Patent Application
20050072342
John N. Basic, Sr., in his U.S. Pat. Nos. 4,438,705, 4,475,469, 4,516,510, 4,706,578, 5,007,353, 5,209,169, and 5,413,715, has significantly advanced the science of refuse incineration and showed how to appropriately control the “three T's” of combustion, viz., time, temperature, and turbulence. In the first and third of these patents, Mr. Basic has disclosed methods and equipment for incineration that have achieved significant improvements in the efficiency of incinerating different types of refuse with the optional recovery of heat for further economic use. These two references establish three zones of combustion, make temperature measurements at significant locations, and alter the conditions of combustion to achieve the desired efficiency and ecological acceptability. Further, the patents accomplish their objectives while using bulk refuse, which simply means that it requires no processing before its introduction into the main combustion chamber. The system displays such versatility that it can adjust to remarkably different types of refuse and yet achieve environmentally sound incineration.
The principles related in these patents have such wide applicability that they do not even require refuse as a fuel. The discoveries find use in effectuating the combustion of hydrocarbon-containing fumes emanating from a generalized, undefined source. The patents specifically cover the use of the system for such fumes without the presence of a main incinerator chamber.
Where a main chamber finds use, however, the patents show improvements for this component of an incinerator system as well. These improvements include, first, a stepped hearth floor with air nozzles located in the vertical faces of the steps. As a separate consideration, the incinerator combustion chamber receives an approximately stoichiometric amount of oxygen for the chamber's burning contents, and the chamber's floor and volume bear general respective relationships to the heat content of the burning refuse. Separately, the air moving into the combustion chamber has an upper limit to its entering velocity to avoid lifting unburned particles of refuse. Alternately, various dimensions of the chamber's wall bear specific relationships to each other for improved incineration.
In the second and fourth patents listed above, Mr. Basic showed how to convey material sitting on a floor, most likely a hearth floor in a main incinerator chamber. The patents disclose nonsinusoidal motion of the hearth or floor that actually pulses the material forward. The motion of the floor closely resembles the activity of shoveling snow or other material. In addition to imparting a general progression of the material, especially burning refuse, the pulsing motion accelerates and decelerates and thus also jostles the mass of refuse vigorously to increase the burning rate and effectiveness.
The first four patents of Mr. Basic discussed above established an entirely new regiment for the incineration of refuse. They gave the essential conditions for the incineration of the waste and showed how to move bulk refuse through the main combustion chamber to facilitate the process. With these parameters established, Mr. Basic then set to work to refine and improve the system that he had developed. In the process, he increased the sophistication of his incinerator system by an order of magnitude and its ability to reliably handle different types of refuse from those even contemplated previously. The issuance of the last three patents above justly rewarded his subsequent efforts.
In the earliest of these three, Mr. Basic sets forth various incinerator improvements. Amongst-these appears the concept of splitting the reburn tunnel into two parallel reburn sections, each capable of performing the same functions on fumes emanating from a source such as the main combustion chamber. The versatility provided by two smaller reburn section dramatically increases the control over the three T's of combustion.
As a separate aspect, the patent places an “excitor” in the reburn tunnel. The excitor actually reduces the cross-sectional area in the center of the tunnel where the mass flow of the flue gas is located and forces the flume gasses to pass around it. The shortened distance between the gas molecules and a wall, be it the outer or the excitor wall, and the concomitant reradiation of heat give dramatically improved control over the three T's. The excitor may, in addition, provide nozzles introducing air into the tunnel for temperature and time control as well as assuring sufficient oxygen for complete combustion. Other aspects of the excitor include providing the air through the excitor's supports in the reburn tunnel and assuring that the excitor exterior has a low thermal conductivity to retain the generated heat. Additionally, the patent has shown that placing a damper at the outlet of the reburn tunnel gives even further control over the time (one of the three T's) of the combustion.
The next U.S. Pat. No. 5,209,169, covers an entirely new feature placed into the combustion chamber having a hearth floor. Specifically, the combustion chamber may include a grate located adjacent to the inlet door and above the hearth. This grate will hold waste having either a high moisture or a high B.T.U. content. In the former case, the material dries while on the grate. In the latter, some of the volatile hydrocarbons burn or are driven off to prevent overheating and possible slagging on the hearth floor. In either case, the fixed hydrocarbon refuse falls through the grate to undergo thorough combustion on the hearth below. The refuse may do so while it still contains over half of its combustible hydrocarbons. Alternately, the grate may have openings of a particular size to accomplish the stated objectives. A fluid passing through the grate, such as air or steam, may serve to cool the grate, and a refractory may serve to further protect the grate. When the grate has air passing through it, the gas may then directly enter the combustion chamber to enhance the combustion efficiency. Moving the grate can jostle its contents to permit the desired burning and encourage dried or partially burned refuse to fall through to the hearth underneath.
The latest U.S. Pat. No. 5,413,715 listed above relates to a scoop for taking ashes out of a pool of water after the incinerator places them there. The scoop travels along a track, and when it reaches the bottom, it closes so that it can grab the ashes. After travelling upward on the track, the scoop opens, and the ashes drop out into a receptacle of some sort, like a truck.
As seen from the above, the art and science of refuse incineration has advanced significantly under Mr. Basic's creativity and tutelage. As the recent history of incineration given above shows, each step forward opens new vistas for further improvements. A number of such advances appear below.
An incinerator typically has a substantially enclosed combustion chamber with an inlet for the introduction of refuse and an outlet for the egress of the products of combustion. The combustion chamber also has floor means for supporting refuse and wall means, located above the floor means and forming a substantially closed perimeter with the floor means. With the floor means, the wall means provides the substantially enclosed combustion chamber.
As discussed above with regards to John Basic's U.S. Pat. No. 4,475,469, the incinerator may also include some form of motion means, coupled to the floor means and the wall means. The motion means moves the floor means along a substantially predetermined path relative to the wall means. Some incinerators, however, move their “floors” along precise paths. One such system utilizes a “rotary kiln” type of arrangement. The rotating kiln may have a simple seal with the exterior wall since the rotary motion follows a precise path relative to the wall. The advantages of the Basic system and especially its pulsed hearth over this type of incinerator have received extensive discussion in various of the patents referenced above.
However, the path along which the moving means moves the floor means may show substantial deviations from the predetermined, desired path as in the Basic U.S. Pat. No. 4,475,469. These deviations may result from one or more of the pulsing bags proving less effective than it should or than the other bags. Or, the load on the hearth may lie towards one side more than the other. These and other factors may well produce actual pulsed motion showing substantial aberrations from the norm. Accordingly, the deviations from the desired path impose substantial burdens on any device incorporated into the incinerator that has the purpose of sealing the space between the floor means and the wall means against the passage of gas between them.
An improvement to the incinerator thus comprises a seal means, coupled to the wall means and the floor means and extending along at least a portion of the closed perimeter. The seal means must substantially prevent the passage of gas between the wall means and the floor means at the portion of the closed perimeter alluded to above when the motion means moves the floor means generally along its path relative to the wall means. The seal means should especially accomplish this task when the actual path followed by the floor means experiences substantial deviations from its predetermined path.
In particular, the seal means may comprise first a retaining means, coupled to one of the floor means and the wall means, for holding a substantially fluidized, nongaseous material. Secondly, the seal means would then include an emersion device, coupled to the other of the floor means and the wall means, and located at least in part, in the fluidized material as the floor means moves along its substantially predetermined path.
Alternately, the seal means may comprise a substantially flexible, gas-impervious, heat resistant web of material coupled to the floor means and to the wall means. As a further possibility, the seal means might incorporate a compressible, resilient substantially gas-impervious, heat-resistant pad of material retained between the floor means and the wall means.
As a further possibility, the seal means includes a flexible, gas-impervious, substantially form-retaining material, affixed to one of the floor means and the wall means and urged against the other of the floor means and the wall means to provide a friction seal as the floor means moves. This material may take the form of a sheet of substantially rigid, but somewhat flexible material such as stainless steel. A very different type of friction seal may constitute a bladder held on one of the surfaces and urged against the other. The bladder, for example, may contain air or some other fluid or a flexible, resilient substantially solid material.
As a separate aspect, the floor means may comprise first and second floor sections meeting along a substantially linear path. As before, the floor means supports burning refuse, A wall means, located above the floor means, along with the floor means provides the substantially enclosed chamber. In this instance, the motion means couples to the first and second floor sections and the wall means and moves the first and second floor sections relative to each other and along first and second substantially predetermined paths, respectively, relative to the wall means., Here the improvement comprises seal means which couples to the first and second floor sections and extends along at least a portion of the linear path. The seal means substantially prevents the passage of gas between the first and second floor sections at the portion of the linear path when the motion means moves the first and second floor sections relative to each other.
The seal means between the two sections of the floor means may take any of the forms described for the interface between the floor means and the wall means described above. In this case, a seal means relates (for example, couples) to one of the first and second floor sections, and, in a similar fashion, also relates to the other floor section in a fashion very similar to the seal means between the floor and wall means. The various types of particular seals may receive the labels of frictional seal, web seal, fibrous pad seal, and fluid seal. The frictional seal, in turn, includes the sheet metal seal and the bladder seal. Any or all of these may find use as the seal means between two moving floor sections.
In even more general terms, a system may comprise first and second surfaces meeting along a substantially linear path. A motion means, coupled to the first and second surfaces, moves the first surface along a substantially predetermined path relative to the second surface. An improvement to this system comprises seal means, coupled to the first and second surfaces and extending along at least a portion of the linear path. The seal means must substantially prevent the passage of gas between the first and second surfaces at its portion of the linear path where the first and second surfaces meet when the motion means moves the first surface relative to the second surface generally along the predetermined path. In particular, the seal means must accomplish this when the motion means actually causes substantial deviations in the motion of the two surfaces from the predetermined path.
Again, the particular types of seal means given above for the interface between the floor means and the wall means or between the two floor sections may find use between the first and second surfaces. As before, such a seal means relates (for example, couples) to one of the first and second surfaces and to the other surface as do the seal means between the floor and wall means or between the two sections of a floor means.
Additionally, the seal means, whether between a floor means and a wall, between two floor means sections, or between two surfaces, may make use of two or more different types of seal means enumerated above. Such combinations may include a fibrous pad seal with a fluid seal, a frictional seal, or a web seal. An additional example may take the form of a fluid seal with a web seal, with or without a fibrous pad seal. Further combinations may prove fruitful for various situations.
A moving hearth, to provide a complete enclosure around the combustion chamber, will require several sections of seals. Several will have a horizontal orientation. Others will follow a vertical line. A seal between two moving hearth, where that occurs, also lies along the horizontal. As a result, a complete enclosure may use different types of seal or combinations of seal depending upon the particular needs and requirements of each section of seal.
Employing an incinerator to burn refuse leads to an effort to improve the atmospheric quality in or around the unit itself. The incinerator may have a substantially enclosed combustion chamber with an inlet for the introduction of refuse and an outlet for the egress of the products of combustion. The chamber may also comprise floor means for supporting burning refuse and wall means, located above the floor means and forming a substantially closed perimeter with the floor means. Together, the wall means and the floor means provide the substantially enclosed chamber. A method of improving the atmospheric quality around or in the incinerator comprises moving the floor means along a substantially predetermined path relative to the wall means. The method further involves substantially preventing the passage of gas between the wall means and the floor means along at least a portion of the perimeter when the motion means moves the floor means generally along the path but with substantial deviations from the path.
In particular, substantially preventing the passage of gas between the wall means and the floor means may entail holding a substantially fluidized, nongaseous material on one of said floor means and said wall means along at least a portion of the perimeter between the floor means and the wall means. An emersion device is held to the other of the floor means and the wall means along the indicated portion of the perimeter, and located at least in part, in the material as the floor means is moved along its substantially predetermined path.
As an alternative to using an emersion system, a substantially flexible, gas-impervious, heat resistant web of material may be attached both to the floor means along at least a portion of the perimeter and to the wall means along the specified portion of the perimeter. Or, a compressible, resilient substantially gas-impervious, heat-resistant pad of material may be retained between the floor means and the wall means along at least a portion of the perimeter. A further choice of method affixes a sheet of substantially flexible, gas-impervious, form-retaining material to one of the floor means and the wall means along at least a portion of said perimeter; and urges this material against the other of the floor means and the wall means.
As discussed above, the floor means may comprise first and second floor sections meeting along a substantially linear path. Improving the atmospheric quality around or in this type of incinerator first comprises moving the first and second floor sections relative to each other and along first and second substantially predetermined paths, respectively, relative to the wall means. The passage of gas is substantially prevented between the first and second floor sections along at least a portion of the linear path when the motion means moves the first and second floor sections relative to each other
Stated in general terms, the method of improving the atmospheric quality on at least one side of first and second surfaces meeting along a substantially linear path comprises moving the first surface along a substantially predetermined path relative to the second surface. The method also comprises substantially preventing the passage of gas between the first surface and the second surface along at least a portion of the substantially linear path when the first surface moves generally along the predetermined path but with substantial deviations from the predetermined path relative to the second surface.
Again, the methods of improving the atmospheric quality on at least one side of two surfaces of in an incinerator with two floor section may adopt the particular techniques discussed above for an incinerator with an enclosed main chamber. Instead of a relationship with a wall means and a floor means, the particular methods here will consider either two sections of a floor means or two surfaces in general.
The actual method used at a specific location may combine two, three, or more of the techniques discussed above depending upon the conditions and requirements encountered and imposed there. Furthermore, a complete enclosure such as an incinerator chamber may well utilize different techniques at different sites of the equipment. Especially is this so where the relevant wall, floor, floor section or surfaces meet along a nonhorizontal line as opposed to a horizontal orientation. Naturally, sealing the juncture between two pulsing floor sections, such as hearths, may require different methods than between other surfaces.
On occasion, the combustion conditions of the incinerator may allow air to enter the main chamber through the space between the floor and the wall. This will permit the use of a positive air pressure to keep the gasses of combustion from leaking out into the environs especially in the case of a failure of the natural and induced drafts. In this case, the incinerator will comprise a substantially enclosed combustion chamber with an inlet for the introduction of refuse and an outlet for the egress of the products of combustion. Further the chamber will comprise floor means for supporting burning refuse and wall means, located above the floor means and forming a substantially closed perimeter with the floor means, for, with the floor means, providing the substantially enclosed chamber. An improved incinerator will comprise (a) containment means, coupled to the wall means and the floor means on the exterior of the substantially enclosed chamber and extending along at least a portion of the perimeter for holding an increased gas pressure. Specifically, the pressure that can be retained should exceed that (1) within the substantially enclosed chamber and (2) on the exterior of the substantially enclosed chamber. The improved incinerator will also comprise a seal means, coupled to the containment means, that will maintain the gas pressure within the containment means and at the portion of the perimeter at which the containment sits at a level greater than that (1) within the substantially enclosed chamber and (2) on the exterior of the substantially enclosed chamber. The increased air pressure will force air into the main chamber and keep combustion gasses from passing in the opposite direction into the incinerator's environs.
The increased air-pressure seal described above may also find use in combination with other types of seals previously mentioned. The presence of the other seals will actually result in a substantial blockage of and reduction in the amount of air entering the combustion chamber through the seal. In fact, the other types of seals may reduce the amount of air thusly introduced to minimal or even negligible levels.
The chamber may further include motion means such as the pulsing mechanism shown in Basic's U.S. Pat. No. 4,475,469, coupled to the floor means and the wall means. The motion means, as before, moves the floor means along a substantially predetermined path relative to the wall means. In this case, the seal means increases the gas pressure within the containment means and at the portion of the perimeter when the motion means moves the floor means generally along the predetermined path but with substantial deviations from that path.
Improving the atmospheric quality around an incinerator can also occur where the combustion chamber may, without excessive deleterious effects, accept outside air from a seal. In this case, the method involves a substantially enclosed combustion chamber with an inlet for the introduction of refuse and an outlet for the egress of the products of combustion. The chamber itself comprises floor means for supporting burning refuse and wall means, located above the floor means and forming a substantially closed perimeter with the floor means, for, with the floor means, providing the substantially enclosed chamber. The method of improving the atmospheric quality on the outside of the incinerator comprises increasing the gas pressure within a containment means, coupled to the wall means and the floor means on the exterior of the substantially enclosed chamber and extending along at least a portion of the perimeter. Specifically, the air pressure in the containment means should be increased to a level greater than that (1) within the substantially enclosed chamber and (2) on the exterior of the substantially enclosed chamber and at the portion of the perimeter. Naturally, the gas pressure should be maintained at this elevated level to force the gas into the chamber rather than the other way.
Again, many benefits result from moving the floor means along a substantially predetermined path relative to the wall means. Nonetheless, the gas pressure should be maintained at the increased level in the containment means when the motion means moves the floor means generally along the path but with substantial deviations from it.
While the refuse burns, it naturally releases heat energy. Part of this energy enters the water wall 78 to heat the fluid contained in it. The heated fluid from the membrane-tube water wall 78 may then travel along the conduit 88 to the boiler 79. Steam removed from the top of the boiler 79 may find constructive use elsewhere either in the incinerator 75 or elsewhere as in electrical generation or for heating.
The refuse, after completing its burning, falls from the second pulsed hearth 77 into the ash pit 89 which contains water. The scoop 90, pulled by the cable 91 attached to the motor 92, travels along the track 93. It then dumps the ashes into the hopper 94, and from there it falls into the bin 95.
The gaseous products of combustion pass from the main incinerator chamber 84 into the passageway 102. There, they join gasses from the raw refuse in the hopper 82, which under the action of the blower 103 travel along the conduit 104. This removes and will serve to destroy the foul aroma of the raw refuse.
The gasses from the passageway 102 then enter the first reburn stage 108. There, with the controlled assistance of the auxiliary fuel burner 109, if necessary, and the air fan 110, they continue to burn at an elevated temperature to destroy combustible moieties in the gas stream. As the incineration of the gaseous products of combustion proceeds, the gasses pass to the second reburn section 111 where they continue to burn. While doing so, they receive controlled amounts of additional air from the blower 112.
After the second reburn stage 111, the gasses could, if a problem existed in the system, escape through the safety relief stack 117. In normal operation, however, the damper 118 keeps the stack 117 closed, and the gasses travel to stage 4 of the system 121. There they receive the addition of cooled gasses from the conduit 122. The cooling of the combustion gas stream thus effected lowers its temperature below the point where various ingredients in the gasses, such as zinc, can exist in the vapor state. These components thus precipitate out in the cooling process and, accordingly, do not condense on the tubes of the boiler convection 79 when the combustion stream enters it. As the somewhat cooled gasses travel through the boiler 79, the give up additional heat for further useful purposes. As discussed in the first Basic U.S. Pat. No. 4,438,705 listed above, the first and second reburn stages 108 and 111 intervene between the water wall 78 and the boiler 79. This permits sufficient heat to remain in the gasses in the two reburn stages 108 and 111 to achieve full burning of the combustible elements of the gas stream.
After exiting the boiler 79, the gas stream enters the economizer 123. There, it preheats feed water that will find use in the boiler system of the water wall 78 and the boiler 79. Accordingly, the economizer saves further heat energy from the combustion process and feeds it back into the water that will pas through the system. This saved heat adds to the steam and electrical generation of the incinerator system 75.
From the economizer 123, some of the gas travels along the conduit 124 under the action of the blower 125. This gas, of course has given up much of its heat content in the boiler 179 and the economizer 123 and thus has a lower temperature then when it entered these latter components. Thus, after traveling along the conduit 122, it enters the stage 4 area 121 and lowers the temperature of the gas stream passing from the second reburn tunnel 111 as discussed above.
The remainder of the gas stream from the economizer 123 passes along the conduit 132 to the heat exchanger 133. The blower 134 passes outside air through the exchanger 133 to further cool the gas stream. At this point, the gasses have given up a substantial portion of their heat in the boiler 79 and in the economizer 123. However, the temperature of the gas stream may still remain above the vaporization temperature, or the dew point, of acids contained in it. The heat exchanger 133 reduces the temperature to a point, generally below about 400° F. where the acids in the gas stream actually condense into the liquid state. This allows their neutralization by combining with a base and their removal in subsequent treatment, as discussed immediately below.
The exhaust gasses then receive dry lime and activated carbon along the conduit 135 to neutralize the condensed acids and remove pollutants, respectively. The gas stream with these added materials then enters the baghouse filter and dry acid gas scrubber 138 which separates the gas from the particulate matter. The solid matter falls into the bin 141 where it awaits removal.
The cleaned gas from the baghouse 138 travels along the conduit 142. At this point, with actual refuse in an operating incinerator, no gas enters the exit conduit 142 from the conduit 143 because the motor 144 has closed the damper 145 to direct the combustion gasses into the baghouse 138.
The gasses in the conduit 142 are pulled by the induced-draft fan 148, and they escape into the atmosphere through the main exhaust stack 149. The continuous emissions monitor system 150 permits the evaluation of the discharge gasses for various combustion products possibly contained in the gasses exiting the stack 149. These could include the particulates, the carbon compounds, the nitrous oxides, the sulfur emissions, as well as others. The exact task of the monitor system 150 depends upon the particular case involved including such factors as the refuse undergoing incineration, the citing of the incinerator, and others.
During the startup operations, the incinerator 75 uses natural gas in its burners 85 and 109 to heat it to its operating temperature where it can start receiving actual refuse. During this warming time, the exhaust gas stream contains virtually no components that the baghouse 138 need remove. Under these limited conditions, the damper 1456 may fully open and allow exhaust gasses to bypass the baghouse 138 and pass through the conduit 143 directly to the conduit 142 and the exhaust stack 149. However, when the incinerator 75 has reached its operating temperature, the damper 145 closes, and the exhaust gas stream enters the baghouse 138 as described above.
However, many situations may indicate the desire or even need for a more positive seal than that afforded by positive air pressure alone. For instance, the positive pressure may introduce unacceptably high levels of air with the combustion area itself. Thus, a physical seal around the pulsed hearth may become appropriate. Such a seal, to prove effective, must accommodate the motion of the hearth as it moves through its pulsed motion. This becomes particularly important in light of the fact that the heath's motion may not be absolutely predictable. Thus, the air bags or other impelling device may not always produce exactly the same or even symmetric motion. Further, the placement of the refuse's weight may vary from load to load and cause substantial deviations of the hearth's motion from its norm.
As seen in
One type of positive seal, seen in
Accordingly, because of the urging resulting from the springiness of the metal strip 174, the bend 179 remains in contact with the hearth 158 as it moves through its range of motion. Of equal importance, the hearth 158 may, due to the factors listed above, have a slight side-to-side, or lateral, component of motion as it undergoes its pulsed motion. In other words, the hearth 158 may move slightly towards and away from the wall surface 176 as it is pulsed. Nonetheless, the springiness of the steel strip 174 accommodates this motion, and the strip's bend 179 remains in contact with the hearth 158 throughout its range of motion to provide a continuous positive seal.
As indicated above, the seal 173 provided by the steel strip 174 acts in two ways. First, it restricts, minimizes, and possibly prevents the gasses of combustion over the hearth 158 from entering the exterior environs of the incinerator. This, of course, has importance because the gasses in the main combustion chamber may prove particularly unhealthful for workers or others present near the incinerator. Especially is this the case where the incinerator sits within an enclosed room as often happens.
Second, the seal 173 restricts the passage of outside air into the incinerator. As the patents of John Basic listed above clearly establish, achieving thorough, environmentally acceptable burning of refuse involves the strict control of all factors of incineration both in the main chamber and in the reburn tunnels. This includes, in particular, the amount of air introduced into the main chamber; the locations from where the air enters the chamber; and the temperature of the air thusly introduced. The seal 173 serves to minimize air entering around the side of the hearth and deleteriously affecting the quality of the incineration occurring inside. This aspect of the seal 173 and the other varieties discussed below has especial significance in light of the fact that the main combustion chamber (as well as the reburn tunnels) should and usually do operate at a negative pressure compared to the surrounding environment. This negative pressure may result from a natural draft that accompanies burning or an induced draft when present. Either or both of these sources of draft (i.e., negative pressure in the main combustion chamber) assure the passage of the combustion gasses in the proper direction towards the stack. This draft would pull in air from around the hearth without the intervention of the seals discussed here and deleteriously affect the conditions of combustion.
On the other hand, a positive partial pressure may occasionally develop within the combustion chamber. This may result from the failure of any natural draft and the induced draft fan. Further, a “blooming” or rapid incineration of highly volatile materials within the refuse may cause a substantial increase in the pressure in the main chamber. Nonetheless, the positive seals discussed here can help prevent the gases within the combustion chamber from escaping to the exterior where they have the potential to effectuate substantial harm.
Similarly,
Greater details of a vertical, frictional sliding seal appear in FIGS. 12 to 14. There, the strip of spring sheet metal 223 has the short leg 224 which slides against the side of the hearth 225. The bolts 228 attach the strip 223 to the bracket 229 held by the bolts 230 to the post 231. The bracket 229 keeps the strip 223 against the side of the hearth 225.
As suggested above, the curved configuration of the strip 251 allows it in effect to provide two sliding frictional seals. The first seal occurs at the uppermost curved portion 252 where the strip 251 contacts the hearth 158. The second seal occurs at the lowermost curved portion 254 where the strip 251 slides along the stationery structure 253. Thus, the gasses of combustion sit in the area 259 where they cannot affect the external area 260 away from the combustion fire or the remaining structure of the strip seal itself. Additionally, squeezing the strip 251 between the hearth 158 and the stationery structure 253 helps assure a tight and sure seal. Specifically, the metal strip 251 of spring steel, with its curved structure, must be squeezed or flattened to fit in the space between the hearth 158 and the base structure 253. When finally placed in this location, the springiness of the steel attempts to undo the squeezing that allowed its placement in this location. This tendency of the steel strip 251 to return to its former configuration results in its pressing against the hearth 158 and the base 253 to provide the two seals mentioned above. As always with a sliding or friction seal, a dry lubricant, typically molybdenum disulfide, at the points of contact of the seal with the structures will extend the life of the seal and reduce required maintenance.
Further protection for the strip seal 174 appears in
The nozzle 264 receives its cooling fluid from the conduit 270 through the control valve 271. The valve 271 may simply operate manually, with the operator turning it on or off depending upon the incinerator's operation. When turned on, it provides a steady stream of the cooling fluid throughout the time that the incinerator remains in use. Alternately, the valve 264 may operate mechanically under the control of the radiating type of temperature sensor 272. When the sensor 272 determines that the temperature of the seal 174 has risen to a predetermined level, it causes the valve 264 to turn on to cool the seal 174. Otherwise, the valve 264 may remain closed. Alternately, the valve may simply open and shut intermittently such as about the time when the hearth 158 actually pulses. In any event, the fluid from the nozzle may also establish an air knife outside of the pulsing hearth 158 to provide a barrier to keep the combustion gasses on the fire side 267 of the incinerator and the air on the outside.
In
As shown in the drawing, ash 290 may accumulate on the furnace side 291 of the seal 284. When this occurs, the operator, with access to the components, may simply pull down on the springy metal strip 284 to let the ashes 290 fall though to the floor. Further, if the seal strip 284 may suffer some damage from the heat, corrosion, and the like, the operator may simply unscrew the bolt 286, remove the strip 284, and replace it with another one.
In
Alternately, the bag 295 could attach to the wall 297 and slide along the shelf 297. The type of bag shown in this figure and in the next
The baggy seal shown generally at 320 appears in
FIGS. 27 to 31 give diagrams for different types of water seals discussed in greater in the subsequent drawings. Accordingly,
The lower, ash-end, cross, horizontal water seal appears generally at 350 in
The external compression spring 373, anchored to the exterior wall 374, urges the water container 361 against the pulsed hearth 158. This urging along with the flexibility of the sides 362 and 364, the bottom 365, and their associated lips results in the sides, bottom, and lips acting as wiper blades against the hearth 158 and minimizing the passage and thus the loss of water between the container 361 along the hearth wall. Further, as the hearth 158 moves along its pulsed direction 162, the sides, bottom and lips function as wiper blades travelling across the surface of the hearth, again minimizing the loss of water.
However, in all likelihood, some water will escape from the container 361 especially during the movement of the hearth 158. To compensate for this leakage, the feed line 375 connects the container 361 to the reservoir 376. Water from the reservoir 376 replaces any water that may have leaked out of the container 361. Typically, a float or other device then makes sure that the water in the reservoir 376 stays at the level necessary to replace any water lost from the container 361.
As discussed before for other types of seals, a complete seal around the hearth 158 generally entails an enclosed perimeter of sections of seals such as those shown in FIGS. 27 to 31. Accordingly, an incinerator main chamber with a single pulsed hearth 158, to have a closed perimeter of water seals, will have a side, horizontal seal 327 (of
The above discussion may seem to suggest using water seals (or any one kind of seal) for all of the sections of a perimeter around the hearth. Thus, FIGS. 27 to 31 provide a water seal for all sections of the complete hearth seal. However, that need not be the case. In particular, as discussed above, the vertical water seal 360 shown in
Typically, the containers 328, 344, and 353, as well as the water trough discussed below, will have a composition of stainless steel to avoid corrosion from the incinerator combustion gasses. The same holds true for the blades 331, 342 and 351 as well as those in the following discussion. In particular, the combustion gasses may contain chlorine, a component of many plastics, for example. Chlorine, when it dissolves in water, produces hydrochloric acid. The stainless steel helps avoid the corrosive effect of the acid. To provide further protection, the water may contain an added base to neutralize the acid. If the combustion gasses should produce a base when dissolved, then the water in the troughs may include a neutralizing acid.
The water 329, 343, and 352 in the troughs 328, 344, and 353, respectively, provides a further important benefit. Specifically, it cools the blades 331, 342 and 351. These blades, during the operation of the incinerator, are exposed either directly or indirectly to the hot gasses of the incineration. This high-temperature environment could destroy the blades. The water cools the blades and helps avoid this destructive effect. The same remarks apply to the blades used in the water seals below. Other features of particular seals, such as heat resistant, fibrous pads may reduce this problem. However, the water does avoid the high temperatures that could harm or destroy the stainless steel blades.
The hold-down bar 386 then attaches the flexible, gas-impermeable web 387 to the underside 305 of the hearth 158 in a gas-tight manner. The web 387 may take the form of ⅛ inch thick combination Kevlar® and Nomex® aramid fabric manufactured by the DuPont Company of Wilmington, Del., or equivalent. Different bags such as rayon, fiber glass Goretex and others, especially those with low micron sieves, may suffice. Other thicknesses, more or less than that given above, may work as well. The bottom portion of the web 387 then sits in the water 381 to provide a gas seal between the furnace side 388 and the exterior 389. The very bottom of the web 387 wraps around the rod weight 390 to keep it in the water 381. As before, the bottom, horizontal cross seal 379 should align with the side, vertical seal 391 whatever form the latter may take.
The seal generally at 394 of
In
In
Accordingly, instead of water as the sealing medium, the trough 380 of
When the tubes 457 do provide air in the trough 380, they provide a fluid flow on the outside of the hearth 158. This can act as an air knife to help prevent the escape of combustion gasses from the furnace area 451 similar to the fluid streams of
An incinerator, as shown in
As seen from
For the upper hearth 158a, the seal provided by the blade 478 aligns with the vertical, side seal location shown by the dashed line 488. Similarly, for the lower hearth 158b, the seal 477 of the blade 485 aligns with the hearth's upper, side, horizontal seal indicated by the dashed line 489. And, the two blades 478 and 485 lie in the same horizontal plane as established by the seal line 489. These relative locations of these seals provide a closed perimeter and thus a continuous seal across the two pulsing hearths 158a and 158b.
Again, a high-temperature lubricant, usually molybdenum disulfide, between the pad 497 and the upper hearth 158a facilitates the motion of the former against the latter. The lubricant is typically sprayed on both the pad 497 and the steel plate 502. The pad 497 has a symbiotic relationship with the lubricant by protecting it against the heat of the combustion fire in the main chamber 504.
The pad 497 should have a composition resistant to the high temperatures and gasses generated in the incinerator environment 504. The fibrous pad 497 should display sufficient compressibility and resilience to fill the space 505 between the hearths 158a and 158b as their respective motions 162a and 162b causes that space to increase and decrease. Pads composed of matted fibers of alumina oxide, silicon oxide, or a mixture of the two in combination should work for this purpose.
The pad 497 serves to generally and largely isolate the water 493 from the incinerator's hot, caustic, and possibly damaging gas environment 504 which, in particular could damage the seal 485. In other words, it acts as a fire stop. In turn, since the pad 497 generally does not provide a complete seal, the water 493 can stop any gasses that could possibly escape through the pad 497. As discussed above and depending upon the refuse undergoing burning, the water 493 may provide an adequate seal without the pad 500. Similarly, the circumstances may permit the pad 497 to function as a complete seal, totally dispensing with the necessity for and presence of the water seal 490.
When the pad 497 provides the seal between the hearths 159a and 158b, the vertical seal for the former should fall along the line 506. This again provides a closed perimeter for a complete seal. Further, as suggested by this figure, a fibrous pad similar to the pad 497 itself can form the upper, loader-end, horizontal cross seal or the lower, ash-end, horizontal seal by itself or in conjunction with another type of seal such as a water seal.
The seal shown generally at 521 in
Additionally, the seal 521 includes the bag 523 held in place against the blades 478 and 485 by the support strips 525 and 526, respectively. The bag 523, in order to provide an effective seal, must completely envelop the blades 478 and 485. It should also display sufficient resilience to accommodate the motion of the hearths 158a and 158b in their pulsed motions 162a and 162b. Finally, the composition of the bag 523 should permit it to withstand the environment of the incineration area 486, or at least as much as may pass through the fibrous pad 522 when that item is included in the construction. The material mentioned as the bag 322 in
The seal 521 in
The upper hearth 158a receives isolating sealing from the loader-end cross seal and trough 537, the side, horizontal seal and trough 538a, the vertical side seal 539a, and the middle, horizontal cross seal and trough 540. Similarly, the sealing perimeter around the lower hearth 158b includes, again, the middle cross seal and trough 540, the side, horizontal seal and trough 538b, the side vertical seal 539b, and the lower, ash-end, horizontal, cross seal 541. All of the seals listed above interconnect and form a closed perimeter and thus a complete seal around the hearths 158a and 158b to isolate the incinerator's interior from its exterior. All of the seals except for the vertical seals 539a and 539b make use of water in a trough. The vertical seals 539a and 539b, as shown, employ some form of a frictional or bag seal discussed before. The interconnection of the water seals for the lower hearth 158b appears below in FIGS. 50 to 53. A similar pattern, albeit with somewhat shorter sides, works as well for the upper hearth 158a.
The interconnected trough system for the lower hearth 158b of
The water in the side troughs 546 and the cross trough 547 may flow freely from and into each other at the corners 548, one of which appears in
The hearth 158 of
As seen in
The pans 562 to 567, in
Other details of the horizontal, side seal appear in
The hearth in
FIGS. 61 to 65 illustrate the use of different media 623 in the trough 582 attached to the stationary structure 583. In the fashion discussed above, the insertion of the blade 556 in the medium 623 provides a horizontal, side seal. Regardless of its exact nature, the medium 623 should allow the hearth to travel through its pulsed, arcuate motion without damaging the trough 582, the blade 556, or the medium 623 itself. Furthermore, any of the media may well find use with any of the other seals set forth above such as the fibrous pad, the baggie, or both to form a multiple seal.
In any event,
The bubble-type material 635 and 636 such as pebbles, alumina, or silica, seen in
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/US03/02557 | Jan 2003 | WO | international |
The present application claims the priority of the PCT application PCT/03/02557 filed on Jan. 29, 2003, which, in turn, claimed the priority of the filing of the U.S. provisional patent application Ser. No. 60/353,850 filed on Jan. 29, 2002, of which the present application also claims the priority.
