US2589639A - Paper machinery - Google Patents

Description

March 18, 1952 A, STA GE 2,589,639

PAPER MACHINERY Filed 001;. 1'7. 1947 r 2 SHEETSSHEET 1 IN VEN TOR.

W BY ATTORNEYS Filed Oct. 17, 1947 5. A. STAEGE PAPER MACHINERY soj 88 O O 77 8/ 85 62 :CL

a T I: INVENTOR.

Mia/J ATTORNEYS Patented Mar. 18, 1952 Stephen :A. *Staege, Hamilton, Ohio, 'assignor to TheBlack-Clawson Company, Hamilton, Ohio,

. a corporation of Ohio SApplica t-ion c'tober17, 1947,-".Seria'l"No. P7803156 J'Iihis invention relates .to paper ..making,..and more particularly :to stock. :supply means for paper; making machines.

"Qne zoi Ithe .principa1 objects -:of the invention is tojprovide aninlet for; supplyingpapertmaking stock :to .ajF-ourdriniergpaper machine having an open head ,box under controlled conditions of substantially uniform velocity flow rand: distribution :of :fiber; across the width of the machine ,to give a thigh degreerof-uniformity of weight and .fiberdistribution in the web or 'sheet.

:Another object-is to ;provide .a stock -inlet for azzFourdrinier paper {machine .having anropen head l-box which is adapted ,to discharge stock through a slot orifice atlrelatively high and substantially uniform velocity across itsflateral .extenttoefiect uniform fiber distribution across the widthcf the machine and which delivers suchstock -,.to the-headbox at atsufiiciently re- .duced velocity with respect-to the velocityof. flow through the slot orifice to avoid turbulence and large --.eddy currents while maintaining desired uniformity of flow conditions across the machine .from ,the slot orifice .to the. forming wire.

.It isalsoan objectof the invention to provide a .stock supply system .for a Fourdrinier-paper machine having an open head box which includes a pair of oppositely tapered conduits having -a..common discharge .orifice of restricted dimensions to receivestockunderpressure and .to discharge the-stock at .arsubstantiall-y uniform and relativly'jhig'h velocity across the width of the machine and which alsoincludes a s'tockinlet passagearranged to 'deliver the stock ,from the discharge orifice to the-headbox and diverging I in {the -direction of flow. of "the stock i therethrough -at such an angle as "to (form with Ithe .jdischarge "orifice a TVenturi passage .for dissipating the velocityenergy. ofthe stock'with minimum turbulenceras thes'tock 'flowsfrom the. discharge orifi'ce -to""the head box while "maintaining :subs'tantial ur'iifform'ity of fiber distributionacross"the 'width *dfrthe'machine.

A *further object-is "to provide a ,stock "inlet having; the "above "characteristics which is:readily ada-ptetl f'or atta'chmenttc the existing open hea'd box-"of a Fourdrini-er'papenmachine "to effect improved :conditions *of'uniform fiber. distributionthroughoutithe stock in theihea'di box" with- :out 1 producing .undesirable turbulence and. large eddy. currents ,in ,the stock as delivered. to ,the forming .wire and withoutrequiring replacement .onxexpensive rebuildingof .the .existinghead ibox and-slice.

Other-.objectsand advantages. of the invention c cams. (c rca-44) 2. will be :apparent: from ,t'hei following description. "the accompanying :;drawings :and .;the :appended :claims. o

. In ithe :drawings:

.;Fi g. J1 isaamore or'less diagrammatic view in side." elevation, partly broken' away to. show details "of-internal construction, illustrating aiportion Toff a *Fourdrinier paper {machine having {an open -headhoxandraportion' of the stockisuppl y:system leading :to'the head .box;

. Fig. 2 :is 1 an "elevational View looking from left to rightin-Fig; lpwith thehead .box and-.a ;part .of the inlet passage removed;

Fig.- ,3.is a sectional view onthe line 3-j,3-.of Fiailrand also .of Fig. 2; and

=Fig..-4ris a diagrammatic viewshowinganother arrangement of stock inlet with a Fourdrinier machine havingan :open head box.

In the drawings, which "illustrate preferred embodiments of the invention, Figll'shows a portionof :a Fourdrinier paper machine having an .open headbox'indicated-generallyat l0 forsupplying stock .to aforming wire ll traveling over a breast roll 12. The. stock isinitially conveyed tothe. machine from thecollecting box 15 o'ione or -.more screens indicated fragmentarily .at 1.6. .The .stock from the v.collecting box 15 passes through conduit H .to .a pump I18. driven by .a .motor .19, .and this pump-min ,turn supplies .the stock .to aflmain conduit .20 which 'is'fibranched. at 21 and 22.110 leadtoa pair-of counterflowlinle't conduits T24 and .'25,shown as of the ,typeof construction disclosed .in LS. Patent "2,34711'1, assigned to the same .alssignee as this application. .AslshownfinFigJB,.theconduits'fl and 25 extend generally transversely. of the forming wire H and 'areiseparated by a bafile 26 except 'forflimi'te'd communication around the ends of this baffleja's indicated-M11. The supply of stock'to the conduit-s 124 (and 25 may be regulated'by means 'of a variable speed drivefor pump 1.8 or .byljaivalve ;such as a ,gatevalve 28 positioned adjacent ;the "discharge side of the pump asshownin "Theba'file '26 is positioned adjacent and par- 'alle'l'to a discharge orifice30 common'to'theitwo 'conduits2'4 and 25 and "formed'by a'pairofwalls which will be substantially higher than the velocity of flow through conduits 24 and 25.

It will be noted that the direction of flow through orifice 30 is substantially at right angles to the direction of fiow of the stock-through'conduits 24 and 25, and in order to minimize possible non-uniform velocity, flow conditions because of the flow component perpendicular to this desired direction of flow through the orifice, the

respective cross-sectional areas of the tapered conduits and the slot orifice are controlled to provide 'a substantial difference .in the velocity of flow through the orifice as compared with the corresponding velocity through the conduits 24 and 25. Satisfactory results have been obtained with these velocities at a ratio of not less than about 4 or5 to 1, and with this ratio still higher it is possible to hold the velocity in conduits 24 and 25' to 'a'low value, for example from 0,5 to 2.5 feet per second, such' that the undesired angu- {la'r flow component is kept to a minimum, while still obtaining desired high velocity rates of flow through the orifice 30. At such accelerated velocities, fiber fiocs tend to be broken up and the fiber is dispersed in passing through the slot orifice, In' addition, since all of the stock is subjected to the same hydraulic conditions, there is minimum tendency tostratification or separation of light and heavy fibers due to inertia or centrifugal force. "It will be noted, as shown in Fig, 2, that the tapered conduits 24 and 25 are provided with extension portions 34 and 35, respectively, which extend outwardly on opposite sides of the machine and are connected adjacent their outer ends-with the branch conduits 2| and 22. The connections between the conduits 2| and 22 and 'the conduit extension portions 34 and 35 are thus located at a sumcient distance laterally of the machine from the ends of the slot orifice to effect adequate guiding and straightening of the j "flow. of .stock into parallel lines of flow before reaching the .slot orifice, satisfactory results haviin'gbeen obtained with distances from each end Iofjthe slotto the. center line of the adjacent branch conduit of 2 feet or more, depending. upon the size of the machine. Furthermore; since the stockis .brought into the conduit exten-- sions 34 and 35 in directions substantially perpendicular to their lengths, as shown in Fig. 2,

Ethe velocity of that component of the flow which is perpendicular to the length of the tapered conduits is largely overcome or practically extinguished, and the stock. hasan opportunity to mcr'ease that component'of flow which 'is in a direction at right angles, tolits entering direction and to establish substantially parallel lines of flow crosswise .of the formin wire before reaching the tapered'conduits' and the slot orifice 30. There is thus provided a cross fiow of stock through orifice 30 at a substantially higher velocitjthan the velocity of flow in the tapered conduita in accordance with the supply pressure and theratio of the respective areas of the orifice and the tapered conduits as 'described,.and

4 this velocity and the distribution of fiber and flow in the stock will be substantially uniform across the Width of the machine.

It is desirable to maintain such uniformity of flow conditions in the stock as it passes from the orifice and is delivered to the forming wire, in order to obtain corresponding uniformity of sheet formation However, under most operating conditions with a Fourdrinier machine having an open head box, the velocity of fiow through orifice 30 is so high that if the stock were allowed to enter the head box at the same velocity, excessive turbulence and objectionable eddy currents wouldresul-t. If the stock were permitted to enter the head box vertically at such high velocities, it would tend to spurt above the level 'of liquid therein and even above the top of the box itself. Accordingly, the present invention provides means for conveying the high velocity stock from the orifice 30 to the head box l0 while at the same time dissipating its velocity energy withminimur'n turbulence and delivering the stock to the head box' at a substantially lower velocity of flow but with substantially maintained uniformity of both velocity and distribution of fiber across the width ofthe machine for uniform sheet formation. Referring to Fig. 1, an opening 43 is forme in the bottom wall 41 of the head box to receive stock for delivery to theforming wire ll. opening 4|) is substantially wider than the slot orifice 36, as shown in Fig. 1, and extends across the lateral extent of the head box adjacent the lower edge of the vertical wall 42. For example, satisfactory results have been'obtained in a head box 33 inches in height with this opening about 6 inches in width as compared with a width of the order of 4 inch for the slot orifice 3!]. Walls 43 and 44 arearranged to form an inlet passage leading from the slot orifice 30 to the ppening 40 in the bottom of the head box. As shown in Fig. 1, the passage wall 43 is substantially parallel with the wall 42 of the head box and extends vertically upwardly from the orifice wall 3|. The wall 44, however, is inclined from the vertical and diverges from wall 43 in the direction of flow of stock frornorifice 30 to opening40. i

The degree of divergence between the passage walls 43 and 44 is controlled to a sufficiently small angle to provide a Venturi action between the passage 45 and orifice 30 and thusto provide velocity energy of the stock as it flows upwardly I "in passage 45 while maintaining the substantial uniformity of fiber distribution crosswise ofthe passage which is imparted to the flow of stock at .the orifice 30. The angular relation of the passage walls 43 and 44 is of critical importance in obtaining preferred results from the standpoint of this maintenance of uniform flow conditions, and if this angle is too large, there is a tendency for some of the stock to slow down relatively abruptly along the outer parts of the passage while the major part shoots through at relatively high velocity, thus creating a high degree of turbulence and preventing the desired uniform deceleration of the entire cross-section of the flow. Tests indicate that the'total included angle between'passage walls 43 and 44 should be not more than about 10 and preferably somewhat less, for example an angle of the order of 7 This suitable slice arrangement, and Fig. lshows the slice as formed by a substantially rigid lower Wallor lip 50-and a flexible upper plate or lip secured to the front of the head box for vertical adjustment to vary the size of the slice opening. Adjusting means for controlling the position-of the upper slice lip 5| are indicated generallyat 52 as supported on a suitable plate or bracketfi53 'welded or otherwise securedto the front of the head box. Within the head box is a baflie 55" comprising a plurality of vertically spaced portions providing a series of apertures or passages 56 through which the stock flows to'theslic'e. Desired results have been obtained in such-cases with the total cross-sectional area of the: passages 56 substantially equalgto the corresponding area of the opening 40, thus providing substantially the same velocity of flow through the passages 56 as the velocity at which the stock; enters the head box and causing sufiicient agitation of the stock within the head box to. prevent stagnation and resulting non-uniform conditions.

:In the operation of'this apparatus-as shown and described,,the pump [8 suppliesstock from the collecting box l5 to the conduit 20 and tapered; conduits 24 and i5 at suflicient' pressure to-provide a cross flow of stock through the orifice 30; at desired high velocity and'volume of flow to 'eifect uniform conditions of velocity and fiber distribution throughout the entire lateral extent of the, slot 30. As this stock .fiows upwardly through the Venturi passage 45, its velocity energy is gradually and smoothly-absorbed and dissipated as-a result of the divergence betweenthe passage walls 43 and 44. Thus when thestock reaches the opening 4!] in the bottom of the head box l0, its velocity has been reduced toa valuesuch that the stock flows into the head box without creating undesirable turbulence or. objectionable eddy currents. In addition, all'the stock is kept in constant motion toward the head box through the Venturi passage 45 and at a velocity which is substantially constant across the passage, changes in velocity being substantially uniform crosswise of the passage and taking place smoothly and with minimum turbulence. The desired conditions of uniform fiber distribution are thus maintained crosswise of passage 45 throughout its entire lengthand the stock is delivered through opening 40 under uniform conditions of velocity and fiber distribution across the entire lateral extent of the, head box, thus providing for the desired uniform flow conditions at the slice for effecting uniform sheet formation.

This construction and arrangement of the counterflow inlet and Venturi passage with a Fourdrinier machine having an open head box provide for operating the machine to produce a sheet of high uniformity at any desired wire speed within the range afforded by the maximum pressure head obtainable in a head box of given dimensions. Thus at low speeds, the pressure head within head box ID maybe only 2 or 3 inches, and under such conditions the supply of stock from the opening 40' to the slice may take place entirely through the lowest of the passages 5.6. On the other hand, speeds as high as 1,600 feetperminute have been obtained with the pressurehead of the order of 12 feet to give a spouting velocity at the slice properly correlated with 55- as well as over the top of the bafile 55, thus creating sufiicient agitation throughout the head box to maintain uniform fiber distribution and avoid stagnation of the stock. Over all this wide range of operating conditions, the counterflow inlet and Venturi passage provide desired uniform conditions of velocity and fiber distribution in the stock across the lateral extent of the head box without undesirable turbulence.

A further advantage of the present invention lies in the fact that the counterfiow inlet-and Venturi passage arrangement is readily adapted for attachment to the open head box already installed on an existing Fourdrinier machine, thus making it possible to achieve the improved conditions of uniform velocity and fiber distribution without the expense of replacing the existing head box andslice. For such installations, as well as in new machines, the size of the open-. ing into the head box corresponding to opening 45 in Fig. l is largely determined by the, speed at which the machine is to be run and hence the velocity at which the stock is to be admittedto the head box. Thus for a low speed machine, operating at a wire speed of the order of 200 feet per minute, desired results from the stand point of uniform flow conditions with minimum turbulence have been obtained with this velocity of the order of 1 foot per second, but for higher speed machines a desirable range for this velocity is approximately 1 to 2 feet per second. The size of the opening 40 is thus properly correlated with the size of the slot orifice 33 to give the desired velocity range, and the total length of the Venturi passage will then be whatever length is required to maintain the total included angle between the passage walls within the desired range of not more than about 10" as already explained.

It should also be noted that the stock inlet of the invention makes possiblea substantial reduction in the size of the open head box used therewith as compared with conventional open head boxes. Thus according to priorpractice, head boxes of considerable length in the directionof wire travel have been used and equipped with a series of baiiles spaced lengthwise of the head box and intended to promote uniform fiber distribution throughout stock entering the head box from a plurality of pipes. With the inlet of the present invention, the stock is already in such highly uniform condition when it enters the head box that such multiple bafiles are not necessary and may even tend to decrease rather than to improve its uniformity. It is desirable to provide a single bafile, as shown in Fig. 1, to prevent a direct flow of stock from opening 40 to the'slice, with resulting stagnation of the stock in the upper part of the box as stated, but more than one such bafile has been found undesirable. Furthermore, the size of the two compartments into which the bafiie divides the head box need only be sufficient to permit ready access for cleaning purposes, satisfactory results having been obtained with each compartment just large enough to allow a man to enter with sufficient room for effective cleaning. It will accordingly be seen that when the stock inlet of the invention is applied to an existing open head box of the multiple baffle type, the head box should be first substantially reduced in size, to approximately the proportions illustrated in Fig. 1, thus affording a substantial saving inspace as well as the improved characteristics of uniform flow conditions as already discussed. h

It should be understood that it is not necessary to arrange the counterfiow inlet and Venturi passage vertically as shown in Fig. 1. Thus Fig. e1 shows a modified arrangement in accordance with the invention in which these parts are arranged for substantially horizontal fiow of stock into the open head box 60 of a Fourdrinier ma:- chine including a forming wire Bl traveling over a breast roll 62. The head box 60 is shown as provided with an internal apertured baflle 85 and an adjustable slice lip arrangement indicated generally at 66, as discussed in connection with Fig. 1. ;;L In the arrangement of Fig. 4, the stock is sup.- plied from a suitable pump and white water return, not shown, to a conduit 10 leading to a screen ll provided with a discharge line 12 for reject material. The stock flows from the screen through the supply conduits indicated generally at 13 to a counterflow inlet constructed as described in connection with Figs. 1 to 3 and including a pair of tapered conduit passages 74 and I5 separated by a baffle 15 and provided with a com mon discharge orifice l1. Walls 18 and 19 are arranged to form a Venturi passage 80 leading from the slot orifice 11 to the opening 8| in head box 60 to supply stock from orifice TI to the head box for delivery to the forming wire 61. a

The opening BI is shown as formed in the rear wall 82-of the head box, and it extends laterally across the head box adjacent the edge of the bottom wall 83. The lower wall 18 of the Venturi passage is accordingly shown as lying in substantially the same horizontal plane as the bottom wall 83 of the head box, and the upper passage wall 19 diverges from wall '18 in the direction'of flow of stock through the passage, the total included angle between the two walls being shown as of the order of 6 to give the desired Venturi effect. A perforated roll 85 may be positioned adjacent the slice opening as shown to assure adequate crossing of the fibers as the stock flows onto the forming wire.

The operation of this system is substantially the same as has already been described in connection with Fig. 1. The stock supplied to the large ends of the tapered conduits l4 and 1,5 is discharged through the slot orifice 11 at apredetermined substantially uniform velocity of flow producing substantially uniform distribution of fiber across the width of the machine. The passage 80 cooperates with orifice TI to provide a Venturi action causing the velocity energy of the stock to be dissipated with minimum turbulence as the stock fiows from orifice 11 toward the head box and thus causing the stock to be delivered through opening 8| at a substantially reduced velocity of flow While maintaining the desired substantial uniformity of fiber distribution across the entire lateral extent of' the head box.

At low wire speeds, the supply of stock to the head box is controlled to a relatively low rate suflicient to maintain the proper'low head within the head box, and under such conditions the supply of stock from opening 8| to the slice may take place entirely through the lowest of the passages or apertures 88 through baflie 65. At higher wire speeds, requiring a higher pressure head, the flow through the head box in the direction of wire travel may also take place through the higher of these passages as well as above bafile' 55, thus creating sufiicient agitation throughout the head box to maintain uniform fiber distribution without undesirable turbulence. {Inder all such operating conditions, the counterflow inlet and Venturi passage coact as described in connection with Figs. 1 to 3 to give highly uniform distribution of fiber and fiow'across the head box without undesirable turbulence and large eddy currents and thus contribute to the desired uniform sheet formation.

Reference is made to my copending applications, assigned to, the same assignee as this application, Serial No. 607,820 filed July 30, 1945, now Patent Number 2,540,301, and Serial No. 684,980 filed July 19, 1946 as a continuationin part of application Serial No. 607,820.

While the forms of apparatus herein described constitute preferred embodiments of the inven-- tion, it is to be understood that the invention is not limited, to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is: i

1. In combinationwith a Fourdrinier pape machine having an open head box, a stock inlet for supplying paper making stock tosaid head box under controlled conditions of uniform velocity'and distribution of fiber across the width of said machine without creating turbulence and objectionable eddy currents in said head box which comprises a pair of oppositely tapered conduits arranged transversely across said machine and each adapted to be supplied at the larger end thereof with stock under pressure, means forming a slot orifice common to said pair of conduits and extending across the full Widtho'i said machine through which said stock isdis' charged from said conduits at'a predetermined velocity of flow with substantially uniform distribution of fiber across the width of said ma chine, said orifice being of restricted cross-sectional area relative to said conduits to maintain said predetermined velocity substantially higher than the velocity of flow of said stock in saidco'nduits and substantially uniform across the width of said machine, walls forming an inlet passage of substantially the same width as said orifice 'and said head box for conducting said stock from said orifice to said head box, said walls diverging in the direction of flow fromsaid orifice to said head box at a predetermined small angle of not more than 10 to form with said orifice a Venturi passage for maintaining said stool; between said orifice and said head box in continuous motion towards said head box at a decelerating velocity which is substantially constant across each crosssectional area of said passage to dissipate the velocity energy of said stock with minimum turbulence as said stock flows fromsaid orifice to said head box while maintaining substantial uniformity of flow conditions in said stock crosswise of said passage and throughout substantially the entire length thereof, and means forming an open connection of substantially the same cross-sectional area as the larger end of said Venturi passage between said passage and said head box to admit stock from said passage to said head 'box at a velocity substantially lower than said predetermined velocity and with maintained uni formity of flow and fiber distribution across the width of said machine. I,

2. A stock inlet for delivering paper making stock to a Fourdrinier paper machine having an open head box which comprises a pair of oppositely tapered conduits arranged transversely across said machine. and each adapted to be supplied at the larger end thereof with stock acrossthefull width; of said machinethrough.

which; said'stock is: discharged from said con"- duitsat a predetermined. velocity of flow with substantially uniform distribution: of; fiber across thewidthwof said machine, saidorifice being-oi restricted cross-sectional area relative to said. j conduits. to maintainsaid predetermined velocitysubstantially higher than the velocity of flow or stock insaid conduits and substantially uniform across the width-of said machine, walls forming.

an inlet. passage of substantially; the: same width: assaid orifice andsaidhead box for-conducting. stock'from said orifice to said head.box, .said walls diverging in the direction of fiow fromsaidori' fice to said head box. at a. predetermined totalincluded angle of not more than 10 to maintain said stock between said orifice and said head box in continuous. motion towards said head box at azdecelerating velocity which is substantially. constant across each cross-sectionalv area of said passage, said passage continuing from said orifice to said head box with substantially undiminished effective flow area to dissipate the velocity energy ofa'said stock with minimum turbulence as said" stock flows from said orifice to said head box whilemaintaining substantial uniformity of flow conditions in said stock crosswise of: said "1 passage and throughoutsubstantially the entire lengththereoflrand. means forming an op'emconi.

nection. between the larger end. of said passage and said head box for. admitting stock from said passage to saidhead box with minimum turbuj v lencevacross the entire width ofsaidlhea'dbox.

3. A stock inlet for delivering paper: making stock to a Fourdrinier paper machine having an v open head box which comprises means forming an opening in said head box extending across.

the width of said machine to receive stock for delivery to the forming member of said machine,

walls forming a passage leading to said opening and of substantially the same width as said head box throughout the entire length thereof, the end of said passage adjacent said head box bein of substantially the same cross-sectional dimensions as said opening, said walls diverging at a stantially smaller cross-sectional area than said opening extending across the width of said ma? chine, and means for supplying stock to said ori fice at a substantially uniform pressure across the width of said machine for discharge through said orifice at a predetermined substantially uniform velocity of flow with substantially uniform distribution of fiber across the width of said ma.-v

chine, the total included angle between said di verging passage walls being not more than 10 to maintain said stock between said orifice and said headbox in continuous motion towards said head box at a decelerating velocity which is substantially constant across each cross-sectional area of said passage while dissipating the velocity energy of said stock with minimum turbulence as said stock flows from said orifice to said head box and to deliver said stock through said opening at a substantially lower velocity er...

flow than said predetermined velocity while maintaining substantial uniformity of flow conditions in-said stock across the entire lateral extent of said opening. 1..

4. In combination with a Fourdrinler paper 10 machine having an; open .head. boxvv provided with. an opening in one Wallthereof and extending. across. thetlateral extent otsaid'head: box adja-- cjentanedge of a second wall thereof to receive. 5' 'stockior. delivery to v the, forming. member. ofv themachine, wallsiormingv a passage leading tov said opening. and of substantially the same width as. "said head' box. throughout. the [entire length, "j thereof, the, end of said. passage adjacent. said head. box being of. substantially the samecrosssectional dimensions. as said opening. and connectingdirectly withisaid headbox through said .opening with undiminished effective. flow-area, one of said walls being substantiallyparallel' to 5" said second. wall. of said head box, saidwalls -.=-idiverging at.a predetermined-angle in the.direc-- tion of flow through said passage towardssaidl opening, meansfo-rming aslot. orifice of. substan- -itially smaller cross-sectional. area than said. 20 opening extending across the width ofsaidmachine: at the smaller. end of said. passage, and. means for: supplying.,-stock to, said. orifice. at; a. substantially uniformpressurev across the, width. of saidmachinerfor discharge through said orificeinto said; passagev at. a. predetermined. substa u tially uniform velocity of flowwith substantially uniform; distribution of fiber-across. the width of 1 said; machine, the. total included; angle. between 'sfaid diverging passage walls. being. of not. more than :10" to provide aVenturi .actioninsaidpasP .sag er causing, the. velocity energyof .said. stock to; be' dissipate'd with minimum .turbulenceassaid stock flows fromsaid orifice; to said; headqbox, said angle between saidipassage wallsbeingbelow a predetermined critical angle to maintain said .7 stock. between... said rifice. and said opening in continuous -motion towards-said. head box... at; a decelerating velocity which is substantially constant across each cross-sectional area of said pas- .-.sage and to effect delivery of said stock through said opening at a substantially lower velocity of 'fiow than said predetermined velocity while maintaining substantial uniformity of flow conditions in said stock across the entire lateral extent of said opening.

A stock inlet for delivering paper making stock to a Fourdrinier paper'machine having an open head box provided with an opening extending across the width of said machine to receive stock for delivery to the forming member of said machine, comprising walls forming a passage adapted for connection with said opening and of substantially the same width as said head box throughout the entire length thereof, the end of said passage adjacent said head box being of substantially the same cross-sectionaldimensions as said opening connecting. directly with said head box through said opening with undiminished effective fiow area, said walls diverging at a,ppredetermined small angle in the direction of flow through said passage towards said opening, means forming a slot orifice of substantially smaller cross-sectional area than saidopening extending across the width of said machine at the smaller end of said passage, a pair of op- """positely tapered conduits arranged transversely across said machine and each adapted to be sup plied at the larger end thereof with stock under 'i-pressure, and means providing a direct connection from each of said tapered conduits to said nri'fice to effect discharge of said stock through said orifice into said passage at a predetermined j substantially uniform velocity of flow-with substantially uniform distribution of fiberacross the :ividth of said machine, the totalincluded angle between said diverging passage walls being not more than 10 to maintain said stock between said orifice and saidopening in continuous motion towards said head box at a decelerating velocity which is substantially constant across each crosssectional area of said passage and to provide for dissipating the velocity energy of said stock with minimum turbulence as said stock flows from said orifice to said head box and delivery of said stock through said opening at a substantially lower velocity of flow than said predetermined velocity While maintaining substantial uniformity of flow conditions in said'stock across the entire lateral extent of said opening.

'6. In a stock supply system for a Foul'drinier paper machine including a formingmember and having an open headbox for supplying stock directly to said forming member, the combination of a pair of oppositely tapered conduits arranged transversely across said machine and each adapted to be supplied at the larger end thereof with stock under pressure, means forming a slot orifice common to said pair of conduits and extending across the full width of said machine through which said stockis discharged through said conduits at a predetermined velocity of flow and with substantially uniform distribution of fiber across the width of said machine,said orifice being of restricted cross-sectional area relative to said conduits to maintain said predetermined velocity substantially higher than the velocity of flow of said stock in said conduits and substantially uniform across the width of said machine, walls forming a totally enclosed inlet passage of substantially the same width as said orifice and said forming member for conducting stock from said orifice to said headbox, said headbox having an opening therein for connection withflsaid passage; said passage being of substantially the same .cross sectional area as said opening at the point energy of said stock as 'said stock flows from said orifice to said opening while maintaining substantial uniformity of flow conditions in said-stock acrossthe Width of said passage over substantially the entire length thereof. r

STEPHEN A. STAEGE.

REFERENCES CITED The following references are of record in the file of this patent:

I UNITED STATES PATENTS 7 Date Number Name 1,775,905 Lang Sept. 16, 1930 1,964,291 Kutter June 26', 1934 2,243,773 Randell May 27,1941 2,249,128 Goldsmith July 15, 1941 2,339,711 Lowe et a1 Jan. 18, 1944 2,347,850 Staege May 2, 1944 2,381,286

Hornbostel et a1. Aug. 7, 1945 OTHER REFERENCES Paper Trade Journal,-April 4, 1946, pages 43 and 44,'Sta-ege. I I

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