US1022750A - Pulp-screen. - Google Patents

Description

J OLSEN. v PULP'SGREEN. APPLIGATIOQT TILED 110119, 1906.

5 SHEETS-SHEET Witnesses .Jj. OLSEN.

I BUL SCREEN. ARPLIUATION FILED N,0Y.19, 31906 I Patented pr. 9-,' .912;

Witn'e SQs;

UNITED STATES PATENT carton.-

' Joni; OLSEN, or? warnnrown, NEW Yomr.

PULP-SCREEN,

,Specification of Letters Patent.

1 Application filed November 19, 1906. Serial No.'343,999.

T 0 all whom it may concern:

.Be it known that I, JOHN OLsEiv, a citizen of the United States, residing at Watertown, in the county of Jefferson and State of New York, have invented certain new and useful Improvements in'Pulp-Sdreens, of which thefollowing is a specification;

This invention relates to improvements in screens, designed for use in connectionwith the manufacture of pulp, fiber and similar aterials employed in making paper and paper products. p

The invention relates particularly to im-' provements in the class of devices described and shown in United States Patents granted to one Darwin B. Gotham, numbered 511,771 and 530,586, dated respectively J anuary 2 and December 11, 189-1.

The object of my invention is to provide a machine for screening or straining pulp or fiber of various kinds, which is simple, strong and effective, and wherein provision .is made for increasing the flow of the mass of unscreened material over the screen plates, therebyeffecting the proper screening of a greater amount of. pulp in a given time, than other machines of the'class are capable of handling. A further ob'ect means for preventing the coarse pulp and screen plates, and a"further object is to provide forthe discharging and carrying awaycombined in such manner that they incline. longitudinally in opposite directions, the

degree of inclination of, each vat being sulficientto efie'ct a'rapid and continuous flow of the unscreened material over the screen plates, thereby making it practicable to construct pulp screening machinesof greater lengths, andfacilitating the rapid and ef-. fective handljng of a larger amount of pulp material, than is possible by the use of the well-known horizontal types of machines.

is to provide simple of 'said matter without hindering or delay- 4 A further feature of the invention conslsts in disposing the inclined sections or vats in such manner that when two of them are joined together, either the two high or elevated ends, or .the two 'low ends 'of .said vats abut and are rigidly attached. In the Patented Apr. 9, 1912,

first instance, the screen'plates incline downwardly in opposite directions away from the abutting point or middle of the machine, and in the second instance,the screen plates incline toward and terminate near the mid vation, and thence flows down the inclines: v

The greater portion of the pulp and the water mixed with it is drawn through the perforati 0ns or slots in the screen plates, by the processofsoreening employed,and the coarse portion of t-he'material' which is not sucked or drawn through the plates gravi tates to and is discharged from the lowest point of the vats, instead of being allowed to accumulate on the plates and requiring removal by hand or otherwise. I Other features and parts of will be more readily understoodfrom the detail description -which' follows, and by reference to the accompanying drawings which form a part of. this specification, and

in which Figure 1 is a side elevation of my. pulp screen, with a portion of one of the inclined sections broken away. Fig.2 is an end elevation ofthe machine. Fig. 3 is a vertical cross-section, substantially on the line 3-3 of Fig.1, showing the position of the working and flow parts. Fig. .4 is 'a vertical longitudinal section of one of the inclined parts the invention I of the machine, substantially on the line'- 44 of Fig. 2, showing feed-box, inclined screen-vat, suction chambers and divided flow-spouts; also showing the vibratory diaphragms and other working parts, Fig.

5 is an enlarged detail view, showing the plunger rod and related parts, also showing a multiple perspectiveview, showing-the principal parts of the diaphragm, also showing the parts. of the bridge-tree. Fig. 7 is aperspective view-of-one of the flow-boxes. Fig. 8 is a perspective view, showing the the cam which operates the same. Fig. 6 E4105 flow spout.w also showing the detachable parts and the manner of eonnectingthem to I tion.

Similar characters of reference are assigned to corresponding parts throughout the several figures.

In the d rawings, 2 represents .a frame, commonly known as the bellows-frame, of a pulp screen, which is provided at its opposite ends and at its middle with standards 3, 3. The frame is built on an incline and is preferably made of any suitable kind of hard wood, but it may be made of a nonrusting metal. The standards are preferably made of cast metal or pressed steel and should be heavy and strong. The standards 3 are tied together longitudinally by channel girders 4, 4, bolts being used for fastening the sam 6 represents a screen-vat, or a .series of screen-vats mounted upon frame 2, and secured thereto by a series .of bolts .7. These bolts pass downwardly through the wooden walls of the vats and engage nuts 9 em bedded in the timbers of the bellows-frame. This'mode of securin the vats tothe frame is employed to facilltate the detaching of the vats, whenever such action becomes neeessary for repairing or cleaning the machine. a.

10 represents a screen plate, or preferably a series of screen plates disposed so as to form a bottom or floor in the vats 6. These plates are usually narrow sheets of brass or other non-rustingor non-corroding metal," having a large number ofnarrow. evenly spaced slots or openings '11, which are arranged so that they practically cover the en'- tire exposed portion of the plates, through which pulp of variouskinds and gradesls drawn, or strained, for the purpose of pro:

diicing stock of evenconsistency for making paper and like products. Screen plates 10' are preferably j di posed crosswise in the vats, and'are moun ed upon a series of crossbars or glrts 12 and 1 2, and-screws 13ers The said bars are rigidly secured to the side employed'to secure the plates to the bars.

timbers of the vats by mortising, or by bolts. The slots in the screen plates are made large or small according to the kind and uality of paper it is desired to make. from t e screened stock.

The vats of myimproved pulp screen are preferably constructed of wood, and are built dam. At the low ends, the severalvats are The screen plates 10 are disposed'in the and disposed so that each vat, as well as the screen plates'carried by it incline in one d rection-or another, as shown in the drawings, and where but two of the vats are joined together to form a complete machine, they are preferably arranged with their low ends abutting, as illustrated in Fig. 1, and by the dotted lines A in Fig. 11. The vats may, however, be so arranged that when only two are joined together, the'highendsthereof are brought together, asshown by the dotted lines B in Fig; 11. In either case the pulp is intended to be delivered to the vats at the high or.elevated ends, and in order 'to provide for a steady and even flow of the liquid material upon and over the screen plates, a feed box 14 is disposedacross thefull width of the high end of each vat. The liquid mass of unscreened' ma- .terial is supplied to'th'e feed boxes by any su1table means, as by pumping or by gravity flow. The inner side or wall 15 of the feed box is formed by cutting a slot 15 in the end ofthe vat, and the top is lower than the other slde and the ends, so that the 1111-, screened material flows over it as over a preferably inclosed by separate end pieces (see dotted lines Fig. l), which permit of the-removal of one vat for repairs or cleanwithout disturbing or distorting the neighboring vats. As far as the screening of the pulp .is concerned, however, one end piece may be employed to separate two vat-s with the same results. V

vats in such manner that a hollow space of several inches in depth occurs beneath the plates and the bottom of the vats, 'as shown in Fig. 3. This hollow space is di- 'vi'ded into a, number of narrow, transverse compartments or suction chambers 16, whlch 1.05 are'formed or defined in part by the crossbars'or girts 12 and the side walls of the 'vats, and each of said chambers or compart' ments is subdivided by a cross-bar 12. Two screen plates 10, one foreach sub-division, form the upper side of chambers 16.

In bellows-frame 2, upon which vats. 6

are mounted, lateral spaces or openings 19 are provided, which correspond with suction'ch'ambers 16. These spaces or openings-extend between the heavy cross timbers 20 and the lighter parailel pieces 21 of frame 2.' Openings 19 are arranged so that their centers are directly beneath cross-bars 12. Each pair of cross-bars 21 are preferably spaced siX or eight inches apart, and between these are disposed a similar part 22, which divides the intervening space centrally. All of the cross pieces 21 and 22 are preferably made of wood, although suitable metal may be employed with good results.

The screening of pulp by my improved machine is accomplished by means of a vacuum draft or by suction, and to do said series of vibratory diaphra'gms, each of which is connected with'and operated by a reciprocating plunger or piston red, by means of which forcible currents are produced throughthe slotted screen plates 10. The suction or vacuum chambers 16 are formed by the screen plates and diaphragms,

' and by the meeting of the girts and other parts of the bellows-frame. and the vats,.

between all of '-which1is disposed strips of rubber or felt packing-23, to make airtight and water-tight joints. Each diaphragm consists of-a flexible sheet 24, preferably made; of rubber or other water-proof material; a wooden diaphragm 25, and an iron base 26. The rubber diaphra'gm is secured to the wooden partby brass screws 27, and the wooden part; is secured to .the

. iron base by means of bolts. or screws.

or girts 20'and 21 of the frame. The rubber.

.In-order to complete the formation of vacuum chambers 16, the outer dgesof the rub her diaphragmsare secured to the cross-bars sheet or part 24; is considerably longer and wider than the wooden part 25, and when its edges are tacked or otherwise secured to the bars and girts, the rubber sheet affords suflicient flexibility to permit-the plunger and other working parts to move upward and downward a short distance. The iron base 26 is provided with a hub 28, which receives the upper taperedend of plunger rod 29.-

Hub 28 projects from the under side of base same at every part of the plates.

26 at an angle which allows the diaphragm to be disposed on an incline corresponding to the slant of the screen vat and screen plates.

It is essential for theeflective working of my machine, that the upper. or rubber face of thediaphragms and screen-plates be arranged so that their planes'are exactly parallel, in order that the suction ,or draft produced by said working parts may be the bridge-tree, which is provided to facilitate I head of the bracket 32. Part 32 is secureddismounting the plunger 29.

30? represents a bushing, preferably of bronze, in which the plunger has its bearing. Near its lower end the plunger passes through a vertical bearing 31, formed on a metallic goose-neck part 32. The bearing at 31 preferably consists of a bronze bushing 33, which is rigidly clamped and held by the to the top of the girder 4'by bolts or other suitable means. On the lower end of piston rod 29 is mounted a plungerhead 34, which extends below the sufficient distance 36. The plunger rods 29 for each section, owing to the inclinatlon of the vats andother parts, are each ofa different length, as will be seen by reference to Figs. 1, 4, 11 and 12.

37 represents a main driving or operating shaft, which is mounted in suitable bearings 38 secured t-o'the standards3 at each end of the machine. ,On one end of shaft 37 is mounted a pulley 89 by which the shaft may be connected with an engine or other source of power. On shaft 37 at intervals corresponding to the location of the diaphragms and plungers are disposed a series of ca1ns preferably four-throw cams 40 secured by keys 41. One of these cams is arranged directly beneath and in contact with each of the shoes 35, as shown in Figs. 4 and 5. Each cam" is inclosed in a casing 42, consisting of two parts bolted together and preferably set rigidly upon girder a at a slight angle to the plane ofshaft 37, as shown in Fig 3, so they may be assembled and taken apart more readily. By this constructionthe millwright is able to get at the boxes from the front side of the machine to make repairs without'going underneath the the shaft, as it is only necessary to remove I the bolts which hold the casings together,

swing the cap around to one side and lift out the shaft. U and serve as-bearings for shaft 37. 'lhey "are hollow and made tight enough to hold a supply of oil for lubricating the cams, shoes and plungers. Near the upper end of each plunger rod 29 is disposed a stiff and powerful coil spring 44 employed to effect the downward stroke or movement of the pl migers and diaphragins after. the cams have forced them upward. The upper end of the springs bear against bridge-trees 30; the lower ends bear against a nut or stop 4-5, which is adjustably secured tot-he plunger rods by means of threads, as shown in Fig. 5. The wooden shoes 35 are connected to cams 40 by contact only, and ordinarily the \veight. of the plunger and diaphragm parts would be Casings 42 are stationarv sufficient to bringi these parts down after they have been lift d by the throw-points of the cams, but who a machine is doing actual work, theworking parts are operated at a very high speed, and the cams force the plunger-s and diaphragms upward six or seven hundred timos per minute, hence, in order to produce the required amount of screened pulp, it requires someadditional force or power to assist in the rapid reciprocation of these parts. Spring at is employed'for this purpose, and it may be given any desired tension by meausof the thread ednut or stop 45. 'Without the-"springs 44 the return movements of the vibratory parts would be too slow to meet the requirements of a rapidly working pulp screen. 46 repre:

sents a check-nut employed to hold the stop in place when set.

47 represents one of a series of flow-spouts." provided to carry away the massof screened material after it isv drawn through" the These plates into: suction chambers 16'. spouts are preferably arranged so that one will take care of the material screened by- .two of the diaphragms, as illustrated in Figs. 1 and 4. Long experience in screening pulp has shown, the necessity of providing and constantly maintaining a complete seal in the flow parts leading away from vacuum chambers 16, in order .to' prevent the admis sion into said chambers of any air to destroy the perfect suction produced by the diaphragms, and to that end, I provide a part-ition 48 in each flow-spout to keep the;liquid- "flowing from each chamber 16 separatedfrom that of the other like chambers. The side walls and the partition ofieach blowspout are'preferably made the same height and their upper edges arespaced to correspond with the under edges of cross pieces 21 and 22 (see Fig. 4). The flow-spouts are de taehably secured to the underside, of the rent-in the spouts, more or less sediment con,

sisting of slime and-fine. grit constantly settles in the bottom of the spouts, and in a ,short time they become filled with-the same to such an extent -that;ttheir capacity. is

greatly reduced. ,Th spouts therefore require frequentcleaning,"and-in order to facilitate clearingthem in a simple manner, I

provide openings 51 in'one'end of the spouts which lead to the separate flow-ducts, and inclose the same with detachable caps 52,

secured byhang'er-bolts 53 and nuts 54. At the other-end of each spout openings 51 shown in-dctted lines in Fig. 8 are provided in the bottomot each duct or channel and these are held normally'closed by caps 55,

secured by-similar hanger- bolts 53 and 54 respectively.

56 represents one or more flow-boxes mounted preferably on the front side of each section of the machine and secured by bolts or other suitable means. These are preferably made of wood and disposed so that the bottom of the flow box and the bottom of frame 2 have about the same. plane. The preferred construction of the flow-boxes is it flows upwardly from each duct of the flow-spouts 47. The joints between the boxes andlspouts are also sealed with felt or rubber packing. The compartments 57 and 57 are formed by means of removable partitions or dams 58, held in place by guide strips or cleats 59. These dams are provided to increase the depth of the liquid and thereby make a stronger seal to exclude air .from suction chambers 16, and are made narrower than the depth ff the box to allow the liquidito fiowover them into the discharge compartments 57 without overflowing the sides of the box and thus causing a waste of the screened material. ate'sized opening 61 in the bottom of each There is a moderof the [compartments 57 and 57. through which the liquidenters whenforced upward from the'jspouts. One of these openings is disposed over. each channel or duct of the flow-spouts. "After the screened material enters a compartment 57 it passes through acircular opening 62 in the bottom thereof, and thence into discharge pipe 63, by means of which it is carried away to be used in makingpaper '&c. '60 represents the pulp shown in the vat and flow-box in Fig. 3.

-In' the screening or straining of pulp by :the use of my inclined screen plates and vats, 'allof the waste or refuse material, such as coarse pulp, slivers, coarse grit and other dirt, gradually work their way down over the plates by the force of the suction and vibratory action of the working parts, and

accumulates finally at the lower end of the vats, or at the foot of each of the inclines. As the inclination of the screen plates is not more than five feet in a machine one hundred feet in length, the refuse or waste material, if allowed to gather at the lower ends of'the vats in any. consider: able quantity, would back up over the slots of the'nearest plates, andinterfere with the free and perfect straining of pulp through the same. For that reason, I provide wastepipes 65 and attach them to the low ends ofthe vats as shown, and these pipes com lmunicate with the interior of the vats by means of a hole .or opening 66. As this waste material, naturally carries -with it more or less good, fiber or pulp, it is preservedin a suitable manner for rescreening in the future.

In the manufacture of ulp, the unstrain;

ed material consists chie y of ground ulp and water which are thoroughly mixed by agitation. This material is pumped up. into the feed-boxesl4 located'at the highest ends ;-As the material flows down theinclined screen plates forming the floor of the vats, a large percentage of the pulp and the water mixed with it, is drawn through the fine slots or openings in the plates, byme us of the strong Sl'iCl'lCIl produced by th diaphragms, and is' carried away through the fliow-spouts Sand flow-boxes, to be used in making paper; All of the coarse particles of the material including the grit and other extraneous matter remaining on top of the to be exerted against and upward through the fine slots in theplates. This feature is employed for the purpose of blowing out any of the material which may become lodged in the slots by the force of a previous suction, and'it therefore clears said slots, so that when the diaphragms are pulled downward by the tension of springs 44, they create a strong suction which draws the fine pulp and water through the plates into the suction chambers. These reciprocating movements of the diaphragms are so short and quick that when a machine 1s running at full speed, the suction is almost.

continuous. v The vertical movement of the diaphragms' is not more than one-quarter of an inch which permits of said parts being operated at an extremely high rate of speed,

-without injury to the ,fl'exibl'e parts of the diaphragms.

In my machines, the-degree of slant or inclination ofthe screen plates is suflicient to cause the'unscreened material to flow from the highest to the lowest end of the vets in a stream which is constantly changing, because when the coarse material and refuse is drawn down upon the plates by the downward operations of the diaphragms and then forced upward free from the plates by the upward stroke of the diaphragms,

which dislodgesthe refuse, the'force of the.

flu-wingstream of new material will carry the refuse farther down the incline, so that when the next suction occurs, it Wlll be drawn against. the plates ata lowefpoint,

and thus said matter will be jogged along, step by stop until it reaches the lower-end of the rat, where. .it will be discharged. llencel claim that machines having the inclined vats are u'aclically self-cleaning, and a greater amount of serviceable stock may/be obtained in a given time, without any loss by reason ofhaving to shut down the machines, and besides there is very little waste of the good pulp.

In most of the machines having horizontal or level vats, the unscreened material is delivered to the vats in such volume as to cover the plates to a depthof three or four inches. Vhen this material is acted upon by the suction created by the downward operations of the diaphragms, that which is fine enough passes through the plates, while the coarser port-ion remains on top of the plates.

At each stroke of the diaphragm some of this latter material is drawn part way through the slots of the plates, and owing to the great force of the suction it sticksthere, at least for a time. Thegreater part of the refuse material remains ontop of the plates and is fo-rcedupward free fromthe slots by the currents produced by eachupward movement of the diaphragms.

Some newmaterial becomes mixed with the refuse at each of the said operations, and

the next downward stroke effects the screena ing of the finer pulp from the whole mass. But in the horizontal machine on account of the large amount of material which is delivered to the plates'for screening, and the rapid working of the suction parts, the ref:

use material increases in amount and depth very rapidly, because it cannot get away, and can onlv be displaced in the manner described, while the machines are running. As the refuse material increases in depth, the amount of fine pulpjobtained becomes less and less, until there is a virtual clog-' ging of the slots, which necessitates the 'frequentshutting down of the maphines for the purpose of cleaning the vats and plates. This results in great loss of time and besides considerable good pulp which becomes mixed with the refuse is wasted. These aceumulat-ionsof refuse material further become a dangerous element, becauseconsiderable sand and other gritty substances formmg a part of the unscreened mass, which are too large to be drawn through the plates in the first instance, are repeatedly drawn into and forced out of the slots by the strong alternating currents produced by the working parts, and thus effects a steady wear on the walls of the slots. After a time, the slots become'enlarged to such an extent that the screened stock is given an uneven consistency, which is very undesirable, especially for making paper of the finer grades. And

in addition to the trouble described, much expense 1s occasioned by the necessity of frequent renewing the worn-out plates. On 1 125- the other hand, by the employment of inclined plates and vats as herein describedand shown, the coarse pulp, slivers andgritty particles are carried to the lowest endof each vat by the force of a gravity flow, which is strong and rapid enough to carry as described refuse material to lodge or remain for more of the machine, the output of screened pulp greatly exceeds, both in quality and value,

' stantially as described.

,plunger rods for actuating-the diaphragm,

the mass of unscreened material down the inclines before they have a chance to clog or injure the plates. Under this arrangement, there is little opportunity for the than an instant on any portion of the plates, because the latter will be kept free from accumulations and cloggings and therefore -a greater amount of strained material can be obtained by the use of my improvement 'in a given period, and with less Wear and injury to the plates, than by any of the old forms of horizontal or level screen vats. I

Where my machines are employed, it is possible to greatly increase the volume of unstrained material which is delivered to the screen in the first instancegand by obviating the delays due to frequent stopping that of any other device ofthe class known to me.

It is'obvious that some of the parts of my machine may be varied without departing from the invention, and I therefore do not restrict myself to the precise construction and arrangement of the same, as herein shown and described.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is-

1. A pulp screen comprising a vat, a screen inclined in the direction of the length of the vat, non-communicating vacuumchambers beneath the screen, a diaphragm for each vacuum chamber, said diaphragms being substantially parallel with the screen, rods for operating said diaphragms, said rods increasing in length from the lowest toward the highest part of the screen, and a flow spout for each vacuum chamber, substantially as described.

2. A pulp screen comprising a vat, a screen inclined in the direction of the length of the vat, non-communicating vacuum chambers beneath the screen, a diaphragm for eachvacuum chamber, said diaphragms being substantially parallel with the screen, means for operating said diaphragms, and an outlet for each vacuum chamber, sub- 3. A pulp screen comprising a vat, a screen, a diaphragm below said screen, the. space between the screen and diaphragm being divided into separate suction chambers,

and a flow spoutleading from adjacent suction chambers and provided with a partition extending upwardly from its bottomv to prevent material from one chamber flowinginto the adjacent chamber, substantially Copies of this patent may be obtained for five cents each, by Washington. D. 0."

4. A- pulp screen of the class described, comprising a vat, an inclined screen in said vat, vibratory diaphragms beneath said screen, the space between the diaphragms and screen being divided into independent vacuum chambers, an independent flowspout, means for permitting the cleaning of said flow-spouts without detaching the spouts, a flow-box having a number of separatecompartments adapted to receive and discharge a volume of screened pulp flowing fromsaid flow-spouts, and means for discharglng refuse material from the screen vat.

5. A pulp screen of the class described, comprising a number of inclined vats, 'a series of inclined screens forming the bottoms of said vats, the inclination extending from the head toward the'tail end of the vat, a

series of inclined flexible diaphragms. disposed beneath said screens, a number of plunger rods of unequal lengths adapted to efl'ect the vibration of said diaphragms, a

series of flow-spouts, each spout having a partition extending upwardly from its bottom, means for cleansing said flowspouts without detaching the spouts, and a flow-box into which the flow-spout discharges.

6. A pulp screen of theclass described, comprising a number ofinclined vats, a series of inclined screens forming the bottoms of said vats, the inclination extending from the head toward the tail end of the vat, a series of inclined flexible diaphragms disposed beneath said screens, non-communicating vacuum chambers between the screens and diaphragms, a number of plunger rods adapted to effect the vibrations of said diaphragms, a series of flow spouts, and a flow box, substantially as described.

7. A pulp screen of the class described, comprising a vat, an inclined screen, the inclination extending from the head toward the tail end of'the vat, inclined diaphragms mounted on incl med frames, plungers of unequal lengths to operate said diaphragms,

".driving shaft to operate said plungers in one direction, springs to operate said plungers in the opposite direction, a suction chamber for each diaphragm, a flow-spout for each pair vof suction chambers, said spout having a partition extending upwardly from its bottom, and a flow-box for a number of flow-spouts.

In testimony whereof I aflix my signature in presence of two witnesses.

JOHN OLSEN.

Witnesses:

EDGAR V. HARDO GH, HARRY DE WALLACE.

addressing the Commissioner of Intent!- ,lll

Images