US2672075A

US2672075A - Machine for treating paper mill waste

Info

Publication number: US2672075A
Application number: US145127A
Authority: US
Inventors: Fraser Douglas
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-03-23
Filing date: 1950-02-20
Publication date: 1954-03-16
Anticipated expiration: 1971-03-16

Description

March 16,1954 1: FRASER 2,672,075

MACHINE FOR TREATING PAPER MILL WASTE Filed Feb. 20, 1950 2 Sheets-Sheet l Inventor @00 /a 5 2/7Se/ Attorney March 16, 1954 FRASER MACHINE FOR TREATING PAPER MILL WASTE 2 Sheets-Sheet 2 Filed Feb. 20, 1950 I rwentor avj/ir f l dfff" w/m Afiorney 7 plates.

- less bulky dimensions.

Patented Mar. 16, 1954,

MACHINE FOR TREATING PAPER MILL WASTE Douglas Fraser, Moi-den, England Application February 20, 1950, Serial No. 145,127

Claims priority, application Great Britain March 23, 1949 4 Claims. 1

This invention relates to an improved machine for treating paper mill waste including brokepaper or esparto grass or straw or the like and has for its object in the case of the first named material, means for returning into pulp stock the made or partly-made paper, common known as broke-paper, and of effectively treating the other waste material that occurs in the various stages of paper manufacture and reducing same also to pulp stock. The broke-paper may be in a partly prepared condition or otherwise and is normally collected by hand and trucked or conveyed away for re-pulping.

Esparto grass is normally put through a machine generally known as a duster to remove sand, dirt, etc. and is then conveyed away for further treatment. In this invention the esparto grass can be fed into the receiving vessel which forms an integral part of the apparatus and can be washed free of sand and dirt. This method of treatment obviates the use of a duster machine and a dust-collecting apparatus with its potential fire danger in the mill. This fire danger is due to the fine dust and "flufP which fills the surrounding air during the working of the duster machine and which renders the air and any place where dust settled highly inflammable.

According to the present invention, immediate- 1y a charge has been fed into the treatment vessel it is wetted with water thereby eliminating all fire risks and in the course of its treatment such raw material as esparto grass or straw is reduced whilst in a wet state to parts of small dimensions by a preliminary tearing process, and then passes under impellers placed above perforate rubbing The pulp produced is then separated from any admixed dust or grit, and can pass to paper pulp refining units for further treatment.

Straw is normally similarly dusted and then chopped by a cutter into more manageable and A dust-collecting apparatus is normally a feature of such a process and the potential fire danger obtains. By the use of this invention the straw can be immediately wetted and the dust laid. The impeller aforesaid reduces straw and straw-like material into small dimensional sizes thus obviating the use of any preliminary cutting operation.

The object of the present invention is to provide an apparatus that will readily receive or actually induct broke-paper and likepaper mill waste or esparto grass, straw or. the like and consists of a chest or tank containing revolvingarms,

' stationary tearers, an attrition impeller or impellers, an adjustable particle size classifier, and

a wet grit trap and separator. V p

The invention consists in an improved machine for treating paper mill waste and comprises in combination a receiving vessel with water supply thereto and pulp inlet thereto and exit therefrom, a driven vertical shaft centrally disposed in said vessel, drag arms fast on said shaft, tearer brackets fast with the internal peripheral walls of said vessel co-operating with said drag arms, horizontal impellers fast with the lower portion of said central shaft, grooved perforate rubbing plates forming a foraminous partition in said vessel below said impellers, means for adjusting one said perforate plate in relation to the other and means for eliminating sand grit below said partition to exit.

The angular relationship of the drag arms with the tearer brackets is such as to provide a shearing action to any pulp or paper stock coming therebetween and both of these parts may be fitted with renewable edge parts to compensate for operative abrasion.

Further, the impellers are formed with concave faces in the direction of drive and since these impellers rotate over the grooved perforate plates producing a secondary shearing action the pulp stock, which is forced into the cavities of the curved impellers, is curled over again and again to be sheared against the ridges or groove edges of the upper foraminous plate. 7

Conveniently the above machine is erected to feed a paper pulp refining machine with means for recirculating the partly refined paper stock to the receiving vessel either above or below th drag arms aforesaid.

In order to eliminate sand grit and other like matter of small particle size from the wet paper pulp stock resulting from the maceration process, it is necessary to provide means to segregate this material from the flow of pulp and eject same as waste. To this end a wet grit trap is arranged below the foraminous plates. This consists of a conical or roof shed structure with an annular launder covered with gauze over which the raw pulped paper stock is compelled to fiow after its passage through the perforated plates. Preferably this gauze cover is formed with a shallow annular depression coincident with the 3 to circulate through the mass at such point and thus assist in the elutriation of the grit and its passage to exit.

To those conversant with paper making it will be obvious that'the above device may take various forms mainly dependent upon the type of paper waste to be treated with accentuation of some of its features or otherwise, but in order that the invention shall be more fully understood reference is made to the accompanying drawings wherein there is illustrated a type of machine that may be called upon to deal with theoverall waste of a modern factory, as a preferred embodiment and wherein:

Fig. l is a part sectional elevation of the invention shown as mounted in flow with a cone type paper refining machine.

Fig. 2 is a sectional plan on line A-A Fig. 1.

Fig. 3 is a part sectional plan on line BB, Fig. 1.

Fig. '4 is a cross section of the rubbing plate.

Fig. .5 is a fragmentary plan of upper rubbing plate.

Referring to the drawings and to Fig. '1 the receiving vessel "D is "formed with a circular body I, a cover i2,-a truncated conical lower part 3, a foraminous.partitionreferred'to as a whole under 4, and a base'bowl 5. The cover has an opening '5 for the admission of paper waste, said cover carries a gear box 1 with means for driving a dependent central shaft/3. The gear in box I is driven by an electric motor 8 or any substituted source of power by means of a shaft it and coupling l l. The shaftB carries a series of drag arms mounted on sleeves i 3.fastiwith the shaft 3.

The said arms I2 are adapted to co-operate with the tearer brackets "M, the latter being formed as shown'and mounted fast cn'theinner periphery of the vessel body '5. The said arms t2 and brackets M are not in radial alignment, the lack of coincidence 'beingafew degrees, as .see'Fig. -2, so that the arms 82 drag the waste paper along a shearing edge en the brackets M1. The edges of thebrackets it maybe serratedor straight and in some cases are faced with toughened or hardened steel to resist wear.

The sha-ftfi may be of the suspended type as shown in Fig. l or may be guided'initsilength by passing through abracket Win the vessel part 3 as shown in dotted lines. At the "lower part of the shaft 8 is mounted'iiast therewith an impeller it having several arms of paraboloid ,or cup secin Fig. 3 the coincidence or otherwise of the perforations 18 in the plates 4a and 4b can be adjusted by manipulating wheel 23 to give a series of maximum openings to practically nil.

Below the partition J ,is mounted a facially grooved support 2'! having'a gritlaunder 28 connected to waste pipe 29; over the support 21 is laid a. wire fabric 30 having any desired mesh opening-dimension. The mesh covering lies upon its iacially grooved support, and is then inbent at 31 to follow the curvature of the launder 28. The meshing 30 is spaced away from the launder lip so that fine paper pulp passing through the mesh is caused to overflow the edges and rejoin the main body of pulp in the vessel base 5.

The device as shown in Fig. 1 is mounted so as to feed a paper pulp refining unit E. This unit E is of a known type pressure fed from a centrifugal pump 32. The outlet 33 is branched andbothbranchescontrolled byvalves 3 and respectively. Valve 35 permits the refined pulp stock to be sent'to a poaeher'chest or other part of the paper making plant, the valve 35 being closed, or if valve 34is closed, the pulp is recirculated through the vessel D again through the pipe "-36. Pipe 35 may also be used -f0r-sup-plying water to "the broke'paper or-may be inserted by conduit B'ientering the cover. Pulp'rnay-be withdrawn 'irom the compartment 3 of vessel D through orifice "3B and pumped back to the top of the'vessel D.

In operation the paper mill waste, including broke paper, cuttings, trimmings, loose'raw paper stock including straw, esparto or other grass is introduced to the vessel D through the cover opening 6 and water is sprayedin. The raw material is engaged by the drag arms 12 which in their rotary motion andinclination induce the entry of material which is stripped away and teased by engagement of the arms l2 with the tearer brackets 44 =fast withthe vessel part 1. Several arms l-2 may be fitted toany one sleeve 1 3 and several 'tearer brackets-may be common to any one-tier of sleeves. The broke material torn tion indicated at Na in Figure .1 and adapted-to rotate horizontally over the upper 'foraminous static partition plate 4a in the direction of the arrow seen inFigure 3.

The plate dca'see Fig. 4,.isformed with a series of sharp edged grooves "H with perforations I8 'overthe whole of the plate in the groove recesses.

A single foraminous plate may be employed if the waste paper material is uniform, but with a view of providing an adjustment of plate orifice beneath the upper plate 4a there is a lower perforated plate to. The plate 4b is formed with perforationsof identical pitch in bothdimensions with those of .the upper plate 4a. Plate 42) is capable of relative movement in relation to plate 4a. This is arranged as shown in :Fig. 1. The lower plate 41) is provided with a bracket 29 accommodating the head 2| of a spindle 22 said spindle being threaded into a-nut 23. Shaft 22 is prolonged to appear externally'and isprovided with a hand wheel or lever 25. "The nut 23 ,is

'madefastwith an entry sleeve 2,5.and the shaft "made tight against leakage by cap 28. 'As shown off the uppermost arm -12 drops to the arm or arms of the next tier. Centrifugal force tends to keep the broke paper away from the central shaft and withwet'paperits'path'along the arms 12 is lubricated so that the bulk of the broke material entering-is engaged by and macerated upon the tearers l4. When the half formed paper pulp reaches section 3 of vessel D it falls upon the partition 4 where the raw pulp is dragged round over the sharp edges of the grooved plate 4a by the impellers It. The paraboloid type of section of these impeller blades tends to cause the-pulp to engage and reengage the surface'of theplatedmand when the predetermined fibre size has been attained, the particles pass through the coincident or partly coincident perforations and fall upon the grit catcher below, the 1 pulp traversing the mesh fabric under water-flow down the incline into the depression 3i whereany remaining grit sepa rates'andpasses-to'the launder below and is removed from the "vesselthrough ,pipe 29. In the passage of the pulp "overthe'mesh fabric anygrit or sand present passes through the openings in the wire meshdown the-surfacegrooves cutin' the face 'of 'the support and are washed into the launder andpassto waste. 'When'the pulppasses thegrit meshing 3i! "it'overfiowsthe'launder and passes to the. refiner 'If the vessel D ,is not keeping pace WithQinputppthe broke paper .is hard or caked, the apertures in the foraminous partition are widened to make the openings in the plates 4a and 4b more coincident by manipulating the handwheel 24, this arrangement being of the push-pull type whereby aperture size can be adjusted with a single control. With this arrangement the coarse ulp is fed to the refiner D and is recirculated in the treatment vessel until the desired texture of pulp is obtained.

I claim:

1. In a machine for treating paper mill waste to reduce same to pulp stock, the combination of a treatment vessel, a horizontal partitionin said vessel defining an upper chamber and a lower chamber, said partition being perforate, a shaft extending vertically in said upper chamber, drag arms radiating from said shaft, tearer brackets on the inside of the vessel in its said upper chamber portion, said chamber portion having inlet means for the introduction of the mill waste and a supply of water, horizontal impeller means on said shaft in close proximity to said perforate partition and within said upper compartment, means for rotating said shaft to rotate said drag arms and said impeller means, said drag arms and tearer brackets cooperating to tear and initially macerate said mill waste in the said upper chamber, said impeller means operating at the bottom of the upper compartment to pulp the macerated waste and discharge same into the lower chamber through the perforate partition, said impeller means being formed to churn the macerated mill waste upon said perforate partition, a grit screening device in said lower chamber immediately beneath said perforate screen and in the path of the discharge of the pulp particles from said perforate partition, said device serving to separate grit from the pulp particles, a discharge outlet in said lower compartment for the discharge of the pulp and a discharge outlet on said grit screening device for discharging the separated grit.

2. I he invention as defined in claim 1, said perforate partition including separate perforate plates mounted in surface contact with one another with their respective perforations in register, and means for adjusting one said plate relatively to the other to vary the effective size of said registered perforations.

3. The invention as defined in claim 2, said impeller means comprising radiating arm members of cup-shape section.

l. An improved machine for treating paper mill waste of the type set forth having means for macerating partly formed paper pulp comprising a rotary impeller disposed above a foraminous grooved upper rubbing plate, said grooves having parallel sides and upper shearing edges, perforations within said grooves, said upper plate being static and constituting a base to the macerating vessel, a perforate lower plate mobile under control in relation to said upper plate for total orifice adjustment, a grit catching device disposed below the foraminous plates, said device comprising a launder mounted below said rubbing plate, a grooved cone or shed disposed within said launder having serrated outer edges, the said cone or shed being provided over its entire superficial area with a covering of wire mesh or gauze, the latter being inbent at the launder edge and passing therefrom, apron fashion, to cause the pulp to overflow said edge and pass into the lower base of the vessel, the launder passing any sand or grit caught in the grooves to a waste pipe and thereby ejected from the vessel as waste.

DOUGLAS FRASER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 785,025 Sherwood Mar. 14, 1905 879,440 Carothers Feb. 18, 1908 1,039,941 Herz Oct. 1, 1912 1,287,439 Richmond Dec. 10, 1918 1,515,336 Brandt Nov. 11, 1924 1,556,926 Fritz Oct. 13, 1925 2,294,060 Wiener Aug. 25, 1942 2,424,726 Wells July 29, 1947 FOREIGN PATENTS Number Country Date 313,611 Great Britain Aug. 21, 1930 653,505 Germany Nov. 11, 1937