US2097910A - Pulverizer - Google Patents

Description

Nov.\2, 1937. H. H; BATES ,09 Q

4 PULVERIZEB Original Filed Sep 15, 1933 Fla. 2.

WITNESSES? 4 lflvEN oR dgfw. HARRY Hb ATES I BY 0ZIWM ATTORNEY Patented Nov. 2, 1937 PATENT OFFICE Zflflpl. I'll], H; 43 mm 11. smaller Park, rs, Substitute for abandoned application Serial No.

689,513, September 15, 1933'.

This application March 14, 1935, Serial No. 11,179

6 Claims. (0!. 83-14) My invention relates to pulverizing apparatus and it has for an object to provide means of this character wherein pulverant material acted upon is torn apart between relatively movable grinding surfaces of the granular abrading type, and the present application is for the same subject-matter as my prior application, Serial No. 689,513,

filed September 15, 1933, and now abandoned.

Pulverizing apparatus for processing pulverant materials, such as coal, are of various types. There is the impact type, which depends upon lumps or particles being hit by movable members and being cast against stationary members.

The effectiveness ofimpact apparatus diminishes v with the particle size. The ball or roller type depends upon a crushing action exerted by balls or rollers on the material. Both of these types involve losses because particles acted on are not sufliciently restrained-in the impact. type, the particles are free and the impact action becomes less and less efi'ective as the particle size is reduced; and, in the roller type, there is only limited particle restraint' On the other hand, my improved pulverizer greatly extends the use of the principle of particle restraint by the use of a stationary member having a roughened or granular abrading internal arcuate surface ar-- ranged relatively close to' the roughened or granular abrading peripheral surface of a wheel, the

closely with respect to the wheel and the stationary member toprovide an arcuate pulverizing passage, material being supplied to the'inlet end of the passage and pulverized material beingdischarged from the outlet end of the latter. A further object of my invention is to provide appara- V 45 tus of this character and having this mode of operation.

'A further object of my invention is to provide apparatus including members defining an arcuate' pulverizing passage with a feed chamber or hopper supplying material to theinlet end of the passage and a separation chamber into which L pulverized material is discharged from the outlet end of the passage, lighter particles being con- 55 veyed away from the separation chamber and stationary surface serving to hold or to ;"re st rain' heavier particles being returned to the inlet end of the passage.

A further object of my invention is to provide a wheel having a peripheral, granular abrading surface and a member having an arcuate surface cooperating with the peripheral surface to define an arcuatepulverizing passage, the arcuate surface including a first part which converges with respect to the'periphery of the wheel in the direction of movement of the latter to provide a first section of the passage wherein pulverization occurs largely by crushing and a second part which is of granular abrading character and is closely spaced with respect tothe wheel periphery to deilne a second section receiving material from the first section and subjecting it to impact and attrition actions to eflect pulverization.

A further object of myinvention is to provide a pulverizer including a wheel having a peripheral, granular abrading surface and a memberhavpassage .outlet is thrown tangentially by the wheel periphery, air entering the separation chamber between the wheel periphery and the stream of material and flowing across the latter to eil'ect separation of lighter from heavier particles, the heavier particles droppingv .onto the wheel'perlphery and being conveyed bythe latter tothepassageinlet.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the, accompanying drawing, forming a. part of this application, in which:

Fig. 1 is a vertical longitudinal sectional vie taken along the line II of Fig. 3;

. Fig. 2 is a-transverse sectional view taken along the line III-II of Fig. 1; and,

Fig. 3 is an end elevational view of the appara- Referring to the drawing more in detail, I show a frame or bed plate In having bearings II for the drive shaft l2 and carrying the housing at l3. As shown, the bearings II are carried by pedestals ll disposed at either side of the housing, it beingunderstood that the bearings may be supported in any suitable manner.

, V The drive shaft l2 carries a high-speed grinding wheel l6 and a fan or blower runner iL'and the housing, at it, is formed with a chamber i8 for the grinding wheel and with a chamber 89 for the fan or blower runner.

The housing, at 63, is provided with an inlet conduit or hopper 20 for material to be ground, such conduit being disposed somewhat tangential with'respect to the wheel to provide the cusp. feed chamber 2!, one wall of which is formed by the periphery of the grinding wheel.

Ground material cast tangentially from the periphery of the wheel it passes upwardly and transversely of the outlet chamber 22 and air arranged interiorly of the housing and it has an internal curved granular abrasive surface 3|! for cooperation with the surface 28.

The stationary grinding member extends part way around the wheel It, the ends being separated by the inlet and outlet conduits 2i! and 2 3. As already pointed out, the inlet conduit is disposed somewhat tangentially with respect to the down-moving side of the wheel to provide the cusp feed chamber M. The outlet chamber 22 extends sumciently toward the up-moving side of the wheel that the curtain of material cast off tangentially from the wheel has sufficient upward trajectory to provide for air enterin the inlet 23 to pass undemeath and through the curtain to carry in suspension the lighter ground particles. The heavier particles drop back on top of the wheel and are carried around and are re-ground. A deflector 36 is disposed so as to prevent the reflection of heavier particles up the outlet conduit.

The wall 20a betweenthe inlet conduit 20 and air inlet 23 is spaced sufflciently from the wheel periphery, as indicated at 2th to provide for the ready passage of heavier particles from the separating chamber 22 to the feed chamber 2|.

The space 20b serves the additional purpose of preventing'arching in the feed conduit or hopper. If the wall 20a extended down adjacent to the wheel periphery, the angle therebetween would provide an abutment for an arch and arching would readily occur on that account; however, due to the space, there is con-' siderable motion of material insuch space and agitation adjacent to the lower end of the wall 200. that arching is prevented.

As shown, the grinding wheel chamber l8 has a removable side 45, which, when removed, exposes the seat 29a at one side to permit removal or insertion of the member 29 when the screws 7 3B and 31 are withdrawn.

One end 32 of the stationary pulverizing her is disposed, referring to the direction of rotation of the wheel l6, adjacent to the near. side of the outlet chamber 22; the major portion 33 of the member 29 is of substantially uniform radius of curvature to provide concentric pulverizing faces 28' and 30; and the portion 3| of the member 29 adjacent to end 35 thereof is formed of larger radius of curvature taken about a center eccentric to the wheel axis and located above the latter so that such portion may pro 'time and time again between the surfaces.

vide a wall of the cusp chamber 2! opposite to the moving wall thereof constituted by the wheel periphery, the portion M, with the wheel periphery, defining a convergent crushing zone or section supplying material to the impact and attrition zone or section. v i

The housing is formed with an arcuate seat 29a for the member 25 and the latter is held in place by screws 36 and 37 and by abutments at the ends of the seat, which takes the peripheral thrust, thereby relieving. the screws of shearing stress.

The granular abrading or pulverizing surfaces 28 and 30 are preferably provided incident to casting of the metallic wheel and arcuate member parts l6 and 29, respectively. For example,

silicon carbide material of sufiicient fineness The wheel It may be made of any suitable width, this being iacilitatedby building up the wheel of laminae ii of suitable thickness. Likewise, the arcuate member 29 is preferably comprised by one or more adjacent sections t2.

The glands or seals 39 and 48 are obviously subjected internally to slight sub-atmospheric pressure, due tothe impeller ll, with the result that atmospheric pressure acting externally is efiective to prevent leakage of dust at the ends of the housing.

From the foregoing, it will be apparent that I have provided pulverizing apparatus which effectively and eificiently utilizes the applied energy in pulverizing by crushing and by impact and attrition, the apparatus including a wheel having a peripheral granular abrading surface and a stationary member having an internal arcuate, granular abrading surface cooperating with and so spaced with respect to the wheel periphery as to define a pulverizing passage comprising a first section in which pulverization occurs largely due to crushing and a second section in which pulverization is due to impact and attrition. The crushing zone or section provides particles which aresmall enough to enter the impact and attrition zone or section; and, as the latter section occupies substantial arcuate extent, the material, in being traversed therethrough, has the opportunity of being crushed Not only is the wheel or disc the active element in the two pulverizing zones or sections, but it conveys material progressively through the zones or sections and discharges the latter tangentially and upwardly from the outlet of the pulverizing wheel a suflicient'distance to provide for the free conveyance of heavier particles into the feed chamber, the space so provided preventingarching of material in the feed conduit. Stated in anaoaacro other way, the single rotary element of my pulpulverizing passage, and, second, by impact or attrition in the portion of the passage of approximately uniform section. The term "pulverize" is used herein to designate any or all of the modes of particle size reduction described herein, and the term pulverlzing passage" includes either a crushing section followed by an impact and at trition section or the latter alone.

T Whfle I have shown my invention'in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof; and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims;

What I claim is:

1. In a pulverizer for pulverant materials, a wheel having a cylindrical and granular peripheral abrading surface; a member having an internal arcuate and granular abrading surface closely spaced with respect to the'wheel surface; side platesv fitting closely with respect to the wheel and the member and cooperating with said surfaces to define an arcuate pulverizing passage; means for supplying material to be ground to the inlet end of said passage; material being ground and moved along the passage due to movement of the wheel; a separation chamber at the discharge end of said passage andtransversely of which material discharged from the passage is thrown by the wheel surface, the bottom of said separation chamber being constituted by the wheel surface; means providing for a current of air entering the separation chamber between the wheel surface and the tangential I stream of discharging material and flowing across the latter to efiect separation oflighter from heavier particles and to carry away the lighter particles-in suspension, the heavier particles dropping onto the wheel surface; and means utilizing the wheel surface to convey heavier particles from the separation chamber to the inlet end of said passage.

2. In a pulverizer, a rotary disc having a roughened cylindrical periphery, a member having an internal roughenedarcuate portionwhich is closely spaced with respect to the disc periphery and cooperates withthe latter to define an arcuate pulverlzing passage, means including a feed chamber for supplying material to be pulverized to the inlet end of the passage, said feed chamber having the wall thereof which extends transversely of the disc periphery spaced from the latter to provide a first opening, a separation chamber open to the periphery of the disc and disposed at the discharge end of the passage so that material leaving the latter is di'scharged'tarn, gentially by the disc transversely of the separaspaced from the latter to provide a second opening, and means for inducing a current of air to enter said second opening underneath the sheet of material discharged tangentially from the passage outlet to pass upwardly across said sheet to effect separation of lighter from heavier particles, the lighter particles being conveyed away by the air current and the heavier particlesdropping on the disc periphery, said separation chamber being relatively so arranged with respect to the disc periphery that the latter is effective to convey heavier particles dropping thereon through said second and first openings and into the feed chamber.

, 3. The combination as claimed in claim 2 with a deflector springing from said transverse wall of the separation chamber for preventing reflection of heavier particles outwardy of the latter, V

4. In a pulverizer, a rotary disc having a roughened cylindrical periphery, a member having first and second arcuate portions cooperating with the disc periphery to define an arcuate pulverizing passage, the first arcuate portion converging with respect to the wheel periphery and in the direction of movement of the latter to provide a crushing section and the second arcuate portion being rough and closely spaced with respect to the wheel periphery to provide an impact and attrition section wherein material received from the crushing section is pulverized, means providing afeed chamber for feeding material to the passage inlet, said feed chamber having the wall thereof which extends transversely of the disc periphery spaced from the latter to provide aflrst opening, means providing a separation chamber open to the periphery of the disc and disposed at the outlet of the pulverizing passage so that material leavingthe latter is discharged tangentially by the disc transversely of theseparation'chamber, said separation chamber having its wall opposite to the passage outlet and extending transversely of the disc periphery spaced from the latter to provide a second opening, means for inducing a current of air to enter the second opening underneath the sheet of materlaldischarged tangentially from the passage outlet and to pass upwardly. across the sheet to eilect particles, the lighter particles being conveyed away by the air current and, the heavier particles dropping back on the disc periphery, said separation chamber being relatively so arranged with respect to the disc periphery that-the latter is eifective to convey heavier particles dropping thereon through said second and first openings to the passage inlet, and a deflector springing from said transverse wall of the separation chamber and serving to prevent the reflection of heavier particles outwardly of the latter.

5. In 'a pulverizer' for pulverant materials, a

wheel having a cylindrical and granular abrading surface, a stationary member having an internal arcuate and granular abrading surface, side plates fitting closely the sides of said wheel and of said member and said surfaces of the wheel and of the member being closely spaced to provide an arcuate pulverizin'g passage through whichmaterial is traversed by the granular abrading surface of the wheel, a hopper for feeding material to the inlet of said passage, a separation chamber arranged between the outlet of saidpassage and the hopper, said separation chamber having its bottom formed by the wheel periphery and being so disposed with respect tothe wheel periph-- ery that the latter is effective to throw material leaving the passage outlet tangentially therefrom separation of lighter from heavier and upwardly and transversely of the separation chamber, means providing for a current of air entering the separation chamber between the wheel periphery and the tangentially discharging stream of material for passage across the latter to effect the separation of lighter from heavier particles and to conduct the lighter particles to a desired point of discharge, the heavier particles dropping onto the wheel periphery, and means utilizing the wheel periphery to convey heavier particles dropping thereon in the separation chamber from the latter to the inlet of the pulverizing passage.

6. In a pulverizer for pulverent materials, a wheel having a cylindrical and granular peripheral abrading surface; a fixed member having first and second internal arcuate surfaces and at least the second surface being of a granular abrading character; the second surface having a substantially uniform radius of curvature whose center is concentric with the wheel and the first surface having a radius of curvature larger than that of the second surface and whose. center is cc,- centric to and above the wheel axis and .both surfaces having a common tangent where they join, whereby the first surface converges with reacer ic spect to the surface of the wheel in the'direction of movement of the latter to provide a first pulverizing section wherein pulve'rization is due Kargely to crushing and said second surface is losely spaced with respect to the wheel surface to provide a second pulverizing section wherein pulverization takes place both by impact and by attrition; side plates fitting closely with respect to the wheel and the member to define an arcuate pulverizing passage including said first and second sections; means for supplying material to be ground to the inlet end of said passage; material being ground and moved along the passage due to movement of the wheel; a separation chamber at the discharge end of said passage and transversely of which material is discharged tangentially by and from the peripheraisurface of the wheel; means providing for a current of air entering the separation chamber between the peripheral surface of the wheel and the tangential stream of material and flowing across the latter to carry away lighter particles in suspension; and means for conveying heavier particles from the separation chamber to the inlet of said passage.

- HARRY H. BATES

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