US1533410A - Pulp-screening machine - Google Patents

Description

April 14, 1925,

A. J. HAUG PULP SCREENING MACHINE:

Filed March 28. 1921 2 Sheets-Sheet 1 vena?? l dlgy.

April 14, 1925. 1,533,41Q

A. J. HAUG PULP SCREENING MACHINE Filed March 28, 1921 2 Sheets-Sheet 2 Patented Apr. 14, 1925.

UNITED STATES ANTON J'. HAUG, 0F NASHA, NEW HAMPSHIRE.

PULP-SCRE'ENING MACHINE. i

Application tiled March 28, 1921;

-To all whom z't may concern Be it known that I, ANToN J. HAUG, a citizen of the United States, residing at Nashua, in the county of Hillsborough and State of New Hampshire, have invented certain Improvements in a Pulp-Screening Machine, of which the following description, in connection with the accompanying drawings, is a specification, like reference characters on the drawings indicating like parts in the several figures.

This invention relates to processes of and apparatus for screening pulp and similar materials.

As is Well understood by those familiar with paper making processes, it is necessary to subject the pulp to one or more screening operations in order to remove the splinters and large pieces of material which have not been reduced to the desired fibrous condition. Usually several of these screening operations are necessary.

The power consumed in these operations, the time required by them, and the amount of good stock lost in screening are important factors. An important object of my invention, therefore, is to improve the processes of and apparatus for screenin pul which will reduce the time consume, will be economical in power, and will save a high percentage of the good stock.

The screening apparatus provided by this invention has as an important feature a submerged rapidly rotating screen. It also includes novel means for disposing quickly and positively of the tailings and residual stock.

An importan? advantage of this machine is that the ra io between its screening capacity and the screen area and the power consumed are very favorable indeed when compared with the results produced by other machines.

' This invention also includes a novel process which may be carried out by the ma-y chine herein shown or in other Ways.

The invention will be herein disclosed as embodied in a machine desi ned especially Yfor the screening of pulp o? the character used in the manufacture of aper, although itwill be understood that t e invention is not limited to use in this particular art.

Referring now to the accompanying drawings,

Figure 1 is a longitudinal-cross sectional utc, f

Serial No. 456,874.

View of a pulp screening ing the invention in the preferred;

Fig. 2 is a vertical transverse cross sectional view on Vthe line 2 2, Fig. 1; and

Fig. 3 is a view partly in cross section on the. line 3-3, Fig. 1, and partly in end ele- Vation.

The machine shown comprises a rotatable screening drum, indicated in general at 2, having two solid or imperforate end members 3 and 4, respectivel connected by suitable parts which sup-port the screen 5. The head or end member 3 of the drum is secured fast to one end of a shaft 6 that is mounted in bearings 7 and 8, this `shaft being provided With a pulley 9 by means of which the screen may be'driven rapldly, for instance with a peripheral speed of 1600 ft. er minrom any convenient source o power. head 4 at the opposite end of the drum has formed integral therewith or secured fast thereto a hollow shaft 12 which runs in roller bearings 13.

The entire drum is supported in a casing 14 which is ada ted to be filled with pul or other liquid and it has an outlet 15, Figs. 2 and 3, which is provided with an adjustable Weir 16. The bearin brackets yand the casin are mounted on a ed plate 17.

ounted within the screening drum 2 is a hollow stationary drum 18. The stock to be screened is delivered to the interior of the screening drum 2 by a conduit 19 provided with an inlet channel 20 which discharges into a bell mouth portion 21 of the stationmachine embodyform at. present The `ary drum 18. It will be seen from an inspection` of Fig. 1 that the drum head or end member 3 is provided with a central projection 22 that extends into the bell mouth 21 and has walls parallel to the walls of they mouth 21.

The pulp to be screened is delivered to the channel 21 from a suitable head box or other convenient arrangement preferably designed to maintain a relatively low but substantially constant head on the incoming stream of p-ulp. This pulp is discharged against the imperforate head 3 of the screening drum andis distributed substantially uniformly to all parts circumferentially of the left-hand end,

ig. 1, ofithe screening drum. The pulp then flows backwardly with reference. to the direction of the inflow, that is', toward the right, Fig. 1, along the screening surface. Th:

rapid rotation of the screen 5 imparts a similar movement to the pulp that is closely adjacent to the screening surface, and the pulp so set in motion is urged through the screen due to the action of centrifugal force. Consequently, a substantial portion of the pulp passes through the screen 5 in the early sta of its backward flow. The continuous fee ing of stock to the screen and the centrifugal force imparted by the rotating drum, which has a levelling effect on the stock with relation Vto the screen surface, :force the stock not immediately screened towards the discharge end of the drum.

The foregoing operation of the submerged screen is utilized in forcing the residual stock or tailings, including the splinters and large particles that cannot pass through the screen, along successive portions of the screening surface. As the stock is constantly fed from the stock tank throu h the stationary drum to the screen 5 and there acquires a rotating movement, all the stock not assing through the screen'tends to proceed 1n a helical course towards the discharge end of the machine. By reason of the perforations in the screen, the good stock begins at once to flow out. The tailings, however, tend to collect on the screen, and'I find it desirable to move them positively to the discharge end of the drum.' For this purpose a series of blade-like members 24 are formed integral with or are secured to the outer surface of the stationary drum 18. These blades are inclined and preferably have as little clearance as is practical with relation to the interior surface of the screen. ln consquence, the blades move positively towards the discharge endof the machine, any tailings which have collected on the perforations of the screen. The rotating liquid stock will also be caused to travel in substantially a redetermined course or path through the rum. Usually these blades are Y inclined so that they advance the tailings in a more or less helical path toward the end member 4 of the drum. The stock thus is presented to substant ally all portions of the screening surface of the drum as uniformly as racticable.

s the tailings near the head 4 of the drum they come into contact with a stationary scraper 25 (see Figs. 1 and 3) which guides them into a tailings discharge channel 26 formed in the upper part of the conduit 19.

Attention is called to the fact that this construction effects the removal of fthe tailings at an upper point of the machine, thusn vobviating the necessity of pumps to raise the tailings tothe level ,ofthe inlet of a subsequent mach'ne into which they .may be fed.

For the purpose of washing the tailings durngtheir rogress through the screening drum 2 and t us removing all the good pulp ncaa-no from them, I preferto provide a water chamber 28 in the end of the stationar drum 1S op site the mouth of the inlet c annel 20, an water is delivered to this chamber through a channel 29, Figs. 1 and 3, formed in the conduit 19. ings 30 is formed in the outer wall of this chamber so that water is directed through them and mixed with the tailings while they are bein advanced along the screening surface 5. his supplemental supply of water for washing the tailings is not always required.

A spray of clean water or other fluid may also be directed against the screen 5 from a pipe 32 which is set into a recess or groove formed in one of the plates of the casing 14. This spra is utilized to clean the screening surface o the drum, and it preferably has sufficient power to operate satisfactorily, even when the top of the screen drum is entirely submerged; but if any difficulty is experienced in clearing the perforations of the drum, the level of the stock outside of` the screen may be lowered so screen drum will be exposed to the spray.

It will now be understood that the stock to be screened is led into the screening cylin- `der through the inlet 20 and is distributed circumferentially over the screening surface of the drum, the screened pulp passing thro h the screen 5, filling thercasing 14 and owing out of the outlet passage 15. The Weir 16 preferably is adjusted at such a height that the drum 2, or all except the top portion thereof, is constantly maintained su merged in screened pulp, since I nd that this practice facilitates the screening operation particularly in that it reduces the tendency of the pulp to mat on or adhere to the screen 5. The tailings work along the inner surface of the drum and are ejected from the machine in the manner above described. Stuffing boxes 33 and 34 are provided, rcspectively, where the shafts 6 and 12 pass through t e casing 14 to prevent thc leakage of liquid from the casing at these points.

It should be noted that since the tailings are moved forward at a rate determined by the head andsup ly of the stock, the speed of revolution of t e screen drum and by the number, inclination and arrangement of the blades 24, by properly predetermining these factors the tailings wi l remain within the screen drum long enough, to ensure their thorough washing and a practically complete separation of the good stock from them. At the same time their discharge "from the machine is effected with sufficient rapidity to prevent their blocking thc scFeen and preven ing the through the erforations.

Attention is also called -to the fact that in this machine' the stock, constantly mainthat the top of the A series of discharge openllll) hul discharge of good stock Areservoir my machine will still i,iiss,41o

tained in a proper condition for screening, is distributed evenly over substantially the entire area of the screening surface, which is at all times ready to receive it, and is screened there by centrifugal force urging it through the meshes of the drum. The drum rotates at approximately the same speed as the stock so that there is little relative movement of the meshes and stock and the long libres thus proceed out throuvh the meshes into the pond 33 and are not lbent violently across the meshes of the screen Where they would form, with other fibres, a filter inipervious to stock, as happens when the stock is caused to revolve rapidly in a stationary drum. Since it is necessary merely to rotate the screening drum, this machine requires only a' relatively small part of the power required in most machines to drive the usual impellers that throw the inflowing stock outwardly against the screen. Furthermore, since the drum may be completely submerged its entire screening surface may be utilized constantly in performing the screening operation, and the maximum capacity for a given screening area therefore is obtained.

It is not necessary for good results to have the top of the Weir as high as the tpI of the screen drum, and the minimum height Imay be determined readily by the machine tender. If the drum is not run in a pond or have certain advantages but will lose a great part of its effectiveness as a pulp screen.

It Will be understood that While I have herein shown and described the best embodiment of the invention of which I am at present aware, this embodiment may be modified in many particulars without departing from the splrit or scope of this invention. For instance, the stock to be screened can be supplied in other ways than that specifically shown and various other modifications may be made in the apparatus while retaining the general principles on which the invention proceeds. be,appreciated that the method herein disclosed may be practiced by other forms of apparatus thanV that shown and described.

hat is claimed as new is:

1. A pulp screening machinecomprising,

in combination, a rotary screening drum, means for rotating the same rap-idly, whereby a substantial centrifugal effect is produced on the stock contained therein, means for delivering Stock to he screened to the interior of said drinn, and a casing in which said drum is mounted constructed to receive the screened pulp and maintain a head of the same about the screening drum.

2. yA pulp screening machine comprising, in combination, a rotary screening drum, means for rotating the same rapidly, whereby a substantial centrifugal effect is -produced on the stock contained therein. means It will also for deliverino' stock to be screened to the interior of said drum, a casing in which llic drum is mounted and into which the screened stock is discharged,` said casing holding a supply of screened stock in which said drum rotates, and means for coni'lucting tlic tailings from the interior of said drinn to a point outside of said casing.

3. A pulp screening mac line comprising, in combination, a rotary screening drum, means for rotating the same rapidly, whereby a substantial centrifugal effect is produced on the stock contained therein, means for delivering stock to be screened to the interior of said drum, and stationary means cooperating with said driiiirto more the tailings in a substantially lircdclcriiined course through the drum.

4. A pulp screeniugniacliine comprising, in combination, a rotary screening driini, means for rotating the saine rapidly, whereby a substantial centrifugal elfectis produced on the stock contained therein, means for delivering stock to be screened iothe interior of said driim,'and stationary inraiis for moving the tailings through the driini at a rate depending upon the speed of rotation of the drum.

5. A pulp screening machine haring, in combination, a horizontal rotatable screening drum, means for rotating said drinn rapidly, whereby a substantial centrifugal effect is produced on the stock contained therein, a casing in which said drinn is mounted arranged to receive the screened product and maintain a head of the saine about the screening drum at a predetermined height, an inlet for feeding the imiterial to be screened' into the screening drinn to the screening surface, a discharge outlet for stock rejected by the screen, and means for forcing the rejected stock from the screening surface to said discharge outlet.

6. A pulp screening machine having. in combination, a horizontal rotatable screening drun'i, means for rotating said di'iiiii rapidly, a casing in which said drinn is mounted arranged to receive the screened product and maintain a head of the same about the screening drum at a predetermined height, means for feeding the material to be screened into the screening drum. means for conducting tailings out of said drum, and stationary blades for forcing the tailings from the screening surface to the discharge therefor.

'i'. A pulp screening machine comprising, in combination, a rotary screening drinn, means for rotating said drum rapidly, whereby a substantial centrifugal effect is produced on the stock contained therein, means for delivering stock to he screened to the interior of said drum. relatively stationary means nioiinted within the drinn for moving the tailings through the drum, and means for mixing water with said tailings during their travel through the drum.

8. A pulp screening machine comprising, in combination, a rotar screening drum, means for rotating said drum rapidly, means for delivering stock t0 be screened to the interior of said drum, blades mounted within said drum to advance the tailings toward one end of the drum, and a stationary scraper mounted within said drum for ejecting the tailings from the drum.

9. A pulp screenin machine comprising, in -ombination, a horizontal screening drum, a ,asing in which said drum is mounted, means vfor rotating said drum rapidly, whereby a substantial centrifugal eil'ect is produced on the stock contained therein, means for conducting pulp to be screened to the interior of said drum, and means within the drum for distributing the pulp substantially uniformly over the entire screening surface of the drum.

10. A pulp screening machine comprising, in combination, a casing, a rotary screening drum mounted within said casing, means for` rotating said drum rapidly, whereby a substantial centrifugal effect is produced on the stock contained therein, means for delivering stock to be screened to said drum, and means for presenting unscreened portions of the stock within the drum to successive parts of the screening surface of the drum.

11. A pulp screening machine comprising, in combination, a rotary screening drum, means -for delivering stock to be screened to the interior of said drum, and means for dischargzgini;r the tailings from said drum at a point above the axis of rotation of the drum.

12. A pulp screening machine comprising, in combination. a rotary screening drum, lmeans for rotating said drum rapidly whereby a substantial centrifugal effect is produced on the stock contained therein, and conducting means for leading stock into said drinn at one end thereof and for dischar ing tailings from the drum at the same en 13. A pulp screening machine comprising, in comblnation, a rotary screening drum, means for rotating said drum rapidly whereby a substantial centrifugal effect is produced on the stock contained therein, conducting means for leading stock into said drum at one end thereof, and means connected with the opposite end of said drum for driving it.

14. A pulp screening machine comprising, in combination, a rotary screening drum, means for rotating said by a substantial centrifu al effect is produced on the stock contained therein, means for delivering stockto be screened to the interior of said drum including a conduit discharp drum rapidly where-Y ing into said drum at one end thereof, and means within said drum for working the tailings toward the opposite end of the drum.

15. A pulp screening machine comprising, in combination, a horizontal screening drum, a head closing one end of said drum, a rotary shaft secured to said head for driving the drum, a hollow shaft supporting the opposite end of said drum., bearings in which said shafts are mounted, and means for conductingmaterial to be screened through said hollow shaft into the interior of said drum.

1G. In a pulp screening machine, the combination of a horizontal screening drum, a hollow shaft supporting one end of said drum, a bearing supporting said shaft for rotation, supply and discharge conduits leading through said hollow shaft to and from sai'd drum, and means for supporting the opposite end of said drum.

17. A pulp screening machine comprising, in combination, a horizontal screening drum means for supporting and rotating said drum, a stationary support mounted within said screening drum, and means mounted on said support for distributing the stock along .the screening surface of said drum.

18. A pulp screening machine comprising, in combination, a horizontal screening drum having heads at its op osite ends, shafts secured to said heads or sup orting them, bearings supportin said sha means carried by one of sai shafts whereby it may be driven to rotate said drum, and means for discharging the stock to be screened a ainst the inner surface of the head to whic the last mentioned shaft is secured.

19. A pulp screening machine comprising, in combinatlon, a. horizontal screening drum having heads at its opposite ends, means for supporting and rotating said drum, a stationary drum mounted within said ,screening drum, means for conducting the stock to bc screened through said stationary drum and directing it against one of said heads, stock distributing members supported b'y said stationary drum, and means adjacent to the other of said heads for discharging the tailings from the drum.

20.' In a ul screening machine, the com, bination o a orizontal screening drum, a hollow shaft Vsupporting one end of said drum, a bearing supporting said shaft, a conduit extending through said hollow shaft and having a stock inlet channel leading into said drum and' a tailings discharge channel leading from said drum.

21. A pul screening machine of the character descri comprising, in combination, a horizontal screening drum, means for supporting and rotating said drum, a stationary drum mounted within said screening drum, means for conductin stock to be screened into said screening rum, a water`chamber in said stationary drum having discharge outlets opening from the periphery thereof, and means for advancing the tailings along the surface of said screening drum and into position to be mixed with the Awater discharged from said chamber.

22. That improvement in the process of scieeiiing pulp, which consists in performing the screening operation by centrifugal force against the head of surrounding screened liquid, and creating said force through motion of the screen itself.

' 23. That improvement in the process of screening pulp, which consists in urging the pulp through the screen by centrifugal force, creating said force throii h the motion of the screen itself, and utilizing said motion to remove the` tailings positively from thcscreening surface.

24. That improvement in the process of screening pulp, which consists in urging the pulp through the screen by centrifugal force, creating said force through the motion of the screen itself, and maintaining one surface of the screen substantially submerged in screened pulp and the other surface in unscreened pulp.

25. That improvement in the process of screening pulp, which consists in owing the pul into contact with a screen, rotating sai screen rapidly to create a -stron centrifugal force urging the pulp throng the screen, maintaining the outer surface of the screen substantially submerged in screened pulp, and utilizing-said motion of the screen to discharge the tailings from the screening surface.

26. A pulp screening machine comprising, in combination, a rotary cylindrical screeniriig drum, means for rotating the same rapiy, whereby a substantial centrifugal effect is produced on the stock contained therein, means for delivering stock to be screened to theV interior of said`drnm, and a casin Vmeans for delivering the stock to be screened to the interior of said di-um, a casing in which the drum is mounted and into which in` which said drum is mounted constructe toV the screened stock is discharged, said casing holding ii supply of screened stock in which Vsaid drum rotates, and means for conductthe tailings in a substantially predetermined course through the drum.

29. A pulp screening machine comprising, in combination, a rotary cylindrical screening drinn, means for rotating the same rap'- idIy, whereby a substantial centrifugal effect is produced on thestock contained therein, means for delivering the stock to be screened to the interior of said drum, and stationary means for moving the tailings through the drum at a rate depending upon the speed of rotation of the drinn.

3D. A pulp screening machine comprising, in combination, a rotary screening drum.l means for rotating said drum with suicient speed to cause it to exert a substantial centrifugal effect on the stock in contact therewith, 'and means for Vmaintaining said drum completely submerged 'in screened stock.

' 31. A pulp screening machine comprising, in combination, a horizontal rotary screening drum, means `for rotating said drum with suicient speed to cause it to exert a substantial centrifugal effect on the stock in contact therewith, a casing in which said drum is enclosed, and a Weir over which the screened vstock discharged from said casing flows, said wer being arranged to back up the screened stock in said casing and keep said drum completely submerged in screened stock. Y

32. That improvement in the process of screening pulp which consists in urging the pul through the screen by centrifugal force, an maintaining said screen completely submerged i'ii and under a hydraulic head of the screened stock.

In testimony whereofV I have signed my name to this'specicaton.

i ANTON J. Haus.

outlets opening from the periphery thereof, und means for advancing the tailings along the surface of said screening drum and into position to be mixed with the water discharged from said chamber. Y

22. That iinpi'ovement in theprocess of screening pulp, which consists in performing the screening operation by centrifugal force against the head of surrounding screened liquid, and creating said force through motion of the screen itself.

` 23. That improvement in the process of screening pulp, which consists in urgiu the pulp through the screen by centrifuga force, creating said force through the motion of the screen itself, and utilizing said motion to remove the' tailings positively from the 'screening surface.

24. That improvement in the process of screening pulp, which consists in urgin .the pulp through the screen by centrifuga force, creating said force through the motion of the screen itself, and maintaining one surface of the screen substantiallysubmerged in screened pulp and the other surface in unscreened pulp.

25. That improvement 'in the process of screening pulp, which consists in liowing the pnl into contact with a screen, rotating sai screen rapidly to create a .stron centrifugal force urging the pulp throng the screen, maintaining the outer surface of the screen substantially submerged in screened pulp, and utilizing-said motion of the screen to discharge the tailings from the screening surface. e 26. A pulp screening machine comprising, in combination, a rotary cylindrical screenin drum, means for rotating the same rapidy, Wliereby a substantial centrifugal effect is produced on the stock -contained therein, means for delivering stock to be screened to the interior of said `drum, and a casin which said drum is mounted constructs receive the screened pul and maintain a head of the saine about t ie screening drum. 27. A pul screening machine comprising, in combination, a rotary cylindrical screening drum, meansfor rotating the same rapidly, whereby a substantial centrifugal effecty is'produced on the stock contained therein means for delivering the stock to be screene to the interior of said drum, a casin 111 which the drum is mounted and into w ich in 'A to the screened stock is discharged, said casing holding a supply of screened stock in which -said drum rotates, and means for conductthe tailings in a substantially predetermined course through the drum.

29. A pulp screening machine comprising, in combination, a rotary cylindrical screen ing drum, means for rotating the same rapidly, whereby a substantial centrifugal eii'ec is produced on thestoclr contained therein, means for delivering the stock to be screened to the interior of said drum, and stationary means for moving the tailings through the drum at a rate depending upon the speed of rotation of the drum.

30. A pulp screening machine comprising, in combination, a rotary screening drum., means for rotating .said drum with sufficient speed to cause it to exert a substantial eentrifugal eii'ect on the stock in contact therewith, and means for maintaining said drum completely submerged in screened stock.

' 31. A. pulp screening machine comprising, in combination, a horizontal rotary screening drum, means for rotating sai-d drum with suicieut speed to cause it to exert a substantial centrifugal eifect on the stock in contact therewith, a casing in which said drum is enclosed, and a Weir over which the screened stock discharged from said casing ows, said Weir being arranged to back up the screened stock inl said casing and kee said drum completely submerged in scrcene stock.

32. That improvement in the process of screening pulp which consists in urging the pulp through the screen by centrifugal force, and maintaining said screen com lctely submerged i'n and under a hydraulic ead of the screened stock.

In testimony whereof I have signed Amy name to thisspecification.

ANTON J. HAUG.

DISCLAIMER Hereby zontal axis 'amai 4mm', 1o, 193s.)

410.-Auton J. Haug, ashua,.N. H. PULP-SCREENING MACHINE. -Patent dated-April 14, 1925. Disclaimer led December 14, 1932, by the patentee.

disclaims from the scope of said claim 32, -anydproeesslof screening y revoY ul fue? ved about a DISCLAIMER 1,533,410.-Amon J. Haug, Nashua, N. H. PULP-SCREENING MACHINE. Patent dated April 14, 1925. Disclaimer led December 14, 1932, by the patentes. Hereby disclaims from the scope of said claim 32, any process of screening gulp excelJ processes in which an enclosed body of pulp is rapid y revolved about a orizonb axis.

Gazette January 10, 1.933.)

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