CA1314447C - Apparatus for cleaning air ports of a chemical recovery furnace - Google Patents
Apparatus for cleaning air ports of a chemical recovery furnaceInfo
- Publication number
- CA1314447C CA1314447C CA000553213A CA553213A CA1314447C CA 1314447 C CA1314447 C CA 1314447C CA 000553213 A CA000553213 A CA 000553213A CA 553213 A CA553213 A CA 553213A CA 1314447 C CA1314447 C CA 1314447C
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- Canada
- Prior art keywords
- port
- cleaning head
- cleaning
- air port
- opening
- Prior art date
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Abstract
APPARATUS FOR CLEANING AIR PORTS
OF A CHEMICAL RECOVERY FURNACE
Abstract Removable apparatus for cleaning excrescent material from air ports in a chemical recovery furnace. A metal cleaning head having a cage-like configuration is pivotally mounted inside a wind box associated with the furnace to a frame adjacent an air port, and is adapted for insertion into the air port for cleaning the peripheral edges of the air port without blocking air flow through the port or obstructing the viewing path through the air port of sensing devices mounted exteriorly of the wind box. The frame to which the cleaning head is attached rests inside the wind box on the floor thereof, and is adjustably attached for positioning adjacent the air port to a mounting plate affixed to the outer wall of the wind box. The mounting plate pivotally carries an actuating cylinder which is coupled to the cleaning head by an actuating rod. The actuating cylinder moves the rod in a reciprocating cycle, first toward and then away from the cleaning head, causing the cleaning head to swing into the air port and clean char buildup along the edges thereof, and subsequently to withdraw from the air port. The rod and cylinder pivot freely by means of a mounting assembly attached to the mounting plate, as the cage swings into and out of the air port. The cleaning head incorporates a hook-like configuration which extends laterally inside the furnace above the upper edge of the air port where buildup of excrescent char is excessive.
In an alternate embodiment of the cleaning apparatus, the actuating cylinder is fixed to the mounting plate and the actuating rod moves in straight-line reciprocating motion which is translated to the cleaning head by a coupling mechanism, while maintaining an unobstructed view between the viewing port and the air port.
OF A CHEMICAL RECOVERY FURNACE
Abstract Removable apparatus for cleaning excrescent material from air ports in a chemical recovery furnace. A metal cleaning head having a cage-like configuration is pivotally mounted inside a wind box associated with the furnace to a frame adjacent an air port, and is adapted for insertion into the air port for cleaning the peripheral edges of the air port without blocking air flow through the port or obstructing the viewing path through the air port of sensing devices mounted exteriorly of the wind box. The frame to which the cleaning head is attached rests inside the wind box on the floor thereof, and is adjustably attached for positioning adjacent the air port to a mounting plate affixed to the outer wall of the wind box. The mounting plate pivotally carries an actuating cylinder which is coupled to the cleaning head by an actuating rod. The actuating cylinder moves the rod in a reciprocating cycle, first toward and then away from the cleaning head, causing the cleaning head to swing into the air port and clean char buildup along the edges thereof, and subsequently to withdraw from the air port. The rod and cylinder pivot freely by means of a mounting assembly attached to the mounting plate, as the cage swings into and out of the air port. The cleaning head incorporates a hook-like configuration which extends laterally inside the furnace above the upper edge of the air port where buildup of excrescent char is excessive.
In an alternate embodiment of the cleaning apparatus, the actuating cylinder is fixed to the mounting plate and the actuating rod moves in straight-line reciprocating motion which is translated to the cleaning head by a coupling mechanism, while maintaining an unobstructed view between the viewing port and the air port.
Description
1 3 1 ~ t/lr ~ ~
APPARATUS FOR CLEANING AIR PORTS
OF A CHEMICAL RECOVERY FU~NAC~
~ckground of the Invention Th~ pres~nt in~ention relat~ to furnace~ and par~icularly to apparatu3 for automatically cl~aning ports introducing co~bustion ~ir into the fire~ox of ~ ch~mical recovery furnace.
Wood pulp for papermaking i8 usually ~anufactured accord~ng to th* ~ulfate proc~3t wh~r~in wood chips ~re treated with a csoking liquor including ~odium sulfide ~nd ~odium hydroxide. ~he wood chips and the cooking liquor, call~d "white liquor," ~re oooked in a dige~t~r under predeter~in~d heat and to~p~rature conditions. After cooking, the u~ed liquor, ter~ed "black l~quor~ containing 3pent cooking chemical~
and ~oluble re~idue ro~ th~ eook, i8 washed out of the pulp and treated in a recov~ry unit wher~ th~
cooking chomicals are reclai~ed. Without reclamation and reu~e of th~ cooking chemical~, the eost of khe pap~rmaking proce~s would be prohibitive.
In the rocov~ry proc~3s, the black liquor i8 first conccntrat~d by ~v~poration ~o ~ water solution containing about 65 percent ~olid~, which ~olution i~ then ~prayed into th~ firebox of a blaek liquor recovery boiler, a type of che~lcal r~duction furnace. The che~ical r~duction ~urn~ce i~ a reactor wherein the proc~s~s of ~vaporation, gasif3cation, pyrolysi~, oxidation and reduction all occur interdependently during r~covery of the cooking che~ical~. The organic ~aterials in th~
black liquor, lignin and other wot~d e~tracts, maintain combustion in the fir~box, ~nd the hea~
.
13l~ 7 produced dri~s ~nd ~elts the spent cooking ch~micals as th~y fall to the floor of the firebox, wh~re th~y build a ~ound of ~aterial call~d a char b~d. The ~har ~d i~ further h~ated to further liquify the chemical~ into a ~olten ~elt th~t flow~ out of ~he furnace through a ~el~ ~pou~ to a collection tank. Concurr~ntly, coDbu~tion heat i~
employed to generate ~t~am in ~ water wall of th~
boil¢r for u~e as proce~s ~tea~ and for generating electricity.
The com~u tion proces~ require~ the introduction of large volu~es of air into the firebo~, air comprising ~bout 80 percent of the naterial 2ntering the furnace. ~he air iA forced into the fir~box from wind bQ~es or ducts di~po~ed at ~everal levels in surrounding relationship to the firebox, through a plurality of air port~ in the wall~ of th~ furnace, viz.: primary, ~econdary and tertiary air port~. The primary air ports, through which about 40 to 50 percent of the air ~nter~ the furnace, are disposed on the ~ide wall~
~f the firebox n~ar th~ bottom of the furnace close to the char bed. 1~e ~condary air ports, through which abouk 35 percent of the air ~nters the furnace, ar~ disposed around the walls of the fir~box, higher than the pri~ary air ports, ~nd below the entry conduit~ through which the bla~k liquor i~ sprayed into the fir~box. While the primary air port~ provide ~ rel~tiv~ly large volu~e of air wi~h considera~le turbulenc~ for ~a;ntaining a fireball in the char b~d, the ~condary air ports provide a finer control and distribution of air above ~h~ char b~d and distribute the air evenly in th~ black liquor ~pray to ~upport the co~bustion thereof.
3 131fl,J~
The black liquor sprayed into the firebox, having a consistency like warm 60 weight oil, swirls, burns and falls toward the bottom of the firebox as combustion products comprising char material and smelt. The smelt and char material contact the outer walls of the firebox and, cooled by the inflowing air, form excrescent deposits around edges of the air ports, par~icularly along the top edges of the secondary air ports where the excrescent material builds up and outward under influence of air rushing through the secondary air port. Such buildup of char material can block air flow through a port by as much as ten percent. In accordance with customary practice, the char buildup is periodically removed by a worker inserting a rod into the air ports successively around the boiler. With manual rodding of the air ports, gradual buildup of char material intermittently around the furnace causes changes in the volume of combustion air, as well as changes in air distribution, velocity and pressure.
Therefore, furnace operation tends to be inefficient and unpredictable with an attendant decrease in the amount of chemicals that can be recovered, a decrease in the amount of steam produced per unit of fuel, and increased emission of noxious gases such as carbon monoxide and sulfur dioxide.
Apparatus for cleaning openings in a recovery furnace are known - see my U.S. patent 4,423,533, entitled FURNACE AIR PORT CLEANER; however, such known apparatus is not always suitable for cleaning secondary air ports. Conventional punching devices, rods or cleaners inserted into the secondary air ports cannot dislodge the buildup of material above the top edge of the air port.
Monitoring devices such as pyrometers for sensing temperature inside the firebox and television cameras for viewing conditions in the furnace are often installed in the secondary air ports of recovery furnaces.
Heretofore it has been necessary to remove such devices in order to clean deposits of excrescent material which build up around the secondary air ports interiorly of the firebox.
It is accordingly an object of the present invention to provide improved apparatus for cleaning air ports of a chemical recovery furnace.
It is another object o~ the present invention to provide improved air port cleaning apparatus installable in an air port of a chemical recovery furnace without interference to a sensing device associated with the air port in which the cleaning apparatus is installed.
Another object of the present invention is to provide improved air port cleaning apparatus for increasing the operational stability of a black liquor recovery boiler.
It is a further object of the present invention to provide improved air port cleaning apparatus for enhancing the efficiency of chemical recovery, increasing steam production, and reducing sulfur dioxide and carbon monoxide emissions from a black liquor recovery boiler.
1 3 1 ~ ~7 4a Summary of the Invention According to a first aspect of the present invention there is provided apparatus for cleaning an opening of a firebox, said apparatus comprising a hook-shaped cleaning element having first and second ends, said cleaning element being pivotally mounted toward the first end thereof outside the firebox adjacent said opening and being adapted for rotational insertion of the second end into the firebox through said opening, the second end of said cleaning element when so inserted defining a locus sweeping inside the firebox vertically and substantially beyond an edge of said opening, and actuating means for inserting the second end of said cleaning element inside said opening to dislodge excrescent material inside the edge of said opening, and for subsequently retracting said cleaning element from said opening.
According to a second aspect of the present invention there is provided apparatus for cleaning a port introducing ai.r into a furnace, said furnace being provided with a wind box for supplying air under pressure to said port, said apparatus comprising a cleaning head ins0rtable through said port, means mounted in said wind box for pivotally mounting said cleaning head adjacent said port, and means mounted to said wind box and coupled to said cleaning head for moving a portion of said cleaning head so as to insert said portion through said port and inside said firebox vertically beyond the upper edge of said port, thereby contacting and :, ~ ' ~., .
4b 1 3 1 ~ 4 llr 7 dislodging excrescent material inside said upper edge, and for subsequently retracting said cleaning head from said port.
According to a third aspect of the present invention there is provided apparatus for cleaning an air port located in a wall of a firebox, said firebox being provided with a wind box supplying air under pressure to said air port, said wind box having an outer wall spaced apart from the wall of said firebox, said apparatus comprising a frame mounted in said windbox, a cleaning head pivotally attached to said frame adjacent said air port, means coupled to said cleaning head for moving said cleaning head into said air port in a manner such that a portion of the cleaning head extends vertically beyond the upper edge of said air port, for dislodging excrescent material along said upper edge, and for subsequently moving said cleaning head out of said air port, mounting means for attaching said frame to the outer wall of said wind box, said frame and said cleaning head being removable as a unit together with said mounting means from said wind box, said mounting means further comprising a mounting plate fastenable to the outer wall of said wind box, and means for supporting said moving means for reciprocating movement through said mounting plate.
In the preferred embodiment of the invention, furnace air ports are cleaned automatically by apparatus comprising a clean-ing head adapted for insertion through a port 1 'j 1 a,~ 7 and pivotally mounted to a fra~e adjacent to the port. The ~leaning head i~ ~oved into the air port and partially in~ide ~he fir~bo~ vertically beyond ~n edge of the air port to dislodge excrescent ~at~rial built up on the sdge. Means ar¢ provided for ~oving th~ clesning head into the port and for ~ub~uently retracting the cleaning head aft~r cleaning ha~ b~en acco~plished.
In a particular e~bodi~en~, ~ounting ~ean~ are provided for re~ovabl~ attachDent of ~he apparatu~
to an outer wall of a wind box, wherein the cleaning head actuating ~ean~ i8 ~oupl~d through the wind bo~ in ~ubstantial alignment with the air port and above an opening in the wind bo~ through which a Rensing ~ean~ det~ct~ condition~ in~ide the furnace through the air port, wi~hou~ obs~ru~ing the path through the wind box between the wind box op~ning and the air port.
In another embodi~nt of the inven~ion, ~ounting ~ean~ are provided ~or removable attach~ont to the outer wall of the ~ind box ~her~in the cleaning h~ad actuating me~n~ i8 ~upported for p~votal and reciprocating ~ovem~nt through th~ wind box wall and preferably include~ a fulcrum block for 31idably receiwing an actuating rod, and bearing ~ean~ for rotatably supporting the ~ulcrum block and providing an ~ir ~eal between the fulcru~ block ~nd the wall of the wind box.
In a~cordan~e with a particular zmbodi~ent o~
th~ invention, ~hield plates are provided on thç
cleaning app~ratus for insertion into th~ air port to protect boiler tubes located in~ide the furnace from danage due to contact by the ~oving cleaning head~
In another embodi~ent a~cording to th~ present 1 3 1 ~ 7 invention, the cleaning h~ad i~ construct~d as an open ~etal cage-like structure substantially the ~ize of th~ air port, 80 as to ~we~p along all the edge~ of the air port when in~erted therein to di~lodge e~crescent ~aterial or char buildup therefrom.
Th~ ~pparatus according to the pre~ent invention i~ ea~ily re~ovabl~ fro~ and adju~table with r~pect to the ~ir port. In particular, the apparatu8 i8 Dounted to the ~ternal wall of the wind bo~ and i~ ~lidably adjustable tow~rd the air port by way of adju~ting means e~t~riorly of the wind bo~. For repair or ~ervicing, the appara~us according to the present inv~ntion i~ ea~ily re~oved fro~ the wind box.
The ~pparatu~ according to the in~tant invention ic suitably operated at regular interval~
on an auto~atically ti~ed ba~ o as to keep the air port ~ubstantially clear of excrescent ~aterial, resulting in improved stability of furnace operation. Conaequently, ~ore ~fficient recovery of chemicals is realized as well as an increaso in ~tea~ production ~nd decrease in ~he ~mis#ion o pollutant gas~s. Whil2 only one apparatu~ according to the pre~ent inYention i8 illu~trated and described herein, it i~ under~tood that a plurality of ~uch apparatus are ordinarily disposed around a particular firebo~ 30 as to clean a co~paratively large number of air inlet~. Th0 ~eparate ~pparatus can be operated ~ither ~i~ultaneou~ly or sequentially.
While the invention is set ~orth with parti~ularity in the app~nded claims, other 7 1 3 1 ~ 7 objects, features, the organization and method of opera~ion of the invention will becom~ Dore appar~nt, and the inv~ntion will bost be und~r~tood by referring to the following detailsd de~cription in conjunction with the acco~panying drawings, in whioh:
FIG. 1 is a ~che~atic Yi2W of ~ portion of a black liqusr recov~ry boiler with which the present invention i8 e~ployed ~IG. 2 i a side olevation view of ~pparatus according to th~ in~tant invention:
FIG. 3 i8 an e~ploded perspecSive vi~w o portion of the FIG. 2 apparatus;
FIG. 4 is a per~pectiYe view o a cl~aning h~ad of apparatu~ according to he pre~ent invention;
FIG. 5 is a ~ide elevation view of a portion of apparatu~ a~cording to the present lnvention showing the cleaning head extended into an air port FIG~ 6 i~ ~ ~odified cros section, partially broken ~way, of apparatus according to the pre~ent invention, taken at 6-6 of FIG. 5;
FIG. 7 iB an exploded view of a mounting ~ean~
according to the pre~ent invcntion:
FIG. 8 i~ ~ tr~n~verse cro~s ~ection of the FIG. 7 ~ean~:
FIG. 9 i~ a plan view of an altern~te e~bodi~ent of cleaning apparatu~ in accordance with the present invention:
FIG. 10 is an end elevation vi~w of the apparatu~ of FIG. 9: and FIG. 11 is a side elevation view of the apparatus of FIG, 9.
1 3 1 lr /l l; 7 De~cri~ti_n f the Pr~ferred ~mbodiment Referring now to the various views of ~he drawing for a ~ore detail~d de~cription of the con~truction, function, operation and o her feature~ of the inætant inv~ntion by charact~rs o~
reference, ~IGo 1 ahows a black 1iquor recov~ry boiler 10 which comprises a firebox 12 of a atea~
boiler. Black liquor, an hereinbefore doscr~bed, i8 ~prayed into the firebo~ 12 through a conduit 14, where the organic ~aterial~ therein ~re ignited, the che~icals being deposited on ~he floor of th~ firebox a~ a char bed 16. A first wind box 18 ~ub~tantially ~urrounds the firebox 12 and delivers co~bu~tion air under pressure into the irebox through a plurality of pri~ary air ports 20 for~ed in the wall 22 of the firebox 12 around the periphery ther~of at the level of the char bed 16 to ~aintain a fireball in the char bed. A molten chemical-containing ~melt ~4 i~ recovered fro~ the burning char bed 16 ~hrough ~elt spouts 26 di~po~ed in the botton of the firebo~ 12, the ~elt b~ing coll~cted for furth~r treatment.
A second wind box 28 ~ubstantially ~urround~
the firebox 12 and d~liver~ coDbu~tion air under pres8ure into tho firebox ~hrough a plurality of ~econd~ry air port~ ~uch a~ air port 30 for~ed in the wall 22 of the firebox 12 around the p~riphery thereof above the char bed 16 ~nd below the levol of the bl~ck liquor entry conduit 14 for ~upporting th~ initial combuetion of the organic ~aterials in the black liquor. As previously d~3cribed herein, excrescent ~aterial 32 co~prising hardened ~Delt and char ~aterial forms on the wall~ 22 of the ~irebox, particularly above the edges vf ~he ~condary ~ir ports 30 as illu~trated in FXG. 1.
9 ~ 3 1 /L 1 1 7 In accordance with the present invention, apparatus 40 for cleaning the air ports 30 is attached to an outer wall 42 of the second wind box 28, and is adapted to clean the excrescent material 32 from the wall 22 of the firebox adjacent the air port 30. A sensing device 34 such as a pyrometer or a television camera for detecting conditions inside tihe firebox 12 may be mounted on the wind box 28, and may include an extendable rod-like sensing element 36 which extends through the wind box 28 to the air port 30. The apparatus 40 of the present invention is adapted ~o clean secondary air ports with such sensing devices installed.
Referring now to FIGS. 2-6 illustrating apparatus 40 in greater detail, the apparatus comprises a frame 44 having a base member ~6 resting on the floor 48 of the wind box 28 and constructed from a pair of steel bars 50, S2 disposed in parallel relation with each other, and joined spaced apart by cross members 54, 56. The base member 46 is attached by bolts 58, 60 to a mounting plate 62 coveriny an access opening 64 in the outer wall 42 of the wind box. The mounting plate 62 is attached by bolts 66 to a rectangular frame 68 suitably made from flat steel bar stock and welded to the hall 42 of the wind box 28 around the periphery of the access opening 64. The frame 44 further comprises a pair of stanchions 70, 72 attached to the base member 46 as by welding and supported by struts 74, 76 in parallel relationship with one another. The stanchions 70, 72, held spaced apart from'each other at the upper ends thereof by a $runnion 78, abut an exterior wall 80 of the firebox at the secondary air port 30 of the firebox. Rectangular guide plates 84, 86 attached to the stanchion~ by bolt~ 88 extend fro~ the upright ~tanchion~ through the air port 30 and into ~he boil~r, a~rving to guide the appar~tu~ 40 ints pQBitiOn adjacent the air port 30 upon installation in the ~ind bo~ 28, and to protect boiler tube3 90 fro~ da~age by ~oving part~ of the ~leanin~
apparatus, as explained hereinafter. Each of the guide plate~ 84, 86 includes an inwardly beveled area 92 on the outwardly facing ~urfa~e thereof to guide th~ plate through the air port 30.
A cleaning head 100 of th~ apparatus 40 co~pri~es a cage-like structure affixed as by weld~ng to a cylindrical sloeve 101 pivotally mounted to the frame 44 by trunnion 78 pa~ing through the ~l~eve 101. The cleaning head 100, configured as an open, generally polyh~dral cage, i8 adapted to pa88 rotatably through the rectangul~r air port 30 dislodging e~crescent ~aterial 32 fro~ around the edge~ of the air port as the cle~nin~ head 100 i~ in3erted and then withdrawn from the opening. The primary cle~ning f~ature o~ the cleaning head 100 i~ embodiod in a hook-lik~ i~plement 102 ~o~pri~ing a pair of arms 104, 106 e~tending in parall~l relation~hip from ~he trunnion 78 and a corre~ponding pair of bars 108, 110 depending from the arms 104, 106 at an acute ~ngle therewith, the bars 108, 110 b~ing ~paced æpart in parallel relation~hip by ~n end ~ros~ ~e~ber 112 at the ends of the bar~ 108, 110, and by a trunnion 114 near the ~un~ture of the bars ~nd the ar~ 104, 106. An actuating rod 116 i6 rotatably attached to the trunnion 114 by a ~leeve 118 to which the rod 116 i8 welded. Th~ ar~ 104, 106 extend beyond the bara 108, 110 and for~ side~
of quadrila~eral structure~ 120~ 122 including 1 3 1 l1r ~1 ~ 7 forward arms spaced apart by an optional cross member 124. The cross member 124 may be omitted to form a bifurcated cage-like structure, i.e., the region bet~een the quadrilateral structures 120, 122 being open in order to preclude interference by the cleaning head 100 with sensing elements which may be mounted inside the wind box. Alternatively, stiffening cross members may be located on the cleaning head 100 at other, non-interfering locations such as indicated by dashed lines at 126 in FIG. 4. The cleaning head 100 is suitably constructed of metal such as stainless steel.
Referring to FIGS. 2 and 3, the actuating rod 116 is connected pivotally and slidably through a mounting assembly 128 to an actuating cylinder 129, preferably an air operated cylinder, for slidably advancing the rod 116 toward the air port 30. It will be observed that advancing the rod 116 swings the cleaning head 100 forwardly on pivot 78 into the air port 30, the end of bar 108 (for examp].e) defining a locus indicated by the dashed line 130 so that the bar 108 contacts and dislodges the excrescent material 32. The rod 116 is provided with an adjusting means such as turnbuckle 132 for adjusting the length of the actuating rod 166 upon installation of the cleaning apparatus 40 in the wind box 28. The frame 44 of cleaning apparatus 40 is slidably positionable in the windbox 28 toward the air port 30 by turning the bolts 58, 60, which are conventionally threaded into bars 50, 52, for forcing bearing members 134, 135 welded, respec-tively, to bolts 58, 60, against mounting plate 62, thereby to move the frame 44 toward the air port 30.
Holes 136, 137 in the mounting plate 62, through which the bolts 58, 60 pass, are not threaded.
f~
. .
12 1 31 1-lr4~7 Referring to FIGS. 2, 7 and 8, the mounting assembly 128 for pivotally and slidably mounting the actuating rod 116 to the mounting plate 62 includes a housing 140 having a transverse bore 141, 142 through both side wa].ls 143, 144 thereof for receiving bearings 145, 146 mounted on a rotating cylinder 1~7, which acts as a fulcrum. The cylinder 147 is received slidably into a cylindrical sleeve 148 of T-shaped member 149, which includes a bore 150 perpendicular to the axis of the sleeve 148, which bore extends through the back wall 151 of the sleeve 148 for slidably receiving and supporting the rod 116. The cylinder 147 is adapted to receive the bearing 145 through which a bolt 153 extends for threadable engagement in an end of the cylinder 147. A lock washer 154 is suitably disposed between the head of the bolt 153 and the bearing 145. The housing 140 is also provided with a vertically elongated opening 155 through which the actuating rod 116 extends, and teflon seals 156, 157 in the rear corners of the housing. This construction provides an effective air seal for preventing the escape of any substantial amount of air from the wind box while allowing pivoting motion of the rod 116. The mounting assembly 128 is provided with a flange 160 integral with the T-shaped member 1~9 for attaching the cylinder 129 for movement therewith.
The cylinder 129 is thus free to pivot in the direction indicated by the arrows 166, FIG. 8, as the rod 116 effects eccentric motion in response to the cleaning head swinging into and out of the air port 30 during a cleaning cycle.
For the purpose of observing conditions inside the firebox, and for access to the firebox through the wind box 28, an access port 170 is provided.
qrD
1 31 llf~r~7 Referring to FIGS. 3 and 6, a frame 172, secured to the mounting plate 62 over a rectangular opening 174 (see FIG. 6), holds a pyrex glass plate 176 against the opening 174, providing a viewing port. The frame 172 may be swung open on pivot 178, or removed, to install a sensing device such as a pyrometer or a television camera (34 in FIG. I) in the opening 174.
Alternatively a camera or pyrometer may be mounted at a separate viewing port in mounting plate 62.
FIG. 2 illustrates the cleaning head 100 in an at-rest or retracted position, withdrawn from the air port 30. It will be observed that the temperature inside the firebox is normally much hotter than in the wind box where the cleaning head 100 normally resides and consequently the cleaning head is protected to a degree from the excessive temperature of the firebox except for a brief period of use. At timed intervals, e.g. about every thirty minutes, the cylinder 129 is actuated for swinging the cleaning head 100 into the air port 30 to the position as illustrated in FIG. 5. The cylinder 129 is then operated in the reverse direction for retracting the cleaning head 100 from the firebox back to its original at-rest position. It will be seen that when the cleaning head 100 is fully engaged into the air port 30 the end 112 of the hook-shaped implement of the cleaning head 100 rises substantially above the upper edge of the air port, while forward arms of the head sweep substantially the entire cross sectional area of the opening. It is also observed that access to the air port 30 from the access port 170 is unobstructed by the cleaning head 100.
Referring now to FIGS. 9-11, apparatus in accordance with an alternative embodiment of the ~.
:14 1~ 4l1~7 present invention comprises a frame 200, a cleaning head 202, and a mounting plate 204 substantially as previously described with reference to FIGS. 2-6. An actuating cylinder 206, preferably air operated, is affixed rigidly to the mounting plate 204 and to a planar mounting member 208 extending perpendicularly from the mounting plate 204. The actuating cylinder 206 is adapted to move actuating rod 209 by way of linkage 210 in reciprocating motion, first toward, and then away from the cleaning head 202, the rod 209 being mounted for said recip~ocating motion in roller assemblies 212, 214 affixed, respectively, to mounting plate 204 and mounting member 208.
A linkage assembly 216, which translates the reciprocating motion of the rod 209 to eccentric motion of the cleaning head 202, comprises a rectan-gular coupling yoke 218 affixed rotatably at one end thereof to the frame 200 by pivot 220. A connecting rod 222 is pivotally connected from the other end of the yoke 218 to the cleaning head 202, and a connect-ing link 224 connects the actuating rod 209 to the yoke 218. A viewing port 226 is provided through the mounting plate, and as with the previously described embodiment of the invention, a sensing device may be mounted thereto and a clear sight is maintained through the cleaning apparatus 200.
A plurality of units of the apparatus according to the present invention are ordinarily installed on a single firebox for the same boiler.
The operations of the units are timed by timing means, not shown, to be substantially completely automatic for inserting the cleaning heads periodically for quickly cleaning the air ports during furnace operation.
In addition to providing improved efficiency 1 31~q~
of boiler operation, the present invention enhances operating safety, not only in eliminating the need for manual cleaning, but also in stabilizing the char bed which reduces the danger of hot spots and boiler tube rupture.
In addition to performing a cleanin~ function, the cleaning head may alternatively or additionally be employed as a damper to control flow rate or velocity through the air port. For this purpose, the cage-like structure of the head is enclosed, and the frame 44 is partially or completely enclosed or walled in, so that, for a given position of the head, air flow tends to be closed off. The head may then be varied from this position to accomplish cleaning or to effect a differing air flow.
While the principles of my invention have now been made clear in the foregoing illustrative embodiments, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions, the elements, material and components used in the practice of the invention, and otherwise, which are particularly adapted for specific environments and operating requirements without departing from those principles. The appended claims are, therefore, intended to cover and embrace any such modifications, within the limits only of the true spirit and scope of the invention.
APPARATUS FOR CLEANING AIR PORTS
OF A CHEMICAL RECOVERY FU~NAC~
~ckground of the Invention Th~ pres~nt in~ention relat~ to furnace~ and par~icularly to apparatu3 for automatically cl~aning ports introducing co~bustion ~ir into the fire~ox of ~ ch~mical recovery furnace.
Wood pulp for papermaking i8 usually ~anufactured accord~ng to th* ~ulfate proc~3t wh~r~in wood chips ~re treated with a csoking liquor including ~odium sulfide ~nd ~odium hydroxide. ~he wood chips and the cooking liquor, call~d "white liquor," ~re oooked in a dige~t~r under predeter~in~d heat and to~p~rature conditions. After cooking, the u~ed liquor, ter~ed "black l~quor~ containing 3pent cooking chemical~
and ~oluble re~idue ro~ th~ eook, i8 washed out of the pulp and treated in a recov~ry unit wher~ th~
cooking chomicals are reclai~ed. Without reclamation and reu~e of th~ cooking chemical~, the eost of khe pap~rmaking proce~s would be prohibitive.
In the rocov~ry proc~3s, the black liquor i8 first conccntrat~d by ~v~poration ~o ~ water solution containing about 65 percent ~olid~, which ~olution i~ then ~prayed into th~ firebox of a blaek liquor recovery boiler, a type of che~lcal r~duction furnace. The che~ical r~duction ~urn~ce i~ a reactor wherein the proc~s~s of ~vaporation, gasif3cation, pyrolysi~, oxidation and reduction all occur interdependently during r~covery of the cooking che~ical~. The organic ~aterials in th~
black liquor, lignin and other wot~d e~tracts, maintain combustion in the fir~box, ~nd the hea~
.
13l~ 7 produced dri~s ~nd ~elts the spent cooking ch~micals as th~y fall to the floor of the firebox, wh~re th~y build a ~ound of ~aterial call~d a char b~d. The ~har ~d i~ further h~ated to further liquify the chemical~ into a ~olten ~elt th~t flow~ out of ~he furnace through a ~el~ ~pou~ to a collection tank. Concurr~ntly, coDbu~tion heat i~
employed to generate ~t~am in ~ water wall of th~
boil¢r for u~e as proce~s ~tea~ and for generating electricity.
The com~u tion proces~ require~ the introduction of large volu~es of air into the firebo~, air comprising ~bout 80 percent of the naterial 2ntering the furnace. ~he air iA forced into the fir~box from wind bQ~es or ducts di~po~ed at ~everal levels in surrounding relationship to the firebox, through a plurality of air port~ in the wall~ of th~ furnace, viz.: primary, ~econdary and tertiary air port~. The primary air ports, through which about 40 to 50 percent of the air ~nter~ the furnace, are disposed on the ~ide wall~
~f the firebox n~ar th~ bottom of the furnace close to the char bed. 1~e ~condary air ports, through which abouk 35 percent of the air ~nters the furnace, ar~ disposed around the walls of the fir~box, higher than the pri~ary air ports, ~nd below the entry conduit~ through which the bla~k liquor i~ sprayed into the fir~box. While the primary air port~ provide ~ rel~tiv~ly large volu~e of air wi~h considera~le turbulenc~ for ~a;ntaining a fireball in the char b~d, the ~condary air ports provide a finer control and distribution of air above ~h~ char b~d and distribute the air evenly in th~ black liquor ~pray to ~upport the co~bustion thereof.
3 131fl,J~
The black liquor sprayed into the firebox, having a consistency like warm 60 weight oil, swirls, burns and falls toward the bottom of the firebox as combustion products comprising char material and smelt. The smelt and char material contact the outer walls of the firebox and, cooled by the inflowing air, form excrescent deposits around edges of the air ports, par~icularly along the top edges of the secondary air ports where the excrescent material builds up and outward under influence of air rushing through the secondary air port. Such buildup of char material can block air flow through a port by as much as ten percent. In accordance with customary practice, the char buildup is periodically removed by a worker inserting a rod into the air ports successively around the boiler. With manual rodding of the air ports, gradual buildup of char material intermittently around the furnace causes changes in the volume of combustion air, as well as changes in air distribution, velocity and pressure.
Therefore, furnace operation tends to be inefficient and unpredictable with an attendant decrease in the amount of chemicals that can be recovered, a decrease in the amount of steam produced per unit of fuel, and increased emission of noxious gases such as carbon monoxide and sulfur dioxide.
Apparatus for cleaning openings in a recovery furnace are known - see my U.S. patent 4,423,533, entitled FURNACE AIR PORT CLEANER; however, such known apparatus is not always suitable for cleaning secondary air ports. Conventional punching devices, rods or cleaners inserted into the secondary air ports cannot dislodge the buildup of material above the top edge of the air port.
Monitoring devices such as pyrometers for sensing temperature inside the firebox and television cameras for viewing conditions in the furnace are often installed in the secondary air ports of recovery furnaces.
Heretofore it has been necessary to remove such devices in order to clean deposits of excrescent material which build up around the secondary air ports interiorly of the firebox.
It is accordingly an object of the present invention to provide improved apparatus for cleaning air ports of a chemical recovery furnace.
It is another object o~ the present invention to provide improved air port cleaning apparatus installable in an air port of a chemical recovery furnace without interference to a sensing device associated with the air port in which the cleaning apparatus is installed.
Another object of the present invention is to provide improved air port cleaning apparatus for increasing the operational stability of a black liquor recovery boiler.
It is a further object of the present invention to provide improved air port cleaning apparatus for enhancing the efficiency of chemical recovery, increasing steam production, and reducing sulfur dioxide and carbon monoxide emissions from a black liquor recovery boiler.
1 3 1 ~ ~7 4a Summary of the Invention According to a first aspect of the present invention there is provided apparatus for cleaning an opening of a firebox, said apparatus comprising a hook-shaped cleaning element having first and second ends, said cleaning element being pivotally mounted toward the first end thereof outside the firebox adjacent said opening and being adapted for rotational insertion of the second end into the firebox through said opening, the second end of said cleaning element when so inserted defining a locus sweeping inside the firebox vertically and substantially beyond an edge of said opening, and actuating means for inserting the second end of said cleaning element inside said opening to dislodge excrescent material inside the edge of said opening, and for subsequently retracting said cleaning element from said opening.
According to a second aspect of the present invention there is provided apparatus for cleaning a port introducing ai.r into a furnace, said furnace being provided with a wind box for supplying air under pressure to said port, said apparatus comprising a cleaning head ins0rtable through said port, means mounted in said wind box for pivotally mounting said cleaning head adjacent said port, and means mounted to said wind box and coupled to said cleaning head for moving a portion of said cleaning head so as to insert said portion through said port and inside said firebox vertically beyond the upper edge of said port, thereby contacting and :, ~ ' ~., .
4b 1 3 1 ~ 4 llr 7 dislodging excrescent material inside said upper edge, and for subsequently retracting said cleaning head from said port.
According to a third aspect of the present invention there is provided apparatus for cleaning an air port located in a wall of a firebox, said firebox being provided with a wind box supplying air under pressure to said air port, said wind box having an outer wall spaced apart from the wall of said firebox, said apparatus comprising a frame mounted in said windbox, a cleaning head pivotally attached to said frame adjacent said air port, means coupled to said cleaning head for moving said cleaning head into said air port in a manner such that a portion of the cleaning head extends vertically beyond the upper edge of said air port, for dislodging excrescent material along said upper edge, and for subsequently moving said cleaning head out of said air port, mounting means for attaching said frame to the outer wall of said wind box, said frame and said cleaning head being removable as a unit together with said mounting means from said wind box, said mounting means further comprising a mounting plate fastenable to the outer wall of said wind box, and means for supporting said moving means for reciprocating movement through said mounting plate.
In the preferred embodiment of the invention, furnace air ports are cleaned automatically by apparatus comprising a clean-ing head adapted for insertion through a port 1 'j 1 a,~ 7 and pivotally mounted to a fra~e adjacent to the port. The ~leaning head i~ ~oved into the air port and partially in~ide ~he fir~bo~ vertically beyond ~n edge of the air port to dislodge excrescent ~at~rial built up on the sdge. Means ar¢ provided for ~oving th~ clesning head into the port and for ~ub~uently retracting the cleaning head aft~r cleaning ha~ b~en acco~plished.
In a particular e~bodi~en~, ~ounting ~ean~ are provided for re~ovabl~ attachDent of ~he apparatu~
to an outer wall of a wind box, wherein the cleaning head actuating ~ean~ i8 ~oupl~d through the wind bo~ in ~ubstantial alignment with the air port and above an opening in the wind bo~ through which a Rensing ~ean~ det~ct~ condition~ in~ide the furnace through the air port, wi~hou~ obs~ru~ing the path through the wind box between the wind box op~ning and the air port.
In another embodi~nt of the inven~ion, ~ounting ~ean~ are provided ~or removable attach~ont to the outer wall of the ~ind box ~her~in the cleaning h~ad actuating me~n~ i8 ~upported for p~votal and reciprocating ~ovem~nt through th~ wind box wall and preferably include~ a fulcrum block for 31idably receiwing an actuating rod, and bearing ~ean~ for rotatably supporting the ~ulcrum block and providing an ~ir ~eal between the fulcru~ block ~nd the wall of the wind box.
In a~cordan~e with a particular zmbodi~ent o~
th~ invention, ~hield plates are provided on thç
cleaning app~ratus for insertion into th~ air port to protect boiler tubes located in~ide the furnace from danage due to contact by the ~oving cleaning head~
In another embodi~ent a~cording to th~ present 1 3 1 ~ 7 invention, the cleaning h~ad i~ construct~d as an open ~etal cage-like structure substantially the ~ize of th~ air port, 80 as to ~we~p along all the edge~ of the air port when in~erted therein to di~lodge e~crescent ~aterial or char buildup therefrom.
Th~ ~pparatus according to the pre~ent invention i~ ea~ily re~ovabl~ fro~ and adju~table with r~pect to the ~ir port. In particular, the apparatu8 i8 Dounted to the ~ternal wall of the wind bo~ and i~ ~lidably adjustable tow~rd the air port by way of adju~ting means e~t~riorly of the wind bo~. For repair or ~ervicing, the appara~us according to the present inv~ntion i~ ea~ily re~oved fro~ the wind box.
The ~pparatu~ according to the in~tant invention ic suitably operated at regular interval~
on an auto~atically ti~ed ba~ o as to keep the air port ~ubstantially clear of excrescent ~aterial, resulting in improved stability of furnace operation. Conaequently, ~ore ~fficient recovery of chemicals is realized as well as an increaso in ~tea~ production ~nd decrease in ~he ~mis#ion o pollutant gas~s. Whil2 only one apparatu~ according to the pre~ent inYention i8 illu~trated and described herein, it i~ under~tood that a plurality of ~uch apparatus are ordinarily disposed around a particular firebo~ 30 as to clean a co~paratively large number of air inlet~. Th0 ~eparate ~pparatus can be operated ~ither ~i~ultaneou~ly or sequentially.
While the invention is set ~orth with parti~ularity in the app~nded claims, other 7 1 3 1 ~ 7 objects, features, the organization and method of opera~ion of the invention will becom~ Dore appar~nt, and the inv~ntion will bost be und~r~tood by referring to the following detailsd de~cription in conjunction with the acco~panying drawings, in whioh:
FIG. 1 is a ~che~atic Yi2W of ~ portion of a black liqusr recov~ry boiler with which the present invention i8 e~ployed ~IG. 2 i a side olevation view of ~pparatus according to th~ in~tant invention:
FIG. 3 i8 an e~ploded perspecSive vi~w o portion of the FIG. 2 apparatus;
FIG. 4 is a per~pectiYe view o a cl~aning h~ad of apparatu~ according to he pre~ent invention;
FIG. 5 is a ~ide elevation view of a portion of apparatu~ a~cording to the present lnvention showing the cleaning head extended into an air port FIG~ 6 i~ ~ ~odified cros section, partially broken ~way, of apparatus according to the pre~ent invention, taken at 6-6 of FIG. 5;
FIG. 7 iB an exploded view of a mounting ~ean~
according to the pre~ent invcntion:
FIG. 8 i~ ~ tr~n~verse cro~s ~ection of the FIG. 7 ~ean~:
FIG. 9 i~ a plan view of an altern~te e~bodi~ent of cleaning apparatu~ in accordance with the present invention:
FIG. 10 is an end elevation vi~w of the apparatu~ of FIG. 9: and FIG. 11 is a side elevation view of the apparatus of FIG, 9.
1 3 1 lr /l l; 7 De~cri~ti_n f the Pr~ferred ~mbodiment Referring now to the various views of ~he drawing for a ~ore detail~d de~cription of the con~truction, function, operation and o her feature~ of the inætant inv~ntion by charact~rs o~
reference, ~IGo 1 ahows a black 1iquor recov~ry boiler 10 which comprises a firebox 12 of a atea~
boiler. Black liquor, an hereinbefore doscr~bed, i8 ~prayed into the firebo~ 12 through a conduit 14, where the organic ~aterial~ therein ~re ignited, the che~icals being deposited on ~he floor of th~ firebox a~ a char bed 16. A first wind box 18 ~ub~tantially ~urrounds the firebox 12 and delivers co~bu~tion air under pressure into the irebox through a plurality of pri~ary air ports 20 for~ed in the wall 22 of the firebox 12 around the periphery ther~of at the level of the char bed 16 to ~aintain a fireball in the char bed. A molten chemical-containing ~melt ~4 i~ recovered fro~ the burning char bed 16 ~hrough ~elt spouts 26 di~po~ed in the botton of the firebo~ 12, the ~elt b~ing coll~cted for furth~r treatment.
A second wind box 28 ~ubstantially ~urround~
the firebox 12 and d~liver~ coDbu~tion air under pres8ure into tho firebox ~hrough a plurality of ~econd~ry air port~ ~uch a~ air port 30 for~ed in the wall 22 of the firebox 12 around the p~riphery thereof above the char bed 16 ~nd below the levol of the bl~ck liquor entry conduit 14 for ~upporting th~ initial combuetion of the organic ~aterials in the black liquor. As previously d~3cribed herein, excrescent ~aterial 32 co~prising hardened ~Delt and char ~aterial forms on the wall~ 22 of the ~irebox, particularly above the edges vf ~he ~condary ~ir ports 30 as illu~trated in FXG. 1.
9 ~ 3 1 /L 1 1 7 In accordance with the present invention, apparatus 40 for cleaning the air ports 30 is attached to an outer wall 42 of the second wind box 28, and is adapted to clean the excrescent material 32 from the wall 22 of the firebox adjacent the air port 30. A sensing device 34 such as a pyrometer or a television camera for detecting conditions inside tihe firebox 12 may be mounted on the wind box 28, and may include an extendable rod-like sensing element 36 which extends through the wind box 28 to the air port 30. The apparatus 40 of the present invention is adapted ~o clean secondary air ports with such sensing devices installed.
Referring now to FIGS. 2-6 illustrating apparatus 40 in greater detail, the apparatus comprises a frame 44 having a base member ~6 resting on the floor 48 of the wind box 28 and constructed from a pair of steel bars 50, S2 disposed in parallel relation with each other, and joined spaced apart by cross members 54, 56. The base member 46 is attached by bolts 58, 60 to a mounting plate 62 coveriny an access opening 64 in the outer wall 42 of the wind box. The mounting plate 62 is attached by bolts 66 to a rectangular frame 68 suitably made from flat steel bar stock and welded to the hall 42 of the wind box 28 around the periphery of the access opening 64. The frame 44 further comprises a pair of stanchions 70, 72 attached to the base member 46 as by welding and supported by struts 74, 76 in parallel relationship with one another. The stanchions 70, 72, held spaced apart from'each other at the upper ends thereof by a $runnion 78, abut an exterior wall 80 of the firebox at the secondary air port 30 of the firebox. Rectangular guide plates 84, 86 attached to the stanchion~ by bolt~ 88 extend fro~ the upright ~tanchion~ through the air port 30 and into ~he boil~r, a~rving to guide the appar~tu~ 40 ints pQBitiOn adjacent the air port 30 upon installation in the ~ind bo~ 28, and to protect boiler tube3 90 fro~ da~age by ~oving part~ of the ~leanin~
apparatus, as explained hereinafter. Each of the guide plate~ 84, 86 includes an inwardly beveled area 92 on the outwardly facing ~urfa~e thereof to guide th~ plate through the air port 30.
A cleaning head 100 of th~ apparatus 40 co~pri~es a cage-like structure affixed as by weld~ng to a cylindrical sloeve 101 pivotally mounted to the frame 44 by trunnion 78 pa~ing through the ~l~eve 101. The cleaning head 100, configured as an open, generally polyh~dral cage, i8 adapted to pa88 rotatably through the rectangul~r air port 30 dislodging e~crescent ~aterial 32 fro~ around the edge~ of the air port as the cle~nin~ head 100 i~ in3erted and then withdrawn from the opening. The primary cle~ning f~ature o~ the cleaning head 100 i~ embodiod in a hook-lik~ i~plement 102 ~o~pri~ing a pair of arms 104, 106 e~tending in parall~l relation~hip from ~he trunnion 78 and a corre~ponding pair of bars 108, 110 depending from the arms 104, 106 at an acute ~ngle therewith, the bars 108, 110 b~ing ~paced æpart in parallel relation~hip by ~n end ~ros~ ~e~ber 112 at the ends of the bar~ 108, 110, and by a trunnion 114 near the ~un~ture of the bars ~nd the ar~ 104, 106. An actuating rod 116 i6 rotatably attached to the trunnion 114 by a ~leeve 118 to which the rod 116 i8 welded. Th~ ar~ 104, 106 extend beyond the bara 108, 110 and for~ side~
of quadrila~eral structure~ 120~ 122 including 1 3 1 l1r ~1 ~ 7 forward arms spaced apart by an optional cross member 124. The cross member 124 may be omitted to form a bifurcated cage-like structure, i.e., the region bet~een the quadrilateral structures 120, 122 being open in order to preclude interference by the cleaning head 100 with sensing elements which may be mounted inside the wind box. Alternatively, stiffening cross members may be located on the cleaning head 100 at other, non-interfering locations such as indicated by dashed lines at 126 in FIG. 4. The cleaning head 100 is suitably constructed of metal such as stainless steel.
Referring to FIGS. 2 and 3, the actuating rod 116 is connected pivotally and slidably through a mounting assembly 128 to an actuating cylinder 129, preferably an air operated cylinder, for slidably advancing the rod 116 toward the air port 30. It will be observed that advancing the rod 116 swings the cleaning head 100 forwardly on pivot 78 into the air port 30, the end of bar 108 (for examp].e) defining a locus indicated by the dashed line 130 so that the bar 108 contacts and dislodges the excrescent material 32. The rod 116 is provided with an adjusting means such as turnbuckle 132 for adjusting the length of the actuating rod 166 upon installation of the cleaning apparatus 40 in the wind box 28. The frame 44 of cleaning apparatus 40 is slidably positionable in the windbox 28 toward the air port 30 by turning the bolts 58, 60, which are conventionally threaded into bars 50, 52, for forcing bearing members 134, 135 welded, respec-tively, to bolts 58, 60, against mounting plate 62, thereby to move the frame 44 toward the air port 30.
Holes 136, 137 in the mounting plate 62, through which the bolts 58, 60 pass, are not threaded.
f~
. .
12 1 31 1-lr4~7 Referring to FIGS. 2, 7 and 8, the mounting assembly 128 for pivotally and slidably mounting the actuating rod 116 to the mounting plate 62 includes a housing 140 having a transverse bore 141, 142 through both side wa].ls 143, 144 thereof for receiving bearings 145, 146 mounted on a rotating cylinder 1~7, which acts as a fulcrum. The cylinder 147 is received slidably into a cylindrical sleeve 148 of T-shaped member 149, which includes a bore 150 perpendicular to the axis of the sleeve 148, which bore extends through the back wall 151 of the sleeve 148 for slidably receiving and supporting the rod 116. The cylinder 147 is adapted to receive the bearing 145 through which a bolt 153 extends for threadable engagement in an end of the cylinder 147. A lock washer 154 is suitably disposed between the head of the bolt 153 and the bearing 145. The housing 140 is also provided with a vertically elongated opening 155 through which the actuating rod 116 extends, and teflon seals 156, 157 in the rear corners of the housing. This construction provides an effective air seal for preventing the escape of any substantial amount of air from the wind box while allowing pivoting motion of the rod 116. The mounting assembly 128 is provided with a flange 160 integral with the T-shaped member 1~9 for attaching the cylinder 129 for movement therewith.
The cylinder 129 is thus free to pivot in the direction indicated by the arrows 166, FIG. 8, as the rod 116 effects eccentric motion in response to the cleaning head swinging into and out of the air port 30 during a cleaning cycle.
For the purpose of observing conditions inside the firebox, and for access to the firebox through the wind box 28, an access port 170 is provided.
qrD
1 31 llf~r~7 Referring to FIGS. 3 and 6, a frame 172, secured to the mounting plate 62 over a rectangular opening 174 (see FIG. 6), holds a pyrex glass plate 176 against the opening 174, providing a viewing port. The frame 172 may be swung open on pivot 178, or removed, to install a sensing device such as a pyrometer or a television camera (34 in FIG. I) in the opening 174.
Alternatively a camera or pyrometer may be mounted at a separate viewing port in mounting plate 62.
FIG. 2 illustrates the cleaning head 100 in an at-rest or retracted position, withdrawn from the air port 30. It will be observed that the temperature inside the firebox is normally much hotter than in the wind box where the cleaning head 100 normally resides and consequently the cleaning head is protected to a degree from the excessive temperature of the firebox except for a brief period of use. At timed intervals, e.g. about every thirty minutes, the cylinder 129 is actuated for swinging the cleaning head 100 into the air port 30 to the position as illustrated in FIG. 5. The cylinder 129 is then operated in the reverse direction for retracting the cleaning head 100 from the firebox back to its original at-rest position. It will be seen that when the cleaning head 100 is fully engaged into the air port 30 the end 112 of the hook-shaped implement of the cleaning head 100 rises substantially above the upper edge of the air port, while forward arms of the head sweep substantially the entire cross sectional area of the opening. It is also observed that access to the air port 30 from the access port 170 is unobstructed by the cleaning head 100.
Referring now to FIGS. 9-11, apparatus in accordance with an alternative embodiment of the ~.
:14 1~ 4l1~7 present invention comprises a frame 200, a cleaning head 202, and a mounting plate 204 substantially as previously described with reference to FIGS. 2-6. An actuating cylinder 206, preferably air operated, is affixed rigidly to the mounting plate 204 and to a planar mounting member 208 extending perpendicularly from the mounting plate 204. The actuating cylinder 206 is adapted to move actuating rod 209 by way of linkage 210 in reciprocating motion, first toward, and then away from the cleaning head 202, the rod 209 being mounted for said recip~ocating motion in roller assemblies 212, 214 affixed, respectively, to mounting plate 204 and mounting member 208.
A linkage assembly 216, which translates the reciprocating motion of the rod 209 to eccentric motion of the cleaning head 202, comprises a rectan-gular coupling yoke 218 affixed rotatably at one end thereof to the frame 200 by pivot 220. A connecting rod 222 is pivotally connected from the other end of the yoke 218 to the cleaning head 202, and a connect-ing link 224 connects the actuating rod 209 to the yoke 218. A viewing port 226 is provided through the mounting plate, and as with the previously described embodiment of the invention, a sensing device may be mounted thereto and a clear sight is maintained through the cleaning apparatus 200.
A plurality of units of the apparatus according to the present invention are ordinarily installed on a single firebox for the same boiler.
The operations of the units are timed by timing means, not shown, to be substantially completely automatic for inserting the cleaning heads periodically for quickly cleaning the air ports during furnace operation.
In addition to providing improved efficiency 1 31~q~
of boiler operation, the present invention enhances operating safety, not only in eliminating the need for manual cleaning, but also in stabilizing the char bed which reduces the danger of hot spots and boiler tube rupture.
In addition to performing a cleanin~ function, the cleaning head may alternatively or additionally be employed as a damper to control flow rate or velocity through the air port. For this purpose, the cage-like structure of the head is enclosed, and the frame 44 is partially or completely enclosed or walled in, so that, for a given position of the head, air flow tends to be closed off. The head may then be varied from this position to accomplish cleaning or to effect a differing air flow.
While the principles of my invention have now been made clear in the foregoing illustrative embodiments, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions, the elements, material and components used in the practice of the invention, and otherwise, which are particularly adapted for specific environments and operating requirements without departing from those principles. The appended claims are, therefore, intended to cover and embrace any such modifications, within the limits only of the true spirit and scope of the invention.
Claims (17)
1. Apparatus for cleaning an opening of a firebox, said apparatus comprising:
a hook-shaped cleaning element having first and second ends, said cleaning element being pivotally mounted toward the first end thereof outside the firebox adjacent said opening and being adapted for rotational insertion of the second end into the firebox through said opening, the second end of said cleaning element when so inserted defining a locus sweeping inside the firebox vertically and substantially beyond an edge of said opening; and actuating means for inserting the second end of said cleaning element inside said opening to dislodge excrescent material inside the edge of said opening, and for subsequently retracting said cleaning element from said opening.
a hook-shaped cleaning element having first and second ends, said cleaning element being pivotally mounted toward the first end thereof outside the firebox adjacent said opening and being adapted for rotational insertion of the second end into the firebox through said opening, the second end of said cleaning element when so inserted defining a locus sweeping inside the firebox vertically and substantially beyond an edge of said opening; and actuating means for inserting the second end of said cleaning element inside said opening to dislodge excrescent material inside the edge of said opening, and for subsequently retracting said cleaning element from said opening.
2. The apparatus according to claim 1 wherein said opening is rectangular, said cleaning element further comprising an arm extending therefrom substantially the length of said opening, said extending arm sweeping substantially the entire length of said opening.
3. The apparatus according to claim 2 wherein said cleaning element is bifurcated to allow visual access to said firebox through said cleaning element and said opening when said cleaning element is inserted therein.
4. The apparatus according to claim 2 wherein said cleaning element is in the form of an open, generally rectangular polyhedral cage to allow visual access to said firebox through said cleaning element and said opening when said cleaning element is engaged therein.
5. Apparatus for cleaning a port introducing air into a furnace, said furnace being provided with a wind box for supplying air under pressure to said port, said apparatus comprising:
a cleaning head insertable through said port;
means mounted in said wind box for pivotally mounting said cleaning head adjacent said port; and means mounted to said wind box and coupled to said cleaning head for moving a portion of said cleaning head so as to insert said portion through said port and inside said firebox vertically beyond the upper edge of said port, thereby contacting and dislodging excrescent material inside said upper edge, and for subsequently retracting said cleaning head from said port.
a cleaning head insertable through said port;
means mounted in said wind box for pivotally mounting said cleaning head adjacent said port; and means mounted to said wind box and coupled to said cleaning head for moving a portion of said cleaning head so as to insert said portion through said port and inside said firebox vertically beyond the upper edge of said port, thereby contacting and dislodging excrescent material inside said upper edge, and for subsequently retracting said cleaning head from said port.
6. The apparatus according to claim 5 wherein said port is rectangular and said cleaning head comprises a metal frame sweeping at least three peripheral edges of said rectangular port.
7. The apparatus according to claim 5 wherein said port is rectangular and said cleaning head comprises an open rectangular frame sweeping the peripheral edges of said port.
8. The apparatus according to claim 5 wherein said furnace includes boiler tubes located inside and abaxially of said port, said mounting means further including means insertable in said port for shielding said boiler tubes from contact by said cleaning head when said portion of said cleaning head is inserted into said port.
9. Apparatus for cleaning an air port located in a wall of a firebox, said firebox being provided with a wind box supplying air under pressure to said air port, said wind box having an outer wall spaced apart from the wall of said firebox, said apparatus comprising:
a frame mounted in said windbox;
a cleaning head pivotally attached to said frame adjacent said air port;
means coupled to said cleaning head for moving said cleaning head into said air port in a manner such that a portion of the cleaning head extends vertically beyond the upper edge of said air port, for dislodging excrescent material along said upper edge, and for subsequently moving said cleaning head out of said air port;
mounting means for attaching said frame to the outer wall of said wind box, said frame and said cleaning head being removable as a unit together with said mounting means from said wind box, said mounting means further comprising a mounting plate fastenable to the outer wall of said wind box, and means for supporting said moving means for reciprocating movement through said mounting plate.
a frame mounted in said windbox;
a cleaning head pivotally attached to said frame adjacent said air port;
means coupled to said cleaning head for moving said cleaning head into said air port in a manner such that a portion of the cleaning head extends vertically beyond the upper edge of said air port, for dislodging excrescent material along said upper edge, and for subsequently moving said cleaning head out of said air port;
mounting means for attaching said frame to the outer wall of said wind box, said frame and said cleaning head being removable as a unit together with said mounting means from said wind box, said mounting means further comprising a mounting plate fastenable to the outer wall of said wind box, and means for supporting said moving means for reciprocating movement through said mounting plate.
10. The apparatus according to claim 9 wherein said moving means includes means for translating the reciprocating motion of said moving means to eccentric motion.
11. The apparatus according to claim 9 wherein said supporting means includes means for supporting said moving means for pivotal movement with respect to said mounting means.
12. The apparatus according to claim 9 wherein said cleaning head comprises a hook-shaped member having first and second ends, the first end of the hook-shaped member being said portion of said cleaning head and the second end being attached to said frame, said moving means being pivotally attached to said hook-shaped member intermediate the first and second ends thereof.
13. The apparatus according to claim 9 wherein said frame and said cleaning head are each at least partially enclosed for restricting air flow according to the relative positions of said frame and head.
14. The apparatus according to claim 9 wherein said mounting plate includes an opening therethrough and means mounted in said opening for remotely sensing conditions inside said firebox through said air port, said opening being located below the level of said moving means and said cleaning head in a retracted position to provide a clear path between said opening and said air port.
15. The apparatus according to claim 14 wherein said air port is rectangular and said cleaning head comprises a metal frame sweeping at least three peripheral edges of said rectangular air port without blocking said clear path between said opening and said air port.
16. The apparatus according to claim 14 wherein said air port is rectangular and said cleaning head comprises an open rectangular frame sweeping the peripheral edges of said air port.
17. The apparatus according to claim 14 wherein said sensing means comprises a plate of glass for optically viewing the interior of said firebox.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000553213A CA1314447C (en) | 1987-12-01 | 1987-12-01 | Apparatus for cleaning air ports of a chemical recovery furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000553213A CA1314447C (en) | 1987-12-01 | 1987-12-01 | Apparatus for cleaning air ports of a chemical recovery furnace |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1314447C true CA1314447C (en) | 1993-03-16 |
Family
ID=4136978
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000553213A Expired - Fee Related CA1314447C (en) | 1987-12-01 | 1987-12-01 | Apparatus for cleaning air ports of a chemical recovery furnace |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1314447C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7735435B2 (en) | 2006-05-24 | 2010-06-15 | Diamond Power International, Inc. | Apparatus for cleaning a smelt spout of a combustion device |
-
1987
- 1987-12-01 CA CA000553213A patent/CA1314447C/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7735435B2 (en) | 2006-05-24 | 2010-06-15 | Diamond Power International, Inc. | Apparatus for cleaning a smelt spout of a combustion device |
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