arrangement. Arms 246 provide support and carry the plate sections 223 and 245. The arms 246 are carried by an adjustable stationary section (not shown) on the rotor which is movable to position the screen as required or an adjustable sleeve (not shown) may be provided for carrying the arms 246.

The arrangement 201D employing two screen plates of different types, which may be used alternately if the paper machine has a varying requirement in flow or type of fiber used, permits the use also of a blank unperforated plate 247, as appears in FIGURE 12, to act as a valve at the slice 203 and block flow to the wire 204. In this arrangement the blank section 247 provides means for defining a pair of chambers 247a and 2471: in the headbox or flow channel arrangement 201E of FIGURE 6, with the plate 247 in the position shown. The wall 212 and bottom wall 210 define the chamber By closing the adjustable slice 203a so that it blocks the outlet 203, the chamber 247a is in condition to be cleaned without requiring the complete termination of flow of the furnish to the head box chamber 24711 or complete shutdown of the forming wire and the paper making machine. An inlet (not shown) to chamber 247a may be provided as may be an outlet 2470 through which a fluid may be tflowed for cleaning the chamber 247a. The furnish in the chamber 247b may be recirculated through means (not shown) communicating with the channel 230 for returning the furnish to the source thereof. Similarly, the channel 247d may be cleaned by flushing with a cleaning .fiuid introduced 10 through the inlet 202 which discharges through the channel 230. The blank member 247 when positioned as shown in FIGURE 12 will prevent flow of the cleaning fluid or stock onto the forming wire 204 from the chamber 24717.

We claim as our invention:

1. In apparatus adapted for minimizing floccing and for increasing dispersion of fibers in papermaking furnish prior to delivery thereof to a web forming means of a papermaking machine comprising a fiow vessel defining a furnish flow path, an inlet to .the flow vessel for introduction of furnish under pressure along the flow path, an outlet of the vessel for delivering furnish to web forming means of a papermaking machine, an arcuately shaped plate in the vessel adjacent the outlet and extending transversely to the direction of flow of furnish, means defining perforations in a portion of the plate positioned for flow of furnish to the outlet, a reject outlet for discharge of tailings, lumps and agglomerations from the vessel, and a rota-table member of generally aerodynamic configuration in cross-section disposed in the vessel between said arcuate plate and the inlet to the flow vessel and in the flow path of the tfurnish for urging furnish toward and away from the perforated portion ofthe plate, the improvement comprising means defining a transverse inlet slot at one edge of the plate extending the full width of the plate positioned for tangentially introducing the furnish to the supply side of the plate.

2. In apparatus adapted for minimizing floccing and for increasing dispersion of fibers in paper-making furnish prior to delivery thereof to a web forming means of a papermaking machine comprising a flow vessel defining a furnish flow path, an inlet .to the flow vessel for introduction of furnish under pressure along the flow path, an outlet to the vessel for delivering furnish to web forming means of a paper making machine, an arcuately shaped plate in the vessel adjacent the outlet and extending transversely to the direction of flow of furnish, means defining perforations in a portion of the plate positioned for flow of furnish to the outlet, a reject outlet for discharge of tailings, lumps and agglomerations from the vessel, and a rotatable member of generally aerodynamic configuration in'cross-section disposed in the vessel between said arcuate plate and the inlet to the flow vessel and in the flow path of the furnish for urging furnish toward and away from the perforated portion of the plate, the improvement comprising means defining a transverse inlet slot at one edge of the plate extend-ing the full width of the plate positioned for tangentially introducing the furnish to the supply side of the plate, said means defining the transverse inlet slot including guide wall means aiming .the furnish flow path tangentially. t

3. In apparatus adapted for minimizing floccing and for increasing dispersion of fibers in papermaking furnish prior to delivery thereof to a web forming means of a papermaking machine comprising a flow vessel defining a furnish flow path, an inlet to the flow vessel for introduction of furnish under pressure along the flow path, an outlet to .the vessel for delivering furnish to web ,forming means of a papermaking machine, an arcuately shaped plate in the vessel adjacent the outlet and extending transversely to the direction of flow of furnish, means defining perforations in a portion of the plate positioned for flow of furnish to the outlet, a reject outlet for discharge of tailings, lumps and agglomerations from the vessel, and a rotatable member of generally aerodynamic configuration in cross-section disposed in the vessel between said arcuate plate and the inlet to the flow vessel and in the flow path of the furnish for urging furnish toward and away from the perforated portion of the plate, the improvement comprising means defining a transverse inlet slot at one edge of the plate extending the full width of the plate positioned for tangentially introducing the furnish to the supply side of the plate, and means defining a transverse reject fiow path, separate 1 1 and apart from the aforesaid transverse inlet slot, and extending the full width of the plate.

4. In apparatus adapted for minimizing floccing and for increasing dispersion of fibers in papermaking furnish prior to delivery thereof to a web forming means of a papermaking machine comprising a flow vessel defining a furnish flow path, an inlet to the flow vessel for introduction of furnish under pressure along the flow path, an outlet to the vessel for delivering furnish to web forming means of a papermaking machine, an arcuately shaped plate in the vessel adjacent the outlet and extending transversely to the direction of flow of furnish, means defining perforations in a portion of the plate positioned for flow of furnish to the outlet, a reject outlet for discharge of tailings, lumps and agglomerations from the vessel, and a rotatable member of generally aerodynamic configuration in cross-section disposed in the vessel between said arcuate plate and the inlet to the flow vessel and in the flow path of the furnish for urging furnish toward and away from the perforated portion of the plate, the improvement comprising means defining a transverse inlet slot at one edge of the plate extending the full width of the plate positioned for tangentially introducing the furnish to the supply side of the plate, said means defining the transverse inlet slot including guide wall means aiming the furnish flow path tangentially, and means defining a transverse reject fiow path, separate and apart from the aforesaid transverse inlet slot, and extending the full width of the plate, said reject flow pathmeans including guide wall means defining a transverse reject slot aiming the reject flow path tangentially away from said arcuate plate.

. 5. In apparatus adapted for minimizing floccing and for increasing dispersion of fibers in papermaking furnish prior to delivery thereof to a web forming means of a papermaking machine comprising a flow vessel defining a furnish flow path, an inlet to the flow vessel for introduction of furnish under pressure along the flow path, an outlet to the vessel vfor delivering furnish to web' forming means of a papermaking machine, an arcuately shaped plate in the vessel adjacent the outlet and extending transversely to the direction of flow of furnish, means defining perforations in a portion of the plate positioned for flow of furnish to the outlet, a reject outlet for discharge of tailings, lumps and agglomerations from the vessel, and a rotatable mem'ber adapted to rotate in a given direction, said member being of generally aerodynamic configuration in cross-section disposed in the vessel between said arcuate plate and the inlet to the flow vessel and in the flow path of the furnish for urging furnish toward and away from the perforated portion of the plate, the improvement comprising means defining a transverse inlet slot at one edge of the plate extending the full width of the plate positioned for tangentially introducing the furnish to the supply side of the plate, said inlet slot being aimed in the aforesaid given direction, and means defining a transverse reject flow path, separate and apart from the aforesaid transverse inlet slot, and extending the full width of the plate, the aforesaid transverse inlet slot being positioned above the aforesaid transverse outlet means, and the aforesaid rotatable member of aerodynamic configuration effecting pulse-feed of furnish to the perforated plate portion.

6. In apparatus adapted for minimizing floccing and for increasing dispersion of fibers in papermaking furnish prior to delivery thereof to a web forming means of a papermaking machine comprising a flow vessel defining a furnish flow path, an inlet to the flow vessel for introduction of furnish under pressure, an outlet to the vessel for delivering furnish to web forming means of a papermaking machine, an arcuately shaped plate in the vessel adjacent the outlet and extending transversely to the direction of flow of furnish, means defining perforations 12 in a portion of the plate positioned for flow of furnish to the outlet, a reject outlet for discharge of tailings, lumps and agglomerations from the vessel, and a rotatable member of generally aerodynamic configuration in cross-section disposed in the vessel between said arcuate plate and the inlet to the flow vessel and in the How path of the furnish for urging furnish toward and away from the perforated portion of the plate, the improvement comprising means defining a transversely extending slotted inlet extending the full width of the plate positioned for introducing the furnish to the supply side of the plate, and means defining a transverse reject flow path, separate and apart from the aforesaid transverse inlet, and extending the full width of the plate, said transversely extended inlet receiving furnish flowing transversely from at least one end thereof inwardly and then converting the transverse flow to flow through the slots thereof generally aligned in planes perpendicular to the initial transverse flow direction and toward the rotatable member.

7. In apparatus adapted for minimizing floccing and for increasing dispersion of fibers in papermaking furnish prior to delivery thereof to a web forming means of a papermaking machine comprising a flow vessel defining a furnish flow path, an inlet to the flow vessel for introduction of furnish under pressure, an outlet to the vessel for delivering furnish to web forming means of a papermaking machine, an arcuately shaped plate in the vessel adjacent the outlet and extending transversely to the direction of flow of furnish, means defining perforations in a portion of the plate positioned for flow of furnish to the outlet, a reject outlet for discharge of tailings, lumps and agglomerations from the vessel, and a rotatable member of generally aerodynamic configuration in cross-section disposed in the vessel between said arcuate plate and the inlet to the flow vessel and in the flow path of the furnish for urging furnish toward and away from the perforated portion of the plate, the improvement comprising means defining a transversely extending slotted inlet extending the full width of the plate positioned for introducing the furnish to thesupply side of the plate, and means defining a transverse reject flow path, separate and apart from the aforesaid transverse inlet, and extending the full width of the plate, said transversely extending slotted inlet mounting a rotary slotted member carrying the aforesaid member of generally aerodynamic configuration, said slotted inlet receiving internally furnish under pressure from at least one end thereof to divert the furnish from an initial transverse flow direction outwardly through the slots of the inlet and the rotary slotted member carried thereby and into an annular region confined by said plate and the vessel walls carrying said plate;

8. An apparatus adapted for minimizing floccing and for increasing dispersion of fibers in paper making furnish prior to delivery thereof to a web forming means of a paper making machine comprising a flow vessel defining a furnish flow path, an inlet to the flow vessel for introduction of furnish under pressure along the flow path, an outlet to the vessel for delivering furnish to web forming means of a paper making machine, an arcuately shaped plate having two portions in the vessel adjacent the outlet and extending transversely to the direction of flow of furnish, means defining perforations in one portion of the plate positioned for flow of furnish to the outlet, a reject outlet for discharge of tailings, lumps, and agglomerations from the vessel, and a rotatable member of generally aerodynamic configuration in cross-section disposed in the vessel between said 'arcuate plate and the inlet to the flow vessel and in the flow path of the furnish for urging furnish toward and away from the perforated portion of the plate, the improvement wherein the other portion of said plate is imperforate, and means defining a generally transverse open slot adjacent said imperforate portion for said rotatable members to tangentially drive tailings and furnish incapable of entering said perforations in a generally tangential direction away from said one portion of the plate and into the reject outlet.

References Cited by the Examiner UNITED STATES PATENTS 1/1961 Baxter 162348 8/1962 Baxter 162-339

Claims (1)

1. IN APPARATUS ADAPTED FRO MINIMIZING FLOCCING AND FOR INCREASING DISPERSION OF FIBERS IN PAPERMAKING FURNISH PRIOR TO DELIVERY THEREOF TO A WEB FORMING MEANS OF A PAPERMAKING MACHINE COMPRISING A FLOW VESSEL DEFINING A FURNISH FLOW PATH, AN INLET TO THE FLOW VESSEL FOR INTRODUCTION OF FURNISH UNDER PRESSURE ALONG THE FLOW PATH, AN OUTLET OF THE VESSEL FOR DELIVERING FURNISH TO WEB FORMING MEANS OF A PAPERMAKING MACHINE, AN ARCUALTELY SHAPED PLATE IN THE VESSEL ADAJCENT THE OUTLET AND EXTENDING TRANSVERSELY TO THE DIRECTION OF FLOW OF FURNISH, MEANS DEFINING PERFORATIONS IN A PORTION OF THE PLATE POSITIONED FOR FLOW OF FURNISH TO THE OUTLET, A REJECT OUTLET FOR DISCHARGE OF TAILINGS, LUMPS AND AGGLOMERATIONS FROM THE VESSEL, AND A ROTATABLE MEMBER OF GENERALLY AERODYNAMIC CONFIGURATION IN CROSS-SECTION DISPOSED IN THE VESSEL BETWEEN SAID ARCUATE PLATE AND THE INLET TO THE FLOW VESSEL AND IN THE FLOW PATH OF THE FURNISHED FOR URGING FURNISH TOWARD AND AWAY FROM THE PERFORATED PORTION OF THE PLATE, THE IMPROVEMENT COMPRISING MEANS DEFINING A TRANSVERSE INLET SLOT AT ONE EDGE OF THE PLATE EXTENDING THE FULL WIDTH OF THE PLATE POSITIONED FOR TANGENTIALLY INTRODUCTING THE FURNISHED TO THE SUPPLY SIDE OF THE PLATE.

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