US1769352A - Pulverizing machinery - Google Patents

Description

July I, 1930. w. J. LIBBEY PULVERIZING MACHINERY Filed July '7, 1928 3 Shee tsSheet l a INVENTOR.

WAL 75/? L/BBEY y H15 ATTORNEY.

July 1, 1930. w. J. LIBBEYI 1,769,352

PULVERIZING MACHINERY Filed July '7, 1928 3 Sheets-Sheet 2 9 INVENTOR.

WAL 727? J /BBEY BY M H/S A TTORNEY.

July 1, 1930. w. J. LIBBEY PULVERIZING MACHINERY Filed July '7, 1928 3 Sheets-Sheet 3 ,1 mm R H JUIDL P W o W L m I m M o N mun w: W M \v m. ow W Y B f u. (I) j ii I A w 1 MW w MM W kw R. m T. A N w. N x W;. H. ,...P j fi a m 5mm Patented July 1, 1930 UNITED STATES WALTER J. LIBBEY, OF OAKLAND, CALIFORNIA PULVERIZIN G MACHINERY Ap lication filed July 7, 1928. Serial No. 291,050.

My invention relates particularly to improvements in and accessory to continuous pulverizing mills for reducing materials from coarse to comminuted form.

In operation of pulverizers, especially on such materials as litharge, it is found that a certain amount of the material is not pulverizable and tends to form itself into flattened heavy particles of a more or less plas-.

- invention to recover a maximum amount of.

any pulverized material entrapped in the mass of tailings or other unpulverized material. i

It is a further object of my invention to 2 provide an improved pulverizing mill, em-

ploying pneumatic removal of pulverized material, in which the air-inlet openings are prevented from clogging.

It is another ob ect of my invention to provide a continuous pulverizing mill which need not be shut down for periodical cleanin %t is a further object of my invention to provide a scavenging attachment applicable to existing pulverizer mills.

Other objects of my invention concern various structural and functional improvements in pulverizing mills and scavenging means therefor, and have as their purposes to reduce the first cost and maintenance, and to improve the functioning of machinery of the character set forth.

The invention possesses other objects and features of advantage, some of which, with the foregoing, wilLbe set forth in the following description of the preferred form of the invention which is illustrated in the drawings accompanying and forming part of the specification. It is to be understood, 5 however, that variations in the showing made by the said drawings and description may be adopted within the scope of the invention as set forth in the clalms.

Referring to the drawings:

Figure 1 is a vertical axial section view of a pulverizing mill embodyin my invention, the pulverizing rollers a n feed plows being shown in elevation.

Figure 2 is a sectional plan view of the mill with the scavenge plow gearing shown in elevation and with segmental fragments of the mill broken away to show the air inlet openings and scavenging mechanism. The plane of section of Figure 2 is indicated generally by a line 2-2 in Figure 1.

Fi ure 3 is an enlargement of a. portion of Figure 1 showing certain scavenging details thereof.

A pulverizer mill chamber or housing is constituted by a base 6 and superstructure 7 ('Fig. l) of generally circular form about a vertical axis. The base andsuperstructure are rabbeted at their matin rims 6 and 7, and are joined together y a plurality of bolts. The mill is supported on a concrete or other suitable sfoundation 9, by a broad squareflange 6 integral with the base' castings), and is secured-to the concrete by foundation bolts 11 (Fig. 2).

The pulverizer within the housing, in preferred form, consists of one or more hardened pulverizer or crusher rollers-12 Fig. 1) rotatable against a. hardened pu verizer ring 13. The ring 13 is received and held in the mouth of the base casting 6 just within the rim- (i thereof. Three or four rollers are commonly employed, but for purposes of illustration, only two are shown. Each roller 12 is carried by the lower'end of a spindle 14'(Fig. 2); which spindle is journaled for free rotation in a stock 16 (Fig. 1). Each stock 16 is pivotally supported near its upper end by a horizontalpivot pin 17 so that its lower end is free: to swing toward or away from thering 13'to' accommodate a greater or lesser thickness of material to be crushed against the ring. In more precise terms, the pin is direct ed horizontally and tangent to an imaginary cone rising from the circumference of the ring 13. Each pin 17 is carried by a radial supporting arm 18' of a spider 18. The spider is eyed to and rotated by a central driving column 19 journaled in the mill housing 6, 7. Gears 22, 23, and a drive shaft 24 are provided for rotating the driving column 19; a pulley 26 being provided on the drive shaft for belt connection. to any suitlable source of power for driving the mil Y In operation, when thedriving column 19 is rotated, it revolves the stocks 16 with their rollers 12 against and around the ring 13, causing coarse particles fed in between the rollers and ring to be crushed and pulverized. Pulverizing pressure of the rollers upon. the ring is produced by centrifugal force which urges the comparatively heavy lower ends of the stocks l6 outward.

It should be noted that although there are certain structural and functional advantages, accruing principally from the arrangements of parts and action of centrifu gal force, in the pulverizer aforedescribed; yet other forms of pulverizer may be employed to more or less advantage within the purview of certain aspects of my invention. 80 too, with the feeder, exhauster, and scavenger next to be described; the embodiments herein described are the preferred but not the only possible forms of mill or parts thereof to which my invention may be aplied. p Exhauster means are provided for separating the pulverized material and for discharging this finished product from the mill. A fluid pump 27 (Fig. 1), herein shown in preferred form as a blower of conventional type, is provided for forcing air or other suitable fluid through the housing at relatively high velocity to convey ofl any material which is fine enough to be carried by the air or other fluid stream. Air enters the housing through a circumferential series of inlet ports or openings 25 in the base casting 6 below the pulverizer ring. The air is directed to tangential issuance 1n the direction of pulverizer rotation by a plu -rality of guide vanes 6 (Fig. 2) separating inlet openings 25 in the casting 6. Theair after entering the housing, passes upward around the rollers and pulverlzing ring, carrying finely pulverized finished material from the pulverizing chamber upward and out through a central discharge opening at the top of the housing. A pipe 28 connects the discharge opening to the inlet of the blower 27. The blower outlet is connected by piping 29 to a conduit or draft casing 31 surrounding the inlet port in the casting 6. A separator 32 is interposed in the piping 29 to remove the pulverized solid matter from the air or other fluid stream. A bleeder pipe 29 is provided merely for the purpose of bleeding the system of excess air,

and may be disregarded for purposes of this description.

hIeans are provided for feeding coarse materials to the pulverizcr. A supply hopper 33 (Fig. 1) is provided for coarse material' to be introduced into the mill, and a metering paddle. wheel 34 or other suitable means is provided therefor. The metering paddle wheel 'is preferably continuously driven at selectively variable speeds by means (not shown) includingselective change speed gearing connected to the drive shaft 24.. The coarse material, after introduction into the housing, drops down into a feeder space 35 below the pulverizer. A plurality of feed plows 36, one for each roller, are provided for continuallyfeeding the coarse material up from the feeder space into the path of the pulverizing rollers. Each feed plow (see Figs. 1 and 2) is essentially a scoop with its lower edge close to the floor of the feeder space, with its upper edge close to the lower inside edge of the pulverizer ring 13, and with its radially outer side edge close to the air inlet openings 25.- The outer edges of the plows 36 are bent forwardly (in the direction of their travel) to scoop material inward and away from the air inlet openings. The feed plows are fixed to a rotary platform 37 forming the floor of the feeder space and keyed to the driving column 19 for rotation with the roller stocks 18. The direction of rotation of the plows 36 and rollers 12 is indicated in Figure 2 by an arrow A.

In operation the rollers and feed plows are driven at high speed; the plows scooping material from the floor of the feeder space and throwing it up into the path of the pulverizer rollers where a portion is reduced to a fineness permitting its carriage and discharge by the air stream, while the remainder drops back into the feeder space to repeat the cycle. The metering paddle wheel 34 introduces fresh material to make up for the pulverized material removed by the air stream and to permit continuous opcollection chamber 30. The collection chamber 30 is defined by the space within the draft casing 31. The unpulverized particles collect in the chamber 30 at the radially outer or inlet. side of the air inlet openings 25. It will readily be understood that if these particles were allowed to acplow arm 41. The blade 38 cumulate, they would pile up and clog the air passage, decreasing the eiiicieney of the mill and necessitating laborious hand cleaning thereof. With litharge there is added the hazard of lead poisoning when the mill is cleaned by hand.

Means are therefore provided for clearing or scavenging the collection chamber or draft casing and the air inlet ing therefrom. At least one, and preferably two pusher or conveyor members are posi tioned and movable in the collection chamber 30 near the fioor thereof and also near the air inlet openings 25. In preferred form each conveyor member is a duplex plow 38, 39, (Figs. 2 and 3) disposed generally'radiallyof the substantially annular chamber 30 and movable throughout the annulus of the chamber in a circular'path concentric with the main axis of mill; i. e. the plows are revolvable about the main axis of the mill. The plows 38, 39 preferably revolve in the. same direction as the pulverizer, but at very much lower speed desirably; and it will thus be observed that the plows travel with rather than against the air stream through the guide vanes 6.

Each 'plow is generally plane vertically and scoop-shaped horizontally, and is formed of a pair of blades 38 and 39 fixed to and extending from opposite sides of a vertical is enerally shaped inhorizontal section and has its short leg secured by rivets or other suitable fastening means to the plow arm 41. The long leg of the L-shaped blade 38 extends radially toward the mill housing to closely clear the inlet ports 25 in the casting 6, and has its outermost end bent forwardly (in the direction of plow travel) from the inlet openings 25. A brace 42 extends angularly from the tip of the blade 38 backward and outward to the plow arm 41. The other blade 39 of the plow is secured at its rear end to the plow arm 41 opposite the blade 38, and is bent outward at its free front end to an acute angle with the plow arm. The blade 39 extends outwardly toward the periphery of the mill and forwardly (in the direction of plow travel) to scoop material toward the center of the chamber 30. The blade 39 is cut away at its lower edge to clear the foundation bolts 11.

As the plows are moved through the collection chamber they gather before them the unpulverized material therein and push it along the floor thereof; at the same time agitating the mass so as to expose any pulverized material entrapped therein to the air stream entering the mill. This agitation frees any light or pulverized material from the heavier unpulverized mass and effects considerably recovery of good material.

The tailings are removed from the collection chamber through an opening 40 (Fig.

openings leadto scoop material away.

2) in the floor thereof and in the path of the scavenge plows 38, 39. A chute 43 leads from the scavenge opening to a standard screw conveyor 44 llig. 1) which serves to remove the tailings while preventing excessive air leakage out of the mill housing.

The plow arms are secured to and driven by a "H -sectional driving ring 46 (Fig. 3) encircling the mill at the level of the top of the draft casing 31. The upper wall of the casing 31 has an annular-opening formed therein to pass the depending web of the T -shaped driving ring (Fig. 3). The plow arms 41 are bolted to the web of the driving ring; the arms being slightly curved and bent to accommodate the curvature and angularity of the web.

The flanges of the T-sectioned driving ring are beveled toform bearing surfaces for the driving ring; a pair of concentric beveled bearing rings 47 and 48 being provided one at either side of the driving ring section to carry the driving ring. The bearing rings are attachable tO;'"tllG mill housing to support the driving ring therefrom. The inner bearing ring 47 has a plurality of integral supporting arms 47 extending inwardly therefrom at spaced points of its inner circumference. The arms 47 are secured by bolts or other suitable means to the lower rim 7 of the upper housing 7 of the mill. An annular bridge cap 49 overlies the driving ring 46, is secured by bolts 51.01- other suitable means at its inner rim to the top of the bearing ring 47 and is similarly secured by bolts 52 to the outer bearing ring 48. The bridge cap, it will be seen, is supported by the inner bearing ring 47, and it in turn supports the outer bearing ring 48. It will be noted that the cap 49 and rings 47 and 48 close the annular opening formed in the draft casing 31 to receive the ring 46.

A series of bolts 53 join the rings 47 and 48 to the edges of the annular opening in the draft casing.

The driving ring 46 has a slightly beveled radial toothed gear cut in its upper surface, and is driven by a pinion 54 (Fig. 1) journaled for rotation in a bracket 56 upstanding from and secured to the top of the annular cap 49 (at the right hand side of Figure The pinion-shaft carries a sprocket 57 at its outer end and is conveniently driven by a chain 58 and sprocket 59 The sprocket 59 is journaled on a jackshaft 61; being driven therefrom by a clutch 62 capable of engagement or the operator. The shaft 61 is conveniently belt-driven directly from the drive shaft 24 of the mill. By means of the clutch 62 it is possible to operate the scavenge plows either continuously to prevent accumulation of unpulverized material, or intermittently at will to scavenge accumulations periodically.

It will be apparent that certain aspects disengagement at the will of I The only modification substantially necessary when a mill is to be supplied without .the scavenging plows for example, is the substitution of a new draft casing 31 without the annular opening in its top wall, and preferably of slightly smaller radius at the inner portion of its convolute periphery. Conversely, if a pulverizing mill of the described or of various other types were supplied originally without scavenging plows, it would be a matter within the purview of my invention to attach such scavenging means thereto.

I claim:

l. The combination with a pulverizer mill having a fluid inlet opening therein and provided with a pulverizer, of mechanical means for clearing said inlet opening, said mechanical means being propellable at angular speeds different from those of the pulverizer.

2. The combination with a pulverizer mill having a fluid inlet opening therein for introduction of conveyor fluid, of a member movable past said opening at the inlet side thereof to clear unpulverized particles therefrom. 3. The combination with a pulverizer mill having a fluid inlet opening therein for introduction of conveyor fluid, of a member movable past said opening at the inlet side thereof to clear unpulverized particles therefrom, and power-driven means for actuating said member.

4. The combination with a pulverizer mill having a fluid inlet opening therein for introduction of conveyor fluid, of a member movable past said opening at the inlet side thereof to clear unpulverized accumulations therefrom, and a member movable past said opening at the outlet side thereof to clear unpulverized accumulations therefrom.

5. The combination with a pulverizer mill having a fluid inlet opening disposed circumferentially therein for introduction of air blast, of a member movable past said openin at the circumferentially outer side thereo to clear unpulverized particles therefrom, a draft casing enclosing said member and forming a conduit to said opening, and means for revolving said member through said casing.

6. The combination with a pulverizer mill having a fluid inlet opening disposed circumferentially therein for introduction of air blast, of a member movable past said opening at the circumferentially outer side thereof to clear tailings therefrom, a draft casing enclosing said member and forming a conduit to said opening, means for revolving said member through said casing, a scavenge outlet in said casin below and in the path of said member, an means for removing solid materials throu h said outlets while resisting passage of 7. The combination with a pulverizer mill, of means for feeding coarse materials thereto, means for removing pulverized materials therefrom, and means independent of the mill for removing relatively heavy unpulverized particles therefrom.

8. In combination, a pulverizer mill comprising a housing, a pulverizer rotatable in said housing, means for feeding coarse material to said pulverizer, means for circulating fluid through said housing to remove pulverized particles; and means located radially outwardly of said pulverizer for scavenging unpulverized tailings from said housing.

9. In combination, a pulverizer mill comprising a housing, a pulverizer rotatable in said housing, means for feeding coarse material to said pulverizer, means for circulating fluid through said housing to remove pulverized particles, and means below and radially outwardly of said pulverizer for scavenging unpulverized tailings from said housing.

10. In combination, a pulverizer, means for feeding coarse materials to said pulverizer, means for circulating fluid past said pulverizer to remove pulverized particles, a collector below said pulverizer, and means for scavenging tailings from said collector.

11. In combination, a pulverizer comprising a generally circular housing, a pulverizer roller revovable within and about the axis of said housing, fluid conveyor means for removing pulverized material from said housin said last-recited means including a flui -inlet opening in said housing; a feeding plow movable within said housin adjacent and between said roller and sai opening, and an auxiliary plow movable outside said housing and past said opening.

12. In combination, a pulverizer mill comprising a generally circular housing, a pulverizer within said housing, fluid conveyor means for removing pulverized material from said housing; said last-recited means including a fluid-inlet opening in the circumference of said housing; a driving ring surrounding said housing adjacent said opening, a member secured to said ring for movement past said opening to clear tailings therefrom, a collector casing enclosing said driving ring and said member, and means for revolving said driving ring.

13. An attachment for pulverizer mills including a housing having a fluid inlet opening therein, comprising a member movable past said opening to clear tailings therefrom, and mounting means for movably securing said member to said housing.

uid therethru.

14. In ascavenging means for a pulverizer having a pulverizing chamber, a chamber surrounding the first and from which fluid is arranged to be drawn into the latter and into which tailings from the first may be discharged, and means arranged to move through said second chamber during the pulverizing operation to move the tailings therein.

15. In a scaven 'ng means for a pulverizer provided wit a pulverizing chamber having an openin through which tailings may be discharge from said chamber, and fluid introduced therein, a chamber arranged in juxtaposition to the first and embraclng said opening, and mechanical means operative during the pulverizing operation to prevent the clogging of said opening.

16. In a pulverizing rocess including the steps of continuously Feeding coarse materials to a pulverizing re ion and continuously blowing pulverize particles therefrom, the step of continuously discharging unpulverizable particles from the ulverizing region into another re 'on, an the additional step of continuous y scavenging unpulverizable particles from the second named region, whereby to permit continuous operation over long periods of time.

In testimony whereof, I have hereunto set my hand at Oakland, California, this 2nd day of July, 1928.

WALTER J. LIBBEY.

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