US2340511A - Method of removing trash from paper pulping machines - Google Patents

Description

Feb, 1,1944; f

E. COWLES METHOD OF REMOVING TRASH F ROM PAPER PULPING MACHINES Original Filed March 18,

3 Sheets-Sheetl 7 xxxmxxx m v Feb 1, 1944. COWLES -2,340,51 1

' METHOD OF REMOVING TRAXSH-FROM PAPER PULPING MACHINES Original Filed March 18, 1940 s Sheets-Shet? r a INVENTOR Patented Feb, 1, 1944 when m'rnon or REMOVING TRASH FROM PAPER 'PULPING memes Edwin Cowles, Cayuga, N. i? assignor to The Cowles Company, Princeton, N. .L, a corporation of New Jersey (Driginal application Marchlii, 1940; Serial No. 324,684. Divided and this application June 10,

E941, Serial No. 397,356

it Claims.

This invention relates to methods and apparahas for treating paper stock, and pertains more particularly to method and apparatus for defibering, refining and otherwise preparing paper stock for use on paper making machines.

This application is a division of Patent No. 2,265,936 issued December 9, 1941 on my copendipg application Serial No. 324,684, filed March 18, 1940.

In a prior patent, No. 1,883,597 issued October It is an object of the present invention to provide an improved machine adapted for continuous operation It is a further object of the present invention to provide a method of removing undesired trash from the material being treated.

Other objects and advantages of the invention will appear hereinafter.

18, 1932, I described a method of treating paper stock in whichthe stock is contained in a,vat, and is circulated by a pump which withdraws stock from the vat and returns it thereto, the returned stock being discharged into the vat at high velocity through submerged nozzles. The high velocity jets discharged by the nozzles exercise a defibering and refining eifect on the stock due to the tearing effect of the high velocity jets moving through therelatively stationary body of stock in the vat.

Subsequently, in a prior patent, No, 2,219,571 issued October 29, 1940, I described a different form of apparatus utilizing the principle of my aforementioned patent. In said patent, however, instead of withdrawing stock from the vat and returning it to the vat through nozzles, I provide ,a rotary impeller which is submerged in the vat,

which said impeller is providedwith open grooves so designed as to discharge high velocity jets from the rim of the impellenwhich said jets have the same refining and defibering effect as the jets discharged from the nozzles in the aforementioned patent.

Subsequently,in application SerialNo. 314,107, I proposed to increase the surface area of the stock which is discharged at high velocity by discharging the same inthe form of a relatively thin circular sheet, such as a relatively thin annular disk. In the preferred embodiment illustrated in said application, this is accomplished by mounting a multiplicity of vanes on the surface of an v a batch of untreated material isplaced in the machine, the batch is treated, and the treated batch is removed from the machine.

.A preferred embodiment of the invention selected for purposes of illustration is shown in the accompanying drawings, in which, I

Figure 1 is a vertical sectional view.

Figure 2 is a plan view of a portion of the impeller.

Figure 3 is a side elevation of one of the impeller vanes;

Figure 4 is a sectionon the line 44 of Figure 2.

Figure 5 is a plan view of a portion of the impeller illustrating a modified form.

Figure 6 is a section on the line 5-5 of Figure 5.

Referring to the drawings, a vat or tank! is provided, preferably cylindrical in shape. bottom of the tank is provided with an aperture to receive the impeller hereinafter described, and the sides and bottom of the aperture may be enclosed to provide a sunken chamber 3. The space between said chamber and the cylindrical side wall of the tank maybe filled with concrete 4 to provide a sloping surface as illustrated in Figure 1. Such a sloping surface directs the stock discharged from the impeller, as hereinafter explained, upwardly along the side walls of the tank and assists in maintaining circulation in the stock contained in the tank as indicated by arrows in Figure 1. If desired, fixed directional vanes 5 may be embedded in the concrete to direct the stock which is discharged from the impeller inan upward direction and to restrain to some extent the circulation in a horizontal plane.

An impeller, in the form of a disk I0, is mounted in aforesaid aperture in the bottom of the tank so as to be surrounded by the chamber 3, and may be rotated in any suitable manner, as by pulley ll, driven by motor l2, operating through suitable reduction gears (not shown) mounted in the housing l3.

The impeller disk is provided with a multiplicity of impeller vanes l4 mounted adjacent the rim of the disk, said vanes projecting upwardly from the upper surface of the disk. The said vanes may be secured to the disk in any suitable manner, butin the embodiment illustrated, the vanes are secured, as by welding, a ring 15 which isset into a groove l8 formed in thedisk, which said ring is held in place by The,

screws ll. Thus, the impeller is of the open" typ being distinguished from closed" type imalong the face. The angle of inclination should preferably not exceed 30 and is preferably somewhat less, as for example, the angle illustrated in the drawings is approximately 18.

The height of the vanes above the surface of the'disk is small relative to the diameter of the disk, and should not exceed a ratio of 1 to 30. For example, using a disk having a diameter of 5', the height of the vanes should preferably be about 1%.', so that the disk of stock discharged from the impeller will be relatively thin.

The impeller should be rotated at a rate sufficient to discharge the stock at the rim. of the impeller ata velocity of at least 1000 ft. per minute and in some cases at considerably higher veloclties, as for example, between 1,000 and 2,000

ft. penminute, th particular velocity selected in excess of,l000 ft. per minute depending on the toughness of the stock being treated. For puriposes of this specification, therefore, the term high velocity" is defined as comprehending veloclties in excess of 1000 ft. per minute, for tests have shown that while some deilbering action may be produced at lower velocities, it is not possible toproduce completely deflbered stock with- 'in the limits of practical operation. At lower velocities it has been found that defibering proceeds with reasonable rapidity until the undefibered pieces of stock reach a certain size, after which the rate of defibering is rapidly reduced or defibering action maycease entirely. Even long continued treatment often fails to produce complete defiberization. Using high velocities, as defined herein, however, defibering action proceeds rapidly to completion.

It is important to maintain proper circulation of the stock at all times in order that all portions of' the stock may be repeatedly subjected 1 pieces of trash to enter the passage, since the said vanes 25 initially accelerate the'stock at the center of the impeller and move it toward the vanes I 4 which additionally accelerate it and discharge it in disk form as previously described. Since the vanes 25 continually move stock away from the center of the impeller, thus drawing stock down centrally from the top of the tank, they assist greatly in maintaining the vortical circulation which has been found so highly useful in the operation of this apparatus. In continuous operations the consistency of the stock is usually low and the vortical cavity may extend all the way down to the impeller, so that the impeller'may be seen from the top of the tank. This vortlcal circulation causes the undefibered material which is being added continuously, which said material is frequently in pieces of large size which otherwise tend to float on the surface, to be drawn down into the vortex and to be immediately subjected tothe defibering action of the impeller.

In order to permit continuous withdrawal of treated material, an outlet conduit 28 is connected to the chamber 3, and means are provided for effectively controlling the flow of material from the main portion of the tank to the chamher 3 in order to prevent the withdrawal of undefibered material and trash. Thus, in the machine illustrated in Figures 2 and 3 a restricted passage 3| is provided between the edge of "the plate 32 and the outside rim of the impeller. Since the passage 3| lies immediately beneath the disk of stock which is being discharged at high velocity by the impeller. it is virtually impossible for pieces of undefibered material or velocity of the stock discharged from the impeller is much greater than the velocity of the material tend to move toward the passage without however, preventing withdrawal of completely deflbered material which flows out with the water.

to the action 01' the impeller. The preferred type r of circulation is that, which is in the nature of a vortex or whirlpool comprising circulation in both horizontal and verticalplanes. It has previously been stated that the sloping sections 4 of the bottom of the tank contribute to this result in directing the stock discharged from the impeller upwardly along the sides of the tank, and it has also been pointed out that excessive circulation in the horizontal plane may be restrained b'y fixed directional vanes 5. a

Another contributing feature in this corinec tion is the relative diameters of the impeller and the tank, for it has been found that in order to maintain proper circulation, the diameter of'.

thev impeller should be greater than one fourth and less than one half the diameter of thetank Still another contributing feature to the maim j tenance of proper circulation is' the supplementary vanes 25 which are also mounted on the upper face of the impeller disk between the vanes l4 and the center of rotation of the impeller.

The advancing face 28 "of the vanes 25 maybe inclined to the faceof the disk, as shown, to prevent pieces of stock rromstapling thereon. The

'However, it is advisable that the trailing ends of the impeller vanes extend across the passage 3| as shown in Figure 3, in order to mechanically dislodge any material which may tend to lodge in the passage, and to clear away any fibers which edge 38 extending across the plate. The edge 38 runs in close proximity tothe surface of the plate and repeatedly clears the perforations of any fibers which may lodge therein. In this form of machine the disk .of stock discharged from the impeller, being discharged immediately adjacent the perforated plate and sweeping across said plate at high velocity, in itself tends toclear the screen perforations, and in so doing enhances the defibering action since thedischarged disk is directed directly against any accumulation or,

concentration of fibrous material which may tend to lodge in the perforations due to their re- 'stricted size.

'In'the continuous operation of such machines, m

particularly in board mills where wastepaper is the material to be deflbered,'it is desirable to provide for the continuous removal of the trash thereto. However, the rope end slowly plied to the mill. The trash content of such waste paper is considerable, frequently running as high as 4%. In a machine having a capacity or 200 tons per day, for example, there will be an accumulation of several hundred pounds oi uselss trash per hour, and unless such trash is removed continuously, frequent shutdowns are necessary. Such trash is of two varieties, heavy materials such as paper clips, tin cans, glass, stones, etc., and lighter materials such as rags, string, rope, etc. For the removal of heavy materials, I provide trash pits 40 located at the periphery oi' the tank and communicating therewith by means of a chute ll." The bottom of the chute may be provided with an aperture 42 opening into the pit and controlled by a gate 43 which may be operated by any suitable means.

The circulating movement or the material brings the waste material eventually to a position over one oi the pits, and the heavy material I be variously modified and drops into the pit The said pits may be dredged out periodically whenever necessary in any suitable manner.

The removal of lighter trash materials is a i much more diflicult problem, but I have devised a novel and extremely simple method of removal.

waste paper are thrown bales. These wires wind themselves into the rope and provide suflicient tensile strength to prevent the self-forming rope of trash from breaking as withdrawn. If desired a reel 5| may be mounted at the top of the tank as a convenient means of withdrawal.

It will be understood that the invention may scope of the subjoined claims.

I claim as my invention:

1. Method of removing trash from a continuously operating waste paper pulping machine which comprises continuously introducing waste paper materialincluding trash containing rags, string, rope and the like, maintaining a vortical circulation of the material being treated, trailing an end or rope-like material in said circulating material below the surface, thereof, and withdrawing said rope-like material after an accumulation of trash has been wound thereon.

2. Method of removing trash from acontinuously operating waste paper pulping machine which comprises continuously introducing waste paper material including trash containing rags, string, rope and the like, maintaining a vortical circulation of the material being treated, trailing By careful observation of the operation of the machine, I have discovered that'the vortical circulation tends to concentrate such trash near the center oi the circulation in the vertical plane, approximately in the area indicated by the reference character T, which said area extends around the tank in annular form. Furthermore,

I have discovered that by trailing the end 01a rope or rope like member 50, such as barbed wire, for example, in the tank, the lighter trash materials such as rags, string, rope, etc., tend to wind themselves around the trailing end of r09 trash such as pieces of wood, Cellophane, rubber, etc., which in themselves withdraw the rope end with the trash c I flnd that -by withdrawing and continuously, the trash will continue to form itself into a rope even after the original rope end has been entirely withdrawn from thetank. This is particularlytmeir the baiingwireacustomaril'yusedtobindupbaleao! and in so doing. tend to wrap in other lightare incapable of winding around the rope and. After an accmnulation or such trash has formed, it is possible to p an nd of rope-like material in said circulating material below the surface thereof, withdrawing said rope-like material slowly after an accumulation oi trash has been wound thereon, and

continuing to withdraw the self-forming rope of trash which forms after withdrawal of aid end oi. rope-like material. a

3. Method 01 removing trash from a continuously. operating waste paper pulping machine which comprises continuously introducing waste paper material including trash containing rags, string rope and the like, maintaining a vortical circulation of the material being treated, trailing an end or rope-like material in said circulating material below the surface thereof introducing strands of wire, into said circulating material with said waste paper material, withdrawing said rope-like material slowly after an accumulationof trash and wire has been wound thereon, and continuing to withdraw the self-forming rope of trash and wire which .iorms after withdrawal or EDWIN, COWLES.

into the tank with the embodied within the

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