US1576472A - Pulverizing machine - Google Patents

Description

I March 9 1926.

R. S. RILEY 'PULVERIZING MACHINE Filed July 21, 1924 //v1 E/vT0/a ROBiRT OWN/FORD fP/Li Y Patented Mar. 9, 1926.

UNITED STATES 1 PATENT OFFICE.

ROBERT SANFORD RILEY, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO SANEORD RILEY STOKER COMPANY, OF WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

rULvERIzIivG MAcHfNE.

Application filed July 21, 1924. Serial No. 727,241.

To all whom it may concern:

Be it known that I, ROBERT SANFORD 111L121, a citizen of the United States of America, residing at \Vorcester, in the county of \Vorcester and State of Massachusetts, have invented cer ain new and useful Improvements in a Pulverizing Machine, of which the following is a full, clear, and exact specification.

My invention relates to fuel pulverizing apparatus and more particularly to the construction of a pulverizer of the type shown in the patent to Blyth, No. 1,446,151, of Feb. 20, 1923.

A machine of this type comprises a cylindrical casing carrying a number of stationary pegs 01.. the two sides thereof between which rotates a disc or rotor carrying pegs on each of its sides. The material to be pulverized is fed into the central portion of the casing and is broken into fine particles by impact against the pegs and the peripheral wall of thecasing.

It is found that these pegs wear away rapidly owing to the enormous friction imposed thereon and if hard materials get into the machine some of the pegs may be broken off. Hence it is necessary to remove the old pegs frequently and to replace them with new ones. Considerable difficulty has been met heretofore in fastening the pegs to theirsupports and making them easily and quickly removableand renewable.

The pegs are ordinarily made by casting in a mold, and they are mounted in sockets or holes in the rotor or casing sides. A casting has a rough irregula/r surface, hence it can not be fitted accurately into a socket but must be machined or otherwise given a smooth surface to permitof such assembly. This means expense and delay. Moreover, if a peg is made of cast iron or other brittle material, and it is fastened rigidly at one end toits support,a sharp blow may break l5 it. Such breakage is serious,-in that a loose peg carried around in the machine may serve to break the other pegs and so do considerable damage and cause the furnace to be shut down for extensive repairs to the pul- 0 verizer- Also, if the peg is made of a hard material, which cannot be machined, the problem must be faced offinding a suitable way of mounting the peg on its support. Heretofore, this has been done by grinding a cylindrical end on thepeg and then keying the peg in a similarly shaped hole. This procedure is objectionable because of the high cost of making and assembling the peg and because the shape of the inner end of the peg is necessarily limited to one which may be produced by grinding.

It is the main purpose of my invention to provide a construction which overcomes these difficulties and allows one to replace Worn out pegs quickly and easily, and to employ 'rough surfaced pegs made of cast metal. v

It is a further object of this invention to provide an improved construction of a pulverizing apparatus suitable for breaking up coal in which the pulverizing impact pegs may be placed loosely in position and clamped removably to their support whereby the pegs may be readily removed when require i r 75 It is another object of my invention to I provide a mounting for the pegs which cushions the shocks and permits the pegs to yield slightly if the strain thereon becomes too great, and thereby minimize breakage and incident delays and expense in making repairs. 3 I g A still further object is to provide a construction which makes it feasible to use an unmachined, durable, long-lived metal for the peg body and to fashion the supported end. of the peg in any shape which is de-* sirable for the purpose of obtaining an efficient operation of the machine.

With these and other objects in View as Fig. 1 is a fragmentary vertical eleva:

. tion of a portion of the casing and rotor of *the pulverizer taken on the line 11 of Fig. 2; 1

Fig. 2 is a fragmentary vertical section on the line 2-2 of 'Fig. 1;

Fig. 3 is an enlarged cross section show-' the framework 10 suitably supports a rotata-' ble shaft 11 adapted to carry the rotor and its grinding pegs. The rotor 12 is essen 'tially a thin disc mounted to rotate between the parallel walls 14 and 1-5 of the casing,

which is substantially cylindrical in shape and has an outer peripheral wall 16 connect ing the side walls 14 and 15. A wear plate or liner 17 may be mounted within the wall 16 to receive the impactof the coal particles as they'are thrown against it, and this plate is ordinarily'made removable so thatit may 0 be replaced when- Worn out. The casing and the frame part may be suitably constructed in order topermit assembly of the rotor, the wear plate and the pegs,-and except as here.

inafter described, this construction does not form a part of my invention.

'A plurality of metal pegs 20 are mounted on the inner faces of the'walls 14 and 15 a and project inwardly parallel with the shaft 11, these pegs being preferably arranged'in concentric circles. The rotor 12 carries similar pegs 22 and 23 on its opposite sides and these are arranged also in concentric circles,

in such a position that they may rotate betweenthe pegs disposed on the casing walls, wherebyany material fed into the central zone ofthe machine'i'through the opening 24 is causedgto pass outwardly through the zone 25'f'ormed' between the pegs on the ,wall 14 and pegs 22, where it is pulverized-by impact with the rotating pegs, the stationary pegsv and the liner 17.; This material must. ass around the periphery of the rotor 12 through theannular'space 26 and thence inwardly against the centrifugal action setup by the rotating pegs tothe ,centrals zone whereit passes outward through the opening}? into a fan cham 'er,'not shown, from wh ch it is driveninto-jthe combustionzone ofja pose to 'employ'pegs of a hard unm'achin'able metal, such as manganese steel or whiteair n,

and fashion themin place-on the rotor or the casmgubymeanswhich permit yl'eldin'g [movement thereof wid r severe, stra n, as

a locking plate.

well .as enables them tobe readily removed for replacement. The peg is preferably fixed to a yielding .orresilient member,

which in turn is fastened to the supporting" a flanged ferrule of a resilient material and clamping the.flange against "its support by To this end I may make the peg support of two plates, one having a socket from which the peg body projects and the other being arranged to clamp the flange between'the twoplates. The socket is preferably largerthan the ferrule, so that the ferrule is held only by its flange. Moreover, I prefer to make the socket and the interfitting end of the in the direction 0 impact and thus provide a stron mounting for the peg.

fpeg of an elongated shape As i1 ustrated, the rotor. may be made of two plates 30and 31 suitably bolted between a flange 32 on the sleeve 33 keyed to the shaft 11=and a clamping ring 34. Each plate 30 and 31 of the rotor is provided with a series of holes 35 arranged in concentric circles which are substantially of the shape of the cross section of' the pegs. In order to make it feasible to utilize roughly cast peg bodies which need not be machined or ground to fit in the supporting plate, I provide ferrules. which maybe accurately shaped in a die, and fix the peg bodies therein, as by casting.

-Each metal ferrule 36 has a shank 37 of such a size that it will pass easily into the hole in the plate in which the peg is to be mounted, and if desired a slight clearance may be 1e so that the peg will be supported mainly by t e'resilient steel flange clamped between its supporting plates. This ferrule is also provided with a flange 38 arranged to be mounted ina plane substantially parallelwith the surface of its supporting plate,

whereby the flangemay be clamped between the. two plates 30 and 31. The flange is shown as coextensive with the end of the peg.

My preferred manner of fixing the peg body in the ferrule is by casting. As shown in Figs. 3, 421ml 5, the ferrule may be provided with inwardly projecting ribs or lugs 39 and if desired an inwardly turned lip 40 on its inner edge. The peg body 41, is in-' tegrally fixed inthe ferrule preferably by casting it in place, in accordance with well known foundry practice. The lug 39 and lip 40 serve to lock the body and the ferrule together, but if they are made of a-drawn metal, they permit the peg to .be drawn gradually and yieldingly'from the ferrule when subjected to any large stress.

Ifithe peg is to be made of a hi h melting metal-suchthat pouringthe mo ten metal directly .into 'the ferrule might injure the latter, I may vmake use of the scheme illusvided with internally projecting ribs or lugs 47 and the peg with a groove 48, the parts being so shaped that clearance is provided for assembling. After the peg has been put in position, a comparatively low melting metal, such as babbitt, is poured into the space between the peg and the ferrule and permitted to harden in place thus forming aconneoting film or layer 49 which fastens the two parts integrally together.

The pegs 20 may be mounted on the easing in a similar manner. In this case the ferrules are inserted in holes in the cheek plate 50 with their flanges projecting outwardly and the flanges are clamped in place by a locking plate 51 which may be fastened to the cheek plate 50 by means of set screws 52. This combination of locking plate and cheek plate is in turn mounted by suitable set screws 58 on the inner wall of the casing walls 1-1 and 15. The pegs on the rotor are arranged with their flanges between the two plates and 31, with the grinding bodies I )ro'ectin on eachside throu h the holes in l a a the plates; hence each plate serves both as a support for one group of pegs and as a clamping plate for the other set; It is found that the flange of the peg may be made of various materials which have the property of yielding slightly under abnormal stresses and of absorbing the shocks and minimizing breakage of the peg, and that a ductile, malleable or resilient material formed into a thin supportingbody, such as a flange'of drawn steel, is particularly suited for this purpose. Such a flange will-absorb any unusual stress applied to the pe due to its l u a l o slight resiliency, and leave the peg in its initial position; but in some instances the flange draws partly out of its fastening and the peg may even move in the ferrule so that the peg will assume a new and permanent position. The hole or socketv in the plate is made larger than the ferrule, so as to give room for movement of the peg and the ferrule, and yet normally prevent contact of the peg body or the adjacent supporting part of the ferrule with the side of the hole or socket in the plate. This insures a yielding mount for the peg, hence any unusual stress will not ordinarily break the peg but will beabsorbed by the supporting flange or serve merely to draw the peg gradually from its initial position in the ferrule or to move the ferrule from its initial position in the socket.

The peg body is preferably made of a nonci'rcular cross section and Wider in one direction than in another, as shown in Figs.

3, 4 and 5, and the narrower side of the peg is-se lccatecton the rotor or the "ta-Sing that be easily formed.

the blows and friction due to the impact action will be received thereon. This insures a longer life to the peg and gives it greater rigidity in itsv mounting because the flange is likewise extended in the direction of travel or impact of the peg. It will also be notedthat the peg is not separable from its ferrule except under abnormal stresses and that they are removable and replaceable together. l.\loreover, this construction makes it feasible to use a peg of uugrindable shape and unmachinable material, as is often desirable, and to mount it easily and removably in a socket on its support which may It will .be obvious that various modifications may be made in the shape of the parts and in the manner of mounting and assembling them within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. A pulverizing machine comprising'a casing, a rotor mounted therein, metallic bodies mounted on one of said parts and arranged to pulverize material by impact thereagainst, and a substantially mounting to hold each of said bodies fixedly in position on its supporting part under the normal stresses of pulverizing the material, but which permits a slight yielding move.- ment of said body only under abnormal stresses.

easmg, a rotor mounted therein, impact bodies arranged to be supported on one of said parts, 'a substantially rigid, but slightly rigid f resilient metal mounting for each body and mean to fasten only the resilient mounting firmlyto the supporting part, said mounti ng being constructed and arranged to hold the body unyieldingly under normal pulverizing stresses but to partially absorb ab normal stresses and minimize breakage of said body.

3. A pulverizi-ng machine comprising a casing, a rotor mounted therein, metallic impact peg bodies having yielding flanges fixed thereon and arranged to be supported on one of said parts, and means removably clamping each flange tightly on the suaporting part so arranged that the peg body is supported only by its flange.

4. A pulverizing machine comprising a casing, a rotormounted therein, one of said parts comprising two juxtaposed plates, and a set of pegs having flanged ferrules rigidly fixed thereon which are removably clamped between the plates.

5. A pulverizing machine comprising a casing, a rotor mounted therein, a set of impact pegs having yielding metal flanges integral'therewith arranged to be supported on one of said parts, said supporting part having sockets thereln larger thanthe pegs,

and means to clamp each peg flange firmly on, the supporting part with the peg loosely positioned in a socket.

6. A' pulverizing machine comprising a casing, a rotor'mou-nted therein one of said parts having sockets of noncircular cross section therein, metallic impact peg bodies of unmachinable material having end POI:

tions shaped to-beinserted freely in said sockets, and means removably fastening said bodies on their support and within the sockets, said parts being so arranged that the pegs may pulverize material by impact.

7. A pulverizing machine comprising a casing, a rotor mounted therein, one' of said parts having a plate. provided with sockets, flanged .ferrules supported in said sockets, a peg body rigidly mounted in and. projecting from each'ferrule, and a plate clamping.

the flanges of the ferrules against the sup porting plate and locking the pegs in position.

8.'A pulverizing machine comprising a casing, a rotor mounted therein, a set of peg in its socket.

pulverizing pegs having flanges rigidly attached thereto, and means to mount the pegs on one of the machineparts including a plate having a hole in which the peg fits loosely and means, to clamp only the flange against said plate.

9. A pulverizing machine comprising a casing, a rotor mounted therein, opposed sets of pegs 'on the casing and rotor between which material is pulverized by impact, the support for one set of pegs having sockets therein, a ferrule in each socket having a flange engaging one sideof said late, a peg body united with the ferrule y casting and projecting'from the socket, and means engaging said flange and holding the 10. A pulverizing machine comprising a casing. a rotor mounted therein, opposed sets of attrition pegs onsaid parts between which material is pulverized by impact, the

supportfor one set of pegs comprising a p I rules fitting loosely in said sockets with the flanges contacting with the face of said plate, peg bodies fixed in said ferrules by casting, and a locking member removably clamping the flanges therebetween.

fastened to said plate and 11. A pulverizing machine comprising casing, a rotatable shaft mounted therein, two juxtaposed disk'p'lates fastened on said shaft, each'having holes ther'ethrough, hollow drawn metal flanged ferrules having plate having sockets therein, flanged fer-f hard metal attrition bodies fixed therein by casting, and projecting therefrom, said ferrules being located in'the holes in each plate metalli'c body integrally fixed by casting in and projecting from the ferrule, said peg.

and ferrule being wider in one direction than in another and the flange being'substantially coextensive with the end of the peg-body. r

-1 t. An attrition peg' for a pulverizing machine comprising a hollow openended ferrule of drawnmetal having an outwardly extending flange and an inwardly projecting lug-z and P 9, OdycaSt in and projecting plates and hold the:

from one end'of said "ferrule and arranged to be held'in place by said lug under normal stresses.

Signed at Worcester, Massachusetts, this 19t h dayof June, 1924. I

ROBERT SANFORD

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