US1724895A - Single-zone pulverizing apparatus - Google Patents

Description

Aug. 20, 1929. BEACH 1,724,895

SINGLE ZONE PULVERIZING APPARATUS Filed May 5, 1926 INVENTOR DAVID f1: BEACH CI/"I Q, 9L 0'14- a) ATTNEY WITNESSES Patented Aug. 20, 19 29.

UNITED STATES.

1,724,895- PATENT OFFICE.

DAVID R. BEACH, 015 WORCESTER, MASSACHUSETTS, ASSIGNOR TO RILEY STOIER CORPORATION, OF WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSA- CHUSETTS.

SINGLE-ZON E PULVERIZING APPARATUS.

Application filed May 5,

This invention relates to pulverizing apparatus and more particularly to a device of the beater type shown in the reissue patent to Blyth N 0. 16,229, which pulverizes such material as coal by means of revolving impact members.

Apparatus of this type, as previously made, involves the use of two separate pulverizing zones on opposite sides of a rotatable disk,-

10 with the fuel inlet and outlet openings adjacent to the axis of the disk. The material is pulverized by means of interfitting sets of pegs mounted on the rotary disk and the stationary casing Walls respectively. If the fuel to be pulverized is likely to include tramp iron it has been necessary to employ some form of separator in connection with the fuel feeding apparatus so as to prevent such hard foreign bodies from entering the casing and breaking the pulverizing pegs, thus making it necessary to shut down the machine for repairs. Moreover, the use of pegs to crush the coarse material preliminarily is sometimes inadvisable, owing to the fragile nature of the impact members.

It is accordingly one object of this invention to overcome such difficulties and to provide a beater type of pulverizer which will handle the ordinary run of coal, or other material, and eliminate safely the hard foreign bodies without interfering with the pulverizing operation.

It is a further object to provide a single zone pulverizing apparatus of simple construction which will crush coarse material and grind it to a desired and regulatable degree of fineness, and which will operate efficiently to produce a substantially uniform product.

\Vith these and other objects in view as will be apparent to one skilled in the art, this invention resides in the combination of parts set forth in the s ecification and covered by the claims appenci ed hereto.

Referringto the drawings in which like reference numerals indicate like parts:

Fig. 1 is a vertical section on the line 1-1 of Fig. 2 of a machine embodying one form of my invention;

Fig.2 is a section on the line 22 of Fig. 1

Fig. 3 is a detail showing the preferred method of mounting the pegs;

Fig. 4 is an isometric View showing one of the swing hammers;

1926. Serial a... 106,982.

Fig. 5 is a perspective rejector blades; and

Fig. 6 is a detail showing the preferred method of mounting the swing hammers.

In accordance with the invention, it is proposed to pulverize the coarse material completely to a fine size in a single pulverizing zone. This is accomplished by means of revoluble heaters, arranged to pulverize the material as it passes inwardly towards a centrally located outlet. In order to insure com- 35 plete pulverization of the material, the coarse material is fed into the apparatus through an inlet adjacent to the peripheral path of the heaters, and the finely ground material is withdrawn b means of an air current through an outlet a jacent to the center of the apparatus, so that the material is obliged to pass towards the center of the machine against'the centriftigal force set up by the revolving impact members. As a result, coarse particles will be thrown back into the pulverizing zone and broken further, until of such size that they will float like dust particles in a cloud through the exit orifice. The heaters may be mounted on various "forms of rotor and the casing correspondingly shaped, and in the preferred form the rotor is disk shaped and the heaters may consist of pegs arranged on one side thereof. The number, size and location of the pegs affects the fineness charac.. teristics of the ground material: For grinding fuel, I prefer to employ a setjof stationary pegsarranged to cooperate with the revoluble heaters and these may be mounted on the casing wall close to the ath of the beaters. An inlet for the material is provided at one side and adjacent to the periphery of the rotating member, and at the bottom of the machine adjacent to the inlet a tramp iron receptacle may be arranged to catch the hard foreign bodies therein. For certain types of material, a preliminary crushingoperation is desirable, and we ma utilize heavy impact members to strike the rst blow. We find it desirable in such cases to utilize yielding or swinging hammers which cooperate with the peripheral wall of the casing to break the material initially and yet yield sufficiently, when large, hard bodies are met, to prevent breaking the apparatus. The tramp iron receptacle and the swing hammers are not found necessary for pulverizing certain materials and one or both of these may be omitview of one of the 5 and assembly of the parts within the cas-' ing, the casing may be split 'on a horizontal plane, as shown in Fig. 1, the lower part being mounted on a suitable base 14 and the upper p art removably fastened thereto by means 'of bolts passing through the flanges 15.

Passing centrally through the two chambers and the connecting passage 13 is a shaft 16 suitably mounted in bearings illustrated diagrammatically as bosses 17 and 18 on the outer sides of the casing. The shaft 16 is adapted to be rotated preferably at high speed by means of suitable driving mechanism indicated by the half coupling 19 located on one end of the shaft 16, which may be connected with a similar part on a driving shaft.

Keyed to the shaft 16 within the chamber is a disk 20 located close to the outer wall 21 "of the casing and spaced by .a considerable distance from the other wall 22 thereof. The impact members for finel crushing the aterial preferably take the orm of pegs, one set of which is suitably fastened on the-rotary disk 20 and another set on the stationary casing wall 22; The preferred peg arrangement comprises several rows of pegs 24 mounted in concentric circles on the lnner face of the disk 20 which intermesh with rows of stationary pegs 25 projecting inwardly from the walls 22 of the casing.

The pegs may be mounted in any suitable mannenbut as shown particularly in Fig.3

they preferably consist of iron pegs (3356111 ferrules 27 of drawn metal. These ferrules have "flanges 28 integral therewith by which the pegs may be supported in place. For this purpose, the disk 20 is provided with a recess adapted to carry therein a clamping plate 29 which may be made in several parts i and suitably bolted to the disk 20. The disk 20 is provided with holes 30 which are slightly larger than the ferrules 2'Zyand the pegs are so mounted in these holes that the flanges 28 are'held securely clamped between'the plates 29 and 20 with the ferrules .centrally located in the holes. This construction is such that the slight resiliency ofi'the ferrule flanges may be brought into-play to prevent excessive shocks from breaking the pegs 24, The

pegs 25 may be similarly mounted between the casing wall 22' and a two-part annular plate 32 which is revolubly mounted about the ring 33 located adjacent to and concentrio with the outlet opening in the plpe 13. These parts are so arranged that the plate 32 may be rotated about the ring 33 when the upper half of the casing 10 has been removed, thereby-permitting ready access to any one of the pegs mounted on the casing. These pegs, as will be understood, are carried in holes in the plate 32 and the plate is clamped to the casing wall 22 by means of cap screws inserted from the outside.

The inlet to the apparatus comprises, as shown particularly in Fig. 1, an enlargement at one side of the pulverizer casing 10 terminating in a feed pipe 40 which is adapted to beconnected ordinarily to a suitable auto matic feeding apparatus arranged to feed material at a desired rate to the machine. At the lower end of the space 41 between the disk 20 and the outer wall forming this inlet area is a space devoted to the reception of tramp iron or other hard foreign bodies. For.

this purpose the lower portion42 ofthe end wall of the casing is arranged to flare outwardly'away from the rotor 20 in a manner to form an opening 43 within which the tramp iron may be deposited, and this opening may beclosed by means of a slide 44 or other suitable device to permit the removal of the tramp iron from the machine.

As will be observed, the material enters the pulverizer casing substantially tangen tially to the edge of the disk 20 and if the disk is rotating downwardly at that side then thematerial is drawn into the pulverizing zone in the direction indicated by the arrow in Fig. 1 and it is then moved in a spiral-like path gradually toward the outlet'opening in the pipe 13. If a piece of heavy tramp iron should fall into the casing, it might strike the pegs and so break them, and in order to insure the heavier matter being sufficiently crushed before they can strike the pegs and to aid in depositing such foreign-bodies in the tramp iron receptacle 43, I preferably make use of revolving swing hammers mounted on the disk adjacent to its periphery in the path of the entering material. These swing hammers are of such size and so arranged that as they revolve they will give the entering material a sharp blow and crush it preliminarily. These hammers 45 are preferably mounted on the inner side of the disk 20 and are'of such a size as to sweep substantially the entire area of the casing so that all. material entering the casing must be struck by them.

To this end, ;I prefer to form each swing a hammer in a T shape and to suspend the hammer from the lower endof the T so that it may swing freely as it is revolved. A simple form of mounting may comprise, as illustrated particularly in Fig. 6, a heavy peg 47 having a flange 48 mounted between the plate 29 and the disk 20. The hammer 45 is provided with a hole 50 so for the swing hammer arranged that the peg may be swingingly mounted on the reduced end 51 of the peg 47, and in order to hold the hammer in place, a collar 52 is mounted on a still further reduced end ofthe peg 47 and this is held in place by a nut 53 threaded on'the extreme end of the peg. The outer head 55 of the T-shaped swing hammer is very massive and arranged to strike the material a hard blow. In order to receive the wear on the interior of the casing caused by these hammers crushing material between their fa'ces and the casing a set of wear' plates 56 may be provided and these may be corrugated as shown in order to provide extra crushing surface against which the hammers ma act.

In a machine of the type, the pegs 24 and 25 may extend nearly the full distance bee tween the rotating disk 20and the opposite casing wall so as to make sure that all of the material is subjected to the impact blows of the pulverizing peg members, and in such a construction one may utilize a greater number of rows of pegs than shown in the drawing, in which case the rows adjacent to the axis of the disk serve as rejectors which throw back into the path of the more rapidly revolving pegs such material as has not. been finely pulverized. The preferred form of re jector, however, is shown in the drawing and comprises revolving arms 60 mounted so as to sweep across the exit 61 which communicates with the pipe 13. These rejector blades may comprise U-shaped members so mounted that the'open side faces in the direction of revolution. Each blade may be fashioned as a casting having a base member 62 shaped to fit within a groove in the sleeve 63 keyed to the shaft 16. The wall 64 is slightly longer 1 than the wall 65 so that the blade may travel within and close to the beveled face 66 of the 7 ring 33. This rejector, it will therefore be seen, is so shaped and positioned that it will sweep across the entire exit orifice and'due to its rapid revolution and because of its width it will prevent the escape of coarse particles from the casing.

The material may be drawn through the casing by means of a fan 70 of any'suitable construction mounted on the shaft 16 within the chamber 12. The material is drawn from the pulverizer chamber 10 through the conduit 13 into the fan fasing and is then forced outwardly through the opehing 72 which communicates with a pipe adapted to convey the material either to the burner of a furnace or to any other desired location. It is, of course, essential that the fan have a capacity more than sufiicient to overcome the fan action of the pegs and swing hammers in the v pulverizer casing and that it'deliver the ma terial at the desired velocity. In order to insure the regulatable introduction of air into the pulverizer casing, any suitable pro- 7 vision may be made, but I have shown this 24 short, a space is provided between their outer ends and the plate 32, so that such fine material may travel directly to the exit orifice and if sufficiently fine pass between the rejector blades as a cloud of dust borne on the current of air drawn therethrough. 'If, however, the material is too coarse to pass the rejector blades, then it is struck by them and hurled against the beveled face 66 of the ring 33 and thrown back into the path of the revolving pegs 24, where it is subjected to a further pulverizing action.

If the stationary pegs 25 are omitted entirely, there is nothing to hinder the whirling movement of the material in the machine except the friction against the interior of the casing. Under these conditions, the material will revolve with the rotor at a speed closely approaching that of the rotor, and this results in a very pronounced centrifugal force. Hence. only the finest of material can be drawn inwardly toward thecenter and pass out of the machine. While this extremely fine grinding is desirable for certain puroses, in many instances it is unnecessary. y utilizing stationary pegs, it is possible to reduce the whirling movement of the material, and thus permit coarser'particles to be withdrawn against centrifugal force. This arrangement also results in a marked reduction in the power required for driving the machine. By varying the number and arrangement of the pegs, the degree of fineness of the product can be controlled as desired.

The operation of the machine will be apparent from the above disclosure. If the disk is rotated in the direction shown by the arrow in Fig. 1 then the action is substantial ly as follows: Material is fed into the pipe- 40 and asuppl of air is admitted through openings 74. he rapidly revolving swing hammers 45 strike the material as it enters the machine and drag it between the ham-. mers and the liner plate 56 of the casing. The tramp iron finds its way to the receptacle 43. The suction of the air caused by the rotation of thefan 70 causes the mate- V is subjected to the centrifugal screening acto such a degree of fineness that it will then travel as a cloud of dust on the air through .theexit and through the'fan casing.

' I It will therefore be seen that I have provided a very simple form of pulverizer in which the material is pulverized inasingle zone and by a single course of treatment. This type of machine will pulverize the material finely, since coarse material cannot escape through the exit until it, is so fine that it will travelas a cloud of dust. If a foreign body enters the casing and does not go immediately into the tramp iron receptacleit will not ordinarily break the swing hammers butthey'will yield slightly and cause the tramp iron to be carried around the casing and ultimately to be deposited again in the, If such tramp receptacle rovided therefor. iron shoul escape into contact with the pegs, they are not so'likely to be broken because they will merely hurl the iron back into the path of the revolving hammers and centrifugal force will ultimately tend to deposit it in the receptacle 43.

Having thus described my invention, what I claim as new, and desire to secure by'Letters Patent, is:

1. A pulverizing apparatus comprising a hollow casing of substantially cylindrical shape which has a centrally located outlet in one of its end walls, apipe forming a localized inlet for the material to be pulverized which opens into the casing at the periphery there- 0 means to move a stream of air from the periphery of the casing to the outlet, a rotor mounted within the casing with its axis con-' centric with the outlet, said rotor being spaced from that end wall of the casing in which the outlet is located so as to form a single pulverizing zone, means includin a' set of beater elements on said rotor revollible between the inlet and'the outlet which serve to break the material by successive impacts thereagainst and screen the coarse from the fine particles, whereby only a cloud of pulverized material borne on the air current may escape from the casing.

2. A pulverizing apparatus comprising a casinghaving a centrally located outlet in one wall, a set of beater pegs revoluble about an axis passing adjacent to the outlet, a set of stationary pegs on the casing cooperating with the revoluble pegs to pulverize material fed thereto, means forming an inlet for feeding coarsematerial directly into the casing ad acent to and outside-of the peripheral path of the beaters, said beaters being spaced from the outlet and so constructed as to set up a centrifugal force tending to move the coarse particles towards the eriphery" of the casing,

and a fan associate thefiewith to draw a cloud of the finely pulverized material. and

force.

3. A pulverizing apparatus comprising a substantially cylindrical casing having a v centrally located outlet, a rotor, axially concentric with said outlet and located close to one end wall of the casing to form a single pulverizing zone, revoluble and stationary impact bodies on said rotor and the opposite casing wall respectively which are arranged concentric with said outlet, means forming a single inlet to deliver coarse material adjacent the periphery of the rotor, and a fan for transporting the finely divided material on a current of air from the inlet to the outlet,

said parts being so constructed and arranged that the material is subjected to the centrifugal screening action of the impact bodies as it passestowards the outlet on the air current.

4. A pulverizing apparatuscomprising a substantially cylindrical casing having a centrally disposed outlet, a shaft concentric with said outlet, a rotor mounted on said shaft,

impact bodies mounted on said rotor to re-- \ly to the impact members, means forming a receptacle to receive hard foreign bodies entering the inlet, and means to pass a current of air through the machine from the inlet to the outlet and transport a dust cloud thereon.

5. A single zone pulverizing apparatus comprising a casing having a centrally disv posed outlet, a rotor having its axis adjacent to the outlet, impact members on the rotor revoluble about the outlet, an inlet pipe for feeding coarse material to the peripheral portion of the casing and directly to the impact members, yielding impact bodies on the r0;

tor to give a preliminary crushing blow to the material and means for transporting a ,currentofv air through the casing. I

6. Afpulverizing apparatus comprising a casing having a centrally located outlet, a rotor axially concentric with the outlet and arranged at one side to form a. single pulverizing zone, swing hammers on the rotor adjaeent to the periphery of the casing which are arranged to give -a preliminary crushing blowto the material, revoluble and stationary pegs on the rotor and the opposite casing wa 1 respectively which are located between v the hammers and the outlet, means forming an inlet -for delivering coarse material di-- rectly" to said hammers, and means for trans- Rportin a current of air and a cloud of pulverize material through the casing to the outlet against'the centrifugal action of the.

hammers and pe s.

7. A pu'lvlerizmg apparatus comprising a casing having a centrally located outlet, a rotor having its axis adjacent to theoutlet,

means forming an inlet to feed coarse material into the casing at the periphery of the rotor, impact bodies on the rotor between the inlet and the outlet to pulverize the material, a revoluble rejector adjacent to the outlet to prevent the exit of coarse particles, and means to transport a current of air through the casing.

8. A pulverizingapparatus comprising a casing having a centrally located outlet, a

rotor arranged axially concentric with the outlet to form a single pulverizing zone, heaters on the rotor, means forming an inlet to feed material into the casing directly to the periphery of the rotor, and means forming a receptacle for hard foreign bodies located in the path of the incoming material.

9. A pulverizing apparatus comprising a casing having a single pulverizing chamber,

means providing a centrally located outlet from said chamber, a rotor mounted with its axis adjacent to said outlet, means to feed material and air directly into the casin adjacent to the periphery of said chamber, eaters on the rotor revoluble about the outlet and adjacent to the peripheral inlet which are arrangedto pulverize the material by successive impacts and to screen the coarse particles from the fine ones as it passes inwardly towards the outlet against centrif ugal force, and means to pass a current of air through the casin at a rate required, to transport a cloud 0% pulverized material therefrom.

' Signed at Worcester, Massachusetts, this 30th day of April, 1926.

DAVID K. BEACH.

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