US3199474A

US3199474A - Incinerator and method of operating the same

Info

Publication number: US3199474A
Application number: US286048A
Authority: US
Inventors: Bertram B Reilly
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-06-06
Filing date: 1963-06-06
Publication date: 1965-08-10
Anticipated expiration: 1982-08-10

Description

Aug. l0, 1965 B. B. REILLY INCINERATOR AND METHOD OF OPERATING THE SAME Filed June 6, 1965 INVENTOR.

BER TRA/W E. RE/LL Y A f orneys 3,199,474 EJCKNERATOR AND METHOD GF QPERAHNG THE SAME Bertram B. Reilly, 17 Briar Cliff Road, Pittsburgh 2, Pa. Filed .inne 6, 1963, Ser. No. 286,048 Claims. (Ci. iiD-8) This invention relates to an incinerator and method for operating the same, and, more particularly, to an incinerator with means provided for causing downdrafts of air through the grates intermittently with the production of updrafts.

The burning of refuse of municipalities presents many problems which must be resolved to effect economical land sanitary disposal of such waste. The combustion of refuse fuels is complicated by the seasonal variation of the type of trash to be burned, and the moisture content of the material which changes Widely from day-to-day because of rain, for example. Also, it may be appreciated that the moisture content of yard trash such as grass and shrubbery trimmings differs materially from that of discarded material for incineration during the winter months. In each instance it is important that the incinerator be capa-ble of burning economically the charge introduced, regardless of the range of moisture content of material to be treated.

In many plants it has become necessary to agitate manually the fuel bed or charge on the stoker grate to break up an undesirable insulating layer of ash and noncombustibles formed on the surface of the fuel bed. To achieve efiicient and complete combustion it has been contemplated to agitate the bed mechanically in order to expose layers of the bed beneath its insulating .surface to the heat of the furnace for burning. These known methods and plants, however, have not been totally successful in the accomplishment of economical and complete combustion of incinerator fuel.

The present invention overcomes the deficiencies of conventional incinerator stokers by the concept of increasing the temperature of refuse material on the grates, and particularly the subsurface material which is not eX- posed directly to radiation from the flames of the incinerator burners. By this concept the moisture content of the incinerator fuel is lowered and the temperature of the total quantity of fuel on the grate is raised to the kindling point. Control of the fuel bed temperature is maintained to avoid heat destruction of the Stoker grates.

It is an object of this invention to provide a new and improved incinerator.

Another object is the provision of an incinerator wherein downdrafts and updrafts of air through the stolcer grate may lbe effected selectively and regulated for raising and controlling the temperatures of the fuel bed on the grate to assure complete and eiiicient combustion.

A further object of the present invention is to provide an incinerator whereby material beds on grates may be temperature controlled to avoid overheating of the grates.

Still another object is to provide an incinerator with a stoker having grate sections with individual windboxes and with means for transferring the heated air within one windbox to another for more eiiicient combustion of material carried on the grate section of such other windbox.

A complete understanding of the invention may be had from the following detailed description of a specific embodiment thereof when read in conjunction with the appended drawing wherein the single figure is a longitudinal sectional view of the incinerator.

There is shown in the drawing an incinerator of the general type shown in my Patent 2,983,234, granted May 9, 196i, but as here shown there is a grate structure generally designated numeral 11 which includes an upper Patented Aug. 10, 1965 grate section 12 and a lower grate section 13 disposed to receive material discharged from the upper grate. Each of the grate sections may have mechanical conveying characteristics, for example, a reciprocating type grate, so that refuse introduced into the incinerator 14 by a charging ram and gate assembly 15 discharges into the incinerator combustion chamber Ztl and onto the upper grate section 12 where it is slowly conveyed while burning to the lower grate section 13 by which it is transported and unburned or unburnable residues are finally dropped into a quench tank 17. A drag conveyor 18 is provided in the tank for the removal of ash and noncombustibles `from the furnace. Exhaust gases from the furnace are directed through a scrubber 19 prior to vent- 'ing to the atmosphere from a stack not shown.

The grate sections 12 and 13 are arranged within the incinerator combustion chamber Ztl of the furnace 14 such that the chamber is divided by the grates longitudinally into two spaces, one above the grate sections designated 29a and the other lying below the sections and indicated by numeral Ztib. The space Ztb is further divided into

independent windboxes

21 and 22 which are defined by the grate sections 12 and 13, respectively, and by baffle plates 23, 2d, and 2S which are secured to and depend from the grate sections which bridge across the tops of the plates. The

windboxes

21 and 22 are sealed across their lower portions by a liquid 26 contained within the quench tank 17 which is disposed beneath the gratos such that the

baiiie plates

23, 24, and 25 extend below the liquid surface 27. As thus constructed, dierential pressures may be maintained under the grate sections covering the respective windboxes.

An air circulatory system 28 for forcing air selectively through the grate sections 12 and 13 and the material thereon is shown to include a fan 29 which forces combustion air from the atmosphere into a header 31. The header branches into a pipe 32, which opens into the windbox 21, and pipe 33, which opens into the windbox 22. A transfer conduit 34 is interconnected to the pipe 33 at a point intermediate the fan 29 and the windbox 22 and to the input of a transfer fan 35. The output of the latter fan forces the air drawn through the conduit 34 onwardly into the windbox 21 via a duct 3d.

For regulation of the tlow of air through the duct 36, pipe 33, and pipe 32

dampers

37, 38, and 39, respectively, are positioned operatively in the circulatory system 2S. The control of the dempers and the fan operation is had by a conventional controller, not shown, or manually. As depicted, the damper 37 is normally closed when the damper 38 is open, and the damper 39 is normally open when the damper 38 is open and the damper 37 is closed. The dampers 37 and 38 are preferably so interlocked such that -when updrafts of air `are introduced simultaneously in both

windboxes

21 and 22 by operation of the fan 29 damper 37 is closed. However, when the transfer fan 35 is operated, a downdraft of heated air and gases is drawn from the combustion space 2da above the grate through the grate section 13 and conveyed through the conduit 34 and the tube 3d to the windbox 21. At such time the damper 37 is open and the damper 3S is closed so that combustion air from blower 29 is forced only into the windbox 21. The fuel bed on the grate section 12 is thus heated by the introduction of heated air and gases into wind-box 21 and forced upwardly with the air from blower 29 through the material on the grate section 12. This accelerates the driving off of moisture from the material not exposed to the radiation of the furnace iiame and in raising the bed temperature under its surface. to the kindling point.

In normal operation with air blowing upwardly through both grate sections, the air cools the grates but when grate section 13 is operating with downdraft, it may be- -to a lesser extent by the grate l2 during the downdraft operation through grate 13 will be recuperated when the operation is reversed, the grates yielding their heat to the air before the air passes into the material above the grate.

The lower grate section 13 is the one selected in the vincinerator 14 through which a downdraft of gases is caused to flow because it is lcloser to the quench tank 17, and, since more ashes will be s-ifted from the grate section 13 into the tank by such downdrafts, it is desirous to remove the sifted ash from the furnace .system without delay to maintain a cleaner exhaust gas.

It is manifest that the above-described embodiment of the invention is merely illustrative and that numerous modifications may be made without departing from the spirit and scope of the invention.

What is claimed is:

1. An ineinerator comprising an enclosing furnace structure, a longitudinally extending grate in the structure with a combustion chamber `above the grate and an air space below the grate, a water retaining quench trough extending under the grate and forming a bottom enclosure for the air space, bafiies extending downwardly from the grate into the quench tank at spaced intervals dividing said space into at least two separate chambers, means for selectively supplying combustion air under pressure to both of said two chambers, and means for selectively blocking the flow of air to one of said chambers and drawing gases downwardly from the combustion chamber through the grate into the said one chamber and delivering the gases so withdrawn into the other chamber.

2. The method of incinerating rubbish which comprises discharging the rubbish onto a grate along which the rubbish is progressively moved, and alternately flowing combustion air upwardly through substantially the entire length of the grate and then through only a rst portion of the entire length while simultaneously drawing gases from above the grate downwardly through another portion and mixing the gases so withdrawn with the air supplied to the first portion before the air supplied to the first portion has moved upwardly through the grate.

3. An incinerator comprising a chamber; grates disposed within the chamber at different levels with material to be burned on each grate being discharged Ito a next lower grate; a tank forming the bottom of the chamber within which a liquid is a-dapted to be confined and into which ash sifted through each grate falls and the burned residue from the lowest grate discharged; bafile plates secured to each grate forming walls with each grate il bridging the respective plates; the plates depending into the tank below the top of the tank sufficiently to extend below the surface of the liquid adapted to be confined in the container whereby when liquid is placed in the tank to a level above the bot-tom edges of the baille plates the liquid surface, a grate, and the respective baffle plates define discrete windboxes; first means for introducing air into each windbox to force an updraft through each grate and material thereon; second means for withdrawing gas from at least one windbox of at least one grate for causing a downdraft of air and gas through the one grate and material thereon and for transferring the withdrawn air and gas to another windbox under pressure while the first means forces air into the other windbox; and third means for terminating the lintroduction of updraft air to the one windbox at the time said downs-f 'A draft of air and gas is being effected.

4. An incinerator comprising a furnace with a grate structure with a combustion space above the grate structure, a succession of at least two windboxes under the grate designed to be operated at different relative pressures, means for selectively supplying air to both of said windboxes or selectively cutting off the air supply to one while supplying air to the other, and means operable for withdrawing gases and air from that box which is cut off from said air supply and forcing it into the one receiving the air supply whereby there is a down-draft flow of air and gases from the combustion chamber into the one so cut off from the air supply and the downdraft gases are mingled with the air in the other wind-box.

5. An incinerator having a furnace structure with a grate for receiving material to be burned at one end and discharging ash from the other, there being a combustion space above the grate, a first windbox under the grate extending from the receiving end part way toward the discharge end, and a second windbox designed to be operated at a pressure differential relative to the first succeeding the first, means for selectively supplying combustion air to the rst and second windboxes or to only the first, and means effective when air is supplied only to the first for withdrawing air and gases from the second and discharging them into the rst to generate a downdraft of heated air and gases from the combustion charnber into the second windboX and accelerate the drying of material on the grate by the subsequent upflow thereof through the grate above said rst windbox.

References Cited bythe Examiner UNITED STATES PATENTS 1,146,255 7/15 Hock 110-72 3,057,308 10/62 Knipping 110-8 JAMES W. WESTHAVER, Primary Examiner.

JOHN I. CAMBY, Examiner.

Claims

2. THE METHOD OF INCINERATING RUBBISH WHICH COMPRISES DISCHARGING THE RUBBISH ONTOA GRATE ALONG WHICH THE RUBBISH IS PROGRESSIVELY MOVED, AND ALTERNATELY FLOWING COMBUSTION AIR UPWADLY THROUGH SUBTANTIALLY THE ENTIRE LENGTH OF THE GRATE AND THEN THROUGH ONLY A FIRST PORTION OF THE ENTIRE LENGTH WHILE SIMULTANEOUSLY DRAWING GASES FROM ABOVE THE GRATE DOWNWARDLY THROUGH ANOTHER PORTION AND MIXING THE GASES SO WITHDRAWN WITH THE AIR SUPPLIED TO THE FIRST PORTION BEFORE THE AIR SUPPLIED TO THE FIRST PORTION HAS MOVED UPWARDLY THROUGH THE GRATE.