US1622695A - Impact pulverizer - Google Patents

Description

March 29, 1927.

v v B62269? A. B. WILLOUGHBY IMPACT PULVERIZER Filad Jan, 31, 1925 s Sheets-Shut 1 INVENTOE w, MESS W firmmvgy March 1927' A. B. WILLOUGHBY IMPACT PULVERIZER Filed Jan. 51, 1925 3 Shoots-Sheet 2 INVENTOI? w/ T'NESS HTTORNE) A. B. WILLOUGHBY IMPACT PULVERIZER Filed Jan. 3l, 1925 3 Shoots-Shoot 5 w/ TNESS Patented Mar. 29, 1927.

ALFRED it. w-rnnouennr; or PHILADELPHIA, PENNSYLVANIA.

IMPACT PUIi-VERIZER'J Application filed January 4 My invention relates to impact pulverizers of the type or class in which two alined and opposing streams of material to be, pulverized are discharged at a high velocity against 5 each other by jets of superheatedsteam to reduce the material in saidstreams to a fine powdered condition by the impact of the pieces against each other.

The type of apparatus to which my invention relates is exemplified iii-U. Letters Patent No. 1,246,514, granted to me November 13, 1917 and the present inventioninvolves certain improvements in suclrapparatus.

The object of the present invention is to increase the capacity or rate at' which material reduced to a powdered condition may be removed from the chamber in'wh-ichitis reduced to its powdered condition; IQ remove the material substantially as fast as it is formed in the pulverizing or impactchamher, and to so construct said chamber that the finely powdered material may not collect andv accumulate int-he said chamber or become mixed and carried along with the larger particles which,..in the normal operation of the device, are resubjectedto the action-t the pulverizer.

Further object-s ot my invention; are to provide an impact or pulverizin-g chamber in whichall the material, after impaot,-is forced to pass transversely through-a fluid current to completely separate thepulverized material from the particles which are. not pulverized and which require a retreatment; to provide a structure whereby all of the fragments which require further treatment are immediately discharged or conducted out of the pulverizing chamberand mayznot-accumulate therein.

A further. objectv of my. invention is to cause the heavier particles to travel over and to keep clear of powdered material, any surface inside of said casing. upon which said powdered material might tend to accumulate.

A further object of my invention is to cause all the unpu-lverized materialafte r impact to move toward and discharge through an opening in the bottom of the pnlverizer chamberthrough which air is beingdrawn into the pulverizingchamber.

A further object of my invention is, to provide the pulverizing. box orchamber with a. large number oi'exhaust pipes or conduits, each provided with an ejector so that when 31, 1925. S eri.a1 No-. 5,827.

material is, being rapidly pulverized it may be removed 'from the pulverizing chamber as fast as is formed without increasing the rate at which any one ejector may be operating. It may here be explained'that ejectors, employed in pulverizing apparatus of the type referred to herein are more or less uncertainin their operation when it is attempted towoperate them under varying con ditions; that is to say, when the steam at just the right velocit-yand quantity is forced into: and through the Venturi tube, the ejector operates-very satisfactorily. The amount and speedof the projecting fluid which will operate. most efli'ciently. with a particular Venturi tube are determined more or less by experimentation, and after a particular ejector has been so adjusted to operate properly the ejector is eificient. But any attempt to make the action of an ejector of'this type more rapid, as by increasing the amount of steam delivered thereto, may result in a substantial'de creasein the efliciency of the apparatus; It is, therefore, highly desirable to operate the 'ejectors under constant conditions that is to say, with that pressure and a volume of steam which'operates most etficiently withthe-Venturi tube of the particular ejector.

The. speed atwhich 7 different materials may be pulverized in an impact pulverizer depends, of course, upon materials. materials are reduced to a powder much more quickly than others; .Therefore, the Speed at which the material may be taken from the pulverizer chamber varies with different materials. lVith amaterial which is easily reduced,i,the powdered materialmay be formed in the pulverizingch'amber faster than it can be carried away by a single ejector, and to remove the material as fast as it is formed, being one of the objects of the present invention, .1 accomplish the removal by providing the side and'top walls of the p'ulverizing chamber each with an independentejector apparatus so that, for instance, in treating a readily pulverized material, two or three or even four independent ejectors maybe simultaneously operated, each operating under the conditions best suited or peculiar to itself. When one, two or more ejectors are operating simultaneously, each ejector willact as itwould if it were operating alone, In treating materials which are reduced with-difficulty, and therefore re].-

Some

atively suffice to remove the pulverized material as fast as it is formed.

Other objects of my invention will. appear in the specification and. claims below.

In the drawings forming a part of this specification and in which the same reference characters are used throughout the various views to designate the same parts,

Fig. 1 is a front elevational view, partly in section of a pulverizcr embodying my invention.

Fig. 2 is a side elevatioual view of the same, partly in section.

Fig. is a plan view of the same, parts being broken away to show the interior of the pulverizcr chamber; and

Fig. 4 is a more or less diagrammatic view of an arrangement whereby varying amounts of pulverized material may be removed from the pulverizing chamber.

The apparatus comprises a pair of hoppers 1-1, the lower ends of which are arranged to discharge into chambers 22 provided in the casing 3, said chambers each surrounding a steam nozzle 4: rigidly secured by screwthreads 5 to the rear wall of the chamber 2. The passage 6 through the steam nozzle t is in alinement with an opening 7 through the, casing, communicating with the end of a steam pipe 8 through which steam superheated to high temperatures and at a high pressure, is conducted to the nozzles. Into the outer end of each nozzle t is secured a tube or nipple 9 of very hard steel, the nipple being preferably secured to the nozzle by screwthreads 10. The jet openings 11 through the nipples 9 are of very small diameter and the superheated steam from the pipe 8 will issue therefrom at very high pressure and velocity. The side of each chamber 2 opposite that to which the steam pipes 8 are attached is preferably provided with a large openi 12 into which is rigidly secured in any suitable manner a bushing 13 having aconcentric circular hole 1st therethrougli into which are tightly fitted wearing tubes 15 of hard steel, each having an axial tapering passage 1( therethrough in axial alinement with the axis of the passage 11 through the steam nipples 9.

The adjacent ends of the wearing tube 15 are provided with a. flange 17 fitting against and substantially covering the inner faces of the bushings 13. The wearing tubes are preferably secured to the bushings by set screws 18 so that when the wearing tubes become worn they may be readily replaced.

The inner ends of the bushings l3 and wearing tubes 15 are enclosed within a suit able casing or housing 19 forn'iing the im pact or pulverizing chamber 20. The side walls 21, 22 of the pulverizing chamber are preferably vertical and are parallel but they slowly, one ejector apparatus might are preferably spaced further apart from each other atthe rear of the apparatus (see Fig. 3) thai'i at the front to provide an enlarged portion in which the separatioi'i of the powder from the unpowdercd material may be more readily effected.

The top wall of the pulverizcr chamljicr it comprises two portions, namely, the horizontal wall portion 23 forming the top of the separating portion 20 of the chan'iber,

and the inclined portion 2% extending forv wardly and downwardly from the front edge of the wall .23 to a. position in front of and Rtll)i ;ltllltlzlll 'y at the level of the axis of the nozzles 4-. The rear wall 25 of the pulvcrizing chamber is prefcral'ily vertical.

he bottom wall of the pulverizcr chamber 20 preferably comprises two downwardly converging steeply inclined walls 26 and 27, the lower ends of which are spaced from each other to provide a relatively narrow and long passage 28 extending the full width of said chamber.

The pulverizcr chamber is preferably constructed in two parts, an upper part or portion and a lower part or portion respectively provided with flanges 29 and 30 secured together with bolts 31.

The top horizontal wall 28, the rear vertical rail 25 and the upper portion of the side walls 21 and 22 are each provided re spectively with a large opening 32, ach communicating with a relatively large conveyor pipe or tube 33 having a Venturi tube 34 therein.

The Venturi tubes 34; are preferably rc movable so that they may be readily replaced when worn, and cooperating with each Venturi tube is a nozzle 35 at the end of a steam pipe 36 arranged axially of the tube 3st in which it may be and arranged to discharge a jet of steam at high temperature and pressure into and through said Venturi tube to produce a current of air and steam through the tube 33 to draw the powdered material out of the pulverizcr chan'ibcr and to convey it to a suitable settling chamber (not shown).

Each pipe 36 is preferably located axially of the conveyor tube 33 in which it is anil serves the double purpose of conveying steam to the l enturi tubes and of reheating the conveyor fluid to prevent the 'ffilli'llllfill of moisture therein between the pulverizcr chamber and the ejector. The steam must be kept dry in order to convey the powder floating therein and to deliver it into the settling chan'ibcrs in a dry condition.

Near the point where the conveyor tubes 38 join to the pulverizcr chamber, each steam pipe is connected to a branch pipe 3. extending radially through the tube 33 and provided with a hand controlled valve 38. These pipes 37 communicate with a suitable source of steam supply and the valves 38 make it possible for the operator to use as many conveyor tubes as may be requiredto carry off the material as fastas it is formed in the pulverizing chamber and to properly adjust the amount of steam delivered to the Vent-uri tube by. each conveyor so that each Venturi tube may be supplied with List the right amount of steam to. operate efliciently independently of any other. conveyor tube.

Below the chamber 2 inthe casing 3 and forming the lower wall of said chamber 2 is a closure or gate 39 preferably pivoted on a bolt 40 so that the closure 39 maybe swung to one side when the handle 41 thereof is grasped and turned about the pivot to give access to the chamber 2" whenever necessary.

Above the hopper 1, 1 is a main-hopper 1-2 having its lower end bifurcated to form chutes 13, 43, terminating respectively over the hoppers 1, 1.. The lower end of' each chute 13 is preferably provided with a gate 14 pivoted on a stud 45 provided with a handle 46 so that the discharge of material from the main hopper 4:2 to either hopper 1 may be interrupted when desired.

Beneath the opening 28 at the bottom of the pulverizer chamber 20 is a chute or hopper 47 into which the particles of material being treated and which have not been reduced to a powder will fall by gravity. In the operationof this type of pulverizer, the chute 17 delivers material passing therethrough-to a suitable conveyor mechanism by meansof which the material which has not been reduced to the requisite fineness is carried back to the top .of the apparatus and discharged'again intothe hopper for retreatment.

I preferably provide the chute 4:7 with branches 48 and 19 extending upwardly and having their upper ends respectively under the gates-or closures 39 so that when either of saidclosures are opened for any reason, any material which may be in the chamber 2 may fall directly into a branch chute 18 or 49 and be carried bythe main chute to the conveyor system.

The operation of my device is as follows: Material tobe pulverized'is introduced in the pulverizer from the hopper 42 through the branch chutes 43 into the hoppers 41 of the machine and the material to be treated substantially. fills the hoppers 1 and the chambers 2 surroundingthe steam nozzle 4. Supcrheated steam at high temperature and pressure is admitted through the steam pipes 8 to the steam nozzles 4 and the jets of steam drive through the tapered passage 16 in the wearing tubes impelling forward with it at high speed thematerial to be pulverized which may bein the chambers 2, 2 and tapered passages 16, 16. Two streams of solid material thus are impelled at high velocity against each other, it-' being new plain that the axes of the passages 6 through the nozzles lm-ust be in alinement and the taperedpassages 16 being also inalinement with each other.. The force of the impact of the particles or pieces of. solid matter against each ot ierpulve'rizes them and the dust and powder together with the particles which havenot been reduced'to powdered form, fly in all directions radially from the point of impact'whichis substantially midway between the nozzles 4L.

The powdered material is suspendedin and floats in the air and steam as an impalpable powder and the whole .pulverizing chamber 20 isimmediately fllled with this powder. The conveyor system havingbeen started "at the same time by. opening one or more of the valves 38, the st'oam'from the end of the nozzle of'the conveyor driving through the Venturi tube 3%, creates a draft or. suction" in the conveyor pipes 33 and draws the fluid (steam and air) up into the conveyor tubeor tubes from the pulverizing chamber 20 and draws it through the Venturi tube and on to suitable settling chambers.

It .is to be notedthat the inside of the pulverizer chambers. contains no levelor approximately level "shoulders or surfaces. The rear wall 25 is, vertical. The front wall 24is inclined downwardly. The bottom walls 26 and 27 slant downwardly sharply and no material of'substantial weight can settle and remain thereon; However, the fragments or particles of solid materialwhich have not been reduced to powdered form are violently thrown and scattered overthe entire interior surface of the. pulverizing chamber 20 and being too heavy to be carried by the draft of airprovidedin the/conveyor 33 fall onto the sharply inclined walls 26 and 27 and slide. down over the inner surfaces of the walls disl'odg'ing any powder that might stick thereto and out through the opening 28 into the chute4. Butthe movementof the heavier particles in the impact or. pulverizing chamber is, generally speaking, transverseto and eventually againstthe direction of the current of air 01 steam'in the pulverizing chamber and drawn into the conveyor tubes; that is to say, the directionof the gaseous fluid in the pulverizing chamber is from the nozzles upwardly toward the conveyor tubes and from the opening or passage 28 up'wardly"to the conveyor tubes, while the direction of a great many of the heavier particles is either across. the pul verizer chamber against the vertical rear wall 25 or downwardly against the inwardly inclined walls 26 and 27 and eventually all the heavier particles will'fall down through the opening or passage'28.- Inv so falling their movement is againstthe movemen'tzof the gaseous fluid in the pulverizing cham her. This movement of the heavier particles transverse to or against the direction of the fluid current frees them of the fine particles which are readily taken away through the conveyor tubes, and as these heavier particles strike against the inner walls of the conveyor chamber or slide down over the inclined walls 26 and 27 they loosen and free any light particles which might adhere to the walls and, being loosened, these light particles are carried upwardly by the current of steam and air and out of the chamber by the conveyor tubes.

If the nature of the material being treated is such that it is rapidly reduced to a powdered condition, and, for instance, two conveyors which may be operating are not removing the powdered material from the chamber 20 as fast as it is formed, or as fast as it may be desired to remove it, one or more other conveyors may be put into operation to remove the pulverized material without disturbing the adjustment or operation or interfering with the etiicient operation of the two conveyors which were already operating.

lVhen, on the other hand, the nature of the material is such that it is slowly reduced to a powdered condition, the quantity of pulverizcd material produced may be so small that itmay be removed from the pulverizing chamber by operating a single conveyor.

From the above it will be seen that by reason of the construction of the pulverizing or impact chamber and the action and movements of the incompletely treated and insufficiently reduced particles and the direction of the fluid current through the chamber all cooperating together, the interior of the pulverizing or impact chamber is kept clean of any accumulation of completely reduced powdered material. There are no surfaces in the chamber on which the powder may lodge and remain and the powdered material is kept suspended in the fluid traveling out of the pulverizing chamber and is carried along with the fluid through the tubular conveyors to suitable settling chambers.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. In an impact pulverizer in which two alined and opposed streams of material to be pulverized are discharged against each other impelled by jets of superheated steam under high. temperature, pressure and velocity whereby the impact of the pieces against each other reduce them to a powder, the combination of a casing, forming an impact chamber and enclosing said jets and having an opening through the bottom thereof, below and offset horizontally from the vertical passing through the axes of said jets, a bottom wall of said casing being inclined sharply downwardly under both of said jets, disposed in a plane parallel to the axes of said jets and tern'iinating in said opening whereby unpulverized material striking against said inclined wall slides downwardly on said wall to said opening, and an ejector communicating with the interior oi? said casing to remove the powdered material floating therein and to separate said powdered material from the heavier particles.

2. In an impact pulverizer in which two alined and opposed streams of material to be pulverized are discharged against each other impelled by jets of superheated steam under high tem 'ierature, pressure and velocity whereby the impact 01 the pieces against each other reduce them to a powder, the combination of a casing, forming an impact chamber and enclosingsaid jets and having an opening through the bottom thereot otl'- set horizontally from the vertical passing through the axes of said jets, a bottom wall of said casing being inclined sharply downwardly under both of said ets and terminating in said opening whereby unpulverized material striking against said inclined wall slides downwardly on said wall to said opening, and an ejector communicating with the interior of said casing to remove the powdered material floating therein and to separate said powdered material from the heavier particles, said heavier particles falling by gravity out of said casing through said opening.

3. The combination with an impact pulverizer comprising a pair of alined nozzles spaced apart and arranged to discharge toward each other streams of small pieces of solid matter impelled by superheated steam at high temperature, pressure and velocity whereby said pieces are pulverized by their impact against each other, of a casing forming an impact chamber and enclosing said nozzles, a bottom wall of said casing being inclined sharply downwardly, extending un der both of said nozzles and terminating in an opening below said jets and substantially offset from the vertical passing through the axes of said jets whereby any material from said nozzles not reduced to powder and striking said bottomwall will slide downwardly over the surface of said wall to said opening and an exhaust tube communicating with the interior oi. said casing at the upper portion thereof, and means to create a current of gaseous conveying fluid from said impact chamber through said exhaust tube to remove the pulverized material floating in said chamher and to separate said pulverized material from the heavier particles.

l. The combination with an impact pulverizer comprising a pair of alined nozzles spaced apart and arranged to discharge toward each other streams of small pieces of solid matter impelled by superheated steam at high temperature, pressure and velocity whereby said pieces are pulverized by their impact against each other, of a casing forniing an impact chamber and enclosing said nozzles, a bottom wall of said casing being inclined sharply downwardly and extending directly under both of said nozzles and terminating in an opening offset laterally from the vertical passing through the axes of said jets whereby any material from said nozzles not reduced to powder and striking said bottom wall will slide downwardly over the surface of said wall to said opening and an exhaust tube communicating with the interior of said casing at the upper portion thereof, and means to create a current of gaseous conveying fluid from said impact chamber through said exhaust tube to remove the pulverized material floating in said chamber and to separate said pulverized material from the heavier particles, said heavier particles falling by gravity out of said casing through said opening.

5. The combination with an impact pulverizer comprising a pair of alined nozzles spaced apart and arranged to discharge toward each other streams of small pieces of solid matter impelled by superheated steam at high temperature, pressure and velocity whereby said pieces are pulverized by their impact against each other, of a casing forming an impact chamber and enclosing said nozzles, a. bottom wall of said casing being inclined sharply downwardly and extending directly under both of said nozzles and terminating in an opening oiiset from the vertical passing through the axes of said nozzles whereby any material from said nozzles not reduced to powder and striking said bottom wall will slide downwardly over the surface of said wall to said opening and an exhaust tube communicating with the interior of said casing at the upper portion thereof, and means to create and to vary the velocity of a conveying gaseous fluid through said casing, comprising a plurality of Venturi tube fluid conveyors communicating with said cas ing and means to operate any and all of them separately or simultaneously.

6. The combination with an impact pulverizer comprising a pair of alined nozzles spaced apart and arranged to discharge toward each other streams of small pieces of solid matter impelled by superheated steam at high temperature, pressure and velocity whereby said pieces are pulverized by their impact against each other, of a casing forming an impact chamber and enclosing said nozzles, a bottom wall of said casing being inclined sharply downwardly and positioned directly under both of said nozzles and terminating in an opening on one side of the vertical passing through the axes of said nozzles extending the full width of said casing whereby any material from said nozzles, not reduced to powder, and striking said bottom wall will slide downwardly on said wall out of said opening and will prevent any accumulation of powdered material on said wall, and means communicating with the upper portion of said casing to create a current of dry gas through said casing upwardly out of said casing to remove from said casing the powdered material floating in said gas.

In witness whereof, I have hereunto set my hand this 30th day of January, 1925.

ALFRED B. VVILLOUGHBY.

Images