US1185795A - Pulp-screen. - Google Patents

Description

A. J. HA-UG.

PULP SCREEN.

APPLICATION AF|LED 1AN.14, |915.

Wlneses .Patented June 6, 1916.

3 SHEETS-SHEET lvivi-on ry' Lg/$65919.

A. J. HAUG.

PULP SCREEN.

APPLICATION FILED JAN. I4, 1915.

1,185,795. l Patented June 6, 1916.

3 SHEETS-SHEET 2.

M 4 Haz-vn @IQ/lazy @h4/md La faam. y@ "z 7 A. J. HAUG.

PULP SCREEN.

APPLICATION FILED IAN. I4, IQIs.

Patented LTune 6, 1916,

3 SHEETS-SHEET 3.

Wfwesses l Inventor: www QW Qn-mz JLM?? OMM www@ by M ANToN J. HAU'G, or NASHUA, NEW HAMPSHIRE, AssIGNoR To IMPRovED PAPER MACHINERY ooMPANY, or NAsHUA, NEW HAMPSHIRE, A CORPORATION oE MAINE.

' PULP-SCREEN.

Specification of Letters Patent.

Patented June 6, 1916.

Application led January 14, 1915. Serial No. 2,249. I

ings representing like parts.

This invention relates to pulp screens or strainers and more particularly, though not' exclusively, to machines of the type wherein the stock is delivered to the. interior o-f the screen and forced against the same by means of an impeller, the fine fibers being forced through the screen and the coarser particles being discharged from within at the end thereof.

For purposes of illustration I vhave -herein shown the invention embodied in a screen of the horizontal-shaft type having a substantially cylindrical straining drum and a centrifugal impeller embodying a series of impeller blades adapted to revolve at a sufficiently high speed to throw or beat the pulp against the inside of the straining drum.

The invention relates more particularly, though not exclusively, to improved means for feeding and distributing the pulp to the impeller blades ,to the etlicient distribution of the pulp with reference to the rate of supply; to the simple and effective application of shower. water to the-stock while being screened; to the reduction'of power required for driving the machine, and to other features designed to increase the effectiveness of the screening action and the capacity of the machine.

The invention will be best understood by reference to the following description when taken in connectionl with the accompanying illustration of one specific embodiment thereof, while its scope will be more particularly pointed out in the appended claims.

'In the drawings: Figure 1 is a central, longitudinal section in elevation. showing a pulp screen embodying one form of the invention; Fig. 2 is a partial section in end elevation of the machine shown in Fig. 1,

looking from the left; Fig. 3 is a plan of a palr or set of impeller blades of the type shown in the machine of Fig. 1, but shown' on' a larger scale; Fig. 4-is a front elevation of the same blades shown in Fig. 3; Fig. 5 1s a section on the lin'e 5-5 in Fig. 4; and Fig. 6 is a section on the line 6-6 in Fig. 4.

Referring to the illustrative embodiment of the invention and more particularly to Fig. 1, the machine there shown is provided wlth end frame members or castings 1 and 2 resting upon the feet 3 and 4 and providlng bearings 5 and'6 for the impeller shaft 7. The latter. is driven by any suitable means, as, for example, by the belt-driven pulley 8 shown at the left in Fig. l1. The end castings hold fixedly supported between them a substantiallyv cylindrical casing 9 within which there is provided a screen 10 ofa smaller diameter than the casing so that there is provided outside of the screen and within the casing an annular screened pulpreceiving chamber 11, the bottom of which 1s provlded wlth a discharge conduit 12 -(Fig. 2) fromv which the screened pulp is discharged (to any suitable receptacle. The

screen may be of anysuitable shape, but is .preferably cylindrical and may be of any usual construction to provide'usual or suitr able screening openings. The opposite ends of the annular screened pulp-receiving chamber are closed byannular end plates 13 4and 14, respectively, through the annular openings of which are discharged from within the screen the coarser particles w'hich can-not pass through the screen. The end plates 13 and 14 are provided with inwardly turned fianges 15 and 16, respectively, which serve as bearing supports for the screen'lO when, as in the case of the illustrative embodimentof the invention, the screen is made rotatable. The screen is secured at opposite ends directly to the annular supportino' members 17 and 18, the latter in turn belng secured-to the bearing rings 19 and 20, respectively, whereby the screen has journaled support upon the flanges 15 and 16 of the vend plates. To prevent the unscreeued particles from being forced through this joint into the screened pulp-receiving chamber or the screened particles from being forced into the waste outlet, the screen supplates so that the passage of the coarserl Waste into the waste" outlet is insured. To

1 force the stock against the interior of the screen the impeller shaft 7 is provided with a centrally arranged hub 23 keyed to the shaft and carryingthe centrally arranged disk 24 to which'are secured impelled blades extending longitudinally of the screen and adapted to rotate in close coperative relation to the interior of the screen. r1`hese blades extend longitudinally of ythe screen and in the illustrative embodiment of the invention have a slight rearwardinclination from the center of the screen outwardly with re'- lation to the direction of rotation so th'at they serve'not only to force the pulp against the screen but to feed the coarser, unscreenedl particles toward the sliver or waste outlet.

To secure certain objects of the invention (though not'essential as to other features) in the illustrative embodiment the impeller blades 'consist of two sets, the blades 30 of one set being substantially alike and the blades 31I of the other set being also substantially alike, but differing somewhat from the blades 30 and arranged in alternation with reference 'to the latter. For conveniencein manufacture the'blades are constructed in pairs as indicated in Figs. 3 to 6, inclusiye,"a blade 30 and a blade 31 being cast or formed in one unit. These are joined at their outer ends by therib or connectingl piece 32 and at their inner ends by the connecting plate 33, the latter beingutilized to bolt or otherwise secure the unit consisting of the ltwo bladesdirectly to one side of the supporting disk 24 on the impeller shaft. @ne unit or pair of blades when thus fastened to the side of the driving disk 24 is arranged tolie inv registration with a similarset of blades secured to the opposite side of the disk and extending in the opposite direction. rllhe adjoining edges of the two sets of blades are inwardly curved at their upper, inner corners 34 and 35 so that they project over the edge of the disk and come into substantial contact. r1`he two sets of blades thereby constitute in edect two continuous blades extendinglengthwise the screen but inclined rearwardly with reference to the direction of rotation from the central support to the ends of the screen asindicated in Fig; 3, so that the stock fed to the impellersas hereinafter described is graduallyworked toward the end of the screen. rllhe two blades '30 and 31 while having substantially the 4and 4. By this provision the head or feeding pressure of the pulp against the back of the preceding blade 30 may be availed of to assist the rotation of the impeller, while the front of the succeeding blade 31 may be used to impel or direct the pulp and may be shaped more eectively for that purpose. r lhis further provides for feeding the pulp intermittently or in batches to the impeller so that each batch so fed to the screen is beaten' against the screen not only by the edge of the impeller blade which feeds it, but also by the edge of the next succeeding pulp-impelled blade 3() which strikes it and gives it a second impact before any further pulp can reach that portion of the screen. To this end the back face of the pulp-impelledblade 30 is best shaped havingreference to the speed of rotation of the blades and the velocity and pulp flow so that the impact ofthe pulp in passingoutwardly through, the pulp-receiving space lends material assistance to the rotation of the impeller. By increasing the number of blades toa point where the velocity of pulp flow is greater than the speed of the blades necessary to press the pulp against the inside of the screening drum, sufficient rotative effect can be absorbed from the flow of the pulp to materially decrease the power required for driving the impeller.

The pulp impelling blade 31 as viewed in cross section after starting at 36 in a direc- Ytion substantially radial sweeps back into edge of the blade, the outer edge at 38 i having a relativelyesharp pitch. rlhe result is that after the `stock rhas entered between the blades it moves along the impelling .blade 31 at' first slowly along the middle or low-pitched portion 37 and then with increasing velocity until it is thrown from the high pitched portion 38 against the screen with considerable force, the edge of the blade tending to beat thepulp through the screen as it passes over the same, 'llhe gradual acceleration given to the movement of the pulp as it passes along the impeller blade diminishes the shock which is imparted to the impeller. The inclination of the impeller blade provides a wide blade in a small, compact, radial space vover which the stock may be spread out and thoroughly distributed. l

rlhe stock is preferably fed from within and radially outward between the blades by any suitable means, but herein there is em ployed one or more stock feeding passages which enter through the annular plates 13 and at one end of the screen and terminate in one or more discharge orifices located within the blades. In the illustrated form of screen the stock is fed through both open' ends of the machine toward the middle thereof, the unscreened particlesbeing fed back by the-blades away from-the center toward the opposite ends of the casing where they are'discharged into a waste chamber 39 at the end of the screen opening into the waste .or sliver outlet 39".

The two opposite sets of feeding passages and orifices are Substantially similar in construction. \Any number lof feeding passages may be provided at each end of the drum, but herein I have shown two such passages comprising an inner, annular passage 40' formed by the inner, fixed walls 41 and the outer, fiXed walls42, and a second eXteri0r,. .annular feed passage 43 formed by the fixed wall 42 .and the fixed enveloping but sepa'- rated wall 44, the latterlseparating the passage 43 fromthe waste outlet 39. Both feed passages communicate with a stock supplyv chamber 45 frmed in the end frame or casing l or 2, said chambers communicating with a common supply chamber 46 at the top of the machine, the latter being connected with any suitable sourcel of pulp supply, preferably under pressure.

Vhile a discharge orifice or orices of any suitable shape or number may be provided,

herein I have shown a discharge orificel for both passages annular in form so that the discharge of the pulp is in a general, radial direction and symmetrical for the entire distance around the impeller. The orifice for the passage 40 consists of an annular opening 47 formed `between the walls 4l and 42, while the discharge orifice for' the passage 4 3 consists of an annular opening 48 between the wall 42 and the wall 44.

The two feeding passages 40 and 43 are utilized in conjunction with a pulp distributing device which is designed automatically to regulate the feed of the pulp so that the latter will be subjected to substantially the same extent of screening, irrespective of the variations in the rate of supply. For most efhcient screening the pulp should be fed to the screen at a constant rate of supply if'the distance through which the pulp travels over the screen is unchanged. 1f the rate of supply decreases the screening becomes too severe, while if it increases beyond the capacity ofthe machine, good stock passes to the waste. Under ordinary working conditions .it is difficult to maintain a constant rate of pulp supply, for the latter is constantly undergoing variations. l have therefore arranged in each supply chamber 45 means for equalizing the screenvThe entire pulp supply is then discharged through the feed orifice 48, the capacity of.

the machine being such that the pulp in traveling from the orifice 48 Aoutwardly over .the screen to the discharging outlet is subjected to a suitable and sufiicient screening action. If thel rate of supply increases the pulp will flow over the adjustable weir plate 50 and the surplus, or that entering the supply passage 40, will fiow to the supply passage 50 and be discharged through the orifice 47. This orifice is so located that the pulp discharged therefrom will be subject to a suitable and sufficient screening action in its travel fromthe orifice 47 to 'the region of .the orifice 48. By this means the variations 1n pulp supply may be automatically taken care of and the screening action be maintained constant irrespective of variations in supply.

While I have herein shown two differently positioned discharge orifices and their respective supply passages, it will be evident that as many separate channels and successive weir plates as is desirable and practicable may be utilized and the same may be 'constructed in widely different forms and shapes from Y'that herein shown. lVhen the weir plates are once set for a certain` condition they automatically take care of the distribution, but they may be adjustable as indicated in Fig. 1, whereby the whole of the pulp may be deflected to any one of the feeding orifices shown.

- In order to provide that the stock fed from the orifices 47 or 48 shall enter in a substantial amount only into the pulp-receiving spaces between the back of the pulp-impelled blade 30 and the pulp-impelling.blade 3l and prevent its entrance to any substantial extent into the intermediate spaces, suitabh` means are provided, herein consisting of obstructionmembers carried by the blades, for obstructing the free passage of the pulp from the annular outlets to the intermediate spaces. rlhese may be of any suitable form. but herein they consist each of a plate 51 (Figs. 1 and 2) which extends between the back of the impelling blade 31 and the front of the impelled blade 30 directly overlying and in' close approximation to the annular orifice 47 so that the pulp cannot escape in any substantial amount from the latter into the intermediate or non-pulp-receiviug spaces between 'the blades. Similar obstruction platesl52 are carried between the blades 31 and 30 to obstruct and prevent the passage of pulp from the orifice 48 to the nonpulp-receiving spaces. rlfhe plates 51 are of a suitable shape to practically cover the orifice 47 and are carried each by the brackets 53 bolted to the back of an impelling blade 31. Similarly the plates 52 are supported by brackets 54 bolted each to the back of an impeller blade 31 at a position directly opposite the annular orice 48.

The described feeding arrangement provides for the intermittent feeding of the stock between the impeller so that eachv unscreened portion of the batch fed to the screen receives the impact not only of the impeller blade 31 which discharges it against the screen, but alsosthe impact of the next adj acentpulp-impelled blade 30 before any further-material is discharged against a screen from the next succeeding pulp-receiving space. lan the disclosed embodiment of the invention there is also provided means for supplying shower water or other liquid and distributing it to the most effective points upon the screen. 'llo supply the shower water supply pipes-60 are providediL one entering each end of thel drum, these pipes adapted vto discharge water each through the open endof a conical-shaped water distributing receptacle61 bolted or otherwise secured to thepside of the rotating' drum 24. The water on being discharged from the stationary pipe 60 .to the rotating chamber is thrown by centrifugal force to that portion of .they chamber or receptacle of greatest diameter, which, herein, is closely adjacent the drum 24, but which might be located at other points lengthwise the blades as desired. At its point of greatest diameter each receptacle 61 is provided with water dischar eorifices 62 through which the water is ischarged radially outward-between the blades and thereby distributed to the pulp being screened. rl`his method. of supplying shower water avoids the necessity of using stuhng boxes.'

To distribute the shower water evenly along the blades means are provided suoli as the deflecting plates 63 to receive the shower water as it is thrown out from the chamber 61 and carry it lengthwise the blade to the desired point. Each defiector is in the form of a shelf attached to or formed integral with the front of the blade v36 forming a trough to guide the water lengthwise the blade until the end of the plate is reached, at which point it is allowed to-discharge radialy outward upon the pulp. By making one set of deflecting plates terminate close to the disk 24 as indicated at the top of Fig. 1, another set extend a little farther, as indicated at the bottom of Fig. 1, and successive sets extend for varying distances toward the outer end of the blades, the water may be directed from one blade close to the center and from the next blade agreater distance from the center and so on, effecting thereby for a single rotation of the impeller an even distribution of the shower water lengthwise the screen.

`While the water might be admitted' therefore consists of a succession of blades forming intervening compartments consisting of pulp-distributing compartments and intermediate and alternating liquid distributing compartments.

While the screen 10' might be held fixed, I

have herein shown the same mounted for rotation upon the annular supporting members 17 and 18 which are rotatable upon the bearing flanges 15 and 16, as heretofore described. The screen might be rotated in either direction by power, but herein l permitthe frictional contact or impact of the pulp itself against the interior of the screen by the impeller blades to rotate the screen, and control its rotation by means of a suitable braking device. For this purpose the bearing rings 19 and 20'are each provided with gear teeth 65 which -mesh with pinions 66 mounted upon a shaft 67 extending parallel with-the screen. At its outer end (see Figs. 1 and 2) the shaft 67 is provided with the brake drum 68 engaged by the brake shoes 69, the latter secured respectively to the pivoted levers 7 0 so that they can be drawn together and frictionally ap- 'plied to the brake drum. To control the brake the upper ends of the levers are jointed to blocks 1 which have threaded engagement withl the right and left threads of a screw shaft 72, the latter journaled in the brake casing 73 and having the hand wheel 74 by which the brake may be released or applied' to a varying extent. A hand wheel 8O (see Fig. l) is keyed to the end of the shaft 67 outside of the brake casing 73, so that the shaft 67 and the screen may be turned by hand when required. rihe hub of the hand wheel 80 is provided with a pin 81 adapted to enter a hole in the side of the brake casing so as to lock the hand wheel and the shaft thereto and prevent the turning movement of the screen as required, or the pin may be withdrawn to permit the free rotation of the screen.

memes By adjusting the brake through -tne hand wheel 74 the speed of the screenmay be controlled and retarded to a sul'licient point to give the required screening action. The impact of the cleansing Water alone is suliilcient to rotate the screen and, in fact, the pressure of the air through the pulp feed spout' for purposes of illustration one specific forml of the invention, it is to be understood that the same is not limited to specific details of construction herein shown or the relative arrangement or relation of parts, but that extensive deviations may be made .therefrom without departing from the spirit of the in-l vention.

Claims:

1. In a machine of the class described, the combination with a casing of a screen drum, blades rotatably mounted within and to cooperate with the drum, a support on which the blades are mounted, means for rotating the blade support, said blades being arranged in pairs and each pair consisting of a preceding pulp-impelled blade and a succeeding pulp-impelling blade, the pulp-impelled blade being inclined to impart a blade-rotating movement to the blade support under the feeding pressure of the pulp, and-means to supply pulp to the back of the pulp-impelled blade only.

2. In a machine of the class described, the combination with a casing of a screen drum, blades rotatably mounted within and to eooperate with the drum. a support on which the blades are mounted, means for rotating the blade support, said blades being arranged in pairs, each pair consisting of a preceding pulp-impelled blade and a succeeding pulp-impelling blade, theV pulp-impelled blade being inclined to impart a blade-rotating movement to the blade support under the feeding pressure of the pulp, the pulp-impelling blade being also inclined with an increasing pitch toward its outei` edge, thereby to afford both a Wide distributing surface andan accelerated discharge' for the pulp, means for feeding pulp from within andradially outward between the blades, said pulp being fed between a pulpimpelled blade and the next succeeding pulp-impelling blade only.

3. In a machine of theclass described, the combination with a screen drum, impeller blades mounted within the drum for rotation relatively to the screen, said blades beingarranged in pairs, said blades being arranged to provide intermediate spaces, and

means for feeding pulp between the blades at alternate spaces only.

4. In a machine of the class described, the combination with a hollow screen of impeller blades Within the screen and means for rotating said blades, certain of said blades being pulp-impelled blades inclined radially backward from the direction of rotation to transform the impact of the pulp into rotative movement, and means for feeding the 4pulp to the back of the pulp-impelled y blades only.

5'. In a machine of the class described, the combination with a casing `of a hollow screen, blades rotatably mounted within and cooperating with the screen, said blades including 'pulp-impelled blades and pulp-impelling` blades, theV former being inclined to transform the pressure of the pulp into 'blade rotative movement and the latter being inclinedradially backward to provide a wide distributing surface with an increasing pitch toward its outer edge, thereby to give an accelerated discharge to the pulp, and

means for feeding pulp to the back of said pulp-impelled blades and the front of said pulp-impelling blades only.

6. In a machine of the class described, the combination with al casing of a hollow screen and blades rotatably mounted within and to coperate with the screen, said blades including pulp-impelling blades inclined radially backward with relation to the direction of rotation and formed to give an .accelerated discharge to the pulp, andl means for discharging pulpfrom within and radiallyoutward upon said bla-des.

7. In a. machine of the class described, the combination with a screen of impeller means including a pulp-impelling blade having a cross section providing for a pulp-receiif'ing surface extending in an approximately ra'- dial direction. succeeded in the radial direction by a distributing surface inclined rearwardly With reference to the pulp-receiving surface and termina-ting in a discharge surface again approximating a radial direction to give an aecelerateddischarge to the pulp.

8. In a machine of the class described, the combination with a casing of a screen, impeller means rotatable within the screen and including a pulp-impelled bladeA and a succeeding pulp-impelling blade, and means for feeding pulp to the back of the former and the front of the latter only.

. 9. In a machine of the class described, the combination with a casing of a screen drum,

impeller means rotatably mounted within let also communicating with the interior of the drum, and means for utilizing the feeding pressure upon the pulp for driving the impeller means.

l0. In a machine of the class described, the combination with a casing of a screen, blades rotatably mounted within and to cooperate with the screen and means for feeding pulp to the front face of each alternate blade only. c

11. In a machine'of the class described, the combination with a casing of a screen, blades rotatably mounted within and to cooperate with the screen, and means for feeding pulp to the front faces of certain blades only while withholding it from the faces of intermediate blades.

12. In a machine of the class described,4

the combination with a screen of impeller means coperating therewith comprising a plurality of impeller blades, means forfeeding pulp to the interior of the screen, and means to impart to each portion of the stock so fed a plurality of blade impacts.

13. In a machine of theclass described, the combination with a casing of a screen, means for feeding pulp intermittently to any given area of the screen, and means for imparting to said Vpulp a plurality of blade impacts prior to the feeding of additional stock to the same area.

14. The method of screening pulp which consists in feeding a portion of pulp to a screening area .and imparting a plurality of beats to it while undergoing screening prior tothe feeding of further pulp to the same area.

15. -In a machine of the class described, the combination with a casing of a screen drum, blades rotatably mounted within and to coperate with the drum, means for rotating the blades, said blades being arranged in pairs, means for feeding pulp from within and radially downward between the blades comprising one or more internally arranged pulp discharge oriiices, and means to direct the pulp from said orice o-r orifices between certain blades only and preventingl its discharge between intermediate blades.

16. In a machine of the class described, the combination with a screen of impeller means within the screen comprising a plurality of blades of alternately varying section.

17. In a machine of the class described, the combination with a screen of impeller means within the screen comprising a plurality of blades of similar length and height but alternately varying inclination.

18. The combination with a screen of im- .peller means within the screen, said impeller means havinga plurality of blades, said blades being of similar length and height but of varying radial inclination.

19. In a machine of the class described,

memes the combination with a screen of impeller means within the screen comprising blades arranged in pairs, each pair being formed in one unit and comprising two di'erently shaped blades. y

20. As a new article of manufacture a pair of impeller blades for a pulp .screen formed as a unit, said blades being of similar shape in projection.

21. As a new article of manufacture, a blade unit for a pulp screen comprising a pair of blades formed integral with a single blade support and adapted to be fastened to a rotative member. l

22. As a new article of manufacture a blade unit for a pulp screen comprising a pair of impeller blades, a common support at one end by which they are to be attached to a rotative member and a connecting rib near the opposite end.

23. As a new article of manufacture, an impeller wheel for a pulp screen having impeller blades and water conducting members extending longitudinally of said blades and terminating at' different longitudinal. locations.

24. As a new article of manufacture, an impeller wheel for a pulp screen having impeller blades and water conducting plates formed integrally with the blades and eX- means for preventing the discharge of stock between certain of the impeller blades.

26. In a machine of the class described, the combination with a. casing of a screen, impeller blades rotatably mounted y'within and to coperate with the screen, a circumferentially arranged pulp supply orifice within the drum and blades to discharge stock outwardly between the blades and means for preventing the discharge of stock between certain of the impeller blades, said means comprising obstruction members carried between the blades and tending to cut oli' communication between the said orifice and the intermediate space between said blades.

27. In a machine of the class described, the combination with a casing of a screen, blades rotatably mounted within and to cooperate with the screen, means to feed pulp from within and outward between the blades, said means comprising an annular discharge orifice for feeding the pulp from the end of the screen-inclosed space to the interior thereof, and means to direct pulp from said orifice vbetween certain bladesy only, preventing its discharge between intermediateblades comprising obstruction members carried by the blades and closing communication from the said orifice to the spaces between intermediate blades.

28. In a machine of the class described, the combination with a casing of a hollow, horizontal screen, impeller blades rotatably mounted withinand to coperate with the screen, means for rotating the blades, means I for feedingthe pulp from within and outward between the blades, said blades being inclined longitudinally to feed the unscreened stock toward one end of the screen, said feeding means comprising a plurality of feeding passages terminating in feeding l orificesarranged at different points length-` wise the blades,-and means dependent on variations in the rate of .pulp .supply for controlling the distributionof pulp to said passages.

29. In a machine ofthe class described, the combination with a easing of a hollow, horizontal screen, impeller blades rotatably mounted within and tocoperate with the screen, means for rotating the blades, means for feeding the pulpv from within and outward between the blades, said blades being inclined longitudinally to feed the unscreened stock toward one end ofthe screen,

said feeding means'comprising a plurality y of feeding passages terminating in feeding orifices arranged at different points lengthwisethe blades, and means dependent on variations, in the rate of p ulp supply for controlling the distribution of pulp to said passages.

30.*In a machine of the class described, the combination with ahorizontal screen of impeller means within the screen, means to direct stock upon said impeller means at a plurality of differently positioned points lengthwise the screen, the unscreened stock being traversed lengthwise the screen to a waste discharge outlet, and means for automatically distributing the stock to said different points dependent on the variations in the rate of pulp supply.

31. In a machine of the class described. the combination with a horizontal screen of impeller means within the screen, means to pulp supply orifices, separate passages connecting said orifices and an overflow plate 33. In apulp screen the combination with I a screen drum, propeller means, a plurality of pulp supply passages and an adjustable weir plate for controlling said passages.

34. In a machine of the class described, the combination with a screen and impeller means to apply the pulp to the screen, means for feeding the pulp to said impeller means from a variable source of supply, and means to distribute thepulp to said impeller means dependent on variations in the rate of supply. i

35. In a machine of the class described, the combination with screening means of means automatically to regulate the extent of screening with. reference to variations in the rate of supply.

36. In a'machine of the class described, the combination with a screen of impeller blades within the screen, means for feeding pulp fromwithin and outward between the blades, said means comprising an annular feeding passage terminating in an annular orifice and a second annular feeding passage within the first and terminating in an annular orifice differentially located with reference to the first orifice.

37. In a machine of the class described,

the combination with a screen ,of impeller blades, said means comprising an annular feeding passage terminating in an annular orifice and a second annular feeding passage within the first and terminating in an annular orifice differentially located with referenee to the first orifice, and means for distributing pulp to said passages dependent on the variations in the source of supply.

38. In a machine of the class described, the combination with a screen of impeller blades vwithin the screen, means for feeding pulp from within and outward between the blades, said means comprising an annular feeding passage terminating in an annular orifice, and a second annular feeding passage within the first and terminating in an annular orifice differentially located with reference to the firstorifice, and means for feeding pulp to said first-named passage and an excess of lsupply to said last-named passage. f

39. In paper/manufacture the combination with a centrifugal screen of a liquid the blades, and means for feeding water between one pair of blades to one point lengthwise the screen and between. another pair of blades to a different point lengthwise the screen.

42. In a pulp screen the combination with a screen drum, a plurality of impeller blades within the drum, means for feeding pulp to the blades, means for feeding water from within between the blades, and deflecting means o-f different longitudinal extent between the blades for applying the water to the screen at different points lengthwise the blades.

43. In a pulp screen the combination with a screen drum of impelling blades within the drum, means for rotating said blades, means for discharging shower water radially outward between the blades and curved deflecting platesto receive the water between the blades, said plates being of dierent longitudinal extent to direct the water from the screen upon the pulp being screened at different points lengthwise the screen.

44. In a machine of the class described, the combination .with` a screen, blades rotatably mounted within and to coperate with the screen, means for rotating said blades, the latter being arranged in pairs, means for feeding pulp between one pair of blades and means for feeding shower water between the next adjacent pair of blades.

45. In a machine of the class described, the combination with a casing of a screen drum, blades rotatably mounted within and to coperate with the drum, means for feeding pulp between the blades and a water distributing member carried and rotatable with the blades, said member having one or more circumferential orifices for centrifugally discharging water between the blades.

46'. In a machine of the class described, the combination with a casing of a screen drum, blades rotatably mounted within and to coperate with the drum, means for feedingpulp between the blades and a water distributing member carried and rotatable with the blades, said member having a plurality of discharge orifices for discharging the water centrifugally to the blades, said orifices registering with the spaces between certain blades only.

47. In a pulp screen the combination with a rotatable screen drum of impeller blades rotatably mounted within the drum, means mamas vfor feedingpulp to the blades to be forced Y against the interior of the screen and means to control the rotation of the screen caused by the forcing of the pulp against the same. 48. In a pulp screen the combination with a rotatable screen drum of impeller blades rotatably mounted within the drum, means for feeding pulp to the blades to be forced against the interior of the screen and means to control the rotation of the screen caused by the forcing of the pulp against the same, said means comprising an adjustable braking member.

49. In a pulp screen the combination with a rotatable screen drum, a shaft geared to said drum, a braking drum on said'shaft, a brake for said drum, means to adjust said brake, impeller means within the screen,

- said impeller blades, means for feeding pulp to said 4impeller blades, and means providing for the automatically controlled rotation of the drum.

- 51. In a machine of the class described, the combination with a casing of a screen drum, blades rotatably mounted within and ktocoperate with the drum, a support on which the blades are mounted, means for rotating the blade support, said blades being arranged in pairs, each pair consisting of a preceding pulp-impelled blade and a succeeding pulp-impelling blade, the pulp-impelled blade being inclined to impart a blade-rotating movement to the blade support under the feeding pressure of the pulp., the pulp-impelling blade being also inclined with an increasing pitch towardrits outer edge, thereby to afford both a wide distributing surface and an accelera-ted discharge for the pulp, means for feeding pulp from within and radially outward ybetween the blades. said pulp being fed between a pulp-impelled blade and the next succeeding pulp-impelling blade only, said feeding means comprising oppositely disposed sets of annular feed spouts for feeding the pulp from the ends of the drum to the interior of the drum-inclosed space and radially outward from between the blades, each set having a plurality of annular dicharge ori ltlfl nate pairs of blades or to certain blades only, preventing its discharge between intermediate blades thereby to provide for an intermittent feeding of the stock from the outlets to the screen drum and for a plurality of impacts by the blades against each portion of stock so fed, such means consisting of obstruction members carried by the blades and obstructing the free passage of the pulp from the annular outlets to the spaces between intermediate-blades or alternate sets of blades, thereby to provide pulp-receiving pockets between the blades and other intermediate non-pulp-receiving pockets.

52. In a machine of the class described, the combination with a casing, a screen drum, blades rotatably mounted within and to coperate within the drum, means for rotating said blades, means for forcing pulp from within and radially outward between certain pairs of the blades, means for supplying water to the spaces between the pulpreceiving blades or to the non-pulp-receivv ing spaces and for distributing the same to a plurality of points lengthwise the blades and the screen drum, said means including a rotatable water distributing chamber carried by and rotatable with the blades, means for supplying water to said chamber com-A prising a fixed supply conduit discharging into said chamber through an open end and means for discharging the water centrifugally from said receptacle, the latter for that purpose having a` central enlargement provided withone or more discharge orifices annular in form in operative relation to the open spaces between the blades, and

Vmeans for conveying the water discharged through said orifice between the blades to different longitudinal distances comprising longitudinally extending bafiie plates of different length.

53. In a machine of the class described, the combination with a casing of a screen drum, blades rotatably mounted within and to coperate with the drum, a support on which the blades are mounted, means for rotating the blade support, said blades being varranged in pairs, each pair consisting of a preceding pulp-impelled blade and a succeeding pulp-impelling blade, the pulp-impelled blade being inclined to impart a bladerotating movement to the blade support under the feeding pressure of the pulp, the pulpimpelling blade being also inclined with an increasing pitch toward its outer edge, thereby affording both a wide distributing surface and an accelerated discharge for the pulp, means for feeding pulp from within and radially outward between the blades, said pulp being fed between a pulp-impelled blade and the next succeeding pulp-impelling blade only, `said feedingmeans comprising oppositely disposed feed spouts having vannular outlet orifices for feeding the pulp from thel ends of the drum to the interior of the drum-inclosed space and radially outward from between the blades, means to direct the stock from said orifices between alternate pairs of blades or to certain blades only, preventing its discharge between intermediate blades thereby to provide for an intermittent feeding of the stock from the outlets to the screen drum and for a plurality of impacts bythe blades against each portion of stock so fed, such means consistingv vof obstruction members carried by the blades and obstructing the free passage of the pulp from the annular outlets to the spaces between intermediate blades or alternate sets of blades, thereby to provide pulp-receiving rotatably mounted within the drum, said drum being rotatable under the influence of pressure from within the same, and means to control the rotation of the drum.

57. An impeller for use with pulp screens comprising a wheel having impeller blades radially distant from the axis thereof, a

water-receiving chamber inwardly vof the blades said chamber having outlets opening to mediately succeeding spaces 'between the blades. 0

58. A process of screening pulp 4conslsting of alternately delivering a batch of pulp to the screening means and discharging water on the delivered batch.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

ANTON J. IIAUG.

Witnesses l EVERETT S. EMERY, THOMAS B. Boo'rH.

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