US2975984A - Pulverizing apparatus - Google Patents

Pulverizing apparatus Download PDF

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Publication number
US2975984A
US2975984A US718877A US71887758A US2975984A US 2975984 A US2975984 A US 2975984A US 718877 A US718877 A US 718877A US 71887758 A US71887758 A US 71887758A US 2975984 A US2975984 A US 2975984A
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US
United States
Prior art keywords
grinding
zone
ring
pulverizing
pulverizer
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Expired - Lifetime
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US718877A
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English (en)
Inventor
Kayatz Karl-Heinz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Babcock International Ltd
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Babcock and Wilcox Ltd
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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
    • B02C15/00—Disintegrating by milling members in the form of rollers or balls co-operating with rings or discs
    • B02C15/12—Mills with at least two discs or rings and interposed balls or rollers mounted like ball or roller bearings

Definitions

  • This invention relates to pulverizing apparatus, and more particularly to a pulverizer having a circular row of rolling grinding elements disposed in a horizontal plane between a rotating upper and a stationary lower grinding race or ring.
  • the raw material to be pulverized is delivered to the central portion of the grinding elements for radial movement outwardly through the pulverizer.
  • the pulverizer is constructed and arranged to overcome the above described drawbacks in the known pulverizing units. This is accomplished by utilizing a stationary lower grinding ring and providing a central raw material inlet for the delivery of the material to the pulverizing zone from above. Such an arrangement results in a substantially uniform distribution of the raw material throughout the inner periphery of the stationary lower grinding ring. Under these conditions, the grinding elements advantageously receive a well-distributed circumferential flow of the raw material for pulverization. The raw material entering the grinding zone moves outwardly over the lower stationary grinding ring in a radial direction so that the raw material is repeatedly subjected to the grinding action of the rolling grinding elements moving through the grinding zone. action of the rolling grinding elements aids in a gradual outward movement of the material being pulverized.
  • the pulverized material discharging over the outer periphery of the stationary lower grinding ring is entrained by an annular upwardly directed stream of carrier medium or air.
  • the entrained particles of pulverized material are subjected to gravity separation in the pulverizer housing immediately above the grinding zone and the remaining entrained pulverized material is subjected to centrifugal classification in the upper 'part of the pulverizer housing.
  • the introduction of the carrier air stream to the unit may be from below the pulverizing zone, thus producing an upward movement adjacent the outer periphery of the lower grinding ring, as described above.
  • the carrier air stream may be directed horizontally from the outside of the pulverizing zone, movinginwardly against the grinding elements whereby very intensive whirling within the grinding zone is attained.
  • the carrier air may be introduced trom the central portion of the pulverizer grinding zone for movement of the carrier air stream-outwardly through the grinding elements of the pulverizing. zone.
  • the preheated carrier air When unusually high moisture raw material is introduced to the pulverizer, it is advantageous to introduce at least some of the preheated carrier air with the material through the central material inlet duct.
  • the preheated air fiows in a direction parallel to the introduction of the entering raw material and is particularly effective in predrying the material before it enters the grinding zone.
  • Such an arrangement for the introduction of carrier air also assists in the movement of the raw material through the grinding zone.
  • a conical coarse mesh screen is provided to cover the upper rotating grinding ring.
  • the incoming raw material passes through the coarse screen whereas oversized material is discharged outwardly as a result of centrifugal force since the screen rotates with the upper grinding ring.
  • the upper grinding ring and the screen are also subjected to vibrations caused by vertical movements of the rotating grinding ring during its grinding operation.
  • an airswept pulverizer is shown. It will be understood that substantially the same grinding zone construction can be used for a gravity discharge type of unit. 'In the latter instance, air flow through the unit for carrier purposes would be unnecessary.
  • the main shaft 7 is shown as being sealed by a labyrinth gland which consists of a container 8, a sealing medium 9, and ahollow cylinder 10 projecting into the container and which is supported on a distributor cone 11.
  • the container 8 has an annular inside wall 12 which is spaced from the outer wall of the container to form an annular spacing for the sealing medium.
  • the hollow cylinder 10 projects into the annularspace.
  • the sealing medium consists of a fluid with a boiling point above the operational temperature of the pulverizer and a higher specific gravity than the ground material produced in the pulverizer. The diiference in the specific gravity of the materials results in a lack of penetration into the sealing medium so that the pulverized material merely rests on the surface of the sealing medium.
  • the fluid can be so constituted that it solidifies at room temperatures but is liquid at a higher temperature.
  • a preferred sealing medium is a metal alloy which is liquid at temperatures of 60 to C. and has a boiling point beyond the operational temperature of the mill.
  • the metal alloy may be such as to require preheating before the pulverizer has started up Where the heating may be accomplished by electric, gas or steam heating means.
  • the pre-heated carrier medium can be introduced through an inlet duct 13 for inward flow toward the elements 4 of the grinding zone.
  • the carrier medium leaving the pulverizing zone moves upwardly along the wall of the housing in an annular stream toward the upper portion of the pulverizer.
  • the distributor cone 11 is provided with a plurality of slots 14 which are constructed to direct a flow of carrier medium in a generally horizontal direction outwardly through the pulverizing zone for upward movement between the exterior of the upper grinding ring and the pulverizer housing.
  • the slots 14 may also be shaped to direct the carrier medium downwardly and outwardly toward the grinding surface of the lower grinding ring 3.
  • carrier medium can also be introduced through the material inlet duct 2 so as to move downwardly through the central portion of the grinding zone to pass outwardly through the grinding zone.
  • the upper rotating grinding ring 5 is provided with a conically shaped coarse screen 15 which intercepts the incoming raw material so. that oversized foreign materials in the incoming raw material are deflected outwardly over the upper screen surface to be discharged against the rising annular stream of carrier medium.
  • provisions may be made for the discharge of foreign materials from the annular space between the outer surface of the lower grinding ring and the inner surface of the housing. Such means are effective in removing foreign materials from the lower portion of the pulverizer without such foreign materials passing the rolling grinding elements 4.
  • the upper portion of the pulverizer housing 1 is provided with a classifying zone which in the present instance is large enough to accommodate a plurality of centrifugal classifiers 17, each of which is provided with an upper circumferential series of vanes 18 which are adjustable for determining the size range of the material discharging through the outlet ducts 19.
  • each of the ducts 19 is connected with a pulverized coal burner (not shown). With such an arrangement, the air-home pulverized coal stream is effectively and uniformly divided in the classifying zone 16 of the pulverizer so that each burner will receive a, controlled quantity of air-borne pulverized coal. Such controlled quantity of fuel to each burner is independent of the supply to any other burner.
  • Apparatus for pulverizing solid materials comprising a housing having a pulverizing zone in the lower portion thereof, said pulverizing zone including a stationary horizontally disposed lower annular grinding ring and a rotatable upper annular grinding ring, a circumferential row of rolling grinding elements positioned between said lower and upper grinding rings, means for introducing fluid carrier medium into said pulverizing zone, means for rotating said upper grinding ring including an upright drive shaft flexibly connected to said ring and means for eXerting a downward force on said upper ring through said shaft, means for introducing raw solid materials into the central portion of said pulverizing zone including an upright duct coaxial with said grinding elements and projecting downwardly into said housing to a lower end position spaced above said lower grinding ring, and means for removing pulverized solid materials discharged by centrifugal force from the outer circumference of said pulverizing zone to a position exterior of said housing by said fluid carrier medium.
  • Apparatus for pulverizing solid materials comprising a housing having a pulverized material outlet duct in the upper portion thereof and a pulverizing zone in the lower portion thereof, said pulverized zone including a stationary horizontal disposed lower annular grinding ring and a rotatable upper annular grinding ring, a circumferential row of rolling grinding elements positioned between said lower and upper grinding rings, means for rotating said upper grinding ring including an upright drive shaft flexibly connected to said ring and means for exerting a downward force on said upper ring through said shaft, feeder means for introducing raw solid materials into the central portion of said pulverizing zone, means for discharging pulverized solid materials from the outer circumference of said grinding zone, and means for passing an annular stream of carrier medium through said pulverizing zone in an outward substantially horizontal direction and thereafter in an upward direction between the outer periphery of said rotating upper grinding ring and said housing toward said outlet duct.
  • Apparatus for pulverizing solid materials comprising a housing having a pulverized material outlet duct in the upper portion thereof and a pulverizing zone in the lower portion thereof, said pulverizing zone including a stationary horizontally disposed lower annular grinding ring and a rotatable upper annular grinding ring, a circumferential row of rolling grinding elements positioned between said lower and upper grinding rings, means for rotating said upper grinding ring including an upright drive shaft flexibly connected to said ring and means for exerting a downward force on said upper ring through said shaft, means for introducing raw solid materials and preheated carrier medium into the central portion of said pulverizing zone, means for discharging the pulverized solid materials from the outer circumference of said grinding zone, and means for passing a separate annular stream of carrier medium upwardly adjacent the outer circumference of said pulverizing zone and toward said outlet duct.
  • Apparatus for pulverizing solid materials comprising a housing having a pulverized material outlet duct in the upper portion thereof and a pulverizing zone in the lower portion thereof, said pulverized zone including a stationary horizontal disposed lower annular grinding ring and a rotatable upper annular grinding ring, a circumferential row of rolling grinding elements p0- sitioned between said lower and upper grinding rings,
  • means for rotating said upper grinding ring including an upright drive shaft flexibly connected to said ring and means for exerting a downward force on said upper ring through said shaft, feeder means for introducing raw solid materials and carrier medium into the central portion of said pulverizingzone, means for discharging pulverized solid materials from the outer circumference of said pulverizing zone, and means for passing a separate annular stream of carrier medium through said pulverizing zone in an outward substantially horizontal direction and thereafter in an upward direction between the outer periphery of said rotating upper grinding ring and said housing toward said outlet duct.
  • Apparatus for pulverizing solid materials comprising a housing having a pulverizing zone in the lower portion thereof, said pulverizing zone including a stationary horizontally disposed lower annular grinding ring and a rotatable upper annular grinding ring, a circumferential row of rolling grinding elements positioned between said lower and upper grinding rings, means for rotating said upper grinding ring including an upright drive shaft flexibly connected to said ring and means for exerting a downward force on said upper ring through said shaft, means for introducing raw solid materials and a controlled flow of carrier medium into the central portion of said pulverizing zone including an upright duct coaxial with said grinding elements and projecting downwardly into said housing to a lower position space above said upper grinding ring, a conical screen positioned between said upper grinding ring and the lower end of said upright duct to divert oversized material to the outside of said pulverizing zone, and means for removing pulverized solid materials discharged from the outer circumference of said pulverizing zone to a position exterior of said housing.
  • Apparatus for pulverizing solid materials comprising a housing having a pulverized material outlet duct in the upper portion thereof and a pulverizing zone in the lower portion thereof, said pulverizing zone including a stationary horizontally disposed lower annular grinding ring and a rotatable upper annular grinding ring, a circumferential row of rolling grinding elements positioned between said lower and upper grinding rings, means for rotating said upper grinding ring including an upright drive shaft :operatively connected to said upper ring and a drive motor connected to the lower portion of said drive shaft and supported therefrom, whereby the weight of said motor and drive shaft are superposed on said upper ring, means for gravitationally introducing raw solid materials from above through a duct into the central portion of said pulverizing zone, means for discharging the pulverized solid materials from the outer circumference of said grinding zone, and means for introducing carrier medium horizontally against said grinding elements and passing an annular stream of said carrier medium upwardly to entrain pulverized material discharging from the outer circumference
  • Apparatus for pulverizing solid materials comprising a housing having a pulverized material outlet duct in the lower portion thereof and a pulverizing zone in the lower portion thereof, said pulverizing zone including a stationary horizontally disposed lower annular grinding ring and a rotatable upper annular grinding ring, a circumferential row of rolling grinding elements positioned between said lower and upper grinding rings, means for rotating said upper grinding ring including an upright drive shaft operatively connected to said upper ring and a drive motor connected to the lower portion of said drive shaft and supported therefrom, whereby the weight of said motor and drive shaft are superposed on said upper ring, means for gravitationally introducing raw solid materials from above through a duct into the central portion of said pulverizing zone, a conical screen beneath said duct and having its outer edge attached to said upper ring, means for discharging the pulverized solid materials from the outer circumference of said 'grindingzone, 'and means forintroducing carrier medium References Cited in the file of this patent

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Crushing And Grinding (AREA)
US718877A 1957-03-06 1958-03-03 Pulverizing apparatus Expired - Lifetime US2975984A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE1202238X 1957-03-06
DE2975984X 1957-03-06
DE821919X 1957-03-09

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BE (1) BE565431A (en(2012))
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114455216A (zh) * 2022-03-04 2022-05-10 广州环投增城环保能源有限公司 一种垃圾焚烧电厂石灰存储供给系统

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US859118A (en) * 1906-05-14 1907-07-02 Fredrick Schieffler Grinding-machine.
US1410851A (en) * 1920-02-25 1922-03-28 Nat Finance Company Ball machine
GB208962A (en) * 1923-03-19 1924-01-03 Fried Krupp A G Grusonwerk Process and apparatus for disintegrating and finely grinding hard and soft substances also for squeezing and pressing out parts of plants and the like
DE436861C (de) * 1924-10-01 1926-11-25 Fried Krupp Grusonwerk Akt Ges Mit einem Windsichter vereinigte Mahlvorrichtung
US1849871A (en) * 1929-03-14 1932-03-15 R & H Green And Silley Weir Lt Pulverizing mill and the like
US2012802A (en) * 1931-11-16 1935-08-27 Fuller Lehigh Co Pulverizing mill
DE671638C (de) * 1937-12-18 1939-02-10 Ludwig Kirchhoff Fliehkraftkugelmuehle
US2214832A (en) * 1937-04-06 1940-09-17 James C Hobbs Pulverizer
US2318175A (en) * 1941-06-24 1943-05-04 Thomas P Bacon Sr Pulverizer mill
US2439721A (en) * 1941-04-22 1948-04-13 Bailey Meter Co Control system for feeding fuel to furnaces
DE828192C (de) * 1948-10-02 1952-01-17 Babcock & Wilcox Dampfkessel W Kugelringmuehle
DE890301C (de) * 1951-10-10 1953-09-17 Peters Ag Claudius Kugelquetschmuehle
US2849189A (en) * 1955-04-07 1958-08-26 Aerofall Mills Inc Material reduction mill

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US859118A (en) * 1906-05-14 1907-07-02 Fredrick Schieffler Grinding-machine.
US1410851A (en) * 1920-02-25 1922-03-28 Nat Finance Company Ball machine
GB208962A (en) * 1923-03-19 1924-01-03 Fried Krupp A G Grusonwerk Process and apparatus for disintegrating and finely grinding hard and soft substances also for squeezing and pressing out parts of plants and the like
DE436861C (de) * 1924-10-01 1926-11-25 Fried Krupp Grusonwerk Akt Ges Mit einem Windsichter vereinigte Mahlvorrichtung
US1849871A (en) * 1929-03-14 1932-03-15 R & H Green And Silley Weir Lt Pulverizing mill and the like
US2012802A (en) * 1931-11-16 1935-08-27 Fuller Lehigh Co Pulverizing mill
US2214832A (en) * 1937-04-06 1940-09-17 James C Hobbs Pulverizer
DE671638C (de) * 1937-12-18 1939-02-10 Ludwig Kirchhoff Fliehkraftkugelmuehle
US2439721A (en) * 1941-04-22 1948-04-13 Bailey Meter Co Control system for feeding fuel to furnaces
US2318175A (en) * 1941-06-24 1943-05-04 Thomas P Bacon Sr Pulverizer mill
DE828192C (de) * 1948-10-02 1952-01-17 Babcock & Wilcox Dampfkessel W Kugelringmuehle
DE890301C (de) * 1951-10-10 1953-09-17 Peters Ag Claudius Kugelquetschmuehle
US2849189A (en) * 1955-04-07 1958-08-26 Aerofall Mills Inc Material reduction mill

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114455216A (zh) * 2022-03-04 2022-05-10 广州环投增城环保能源有限公司 一种垃圾焚烧电厂石灰存储供给系统
CN114455216B (zh) * 2022-03-04 2023-08-29 广州环投增城环保能源有限公司 一种垃圾焚烧电厂石灰存储供给系统

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BE565431A (en(2012))

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