US2003150A - Pulp screening machine - Google Patents

Description

y 1935- 0 N. M. KNIGHT 2,003,150

PULP SCREENING MACHINE Filed Oct. 29, 1934 5 Sheets-Sheet l 2 \6 \nvenTor.

Neison M.Knighr b M M&M

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May 28, 1935. N. M. KNIGHT 2,003,150

PULP SCREENING MACHINE Filed Oct. 29, 1934, 5 Sheets-Sheet 2 lnvenTor.

Nelson M. Knighr b fwa May 28, 1935. N. M. KNIGHT PULP SCREENING MACI-YINE Filed Oct. 29, 1954 5 Sheets-Sheet 3 a 5 so 4s lnvenTor "N'ison MKnighT la /6W4 MA'W Aflys,

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y 1935. N. M. KNIGHT 2,003,150

PULP SCREENING MACHINE Filed Oct. 29, 1934 5 Sheets-Shet 4 Fig.

\n v enTor.

Nelson M. KnighT M SJMM ATTys.

y 35 v N. M. KNIGHT 2,003,150

PULP SCREENING MACHINE I I Filed 001;. 29, 1954 s Sheets-Sheet 5 Fig. 8.

Invenror. Nelson M. Knighr Atfys.

Patented May 28, 1935 UNITED STATES PATENT OFFICE PULF SCREENING MACHINE Nelson Moore Knight, Weymouth Heights, Application October 29; 1934, Serial No. 750,481

10 Claims. I (Cl. 92-34) This invention relates to pulp screening mawhich'the screened pulp is discharged from the chines and it has for its general object to provide casing. The side wall of the casing is formed by an improved pulp screening machine which is two oppositely-disposed .supporting members 6- constructed to facilitate the screening operation, which are secured at their lower ends to the lower and for another object to provide a novel pulp head 4 and at their upper ends to the upper head 5 screening machine which is constructed so that 2, andtwo curved plates 1 which are connected the screening operation can be performed with at their vertical edges to the supporting memthe expenditure. of a relatively small amount of hers 6. Each supporting .member 6 is formed power for operating the machine. with an outwardly-extending flange 8 at each 10 My improved-pulp screening machine is proedge thereof, and each plate 'lhassecured to each 10 vided with a vator casing having an inlet in its vertical edge an angle iron member 9. The radi-. top through'which the pulp to be screened is de-- a1 leg of each angle iron 9 is bolted to the radial livered to the vat, and a discharge opening in its flange 8 of the adjacent supporting member 6 by lower end through which the screened pulp is dismeans of suitable bolts 'lfl, and the members 6,

' charged, and a'screening element having vertical which are slightly curved as shown in Fig. 2, to- 5 screening walls situated between the inlet and gether with the plates 1 form the side walls of the discharge opening. The device also is provided casing I. The upper and lower edges of the with means for causing the pulp to be forced back 1 plates I are clamped to the upper and lower heads and forth through the screening walls during its through the medium of clamps H and clamping flow from the inlet to the discharge opening, and bolts l2. Each clamp l I has two legs l3 rest- 20 with cleaning runners situated closely adjacent ing against the outside of the plate I as is clearly the inlet side of th'escreening walls, together with seen in Fig. 2, and the corresponding clamping means for producing a relative motion between bolt extends through the clamp and screws into said runners and said walls whereby the runners the head. v assist in keeping the screening walls free from ac- The upper head 2 has a fitting i4 secured there- 35 cumulating deposits of refuse or other material to, which fitting is provided with an inlet paswhich is screened from the pulp. sage l5 communicating with the inlet port 3.

In order to give an understanding of the in- This fitting will be connected to asuitable inlet; vention I have illustrated in the drawings a sepipe for deliveringto the passage I! the pulp to lected embodiment-thereof which will now be debe screened. It indicates a discharge pipe se- 30 scribed after which the novel features will be cured to the lower head 4 and communicating pointed out in the appended claims. v with the discharge opening 5, the screened pulp Fig. l is a vertical sectional view through a being delivered through said pipe l6. pulp screening device embodying my invention. Located within the casing Us a screeningele- 85 Fig. '2 is a section on the line 2--2 Fig. 1. ment presenting a vertical screening plate situ- Fig. 3 is a view showing the cleaning runners ated to intercept the pulp as it flows from the removed from the screen. inlet to the discharge opening. In the illus- Fig. 4 is a view similar to Figalbut showing a, trated embodiment of the invention the screendifferent' embodiment of the invention. ing element is in the form of a vertically-arranged 40 Fig. 5 is a section on the line 5-5 Fig.4. stationary cylinder [1 having periorated screen- 40 Fig. 6 is a section on the line 6-6 Fig. 4. ing side walls and an upper-head l8 and a lower Fig. 7 is a fragmentary section on the line l--l head IS. The lower head I! is formed with a Fig. 2. central opening 20 which communicates with the Fig. 8 is a side view of a screening devices emdischarge op g 5 through the IOWB! head 4 0 bodying the invention. the casing. The screening element is stationarily 45 Referring first to the construction shown in mounted and the lower head I! is formed with a Figs. 1, 2 and 3, l indicates generally a casing fla ge p tion II w ch e s the lower head 4 which contains the pulp screening elementand the Casing, the Said Screen-i118 lelement'being through which the pulp flows during the screen clamped to the lower head of the casing by suiting operation. This casingis shown as cylindriable'tie rods 22 which are anchored at their up- 50 cal in shape with its axis extending vertically. per ends in the upper head i8 01' the screening The casing comprises an upper head 2 provided element. and which extend through'the lower with a pulp inlet 3 through which the pulp to be head of the screening element and also through screenedis delivered to the casing, and a lower the lower head 4 of the casing, said tie rods havhead 4 having the discharge opening 5 through ing clamping nuts 21 thereon by which the screening element is clamped to the lower head of the casing.

The pulp to be screened flows into the casing I through the inlet 3 and through the stationary cylindrical screening plate l'l into the interior of the screen and thence through the discharge openings 20 and 5.

Means are provided for causing the pulp to be forced back and forth through the screening plate ll during its flow from the inlet to the discharge opening, the purpose of this pulsating movement of the pulp being to assist in keeping the screen free. The cylindrical screening plate or wall H has rigid therewith a plurality of plates or partitions and between each two adjacent stationary plates is a movable plate or vane. Means are provided for vibrating the movable plates or vanes between the stationary plates, thereby causing the pulp to be forced back and forth through the screening wall H. In the embodiment of the invention shown in Figs. 1, 2 and 3, the stationary plates or partitions are indicated at 24, said plates extending horizontally or transversely to the axis of .the screening elev other by spacing sleeves 33 which encircle the tie rods 22 as shown in Fig. '7 and which pass through openings. The movable plates 'or vanes are in the form of disks which are indicated at 26 and these also extend horizontally and parallel to the plates or partitions 24 and each of which has a central opening 65. The movable plates or vanes 26 are arranged for vertical movement, each plate or vane being movable between the two dotted line positions indicated at a and b. The movable plates or vanes 26 are carried on a vertical reciprocating spindle 21 which reciprocates in two bearings 28, 29 carried by the lower and upper heads i9, i6 of the screening element. This spindle 21 has rigid therewith two sets of radial arms 30 and 3|, the ends of the arms of each set being bifurcated and receiving in the bifuroations one of the movable plates or vanes 26 as is best seen in Fig. 1. The movable vanes 26 are all rigidly connected by tie rods 32 and the adjacent plates or vanes are held properly spaced by spacers 33 in the form of sleeves which encircle the tie rods 32. Since one of the movable plates 26 is anchored in the arms 30 and another of said plates is anchored in the arms 3|, the said plates are not only rigidly connected by the tie rods 32 and spacers 33, but they are also rigidly secured to the arms 30 and 3| which in turn are rigid with the vertical spindle 21. The spacing sleeves 33 extend through apertures 34 formed in the stationary plates or partitions 24. The movable plates 26 are provided with apertures 84 through which the spacing sleeves 83 extend as shown in Fig. 7. I

Vertical reciprocating movement of the spindle 21 will, therefore, reciprocate the movable vanes 26 in a vertical direction, such reciprocation mov ing the vanes between the dotted line positions a, b as stated above.

The spindle 21 extends upwardly through the central or hub portion 34 of the fitting l4 and the upper end is connected by a connecting member 35 to an eccentric strap 36 which encircles an eccentric 31. This eccentric is mounted in suit-' able bearings in the fitting i4 and has rigid therewith a sprocket wheel 38 which is connected by a sprocket 39 to a driving sprocket 40 on a shaft 4i, the latter having a driving pulley 42 thereon by which it is operated.

The plates or vanes 26 are shown in full lines in Fig. l in approximately their central position, and as these plates or vanes are moved downwardly by the operation of the eccentric 35, the pulp between each movable vane and the stationary plate 24 directly below it will be forced outwardly through the screening wall l1, and as each movable plate or vane moves away from the stationary partition above it the pulp will be drawn inwardly through the screening cylinder. When the plates or vanes 26 move upwardly the pulp between each plate -or vane and the stationary partition 24 above said plate or vane will be forced outwardly through the screening wall i1, while at the same time the pulp will be drawn inwardly through said wall into the space between the upwardly moving plate or vane and the stationary partition below it. Each moving plate or vane, therefore, will cause a local pulsation or movement of the pulp back and forth through the screening cylinder I1, and hence there will be a plurality of such local movements throughout the vertical dimension of the screening cylinder.

There will also be a general movement of the pulp through the casing I from the inlet passage l5 to the discharge pipe i6 and during this forwardly flowing movement the pulp is repeatedly forced back and forth through the cylindrical screening wall 11. This operation serves to keep the exterior of the wall free and prevents it from becoming clogged either with the fibres in the pulp or with the refuse or rejects which are being screened out from the pulp.

As a further means of keeping the screen free and preventing it from becoming clogged, I employ a plurality of cleaning runners which are located on the exterior of the cylindrical screen adjacent the surface thereof and which are moved over the surface of the screen. These runners are indicated at 43, said runners preferably having the cross-sectional shape shown in Fig. 2, and each runner having an inclined or slightly spiral shape. Each runner is connected at its lower end to' a ring member 44 and at its upper end to another ring member 45, the runners pref erably being integral with said ring members. The upper ring 45 is secured to the periphery of a flange or plate 46 which is keyed to or otherwise made rigid with a sleeve 41 and this is journalled in the hub portion 34 of the fitting i4. The inner face 48 of the lower ring 44 encircles and bears on bearing rollers 49 which are secured to studs 56 that are anchored inthe lower head IQ of the screening cylinder, these rollers 49 thus serving to center the ring 44.

Means are provided for rotating the sleeve 41 and flange 46, together with the runners connected thereto so that the runners are moved around the cylindrical surface of the screening cylinder IT. For this purpose the upper end of the sleeve 41 has a worm gear 5| fast thereon which meshes with a worm 52 on the shaft 4|. The runners 43 are shown as wedge-shaped in cross section (see Fig. 2) and the edge 53 of each runner lies closely adjacent the exterior surface of the screen cylinder l1. These wedge-shaped runners are arranged at an angle to a radial direction so that the front or leading face 55 makes an obtuse angle with the outer face of the screen cylinder l1, while the rear or following face 56 makes an acute angle with said cylinder face. As the cleaning runners move around the cylinder, each runner tends to remove from the exterior'face of the screen cylinder any mass of fibres or refuse or dirt which is screened out of the pulp, thereby preventing the screen from becoming clogged. Because of the shape of the runners 43 and their angular relation to the exterior surface of the screening cylinder I1, the movement of each runner through the pulp will cause a suction at the rear face of the runner, and thissuction tends to remove from the exterior face of the screen any dirt which may be accumulated thereon but which is not scraped off from the screen by the edge '53of the runner. It will be noted that these edges 53 do not contact with the screen 'but are spaced slightly therefrom, outside of the screen but passes between the edge 53 and the runners will be loosened from the screen by the suction createdat the rear face of each runner.

I propose to construct the means for vibrating the spindle 21 and for rotating the cleaning runners so that each runner will travel through the angular distance between adjacent runners during the movement of the movable plates or vanes 26 from their upper to their lower position or vice versa. Hence, ,any fibre mass'or refuse which collects on the exterior of the screen plate during the pulsating movement of the pulp due to the downward movement of the plates or vanes 26 will be removed by the cleaning runners before the plates 26 are given their reverse or upward movement, and similarly any fibre mass or refuse which collects on theexterlor of the screen plate during the upward movement of the vanes 25 and which would tend to clog the screen, will be removed by thecleaning runners 43 before the plates or vanes are again given their downward movement.

The flange 45 carrying the runners is shown as having openings 51 therein. As the unscreened pulp flows through the inlet port 3, the greater portion thereof will flow outwardly over the flange 46 and downwardlyaround the screen cylinder- I'l, said pulp gradually flowing through said screen cylinder I1, but at the same time being forced back and forth through the screening cyl-' inder by the vertical vibration of the plates or vanes 25 as said pulp flows to the discharge opening. g

Some of the pulp will flow through the apertures 51 into the space between the flange '46 and the head I8 of the screening cylinder, this pulp flowing around the head I8 and to the upper end of the cylinder.

The inlet I communicates with a tank or vat 30 to which pulp may be supplied from a supply pipe IL. The discharge pipe I5 leads to a delivery box 32 having a discharge 33, said delivery box 32 with its discharge being so situated relative to the supply box 83 that the level of the pulp in the delivery box or chest 82 will be slightly below the level of the unscreened pulp in the supply box or chest 80. This difference of level between the supply box or chest 80 and the delivery box or chest 82 provides the necessary head for causing theflow of the pulp through the screening cylinder. As a. result of'this arrangement, the casing I will always be kept filled with pulp and will have no air spaces therein.

The lower head 5 of the casing I is shown as having discharge openings I4 therein for the discharge of the rejects or refuse which is screened from the pulp. Suitable pipes 84 are connected to these discharge openings I4, and these pipes and any dirt which accumulates on the chest 30 and the discharge end of the pipes 34 as between the inlet chest 30 and the discharge chest 82. g

As the screening action takes place the refuse I andother materials screened outof the pulp will be gradually worked down to the lower end of the casing I by the runners 4,3 and will then be discharged through the discharge openings I4 and discharge pipe 84.

I1 indicate supporting feet secured to the lower head 6 and which rest on suitable supports 13.

In Figs. 4, 5 and 6 I have illustrated a different embodiment of: the invention wherein the sta tionary and movable plates or vanes extend vertically instead of horizontally and the movable vane-s have a horizontal vibrating movement. In the device shown in Fig. 4 the vat or casing I and the screening cylinder I! are the same as above described with reference to Figs. 1, 2 and 3 except that the stationarypartitions or plates which are rigidwith the screening cylinder extend vertically and have a radial arrangement. These stationary plates are indicated at ",each plate being rigidly secured at its outer edge 53 to the inner wall of the cylinder I1, and having its upper andlower edges engaging the upper and lower heads I8, I9 of the screen cylinderand clamped therebetween. The movable plates or vanes are indicated at 60, and these have a radialarrangement and are rigid with a sleeve or hubmember 6| which is fast on a shaft 62 that is journalled at its lower end'in the bearing 53 carried by the lower head I9 of the screening cylinder, and at its upper end in the bearing 84 carried by the upper head II of said screening cylinder. This shaft 62 is given an oscillating movement whereby to oscillate the plates 50 between the dotted line positions 0, d (see Fig. 5). This oscillating movement of the plates 60 has the same effect in causing localpulsation of the pulp as the vertical vibrating movement of the plates or vanes 20 in Fig. 1. The means for vibrating the plates 65 and for rotating the cleaning runners 43 is best shown in Fig. 6. The upper end of the shaft 62.

has an arm 65 rigid therewith which is pivotallyconnected to a connecting member Cl extending from an eccentric strap 81 that encircles an eccentric 58 formed on a shaft 53. The shaft 03 is provided with a driving pulley ID by which it is rotated and as the shaft rotates the eccentric O3 and connections, 85 produce the necessary oscillating movement in the shaft 62to-cause the plates 60 to move between the dotted line posI-.

tions c, d. v

Theshaft 69 has a gear II thereon meshing with a gear I2 which is secured to the upper end of the sleeve 41 which carries the cleaning runners. The gearing for rotating the runners and for vibrating the shaft 62 will preferably be so constructed that each runner will move through the angular distance between adjacent runners, while each plate BI) is 'moving from one to the other dotted line position.

The device shown in Figs. 4 to 6 operates in the same manner as that described in Figs. 1 to 3 except that the local pulsations of the pulp are in zones extending vertically of the screening cylinder, rather than in zones extending circumferentially thereof as is the case in the construction shown in Fig. 1.

I claim:

1. A pulp screening machine comprisinga casing having an inlet at'its upper end anda-discharge opening at its lower end; ascreen element situated within t easing betweenthe inlet and the discharge opening and having a vertical screening wall, means for forcing the pulp back and forth. through the screening wall as said pulp flows from the inlet'to the discharge opening, screen-cleaning runners on the inlet side of the screening wall and means to produce a relative movement between said runners and said wall.

2. A pulp screening machine comprisinga casing having an inlet at its upper end and a discharge opening at its lower end,'a screen element situated within the casing between'the inlet and the discharge opening and having a vertical screening wall, means for forcing the pulp back and forth through the screening wall as said pulp flows-from the inlet to the discharge opening, screen-cleaning runners on the inletside of the screening wall and means to move the screencleaning runners relative to the screening wall.

3. A pulp screening device comprising a casing having an inlet at its upper end and a discharge opening at its lower end, a screening element within the casing having a vertical cylindrical screening wall, means for forcing the pulp back and forth through the cylindrical screening wall as it flows from the inlet to the discharge'opening, screen-cleaning runners on the exterior of the screening wall and means to produce a rela tive movement between said runners and said cylindrical wall. a

4. A pulp screening device comprising a casing having an inlet at its upper end and a discharge opening at its lower end, a screening element within the casing having a vertical cylindrical screening wall, means for forcing the pulp back andforth through the cylindrical screening wallas it flows from the inlet'to the discharge opening, screen-cleaning runners on the exterior of the screening. wall and means to cause the screen-cleaning runners to rotate around the cylindrical screening wall.

5.'A pulp screening apparatus comprising a casing having an inlet atits upper end and a discharge opening at its lower end, a screening element within the casing having a vertical cylindrical screening wall situated between the inlet and the discharge opening, a plurality of plates or partitions within the cylindrical screening wall and rigid therewith, movable plates or vanes situated between the partitions .,and means to vibrate'the movable plates toward and from the stationary partitions thereby causing the pulp to be forced back and forth through the cylindrical screening wall as it flows from the inlet to the discharge opening.

6. A pulp screening apparatus comprising a casing having an inlet at its-upper end and a discharge opening at its lower end, a screening element within the casing having a vertical cylindrical screening wall situated between the inlet and the discharge opening, a plurality of plates or partitions within the cylindrical, screening wall and rigid therewith, movable plates or vanes situated between the partitions, means to vibrate the movableplates toward and from the stationary partitions thereby causing the pulp to be forced back and forth through the cylindrical screening wall as it flows from the inlet to the discharge opening, a plurality of screening runners located on the exterior of the cylindrical screening wall "in close adjacency thereto and means to rotate the runners about said screening wall.

7. A pulp screening machine comprising a casing having an inlet at its upper end and a discharge opening at its lower end,'a verticallyarranged screen plate situated within the casing between the inlet and the discharge opening, means for forcing the pulp back and forth through the screen plate assaid pulp flows from the inlet to the discharge opening, screen-cleaning runners on the inlet side of the screen plate, means to produce a relative movement between the runners and the plate and discharge openings in the bottomofthe casing on the inlet side of the screen plate for the discharge of rejects.

8. A pulp screening machine comprising a casing having an inlet atits upper end and a discharge opening at its lower end, a verticallyarranged screen plate situated within the casing between the inlet and .the discharge opening, ,means for forcing the pulp .back and forth through the screen plate as the pulp flows from the inlet to the discharge opening, an inlet chest communicating with the inlet opening and from which pulp is supplied thereto and a discharge conduit connecting tothe discharge opening of the casing and leading to the level slightly below that of the pulp supplied to said inlet opening.

9. A pulp screening machine comprising a casing having an inlet at its upper end and a discharge opening at its lower end, a verticallyarranged screen plate situated within the casing between the inlet and the discharge opening, means for forcing the pulp back and forth through the screen plate as the pulp flows from the inlet to the discharge opening, an inlet chest communicating with'the inlet opening and from which. pulp is supplied thereto and a discharge chest having an outlet slightly below the level of the pulp in the supply chest and a discharge pipe-connecting the discharge opening of the casing with said discharge chest.

10. A pulp screening.machine comprising a casing having an inlet at its upper end and a discharge opening at its lower end, a verticallyarranged screen plate situated within the casing between the inlet and' the discharge opening, means for forcing the pulp back and forth through the screen plate as the pulp flows from the inlet to the discharge opening, an inlet chest communicating with the inlet opening and from which pulp is supplied thereto and a discharge conduit connecting to the discharge opening of the casing and leading to, the level slightly below that of the pulp, supplied to said inlet opening,

said casing having in its bottom a discharge open-,

ing for rejects on the supply side of the screen plate and a discharge pipe connected to said latter discharge opening and leading to a level slightly below the pulp level in the supply chest.

, NELSON MOORE KNIGHT.

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