EP0409498B1 - Pulverizer having rotatable grinding table with replaceable air port segments - Google Patents

Pulverizer having rotatable grinding table with replaceable air port segments Download PDF

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Publication number
EP0409498B1
EP0409498B1 EP19900307681 EP90307681A EP0409498B1 EP 0409498 B1 EP0409498 B1 EP 0409498B1 EP 19900307681 EP19900307681 EP 19900307681 EP 90307681 A EP90307681 A EP 90307681A EP 0409498 B1 EP0409498 B1 EP 0409498B1
Authority
EP
European Patent Office
Prior art keywords
pulverizer
ring
grinding table
segmented
inner ring
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19900307681
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0409498A2 (en
EP0409498A3 (en
Inventor
Randall John Novotny
Ralph L. Cummins
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.)
Foster Wheeler Energy Corp
Original Assignee
Foster Wheeler Energy Corp
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Filing date
Publication date
Application filed by Foster Wheeler Energy Corp filed Critical Foster Wheeler Energy Corp
Publication of EP0409498A2 publication Critical patent/EP0409498A2/en
Publication of EP0409498A3 publication Critical patent/EP0409498A3/en
Application granted granted Critical
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Classifications

    • 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
    • B02C15/001—Air flow directing means positioned on the periphery of the horizontally rotating milling surface

Definitions

  • This invention pertains to pulverizers of the roll and race type which have a rotatable grinding table containing air port flow passages. It pertains particularly to such pulverizers for coal having a grinding table with multiple replaceable air port segments provided at the table periphery adjacent an outer segmented ring.
  • Pulverizers for coal having a centrally located coal feed conduit and a rotary grinding table and rolls provided in the pulverizer lower portion for pulverizing coal and pneumatically conveying it upwardly to boilers for combustion therein are well known.
  • such pulverizers for coal are disclosed by US-A- 4 264 041 to Kitto, Jr. et al and US-A- 4 687 145 to Dougan et al.
  • the carrier air passes upwardly from a plenum through air ports containing a plurality of vanes and entrains pulverized coal upwardly from the outer edge of the rotatable grinding ring.
  • US-A- 4 752 037 shows a pulverizer with air ports defined between an outer, stationary segmented ring and an inner segmented assembly fixed to the rotatable table.
  • a pulverizer for pulverizing particulate materials including a housing, a grinding table rotatably mounted in the housing and having annular air port openings provided between the table and the housing, roller means contacting the grinding table upper surface for pulverizing the particulate material thereon, an outer segmented ring attached to the housing inner wall at a location opposite the grinding table, and an inner segmented ring removably attached to an outer peripheral surface of the grinding table, so as to provide a narrow radial gap between the segmented outer ring and the segmented inner ring, characterised in that the inner ring segments include a lower part, removably attached to the grinding table outer periphery and having upright flow passageways therein, and an upper part, also removably attached to the outer periphery of the grinding table in an overlapping arrangement with the segment lower parts, each upper part having a plurality of upright flow passages therein, whereby the ring segment upper parts can be removed and replaced independent of the segment
  • a pulverizer according to the invention can pass primary air to pulverized material and pneumatically convey the material such as coal upwardly to a boiler for combustion therein.
  • This invention advantageously provides a pulverizer having an air port unit for which the ring segments upper part, which receive the most erosion war, can be replaced easily and economically without requiring replacement of the entire air port assembly.
  • the air port configuration also advantageously provides for changes in air flow requirements as needed to meet changes in pulverizer operations.
  • the air flow passageways provided in the inner ring segments are angled radially inwardly at an angle of 10 to 20° relative to a vertical plane.
  • the flow passages are angled forwardly relative to the intended grinding table direction of rotation at an angle of 40 to 60° and preferably at about 45° angle with the horizontal plane.
  • the use of a 40 to 60° forward angle as compared to a smaller angle of about 30° results in less direct impingement if the entrained coal stream against the housing, which reduces housing erosion.
  • the radial gap between the stationary outer segmented ring which is rigidly attached to the inner wall of the pulverizer housing and the air port rotatable inner ring segments is desirably from 0.100 to 0.190 inch (approx. 2.54 to 4.83mm) and preferably about 0.125 inch (approx. 3.175mm).
  • the outer ring includes multiple segments, and preferably each segment has a lower part rigidly attached to the housing wall as by welding, and an upper part removably attached to the outer ring segment lower part such as by bolting.
  • air port ring multiple segments having replaceable lower and upper parts provides an improved means for matching of the pulverized air port air flow requirements to a particular pulverizer installation.
  • this configuration permits the air port lower segments to be sized to accommodate the largest volumetric air flow for a given pulverizer housing size, and permits the segments upper parts to be sized to provide a desired smaller air flow rate as required to attain the proper air velocity for upward coal transport desired for the particular pulverizer installation.
  • the air port ring segment upper parts openings have flow passages which have between about 50 to 100% of the cross-sectional area of the ring segment lower parts.
  • a coal pulverizer assembly 10 includes an outer casing 12 which encloses a rotary grinding table 14.
  • the grinding table 14 is supported by rollers in a stationary base structure 16, and is rotatable by a pulverizer gear reducer and drive motor 18 within the base 16.
  • Triple equally spaced rollers 20 are pivotably attached to the housing 12 above the rotary grinding table 14. Rollers 20 can each rotate about their own shafts 21 which are pivoted at 22 to housing 12, so that the rollers 20 are each rotated in race 15 and on the coal therein by the rotation of the grinding table 14.
  • the coal feed enters the pulverizer via a central downcomer unit 24 and falls onto a central portion 14a of the rotatable grinding table 14.
  • FIG. 2 A plan view of the pulverizer rotatable grinding table 14 and multiple air ports 30 is shown by Figure 2. It is seen that the multiple peripheral air ports 30 are provided by a segmented ring 32, which is rigidly attached to the periphery of the grinding table 14. The multiple air ports 30 are provided circumferentially spaced apart in the segmented ring 32, which is removably attached to the periphery of grinding table 14 such as by bolting.
  • the segmented ring 32 contains multiple segments 31, with at lease 8 arcuate segments and usually not exceeding 20 segments being provided.
  • each ring segment 31 consists of an upper piece 31a and a lower piece 31b.
  • a multi-piece segmented retainer ring 34 is bolted to the periphery 14b of the grinding table 14 by bolts 35. Both the upper piece 31a and the lower piece 31b are bolted to the segmented retainer ring 34 using a staggered bolting arrangement of bolts 37a and 37b.
  • a plurality of passageways 33 are provided through the ring segments 31, with the passageway walls being oriented radially inwardly by an angle A of 10 to 20° related to a vertical plane, and preferably at an angle of about 15°.
  • a refractory cement material 39 can be provided in any gap between upper part 31a and rotatable table 14.
  • An outer stationary ring 40 has a plurality of segments rigidly attached to the pulverizer housing 12 such as by welding, so as to provide a radial gap 42 between the outer ring 40 and the air port segmented ring 32.
  • the radial gap 42 should be 0.100 to 0.190 inch (approx. 2.54 to 4.83mm) wide and is preferably about 0.125 inch (approx. 3.175mm) wide.
  • a plurality of upper wear segments 41 are removably attached by bolts 43 onto the upper surface of the outer ring segments 40.
  • the outer ring segments 40 consist of a plate 40b and cover 40a which are both welded together and also welded to the pulverizer housing wall 12.
  • the segmented upper parts 41 are bolted onto the lower part cover 40a by at lease three spaced apart bolts 43 per segment.
  • the outer stationary ring 40 includes at least 8 segments and usually not exceeding 20 segments. If desired, a refractory cement material 44 may be provided between the cover 40a and vertical plate 40b and housing 12. Also, a refractory cement material 45 may be provided between upper wear segments 41 and housing 12.
  • the orientation and size of the air port flow passages 33 in ring 32 is further shown by figure 4.
  • the flow passages 33 are all angled forwardly, i.e. in the direction of rotation of the grinding ring 14, by an angle B of 40 to 60° relative to a horizontal plane, and preferably by about 45° angle.
  • the passages in the segmented ring lower pieces 31b are sized to accommodate the largest volumetric flow for a particular pulverizer frame size.
  • the passages in the ring upper pieces 31a are sized to provide the proper air velocity for particulate coal transport based on the actual volumetric flow required for a particular pulverizer installation. As a result, the opening area in the upper pieces 3la are always equivalent to or smaller than the opening area in lower pieces 31b.
  • the total cross-sectional area of the flow passages 33 in the upper pieces 31a should be made 50 to 100% of the cross-section area of the flow passages in the lower pieces 31b.
  • portions of the upper pieces 31a may overlap portions of the flow passageways in the lower pieces 31b, as in shown by Figure 4.
  • a pulverizer for coal having a configuration generally as shown in Figure 1 was constructed having a segmented air port configuration.
  • the air port included a segmented inner ring bolted onto the periphery of the grinding table and having a plurality of air passageways which are angled both inwardly and forwardly.
  • the segmented inner ring included upper and lower parts each separately bolted onto a segmented retainer ring which is bolted onto the periphery of the grinding table.
  • the air port also included a segmented outer ring, which had lower parts welded onto the pulverizer housing walls and upper parts bolted onto the lower parts.
  • the air port segments had the following characteristics: Grinding table outer diameter - 120in (approx 3048mm) Number of inner ring segments - 15 Number of outer ring segments - 12 Radial gap between inner and outer rings - 0.125in (approx 3.175mm) Radial width of flow passages - 4in (approx. 101.6mm) Radial inward angle of flow passages - 15° Forward angle of flow passage - 45° Number of ports - 30

Landscapes

  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Crushing And Grinding (AREA)
  • Crushing And Pulverization Processes (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
EP19900307681 1989-07-20 1990-07-13 Pulverizer having rotatable grinding table with replaceable air port segments Expired - Lifetime EP0409498B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US382374 1982-05-27
US38237489A 1989-07-20 1989-07-20

Publications (3)

Publication Number Publication Date
EP0409498A2 EP0409498A2 (en) 1991-01-23
EP0409498A3 EP0409498A3 (en) 1991-04-17
EP0409498B1 true EP0409498B1 (en) 1994-05-18

Family

ID=23508682

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900307681 Expired - Lifetime EP0409498B1 (en) 1989-07-20 1990-07-13 Pulverizer having rotatable grinding table with replaceable air port segments

Country Status (4)

Country Link
EP (1) EP0409498B1 (ja)
JP (1) JPH0783839B2 (ja)
CA (1) CA1311232C (ja)
ES (1) ES2053114T3 (ja)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5127590A (en) * 1991-04-09 1992-07-07 March-Sourthwestern Corp. Rotating throat/air port ring assembly
US5340041A (en) * 1992-11-25 1994-08-23 The Babcock & Wilcox Company Welded rotating annular passage segment for coal pulverizers with replaceable vanes and adjustable passage port area
US5605292A (en) * 1995-09-06 1997-02-25 March-Southwestern Corp. Pulverizer mill high performance classifier system
JP5030430B2 (ja) * 2006-02-07 2012-09-19 三菱重工業株式会社 竪型ローラミル
JP4814127B2 (ja) * 2007-03-13 2011-11-16 象印ベビー株式会社 歩行補助器
GB2458354B (en) * 2008-03-20 2010-03-24 Paul Andrew Comer Pulveriser mill with port ring
JP5412801B2 (ja) * 2008-11-17 2014-02-12 株式会社Ｉｈｉ バイオマスミル

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4264041A (en) * 1979-09-28 1981-04-28 The Babcock & Wilcox Co. Low pressure drop pulverizer throat
US4523721A (en) * 1982-12-08 1985-06-18 Combustion Engineering, Inc. Bowl mill with primary classifier assembly
US4687145A (en) * 1985-12-12 1987-08-18 The Babcock & Wilcox Company Roll-and-race pulverizer with rotating throat
JPS62160148A (ja) * 1986-01-06 1987-07-16 株式会社神戸製鋼所 ロ−ラミルのノズル構造
JPS62266147A (ja) * 1986-05-13 1987-11-18 株式会社神戸製鋼所 ロ−ラミルのノズル装置
US4752037A (en) * 1987-04-01 1988-06-21 Combustion Engineering, Inc. Vane wheel assembly for rb mills
DE3822290A1 (de) * 1988-07-01 1990-01-04 Babcock Werke Ag Walzenschuesselmuehle

Also Published As

Publication number Publication date
ES2053114T3 (es) 1994-07-16
JPH0783839B2 (ja) 1995-09-13
EP0409498A2 (en) 1991-01-23
JPH0380943A (ja) 1991-04-05
EP0409498A3 (en) 1991-04-17
CA1311232C (en) 1992-12-08

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