US3544015A - Mill for pulverizing hard material - Google Patents

Mill for pulverizing hard material Download PDF

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Publication number
US3544015A
US3544015A US693539A US3544015DA US3544015A US 3544015 A US3544015 A US 3544015A US 693539 A US693539 A US 693539A US 3544015D A US3544015D A US 3544015DA US 3544015 A US3544015 A US 3544015A
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United States
Prior art keywords
mill
rotor
housing
crushing
coal
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Expired - Lifetime
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US693539A
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English (en)
Inventor
Milos Gulic
Dobren Stojkovic
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Individual
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Individual
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C13/00—Disintegrating by mills having rotary beater elements ; Hammer mills
    • B02C13/13—Disintegrating by mills having rotary beater elements ; Hammer mills with horizontal rotor shaft and combined with sifting devices, e.g. for making powdered fuel
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C13/00—Disintegrating by mills having rotary beater elements ; Hammer mills
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C13/00—Disintegrating by mills having rotary beater elements ; Hammer mills
    • B02C13/14—Disintegrating by mills having rotary beater elements ; Hammer mills with vertical rotor shaft, e.g. combined with sifting devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C13/00—Disintegrating by mills having rotary beater elements ; Hammer mills
    • B02C13/14—Disintegrating by mills having rotary beater elements ; Hammer mills with vertical rotor shaft, e.g. combined with sifting devices
    • B02C13/18—Disintegrating by mills having rotary beater elements ; Hammer mills with vertical rotor shaft, e.g. combined with sifting devices with beaters rigidly connected to the rotor
    • B02C13/1807—Disintegrating by mills having rotary beater elements ; Hammer mills with vertical rotor shaft, e.g. combined with sifting devices with beaters rigidly connected to the rotor the material to be crushed being thrown against an anvil or impact plate
    • B02C13/1835—Disintegrating by mills having rotary beater elements ; Hammer mills with vertical rotor shaft, e.g. combined with sifting devices with beaters rigidly connected to the rotor the material to be crushed being thrown against an anvil or impact plate by means of beater or impeller elements fixed in between an upper and lower rotor disc

Definitions

  • the material is discharged by centrifugal force from the rotor into the housing wherein the material undergoes a second crushing operation and is thereafter discharged to a distributor.
  • the degree of crushing in the second crushing operation is regulated by the period ofdetention ofthe material in the housing as controlled by the size ofa throttle outlet aperture from the housing to the distributor and the length of the housing between the rotor and the distribu- Pa tented Dec. 1, 19 70 I Sheet 1 or s
  • This invention relates to ventilating mills for the pulverizing of coal as well as to the pulverizing of other materials in the milling industry.
  • the degree of fineness ofthe pulverized coal is achieved in that coal particles which were not crushed in the first pass through the crushing rotor to the desired degree of specific fineness, are separated in a centrifugal separator, which is'located after the mill, and returned for subsequent milling by the crushing rotor of the ventilating mill.
  • the pulverization of the fine particles of coal and other materials returning to the crushing rotor is not efficient due to the small mass of the particle, and therefore their pulverization is conducted by friction between the crushing plates of the rotor and the housing body.
  • a further deficiency of the known arrangement is that the lateral supply of raw coal to the crushing rotor by gravity, decreases the drying intensity due to insufficient contact of the entire fluid drying mass with the entire coal quantity, thus causing irregular rotor wear, resulting in a state of unbalance ofthe rotor.
  • centrifugal separators must be larger, causing an increase in the pressure loss in the pressure tubing of the mixture of pulverized coal and carrier or transport fluid thereby raising the level of the firemans station and making the mills mounting next to the boiler more difficult, while also increasing the size of the boiler due to asymmetric design.
  • An object of the present invention is to provide a ventilating mill which does not employ a separator and which is free of the mentioned disadvantages.
  • the mill includes means for subjecting the material to be pulverized to two stages ofcrushing, the second stage being controlled in such a way that the particle size ofthe discharged material corresponds to that desired.
  • a rotor with crushing plates thereon is disposed in a housing and the material to be pulverized is fed with a carrier, constituted by a heated drying fluid, to the crushing plates and thereat subjected to the first stage of crushing.
  • the material passes, under the influence of centrifugal force, from the crushing plate into the housing where the material undergoes the second stage of crushing, where after the material passes to a distributor and is fed to a combustion chamber of a steam generator.
  • the period of detention of the material in the housing is controlled by regulating the length of the housing along which the material passes as it flows towards the distributor, and the size of a throttle outlet opening from the housing to the distributor. the latter being achieved with a plate having a diameter of particular size.
  • FIG. I is a vertical section through a ventilating mill according to the invention along line H of FIG. 2;
  • FIG. 2 is a plan view of the mill of FIG. I partially broken away along line II-II in FIG. I;
  • FIG. 3 is a side elevation view diagrammatically showing a plurality of mills and a steam generator
  • FIG. 4 is a sectional view taken on line IV-IV in FIG. 3;
  • FIG. 5 is a sectional view of a modified version of the mill of FIG. I.
  • FIG. 6 is an end view of the mill of FIG. 5 partly broken away along line V-V in FIG. 5.
  • raw coal with recirculated gases or other transporting fluid fall through a hollow shaft 1 onto a disc 2 of a crushing rotor which serves for the first stage of coal pulverization as wellas for increasing the pressure in the milling system.
  • the raw coal will be pulverized by impact with crushing plates 3, and due to the action of centrifugal force will be forcibly discharged against cylindrical frame 4 where a second stage of coal pulverization will be effected due to the friction between each coal particle and the portion of the housing frame opposite the plate 3.
  • the particles will remain on the aforesaid portion of the housing 4 until they are pulverized to the degree of intended fineness, after which they will be conveyed by the transporting gases into a distributor shown schematically as 5.
  • the distributor may be of a type provided with an optional number of discharge outlets 6, see FIG. 2, depending on how many burners will be supplied from the mill with gaseous mixture.
  • the size ofthe pulverized coal can be increased by reducing the height h and/or increasing the exit diameter d leading to the distributor 5. By varying the above parameters in the op posite direction, the size of the pulverized coal can be decreased.
  • the mill is driven by an electromotor 11 which is coupled by a fluid coupling or torque converter 12 to a bevel gear transmission 13.
  • a driving mechanism enables the use of low-price electromotors with a smaller number of poles.
  • the mill according to this invention can also employ a directly coupled electromotor, which is vertically installed.
  • FIGS. 3 and 4 show an assembly of six mills coupled to one greater steam generator.
  • Coal is supplied to each mill 19 from a coal bunker 14 via a supplying device 15 and vertical shaft 16.
  • Through the shafts 16 are passed the recirculated combustion products from the furnace 17, together with heated air 18 from an external air heater (not shown)- v
  • the pulverized and dried coal is conducted tothe burners through air mixture conduit 20 where it is mixed with secondary air and burned!
  • the heated combustion products serve to generate steam as they flow past the boilers.
  • FIGS. 5 and 6 A mill with a horizontally installed drive axle is represented in FIGS. 5 and 6 and is constructed in a manner similar to the mill, according to this invention, with the vertical drive axle,
  • raw coal is supplied through shaft 21 and fed to rotor 22, so that the coal is crushed by plates 23 in the first milling stage.
  • the crushed coal particles are then discharged against cylindrical frame 24 where a secondary milling stage will be achieved by friction between the coal particles and the housing body.
  • a plate 27 with reduced passageway enables the pulverized coal to remain in the cylindrical frame, as in the previously described embodiment with the vertical driving axle.
  • the pulverized coal is supplied to distributor 25 and thence past a connection flange 26 to the burners.
  • a second pulverization stage by friction is achieved through longer detention of coarse-grained particles. in housing body 4;
  • the required degree of fineness of the milling may be obtained by proper sizing of the height of housing 4 and the diameterdofplate 7;
  • the compact design of the mill enables it to be located close to the boiler resulting in a smaller overall size of the assembly; and the single support of the rotor enables operation of the mill with very high temperature of drying fluid, thus resulting in a high drying intensity.
  • a ventilating mill for the pulverization ofa hard product comprising a housing, a rotor in said housing, means for supplying material to be pulverized to said rotor, means peripherally located on said rotor for subjecting said material to a first crushing operation and for discharging the thus,
  • said means on said rotor being spaced from andcooperating with said housing for subjecting all ofthe crushed material interposed therebetween to a second crushing operation while said crushed material is under the influence of centrifugal force
  • a distributor connected to said housing for receiving the crushed material from said housing, means for controlling the period of detention of the crushed material in the housing before the crushed material is fed to the distributor thereby to control the degree of crushing ofthe material in the second crushing operation, and means for preventing recirculation ofthe crushed material in the housing to impinge against the means for subjecting the material to the first crushing operation after the crushed material has been subjected to the second crushing operation.
  • a mill as claimed in claim 1 wherein said means which controls the period of detention of the particles comprises a plate between the distributor and the housing, said plate having an outlet ofdeterminable size for influencing the detention of the particles in the housing and opening into said distributor.
  • a mill as claimed in claim 2 comprising means for supplying a heated carrier fluid to the rotor with the material to be pulverized whereby the material is transported through the housing and distributor by said carrier fluid.
  • a mill as claimed in claim 6 wherein said means on said rotor for crushing the material comprises a plurality of spaced vertical crushing plates arranged radially on the rotor in a region encircling the discharge aperture of said hollow shaft, said housing extending a determinable distance above the crushing plates thereby also serving to control the period of detention ofthe particles in the housing.
  • a mill as claimed in claim 4 wherein said rotor is mounted for rotation about a horizontal axis and the distributor is located adjacent the housing in alinement therewith along a horizontal line.
  • a mill as claimed in claim 10 wherein said means for supplying material to the rotor comprises a hollow shaft with a vertical inlet portionand a horizontal outlet portion from which the material is fed to the crushing means on said rotor.
  • a mill as claimed in claim 11 wherein said crushing means comprises a plurality of crushing plates arranged radially on the rotor in a region encircling the discharge aperture of said outlet portion, said housing extending a determinable distance beyond the crushing plates towards the distributor thereby also serving to control the period of detention of the particles in the housing.
  • a mill as claimed in claim 13 wherein said means for controlling the period of detention of the crushed material comprises a plate parallel to the opposed .plates of the rotor and encircling said hollow shaft.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Crushing And Pulverization Processes (AREA)
US693539A 1966-12-27 1967-12-26 Mill for pulverizing hard material Expired - Lifetime US3544015A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
YU244566 1966-12-27

Publications (1)

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US3544015A true US3544015A (en) 1970-12-01

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US (1) US3544015A (de)
CH (1) CH489277A (de)
FR (1) FR1578749A (de)
GB (1) GB1148028A (de)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3782643A (en) * 1971-01-21 1974-01-01 Carborundum Co Apparatus for conditioning a granular material
US3860184A (en) * 1971-11-09 1975-01-14 Acton V E H Impact crushers
US3897014A (en) * 1974-05-13 1975-07-29 Ingersoll Rand Co Material disintegrating-and-blowing apparatus
US3920116A (en) * 1974-04-29 1975-11-18 Technovators Inc Impeller loading device
US4138067A (en) * 1976-04-07 1979-02-06 Rene Planiol Centrifugal vacuum impact pulverizing mills
EP0053882A1 (de) * 1980-12-02 1982-06-16 Taiyo Chuki Co., Ltd. Vorrichtung zum Regenerieren von Giessereisand
FR2778586A1 (fr) * 1998-05-14 1999-11-19 Nordberg Bergeaud Sa Montage d'arbre de rotor pour broyeur a axe vertical
FR2778585A1 (fr) * 1998-05-14 1999-11-19 Nordberg Bergeaud Sa Montage de rotor pour broyeur a axe vertical
WO2017199895A1 (ja) * 2016-05-17 2017-11-23 株式会社サタケ 粉砕機
US11975332B2 (en) 2016-08-24 2024-05-07 Schäfer Elektrotechnik U. Sondermaschinen Gmbh Impact reactor

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3782643A (en) * 1971-01-21 1974-01-01 Carborundum Co Apparatus for conditioning a granular material
US3860184A (en) * 1971-11-09 1975-01-14 Acton V E H Impact crushers
US3920116A (en) * 1974-04-29 1975-11-18 Technovators Inc Impeller loading device
US3897014A (en) * 1974-05-13 1975-07-29 Ingersoll Rand Co Material disintegrating-and-blowing apparatus
US4138067A (en) * 1976-04-07 1979-02-06 Rene Planiol Centrifugal vacuum impact pulverizing mills
EP0053882A1 (de) * 1980-12-02 1982-06-16 Taiyo Chuki Co., Ltd. Vorrichtung zum Regenerieren von Giessereisand
FR2778586A1 (fr) * 1998-05-14 1999-11-19 Nordberg Bergeaud Sa Montage d'arbre de rotor pour broyeur a axe vertical
FR2778585A1 (fr) * 1998-05-14 1999-11-19 Nordberg Bergeaud Sa Montage de rotor pour broyeur a axe vertical
WO2017199895A1 (ja) * 2016-05-17 2017-11-23 株式会社サタケ 粉砕機
US11975332B2 (en) 2016-08-24 2024-05-07 Schäfer Elektrotechnik U. Sondermaschinen Gmbh Impact reactor

Also Published As

Publication number Publication date
GB1148028A (en) 1969-04-10
CH489277A (de) 1970-04-30
FR1578749A (de) 1969-08-22

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