US1918621A - Separating apparatus - Google Patents

Description

July 18, 1933. c. a. THORNE SEPARATING APPARATUS Filed Dec. 7, 1951 4 Sheets-Sheet 1 July 18, 1933. c. B. THORNE SEPARATING APPARATUS Filed Dec. 7, 1931 4 Sheets-Sheet 2 ATTolzueye.

y 1933- c. THORNE 1,918,621

SEPARATING APPARATUS Filed Dec. 7, 1951 4 Sheets-Sheet 3 INVENTOR'. CARL B. THOZN E.

B) ATToRNE /s.

July 18, 1933. c. B. THORNE SEPARATING APPARATUS 4 Sheets-Sheet 4 Filed Dec. '7, 1931 INVENTOQ CARL B. THOZNL.

sirable solids.

Patented July 18, 1933 UNITED STATES,

PATENT OFFICE CARL BUSCH THOBNE, OF HLWKESBURY, ONTARIO, CANADA sm m'rme A'mmnarus Application filed December 7, 1981. Serial No. 579,586.

0 fiour, and has for its object to provide a reliable and efiicient machine of large capacity and relative small size for this or any analogous purpose.

The invention also has for object to provide a machine in which clogging of the wire screen is effectively prevented by continuously agitating the mat of solid material which forms thereon.

Cellulose pulp manufactured from wood may contain not only the so-called long fibres but may also contain a certain percentage of short fibres and wood flour, and these short fibres and wood flour tend to reduce the value of the pulp for the manufacture into certain finished products.

There are many unavoidable sources of these undesirable short fibres and flour, for instance, the tree itself contains a certain amount of minute cells which are a source offlour, also wood fiour is produced in the chipping process. The actual cooking of the wood may also influence the fibres in such a way as to make short fibres and flour. The common method of emptying a digester exerts a severe mechanical action on the fibres. When the pulp is blown out of the digester under pressure into the blow pits, the sudden explosion-like expansion not only separates the fibre bundles, but will also tear and damage some of the individual fibres to a certain extent and so produce undesirable short fibres and wood fiour. The undesirable factors of the Wood flour are that it not only carries with it comparatively large proportions of resin but its general chemical properties are such that make it undesirable when pro ducing the highest grade of cellulose pulp. The short and broken fibres are objectionable principally because when included in the manufacture of certain finished products they tend to reduce the physical strength.

It will therefore be understood that for the manufacture of certain articles where long fibres only (or a larger proportion than usual of long fibres) are most desirable, a machine such as hereinafter described can be very effectively and economically employed.

The invention consists in theconstruction, combination and arrangement of parts hereinaf-ter described and more particularly pointed out in the appended claims.

Referring now to the accompanying draw ings, which illustrate, byway of example,3

several embodiments of the invention,

Figure 1 is a plan view with certain parts omitted for clearness of illustration;

Figure 2 is a sectional elevation on the line 22 of Figure 1;

Figure 3 is an end elevation looking on the right hand end of Figure 2;

Figure '4 is a transverse section substantially on line 4-4 of Figure 1;

Figure 5 is a diagrammatic longitudinal section of a modified form of the invention;

Figure 6 is a-section on line 6-6 of F igure 5, and

Figure 7 is a diagrammatic, isomctricview of a further form of the invention.

In Figures 1 to 4 the apparatus comprises a rigid drum 1 mounted to rotate in bearings 2 and 3. The drum 1 has endmembers 4 and 5 connected by longitudinal bars 6, and circular spiders 7 are placed at intervals between the end members. On the spiders 7 and flanges on the members 4 and 5 is provided a heavy, coarse wire screen or perforated drum 11, and over the screen 11 is placed a fine wire screen 12. The fine wire 12 is shown as being made in longitudinally extending sections clamped at their edges to the bars 6, see Figure 4. The bars 6 and bridge pieces 13 hold the two screens 11 and 12 in contact with each other against the circular spiders 7.

The end member 4 has a cylindrical extension or fiange 14 rotatably mounted in a fluid-tight manner in an aperture in a wall 15 forming part of a compartment 16. The

end member 5 has a similar flange 17 journalled in bearing 3.

The drum 1 .is divided into a plurality of compartments of diflerent volume by partitions 18 which are formed with openings 19 which are angularly displaced with reference to one another, see F lgures 2 and 4. In the illustrated example the compartments are of gradually diminishin volume in the direction of flow of the solids through the drum.

On a hollow shaft 8, which is mounted at one end in a bearin 9 and at the other end in a boss 10 carried y the end member 4, are rigidly mounted paddles or a itators 20 projecting towards the bottom 0 the drum, and spray pipes 21 which extend towards the top of the drum. The hollow shaft 8 is supplied with water, for example, by means of a flexible hose 22, and the spray pipes 21 are perforatedso as to project sprays of water against the top'of the screen drum as indicated at 23. If desired, the agitators 20 may also be in the form of perforated pipes, so as to project jets of water against the bottom of the drum as shown on one of the agitators at 24.

In the right hand end compartment of the drum 1 is provided a chute 25.

The drum is mounted in a box or tank 26 and communicates through the neck 14 with the flow box compartment 16 which in turn communicates with an inlet box 28 through an aperture 29 controlled by a throttle valve 30 which is automatically opened and closed by a float 31. An inlet pipe 32 feeds solidcontaining water into the compartment 28, the level in which is maintained substantially constant by means of a weir 33 which discharges into an overflow box 34 leading, for example, to the sewer. A pipe 35 supplies water to the bearing 2.

-Over the drum 1 and arranged parallel thereto, is mounted a perforated spray pipe 36 rotatably mounted in bearings 37 carried by any suitable frame members, such as 38.

The drum 1 is rotated slowly by any suitable gearing and preferably a rotary and longitudinal oscillating movement is imparted to the shaft 8 which carries the agitators 20 and spray pipes 21. As shown in the drawings, this may be accomplished by the gearing indicated in Figures 1, 2 and 3.

pur gears 39 are mounted on the end members 4 and 5 and are driven through reduction gearing 40, for example, from a motor 41. A small crank or eccentric 42 is coupled by a rod 43 to a lever arm 44 keyed to the hollow shaft 8, and a screw-threaded sleeve 45 on the shaft 8 engages a similarly threaded bore in the bearing 9. Thus the rotation of the eccentric 42 causes the shaft 8 to oscillate both in a rotary and longitudinal direction. The spray pipe 36 may also be caused to oscillate in a rotary direction by providing it with an arm 46 coupled by a rod 47 to an arm 48 on the shaft 8.

The level of the liquid in the compartment 26 is controlled by means of a weir 49 which discharges surplus into an overflow box 50.

The operation of the apparatus is as follows: The water containing the fibre, wood flour, etc. enters from pipe 32 and compartment 28 and flow box 16 to the inside of the drum 1 through the neck 14. The wire agitators or paddles 20 are oscillating back and forth, and the cylindrical screen is rotatmg at a comparatively low speed. The water flows through the screens 11, 12 and deposits the fibre, wood flour, etc. on the inner surface of the screen 12. A mat of fibre, wood flour, etc. forms very quickly on the wire and would tend to seal it so that very little water would flow through, but by removing the small fibres and wood flour the capacity of the machine is very much increased. Also only the good fibres are recovered. As the screen revolves, a portion of the mat of wood flour and fibre is continuously being agitated by the paddles 20. Thls agitation stirs up the mat of fibres, etc. that has formed on the wire and temporarily cleans it and allows the fine particles, small fibres, etc. to flow through the wire while the good fibres which are too large to pass through the wire are retained in the drum. The fibre is continuously deposited, carried up and washed ofl the wire screen by the water from spray pipe 36 until it is cleaned of all the wood flour, small fibres, etc. The three or more separate divisions in the cylinder are so arranged as to ensure that the fibre is washed at least three times though, of course, the invention is not limited to any particular number of compartments. From the first large chamber the fibre, after it is agitated off the wire, passes to the second chamber through the hole 19, in the first partition 18, and is again deposited on the wire, agitated off and thus further washed. This again happens in the third chamber and more times if required. Also, if desired, a series of separate machines may be used instead of the one machine with the various divisions or compartments. It will be noted that each of these successivechambers is smaller than the preceding one, the reason being that as the fibres become cleaner, they allow wa-. ter to pass through them much easier. Therefore, while the sizes of the chambers are different, their capacities are approximately the same. The last compartment has no paddle or agitator and simply serves 'to collect the recovered fibres. The fibres are collected on the wire as the screen drum revolves, and are thus carried towards the top of the drum, where the water from the spray pipe 36 washes the good, cleaned fibre off the wire into the chute 25 and so out of the compartment 26, into a compartment 51 from where it may be pumped to an place desired. The spray pipe 36 prefera ly extends the whole length of the cylinder and sprays water on the outside of the wire thereby keeping the wire clean.

It is desirable for the best operation of the machine that the head of water flowing to the machine be kept reasonably constant. Should the water rise in the flow box 16, the float 31 will also rise and so partially close the valve 30. or open it if the water level in the ilow box 16 should become lower, when the butterfly valve will automatically open and allow more water to flow to the drum 1.

This machine has a very large capac ty per square foot of wire and satlsfactorily recovers a very high percentage of the fibre in a continuous manner and at the same time allows the wood flour and small fibre to be washed away.

The paddles or agitators 20 are shown in the drawings as being of a substantially triangular shape, but these can of course be of any other shape, as it has been found advantageous to change the shape of these paddles according to the kind of material being recovered.

In the form of the invention just described the water flows from the inside to the outside of the screen drum. Figures 5 and 6 illustrate diagrammatically an example of an arrangement whereby the water flows from the outside to the inside of the drum. According to this modification the white water flows to a tank 52 through a pipe 53, a divislon wall 54 being placed in the tank so that the water will flow into the tank in a quiet manner. The wire screen-covered cylinder 55 is rotated slowly in the tank by suitable gearing 56 and the water flows inwardly through the wire and out through an opening 57. The pulp which collects on the outside of the cylinder wire is recovered by the use of a collector roll 58 and a scraper 59 in a known manner. Agitators 60 which are mounted on the central shaft 61' are caused to oscillate back and forth in a manner similar to that previously described and continuously agitate the mat of fibre, etc. to prevent clogging of the screen.

The invention is not limited to the use of a cylindrical screen, but may employ a continuously travelling flexible wire screen of the Fourdrinier type. as illustrated diagrammatically in Figure 7. Rollers 61'and 62 are reduced in diameter at each end to receive deckle straps 63. Over the top of both the rollers and the deckles is placed a fine mesh wire screen 64. Small rollers 65, commonly known as table rolls, support the wire 64 as it travels from one large roller to the other. A pipe 66 carries the white water containing fibre to the inside of the wire and the water which goes through the wire is collected in a tank 67 and flows from the tank out through a pipe 68. Agitators 69 are placed close to the surface of the wire between the cylindrical rollers 61 and 62 and are oscillated back and forth by revolving cranks, such as 70. A trough 71 collects the recovered fibre which is washed off the wire by a spray 72.

In operation the rollers 61 and 62 rotate in the direction shown by the arrows and ca with them the wire 64. The water contaimng the fibre is carried to the inside of the wire by the ipe 66 and is prevented from spilling over t e edges of the wire by the deckle straps 63 in a way similar to that on a Fourdrinier machine. The machine is immersed in the tank 67, and the overflow 68 from the tank is so arranged that the level of the water is maintained nearly to the top of the deckles 63. The flow of the water and the small fibres, wood flour, etc. is from the pipe 66, through the wire 64 into the tank 67 and out through the pipe 68. The good fibres are retained on the inside of the wire and the agitators 69 agitate it oil in a manner similar to that previously described. After the wire passes thelast agitator the fibre stays on the wire and is carried up over the roller 62 to a point over the trough 71. Here the spray from the pipe 72 washes the recovered fibre oil the wire into the trough from where it flows out through a pipe 73 to any place desired.

It will be understood that the accompanying drawings and foregoin descri tion are given by way of example on y and t at many further modifications may be made without departing from the scope of the invention as defined in the appended claims.

I claim:

1. Apparatus for separately recovering solid particles from suspension in a liquid comprising a horizontal hollow shaft, a c lindrical wire screen coaxial with said s aft, agitators carried by said shaft and projecting towards the bottom of said screen, spray pipes carried by said shaft and projecting towards the top of said screen, a tank having a weir for maintaining a substantially constant level of liquid over the lower portion of said screen, a flow box for introducing solid-containing liquid into one end of said screen, and means for discharging the larger particles which remain in said screen.

2. Apparatus for separately recovering solid particles of different sizes from suspension 1n a liquid, comprising ascreen of a mesh which permits passage of the smaller particles, means for imparting a slow motion to said screen, means for maintaining a level of the solid containing liquid over the lower portion of the screen and for causing the iquid to flow longitudinally of the screen thereby forming a mat of solid particles on said screen, means for engaging and agitating the mat-forming particles which collect on each of a plurality of successive portions of the screen to permit progressive release of fine particles, means for raying the top of the screen, means for contmuously collecting the larger particles from one side of the screen and means for continuously dischar ing the liquid and smaller particles from t e other side of the screen.

3. Apparatus for separately recovering articles of different sizes from suspension in a liquid, comprising a screen of a mesh which permits passage of the smaller particles, said screen being divided into a plurality of compartments by apertured transverse partitions, means for imparting a slow motion to the screen, means for maintaining a level of the solid containing liquid over the lower portion of the screen and for causing the liquid to flow longitudinally of the screen, means for agitatin the particles which collect on each of ap urality of successive portions of the screen to permit progressive release of fine particles, means for spraying the top of the screen, means for continuously collecting the larger particles from one side of the screen and means for continuously discharging the liquid and smaller particles from the other side of the screen.

4. Apparatus as defined in claim 3, wherein the apertures in said partitions are angularly displaced with respect to one another.

5;- Apparatus as defined in claim 3, wherein said artitions are so a seed as to form a series 0 compartments 0 different volume.

6. Apparatus as defined in claim 3, wherein said artitions are so aoed as to form a series 0 compartments 0 gradually diminishing volume in the direction of flow of the solids through the screen.

7. Apparatus for separately recoverin solid articles from suspension in a liqui comprising a continuous screen of a mesh which permits passage of the smaller particles, means for imparting a slow motion to the screen, means for maintaining a level of the solid containing liquid over the lower portion of the screen and for causing the liquid to flow longitudinally of the screen, a plurality of spaced agitating devices to en age and disturb masses of particles forme on successive portions of the screen to cause repeated washing of said masses to free the same from fine particles, means for reciprocating said agitating devices, means for spraying the top of said screen, means for continuous] collecting the larger particles from one side of the screen and means for continuously discharging the liquid and smaller particles from the other side of the screen.

CARL BUSCH THORNE.

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