US20070006786A1 - Roller grate - Google Patents

Roller grate Download PDF

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Publication number
US20070006786A1
US20070006786A1 US11/423,187 US42318706A US2007006786A1 US 20070006786 A1 US20070006786 A1 US 20070006786A1 US 42318706 A US42318706 A US 42318706A US 2007006786 A1 US2007006786 A1 US 2007006786A1
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US
United States
Prior art keywords
grate
roller
covering
coolant
recited
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.)
Abandoned
Application number
US11/423,187
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English (en)
Inventor
Bernhard Zimmermann
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.)
General Electric Technology GmbH
Original Assignee
Alstom Technology AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Alstom Technology AG filed Critical Alstom Technology AG
Publication of US20070006786A1 publication Critical patent/US20070006786A1/en
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23H—GRATES; CLEANING OR RAKING GRATES
    • F23H9/00—Revolving-grates; Rocking or shaking grates
    • F23H9/02—Revolving cylindrical grates
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23H—GRATES; CLEANING OR RAKING GRATES
    • F23H1/00—Grates with solid bars
    • F23H1/02—Grates with solid bars having provision for air supply or air preheating, e.g. air-supply or blast fittings which form a part of the grate structure or serve as supports
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23H—GRATES; CLEANING OR RAKING GRATES
    • F23H3/00—Grates with hollow bars
    • F23H3/02—Grates with hollow bars internally cooled
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23H—GRATES; CLEANING OR RAKING GRATES
    • F23H2900/00—Special features of combustion grates
    • F23H2900/03021—Liquid cooled grates

Definitions

  • the present invention relates to the field of incineration technology. It refers to a roller grate for an incineration plant, in particular for a waste incineration plant.
  • Roller grates consist of a plurality of rollers which are arranged axially parallel directly one behind the other and which rotate slowly and codirectionally.
  • the waste is fed onto the uppermost grate roller and, as a result of the rotation of the grate rollers, is transported and circulated through the drying, ignition, main incineration and burn-out zones.
  • An angle of inclination of the grate rollers of 20°, 25° or 30° to assist the conveying mechanisms is customary.
  • Each roller has a carrying structure consisting essentially of a drivable hollow shaft on which radial holders for carriers are fastened peripherally. The carriers are arranged so as to run parallel to the axis of the roller.
  • This carrying structure is provided with a grate covering which consists of numerous circularly arcuate grate bars fastened to the carriers. These grate bars form the outer surface of the rollers. They are, as a rule, lined up with respect to the circumference in 10 rows. A gap, through which the primary air enters the furnace space, is located in each case between the grate bars. Below the rollers are arranged funnels, into which, on the one hand, the primary air is fed and in which, on the other hand, the grate screenings are intercepted. The primary air entering through the gaps between the grate bars has the additional task of cooling the grate bars adjacent to the gap.
  • DE 199 52 198 A1 discloses a grate roller for a roller grate of a waste incineration plant, in which all the grate bars of the grate roller are provided with orifices in the head and are pushed, largely free of gaps, onto the carrier with their side faces lying next to one another.
  • the orifices are preferably incorporated as edge recesses into the side faces of the grate bar head. An improved air distribution on the roller grate is thereby achieved.
  • Plants with roller grates are usually equipped with additional burners in the combustion chamber which are in operation while the plant is being started up.
  • additional burners in the combustion chamber which are in operation while the plant is being started up.
  • an extremely high thermal load on the roller grate occurs when the plant is being started up. This is manifested, inter alia, in that the expansions of the entire structure which are caused thereby may ultimately lead to the blockage of the rotational movement of the rollers. Since the roller movement must be maintained without fail, blockage can be counteracted by an increased supply of primary air. However, an increased primary air stream makes it more difficult to reach the required minimum temperature in the first pass.
  • DE 699 10 783 T2 discloses a grate device with a grate element and with a rotatable shaft arrangement connected to the latter, the grate element, on the one hand, comprising a carrier device which is connected nonrotatably to the shaft arrangement and, on the other hand, comprising a plate device which is attached to the carrier device and forms a grate region.
  • the grate element has a first system of lines for the circulation of liquid coolant, and the shaft arrangement has a second system of lines for the circulation of liquid coolant, the carrier device containing part of the first system of lines, and this part being connected to the second system of lines.
  • the plate device of the grate element contains the remaining part of the first system of lines for cooling.
  • WO 96/29544 discloses an incineration grate which is both gas-scavenged and liquid-scavenged completely or partially via a control loop.
  • this document mentioned describes the invention in terms of a thrust-type grate, it nevertheless at the same time discloses that it can also be used for other grate designs, for example for a roller grate.
  • This grate is suitable for the incineration of waste with a high, but also with a low calorific value.
  • An object of the present invention is to develop a grate covering, consisting of a multiplicity of grate bars, for a roller grate and also a roller grate, on which waste with a high calorific value can easily be incinerated and which is distinguished by high wear resistance.
  • the present invention provides a grate covering for a roller grate having grate bars with a cavity through which a liquid cooling medium, preferably water, can be conducted.
  • a liquid cooling medium preferably water
  • the present invention also provide a roller grate, wherein each roller has, on the side facing away from the roller drive, a rotary lead-in which contains a supply line and a discharge line for the supply and discharge of liquid coolant.
  • a rotary lead-in which contains a supply line and a discharge line for the supply and discharge of liquid coolant.
  • Two annular chambers are arranged inside each roller, on the one hand the first annular chamber being connected to the supply line and the second annular chamber being connected to the discharge line of the liquid coolant, and, on the other hand, a plurality of separate and parallel-connected sublines for the coolant being branched off from the first annular chamber and being combined again in the second annular chamber.
  • a subline is assigned in each case two series-connected grate bar rows lying opposite one another.
  • the inflow and the outflow for the coolant is arranged on that roller side on which the rotary lead-in is arranged.
  • a reversal of the flow direction of the coolant with respect to the roller axis is provided on the opposite roller side from the exit from the first grate bar row to the entry into the opposite grate bar row.
  • the liquid cooling medium absorbs the heat flow from the furnace space to the grate bar and thus lowers the operating temperature of the grate bar, so that a relatively cold surface of the rollers is obtained, the entire grate structure being cooled as a result of radiant exchange with this relatively cold roller surface. Consequently, thermally induced expansions of the grate structure are minimized, and the wear of the grate covering is lowered, even at high incineration temperatures, such as occur, for example, during the incineration of fuel having a high calorific value.
  • the grate bars are produced as a casting and in each case have an inlet and an outlet for the coolant and a straight, serpentine or spiral cooling duct, and the grate bars are fluidically connected in series in such a way that the coolant outlet of the first grate bar is connected to the coolant inlet of the adjacent grate bar. Effective cooling can thereby be achieved.
  • the grate bars have a width such as to achieve a roller spacing system of 500 mm. This spacing amount which is conventional for roller grates ensures the retrofittability of existing grates.
  • connection of the coolant outlet of the first grate bar to the coolant inlet of the adjacent grate bar takes place with the aid of a hose connection, the hose connection consisting of two hose halves which are connected centrally via a screw connection.
  • the screw connection is completely encased, and the hose connection is completely covered by means of a protective plate.
  • both the screw connection and the entire hose are completely covered and protected against grate screenings.
  • the grate bar is provided on is underside with ribs, because this ensures the necessary strength.
  • orifices for the supply of primary air which preferably have a circular cross section, may be arranged in a grate bar. Additional cooling of the grate bars consequently becomes possible.
  • FIG. 1 shows a section through a diagrammatically illustrated roller grate of an incineration furnace according to the known prior art
  • FIG. 2 shows a cross section through a diagrammatically illustrated grate covering according to the invention for a roller grate
  • FIG. 3 shows a longitudinal section through a diagrammatically illustrated grate covering according to the invention for a roller grate
  • FIG. 4 shows a cross section through the grate roller according to the invention along the line IV-IV according to FIG. 5 ;
  • FIG. 5 shows a longitudinal section through a roller grate according to the invention.
  • FIGS. 1 to 4 The invention is explained in more detail below by means of an exemplary embodiment and FIGS. 1 to 4 .
  • FIG. 1 shows a section through a diagrammatically illustrated roller grate according to the known prior art.
  • the roller grate 1 consists of a plurality of rollers 2 which are arranged axially parallel directly one behind the other and which rotate slowly and codirectionally.
  • the waste is fed onto the uppermost grate roller and as a result of the rotation of the rollers 2 is transported and circulated through the drying, ignition, main incineration and burn-out zones of the furnace space 3 of a waste incineration furnace.
  • the rollers 2 are arranged at a specific angle of inclination, for example 25°.
  • Each roller 2 has a carrying structure 4 consisting essentially of a drivable hollow shaft on which radial holders for carriers are fastened peripherally.
  • the carriers are arranged so as to run parallel to the axis 5 of the roller 2 .
  • the carrying structure 4 is provided with a grate covering which consists of numerous circularly arcuate grate bars 6 fastened to the carriers. These grate bars 6 form the outer surface of the rollers 2 . They are, as a rule, lined up with respect to the circumference in 10 grate bar rows. Between the grate bars 6 is located in each case a gap through which the primary air enters the furnace space 3 . Below the rollers are arranged funnels 7 , into which, on the one hand, the primary air is fed and in which, on the other hand, the grate screenings are intercepted. The primary air entering through the gaps between the grate bars 6 have the additional task of cooling the grate bars 6 adjacent to the gap.
  • FIG. 2 illustrates a sectional illustration (cross section) of an exemplary embodiment of a grate bar 6 according to the invention.
  • FIG. 3 shows a longitudinal section through the grate bar 6 according to the invention. The two figures are advantageously to be referred to simultaneously in order to understand the invention.
  • the grate bar 6 is a casting which is mounted on the carrying structure 4 of the roller 2 , of which only a segment is illustrated in FIG. 2 .
  • the grate bar 6 is designed as a hollow body, that is to say it has inside it a cavity 8 ( FIG. 2 ) or a cooling duct 9 ( FIG. 3 ), through which a liquid cooling medium, preferably water, is conducted during the operation of the roller grate 1 .
  • Each grate bar 6 possesses an inlet 10 and an outlet 11 for the cooling medium.
  • the grate bars 6 of a grate bar row are fluidically connected in series, so that in each case the outlet 11 for the coolant from one grate bar 6 is connected to the inlet for the coolant 10 of the adjacent grate bar 6 .
  • the cooling duct 9 may be designed differently, for example so as to be straight, serpentine or else spiral.
  • the liquid coolant absorbs the heat flow from the furnace space 3 to the grate bar 6 and thus markedly lowers the operating temperature of the grate bar 6 .
  • the grate bars 6 cooled by means of liquid coolant thus give rise to an overall relatively cold surface of the rollers 2 .
  • the entire grate structure is cooled by radiant exchange with this relatively cold roller surface.
  • thermally induced expansions of the grate structure are minimized, and the wear of the grate covering is lowered, even at high incineration temperatures, such as occur, for example, during the incineration of fuel having a high calorific value.
  • the width of the grate bars 6 is advantageously selected such that a roller spacing of 500 mm is achieved. This conventional spacing amount ensures the retrofittability of existing roller grates.
  • the connection of two grate bars 6 in terms of the coolant is implemented via a hose connection 12 .
  • the advantage of this is that grate bar expansions and grate bar movements can thereby easily be compensated.
  • the hose connection 12 consists of two hose halves which are connected to one another in the middle via a screw connection 13 .
  • the grate bar 6 is designed such that the screw connection 13 of the two halves of the connecting hose 12 is completely encased after the two grate bars 6 have been pushed together. The screw connection is thereby protected with respect to the grate screenings.
  • the hose connection 12 is likewise protected against the grate screenings and consequently from damage in that it is completely covered ( FIG. 3 ) by a protective plate 14 mounted on the underside of the grate bar 6 .
  • the latter is provided with ribs 15 on its underside ( FIG. 3 ).
  • orifices 16 of preferably circular cross section which serve for the supply of primary air, may be arranged additionally in the grate bar 6 .
  • An additional cooling action can consequently be achieved.
  • the supply of primary air also takes place through defined gaps 28 ( FIG. 3 ) between two adjacent grate bars 6 .
  • FIGS. 4 and 5 show diagrammatically the rollers 2 according to the invention in a cross section ( FIG. 4 ) and in a longitudinal section ( FIG. 5 ).
  • the rollers are equipped circumferentially with 10 grate bar rows.
  • the coolant is supplied to and discharged from each roller 2 by means of a rotary lead-in 17 .
  • the rotary lead-in 17 is arranged on that side of the roller 2 which faces away from the roller drive 18 .
  • the rotary lead-in 17 has a supply line 19 and a discharge line 20 for the supply and discharge of a liquid coolant.
  • Two annular chambers 21 , 22 are arranged inside each roller 2 , on the one hand the first annular chamber 21 being connected to the supply line 19 and the second annular chamber 22 being connected to the discharge line 20 (or exactly conversely) for the liquid coolant, and, on the other hand, a plurality of, specifically in the present exemplary embodiment 5 , separate and parallel-connected sublines 23 for a part stream 25 of the coolant being branched off from the first annular chamber 21 and being combined again in the second annular chamber 22 .
  • a subline 23 for a part stream 25 of the coolant is in each case assigned two grate bar rows lying opposite one another. These two grate bar rows are connected in series.
  • the part streams 23 of two adjacent grate bar rows 26 and 27 may be contradirectional (as illustrated in FIG. 4 ) or codirectional.
  • the inflow and outflow of the coolant are arranged on that roller side on which the rotary lead-in 17 is arranged.
  • the cooling stream is conducted from the outlet from the grate bar row to the inlet of the opposite grate bar row, at the same time with a reversal 24 of the flow direction with respect to the roller axis 5 .
  • the 5 sublines 23 are combined in the annular chamber 22 downstream of the outlet of the second grate bar row and leave the inside of the rollers 2 in the discharge line 20 by means of the rotary lead-in 17 .

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Incineration Of Waste (AREA)
  • Rollers For Roller Conveyors For Transfer (AREA)
US11/423,187 2005-06-10 2006-06-09 Roller grate Abandoned US20070006786A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH00987/05A CH697973B1 (de) 2005-06-10 2005-06-10 Rostwalze.
SE00987/05 2005-06-10

Publications (1)

Publication Number Publication Date
US20070006786A1 true US20070006786A1 (en) 2007-01-11

Family

ID=34975018

Family Applications (1)

Application Number Title Priority Date Filing Date
US11/423,187 Abandoned US20070006786A1 (en) 2005-06-10 2006-06-09 Roller grate

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US (1) US20070006786A1 (de)
CH (1) CH697973B1 (de)
DE (1) DE102006024632A1 (de)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE202010016603U1 (de) 2010-12-15 2011-02-17 Dörrenberg Edelstahl GmbH Innengekühlter Roststab
SI2751488T1 (en) * 2011-09-01 2018-08-31 Ernst Schenkel Grill for burning solid material
WO2020009620A1 (ru) * 2018-07-03 2020-01-09 Александр Петрович СЕМЕНИХИН Колосник

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2501763A (en) * 1945-03-26 1950-03-28 Charles T Denker Solid fuel furnace of the rotary grate progressive feed type
US4224926A (en) * 1978-09-15 1980-09-30 Solar Unlimited, Inc. In-line manifold solar heat collectors
US5042401A (en) * 1990-06-04 1991-08-27 Westinghouse Electric Corp. Water cooled rolling grate incinerator
US5057011A (en) * 1989-05-25 1991-10-15 Fours Picard Furnace grate roller namely for incinerating refuse with a tubular casing formed by rings of bars separated by blow gaps of set width
US5899150A (en) * 1996-06-04 1999-05-04 Martin Gmbh Grate element and grate with fluid cooling
US6422161B2 (en) * 1995-03-23 2002-07-23 Theodor Koch Combustion grate and process for optimizing its operation

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE836386C (de) * 1949-12-25 1952-04-10 Peter Liebig Feuerungsrost mit drehbaren, den Brennstoff umwaelzenden und transportierenden Roststaeben
AU8607575A (en) * 1975-10-28 1977-05-05 Martin J J Dr Ing Firing grate with rotating roller
DE3316363A1 (de) * 1983-05-05 1984-11-08 Deutsche Babcock Anlagen Ag, 4200 Oberhausen Walzenrost fuer muellverbrennungsanlagen
DE19952198A1 (de) * 1999-10-30 2001-05-10 Bbp Environment Gmbh Rostwalze für einen Walzenrost

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2501763A (en) * 1945-03-26 1950-03-28 Charles T Denker Solid fuel furnace of the rotary grate progressive feed type
US4224926A (en) * 1978-09-15 1980-09-30 Solar Unlimited, Inc. In-line manifold solar heat collectors
US5057011A (en) * 1989-05-25 1991-10-15 Fours Picard Furnace grate roller namely for incinerating refuse with a tubular casing formed by rings of bars separated by blow gaps of set width
US5042401A (en) * 1990-06-04 1991-08-27 Westinghouse Electric Corp. Water cooled rolling grate incinerator
US6422161B2 (en) * 1995-03-23 2002-07-23 Theodor Koch Combustion grate and process for optimizing its operation
US5899150A (en) * 1996-06-04 1999-05-04 Martin Gmbh Grate element and grate with fluid cooling

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Publication number Publication date
CH697973B1 (de) 2009-04-15
DE102006024632A1 (de) 2006-12-28

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