US2665853A

US2665853A - Toothed cutting impeller for pulping solid materials in liquid suspension

Info

Publication number: US2665853A
Application number: US243326A
Authority: US
Inventors: Jr George B Nicholson
Original assignee: Black Clawson Co
Current assignee: Black Clawson Co
Priority date: 1951-08-23
Filing date: 1951-08-23
Publication date: 1954-01-12
Anticipated expiration: 1971-01-12

Description

Jan. 12, 1954 G B c o so JR 2,665,853

TOOTHED CUTTING IMPELLER FOR PULPING SOLID MATERIALS IN LIQUID SUSPENSION Filed Aug. 25, 1951 INVENTOR. 650265 B. NIcHqLsoNJR. BY 3 W iw ATTORNEYS V mounted for rotation Patented Jan. 12, 1954 UNITED STATES TOOTHED CUTTING IMPELLER FOR PULP- ING SOLID MATERIALS IN LIQUID SUS- PENSION George B. Nicholson, Jr.,

to The Black-Clawson Company, Hamilton, Ohio, a corporation of Ohio Application August 23, 1951, Serial No. 243,326 6 Claims. (01. 241 -298) This invention relates to apparatus for pulping or disintegrating solid materials in liquid suspension.

The invention has special application to apparatus for mechanically disintegrating or pulverizing solid materials such particularly as materials which are not soluble in water but are readily handled in water suspension and which it is desired to reduce to particles of relatively small size without crushing or bruising. For example, the invention has been practiced successfully with varied materials of this general nature such as chunks or large particles of cellulose acetate for reduction to substantially uniform small particle size, large pieces of orange peel for reduction to slurry form in preparation for further processing, and particles of animal fat or fatty tissue for disintegration of the fat globules and connecting tissues to facilitate rendering of the fat, and the invention has as a major objective the provision of apparatus for efiect-disintegrating or pulverizing of solid materials of the above type under controlled conditions giving substantially small particle sizes at economical cost in terms of the requirements of both power and operating time while avoiding crushing or bruising of the material.

This general objective is accomplished in accordance with the invention by treating the solid materials in liquid suspension in pulping apparatus provided with a chamber adapted to contain a quantity of the suspension and equipped with an impeller having special structural and operational features such that it causes continuous radial circulating movement of the suspension and at the same time subjects the solid particles therein to repeated cutting action by a plurality of rapidly moving blades which operate both to sever the particles and also to cause these severed particles to be comingled at high speed and with high turbulence creating a further disintegrating eifect. Thus both inertia and hydraulic pressure cooperate with the cutting blades in performing the disintegrating operation, and since both of these factors decrease as the sizes of the particles become smaller, it is possible in the practice of the invention to establish a desired size of the particles and to reduce all the solid material to this predetermined size with'a high degree of uniformity.

It is accordingly an object of the invention to provide disintegrating apparatus for operation on solid materials in liquid suspension which includes an open chamber having an impeller therein and formed with a Fulton, N. Y., assignor plurality of thin blades arranged in such relation to its rotational axis that as the impeller rotates and causes the suspension to circulate continuously across its surface in generally radial directions, the cutting blades intersect the path of travel of the suspension substantially at right angles to effect repeated cutting action on the particles coupled with a high propulsive action causing the cut particles to rush against each other for further disintegration.

Another object is to provide disintegrating apparatus of the above character for solid materials in which the impeller is formed with two or more radially spaced circumferential rows of cutting blades adjacent its periphery, and in which adjacent blades in each row are arranged at different angles to the rotational axis of the impeller to give a high number of blades with intervals therebetween in each row for high cutting action with minimum bruising.

It is also an object of the invention to provide an impeller for disintegrating apparatus as outlined above which-may be readily fabricated from sheet metal in different sizes and different numbers of rows of cutting blades and relative sizes of blades in accordance with a given material to be treated and the desired conditions of operation thereon.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawi gs and the appended claims.

In the drawings Fig. 1 is a view partly in side elevation and partly in vertical section showing pulping apparatus including an impeller constructed in accordance with the invention;

Fig. 2 is a plan view of the impeller;

Fig. 3 is an enlarged section on the line 3-3 of Fig. 2;

Fig. 4 is a fragmentary view of one of the rows of blades on the impeller;

Fig. 5 is an enlarged fragmentary view showing structural details of on of the cutting blades; and

Figs. 6 and 7 are enlarged fragmentary sections on the lines 6-6 and 1-! respectively of Fig. 4.

Referring to the drawing, which illustrates .a preferred embodiment of the invention, Fig. 1 shows a pulping apparatus generally of the con struction disclosed in Martindale Patent 2,371,837, issued March 20, 1945, to the assignee of this application. This pulper includes a tub or vat having a cylindrically extending upper wall portion l0, an inwardly tapered lower wall tom of the tub and above. its bottom ,.w,al1 '.ihev

rapid rotation of the irripeller;..2il .:vprovides "an effective circulation outwardly and then upwardly along the outer portions of the tub with a return downflow towards theriimpeller, as indicated by the arrows, and vanes .oi plate's z It are-mounted on the wall portion 4 to guide the upward now of the pulp or stock. Adjacent thejbottom of the tub is an annular chamber or compartment 22 partitioned from the space above the' impeller by a perforate extractor plate 25 of fruston l rfor v wh h-perm ts t e passage ofxthe 1 fi p t e .rccm ar ment...nafromewhich it -may be withdrawnas desirec l-by way, of the ;conduit 26 shown as proyidedgwitha shutoffvalve 21.

- Ihe impeller :1ncludes a main plate orgdisk ;having a shaftportionqtlior. connectionv to v the drive for rotation as-described about its central axis 33.. ,Anadapterplate35. is secured to the upper-surface of plate-30 by meanssuch, as

bolts 36, and the impeller..-is alsoprovided on its upper surfacepwith ea plurality. of, nested; disks each formed with a, row of cutting blades around its; periphery. Threeof these disks are, shown and are identified ;as .40-, ligand 42., respectively,

and they are of difierent;,diameters and-mare mounted on the; impeller by-.-..means of; thebolts .7 36, and a central holddowrr plate 44;. ;A plurality ofcurved vanes are ;shown; as, mounted near the center ofthe impeller to. serve as pumping the diameter of the disk and the desired number of teeth, satisfactory results having been obtained with this dimension varying from approximately of an inch to two inches or more.

As one example of the type or disintegrating or pulverizing action for which .theapparatus ofthe present invention has proved highly successful, it has been used for reducing large chunks of cellulose acetate to a substantially uniform small. particle size. In one series of test 'runs :for: this purpose, using pulping apparatusbf-the type shown in Fig. 1 having the tub five feet in diameter was used, the cellulose gacetate particleaiwhich varied from sizes of the order-of ahead of cabbage down to approxi- --mately-=the size of a grain of sugar, were added 1 ina solutionofiwater and glacial acetic acid,

with the total weight of the cellulose acetate -varyingfrom 240 to 430 pounds and with the total volume of the suspension being of the order 013-400;: gallons: In. some gruns;-=.the-: impeller was :constructed as;shown:in,Fig. 3'zwithgth-ree; disks respectively 18, 24 and 30 inches in diameter, and inyother runs only the, smaller='-;twd31iisks were used. In .each case with the :;impeller;; ro-

. tatingat a rate giving a'peripheral speed 0f155100 feet per ,minute for the largest disk, reduction of the cellulose acetate to an extent-such "that -:-less than 2% was retained. on a 5-meshrscreen was accomplished infrom 10 to 15.: minutes with ---economica1 "expenditure of power.

' Another use for which -.apparatus in accordance cwiththe invention hasbeen satisfactorily. used is the mechanical, disintegration of the residual fatty tissue-resulting: from rendering raw; animal vanes urging the pulp .-.rgadi ally,outward across 40 ,.tissue, which comprises approximately-70 %.rfat, is moredifiicultto break down.l lighlyvsatisfac- .the surface;of. the.plate as the, impellergrotates in operation, ,the use; ofgthese yanes bein opnal p d up n v: he. particu ar. materials and operating conditions. desired.

. The construction and; arrangement of the in;

. .dividual blades on each -ofthe disks or1plates .40-42areshown injfijigsyd to 7.,Thesehlades 50 are generally saw-toothed in shapa-yandzeach is formed on itsleading -edge with; ;,s harp,ened

. c tt ed 5 ae enqinet initia r..-. enerally disk vary .with .,th e diameter Of'rthQ. disk butnin generalsatisfactory results have been obtained. 7 with pulping apparatus of, the type, shown in Fig. l Qfdifierent sizes; requiring impellerslof correspondingly ,di ff er,ent;-., diameters,;-; .wherein the blade disks =,arefor1 ned of ;l 1g auge;.-stainless is approximetfily yi otwan inch. in.;length;and is inclined. slightly backwards; foneexamplecabout 2", from a radius: -traversing;-its:.zinnermostcend.

The length of; the.cbladesgmeasured:along the eline flames be.-;varied.in accordance with 20 .minutes,- -but the :remaining adipose fatty toryphysical disintegration of, this fatty tissue and, release of..the remaining fat has been-.ac-

.complished in a pulpingrapparatust constructed as described .above, with the .rapid' rotating impeller blades acting to disintegrate .the-tissues and .thereby to. rupture .the fat cells and: permit release or thefat and recovery of- -thec-valuable ,proteinresidue. without damage such: as would tend tore's'ult fromtheprolonged heating usually relied onfor, this purpose.

{Tests of, the above character indicate-that in the operation of the apparatus of the invention,

'the peripheral. speed 'ofthe cutting blades is of material importance in'obtaining'eff'ective. cutting action with alminimumf or bruising. In general the preferred blade speedappearsto be not .substantially less than approximatelyfififidfeet.per

- minute, .computed for the outermost row ofblades where'more than one row, of blades isused, speeds of this" order having. been foundhighlysatisfactory for 'suchiwidely differing materials aslthe cellulose acetate" and animal fat residue. mentioned'above. In'this speed range,v thepaths' of the radially circulating'particles and the blades -crossat angles-ofthe maximum sizeyand the relative speeds of both particlesand blades are sufficiently high for-the"desiredshearing action ofthe blades on the -particleswithout bruisin tion, it is to be understood thatthe invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimedis:

1. An impeller adapted for use in disintegrating solid materials substantially without bruising thereof in apparatus of the character described including a chamber adapted to contain a quantity of relatively large particles of said materials in liquid suspension, comprising a plate adapted for rotation in said chamber about an axis substantially normal to said plate to subject said suspension to centrifugal force causing said suspension to circulate radially across the surface of said plate, means forming a plurality of relatively thin cutting blades adjacent the periphery of said plate and extending at substantial angles with respect to the plane of said plate, each said blade having a, cutting leading edge thereon facing in said direction of movement to cross said radially circulating suspension at relatively large angles for effective shearing action on said particles therein, said blades being generally saw-toothed in shape and extending generally in line with the direction of movement thereof with said impeller to present minimum surface area to the radial flow of said suspension in use for avoiding bruising of said solid materials therein, and said blades being located adjacent the periphery of said plate to provide substantially maximum linear velocity therefor for a given angular velocity of said plate.

2. An impeller adapted for use in disintegrating solid materials substantially without bruising thereof in apparatus of the character described including a chamber adapted to contain a quantity of relatively large particles of said materials in liquid suspension, comprising a plate adapted for rotation about an axis substantially normal thereto in said chamber to subject said suspension to centrifugal force causing said suspension to circulate radially across the surface of said plate, means forming a plurality of circumferential rows of thin cutting blades concentrically arranged in radially spaced relation on said plate and extending at substantial angles with respect to the plane of said plate, each said blade having a cutting edge facing in the direction of movement thereof with said impeller and having the radially inner edge thereof substantially tangent to the same circle concentric with said plate as the other said blades in the same said row therewith to align the remainder of said blade generally with said direction of movement to avoid bruising of said solid materials in use, and the outermost of said rows being located substantially at and in said tangential relation with the periphery of said plate to provide maximum linear velocity therefor for a given angular velocity of said plate.

3. An impeller adapted for use in disintegrating solid materials substantially without bruising thereof in apparatus of the character described including a chamber adapted to contain a quantity of relatively large particles of said materials in liquid suspension, comprising a plate adapted for rotation about an axis substantially normal thereto in said chamber to subject said suspension to centrifugal force causing said suspension to circulate radially across the surface of said plate, a disk of sheet material secured to the upper surface of said plate, said disk having a plurality of cutting blades formed along the periphery thereof eachhaving a cutting edge thereon facing in the direction of movement thereof with said impeller, said blades being bent out of the plane of the remainderof said disk along lines substantially tangent to a common circle to cross said radially circulating suspension at relatively large angles for effective shearing action on said particles therein and to locate the remainder of each said blade generally in line with said direction of movement thereof, and said blades being generally saw-toothed in shape with, said cutting edges thereof generally radiallyarranged with respect to said plate axis for maximum cutting action on said solid ma-v terials while presenting minimum surface area to theradial flow of said suspension to avoid bruising of said solid materials therein.

4. An impeller adapted for use in disintegrating solid materials substantially without bruising thereof in apparatus of the character described including a chamber adapted to contain a quantity of relatively large particles of said materials in liquid suspension, comprising a plate adapted for rotation in said chamber about an axis substantially normal to said plate to subject said suspension to centrifugal force causing said suspension to circulate radially across the surface of said plate, a disk of sheet material secured to the upper surface of said plate, said disk having a plurality of cutting blades formed along the periphery thereof and bent out Of the plane of the remainder of said disk, and each said blade having a cutting edge thereon facing in the direction of movement thereof with said impeller to cross said radially circulating suspension at relatively large angles for effective shearing action on said particles therein, adjacent said blades being arranged at different angles to the plane of said disk to provide an interval between alternate said blades.

5. An impeller adapted for use in disintegrating solid materials substantially without bruising thereof in apparatus of the character described including a chamber adapted to contain a quantity of relatively large particles of said materials in liquid suspension, comprising a plate adapted for rotation in said chamber about an axis substantially normal to said plate to subject said suspension to centrifugal force causing said suspension to circulate radially across the surface of said plate, a plurality of superimposed disks of sheet material secured to the upper surface of said plate, said disks being generally circular and each being of smaller diameter than the adjacent disk therebelow, each of said disks having a plurality of cutting blades formed along the periphery thereof and bent out of the plane of the remainder of said disk, and each of said blades having a cutting edge thereon facing in the direction of movement thereof with said impeller to cross said radially circulating suspension at relatively large angles for effective shearing action on said particles therein.

6. An impeller adapted for use in disintegrating solid materials substantially without bruising thereof in apparatus of the character described including a chamber adapted to contain a quantity of relatively large particles of said materials in liquid suspension, comprising a plate adapted for rotation in said chamber about an axis substantially normal to said plate to subject said suspension to centrifugal force causing said suspension to circulate radially across the surface of said plate, a plurality of superimposed disks of sheet material secured to the upper surface of said plate, said disks being generally circular