Apparatus and method for incinerating rubbish and cleaning the smoke of incineration

[57] ABSTRACT

This specification discloses apparatus for carrying out a method of incinerating rubbish and cleaning the resultant smoke. The apparatus comprises essentially a fire pit, a plenum where smoke is collected, a filter, an after burner, an electrostatic precipitating chamber, an alkaline water wash, a plain water wash, a filter, and a motor driven exhaust fan which passes clean gas to a stack.

Claims, 4 Drawing Figures

SOLID RESIDUE REMOVED

PRECIPITATE REMOVED

STACK

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PLAIN WATER WASH

ALKALINE WATER WASH

ELECTRO STATIC STATIC

PRECIPITATOR

AFTER BURNER

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P L E N U M

FIRE PIT

PRECIPITATE REMOVED

SOLID RESIDUE REMOVED

PATENTED JUH131972

3,668,833

SHEET 1 OF 4

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INVENTOR

WILLIAM FRANCIS CAHILL, JR.

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ATTORNEY

PATENTED JUN 13 (972

3,668,833

SHEET 2 OF 4

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INVENTOR

WILLIAM FRANCIS CAHILL, JR. BY

ATTORNEY

PATENTED JUH 13 1972

3,668,833

SHEET 3 Of 4 to

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INVENTOR

WILLIAM FRANCIS CAHILL, JR. BY

ATTORNEY

PATENTED JUN131972

3,668,833

SHEET U OF 4

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3,668,833

APPARATUS AND METHOD FOR INCINERATING RUBBISH AND CLEANING THE SMOKE OF INCINERATION

The present invention relates to the incineration of trashes, rubbish, and other forms of combustible waste and is concerned primarily with a novel method and apparatus for cleaning the smoke generated by the combustion of such materials whereby it is exhausted into the atmosphere as clean gas.

BACKGROUND OF THE INVENTION

At the present time the public is aroused to the dangers of pollution; Perhaps the most important aspect of this peril is the pollution of the atmosphere around large cities. Another problem is the disposal of all forms of waste. Many types of waste contain some materials which are susceptible of being consumed by combustion and converted into ash. Thus some waste often contain glass and metal which may be reclaimed for future use rather than being deposited in a dump.

A classic example of waste of this character is an automobile which has been wrecked or junked. The upholstery, tires, and other combustibles may be incinerated to remove them from the metal which may be reclaimed as scrap and the glass which can be recycled to fulfill a useful purpose.

The disposition and reclaiming of all forms of waste, such as municipal trash and rubbish, industrial waste, and the like by a method which includes incineration, immediately creates the problem of polluting the air by the smoke of incineration. While those working in this field have attempted to clean this smoke, it is believed the results so far achieved are not satisfactory to the degree required.

OBJECTS OF THE INVENTION

With the foregoing conditions in mind, the invention has in view the following objects.

1. To provide a method of and apparatus for incinerating all forms of waste to reclaim incombustible components thereof and convert the combustible components to ash and smoke, and clean the smoke to exhaust it to the air as clean gas.

2. To provide, in a method and apparatus of the type noted, a fire pit which receives the waste and which has associated therewith a plenum or smoke collecting chamber.

3. To provide, in apparatus of the character aforesaid, a fire pit which is adapted for installation at least partially underground together with chutes for charging waste thereinto.

4. To provide, in apparatus of the kind described, a plurality of smoke treatment chambers, arranged in series and connecting the plenum to a stack.

5. To provide, in apparatus of the character noted, smoke treatment chambers that are constructed as individual modules which may be constructed “off site” and transported to the area of the fire pit where they are installed.

6. To include, in a method of the type described, the step of monitoring the treated smoke just before it enters the stack.

Various other more detailed objects and advantages of the invention such as arise in connection with carrying out the above noted ideas in a practical embodiment will in part become apparent and in part be hereinafter stated as the description of the invention proceeds.

SUMMARY OF THE INVENTION

The foregoing objects are achieved by providing a fire pit which is preferably installed underground and which has associated therewith chutes for charging the pit with waste. The fire pit is covered and on one side of the roof is a plenum in which smoke is collected. Adjacent to the plenum is a filter assembly and then an after burner chamber. Following the latter is an electrostatic precipitator chamber together with means to remove the precipitate. Next in line is an alkaline water wash followed by a plain water wash. The treated smoke is then drawn through a filter assembly and passed to a stack. A monitor is included in the chamber in which this last filter is located.

For a full and more complete understanding of the invention, reference may be had to the following description and accompanying drawings wherein:

FIG. 1 is a flow sheet which illustrates diagrammatically the method of the subject invention;

FIG. 2 is a perspective, largely diagrammatic of an incinerator installation in which the method may be conducted;

FIG. 3 is a view in end elevation of the fire pit; and,

FIG. 4 is a longitudinal vertical section through the incinerator and smoke treating apparatus being taken about on the plane of line 4—4 of FIG. 2.

Referring now to the drawings wherein like reference characters denote corresponding parts and first more particularly to FIG. 1, the method will be described.

All forms of waste, both municipal and industrial are charged into a fire pit 10. All combustible components of the waste is consumed by burning. This combustion may be facilitated by a forced air draft and the injection of oil.

Ash and other solid residues are removed from fire pit 10 from time to time as represented by arrows 11. Smoke is collected from fire pit 10 in a plenum 12. This is accomplished by a draft generated by a motor driven fan as will be later described. This draft may be in the nature of 30,000 cubic feet per minute.

The smoke now passes through a filter assembly 13 which may comprise two coarse filter which remove large particles from the smoke. The filtered smoke now passes to an after burner chamber 14 in which it is subjected to a temperature on the order of 6,000° F. created by an arc flame. Entrained particles and gases are burned by this high temperature.

From the after burner the smoke passes to an electrostatic precipitating chamber 15 in which an electrostatic precipitator operates at a potential of 140,000 volts. This causes particles to be picked up and removed to the side of the chamber from which they are periodically removed by mechanical brushes or manually.

The smoke now is subjected to an alkaline water wash represented at 16. This wash neutralizes any acid fumes and also collects particles which may still be entrained in the smoke. The pH of the wash is controlled by an electrometric pH meter on the outside of the chamber.

A chamber 17 which is a duplicate of chamber 16 houses a plain water wash. Clear water used at station 17 picks up particles still remaining in the smoke. A second filter assembly is shown at 18 and includes both mechanical and chemical filters. A continuous air testing monitor 19 is located in the chamber housing filter assembly 18. A motor driven fan is represented at 20 and is effective to create the draft that draws the smoke from fire pit 10 through the various stages of the method and passes it to a stack 21 as clean gas which may be exhausted to the atmosphere without danger of pollution.

Referring now to FIGS. 2 and 3, the construction of the free pit 10 will be described. The construction illustrated is particularly adapted for underground installation which is desirable when it is considered that many forms of waste often include explosives. By having the fire pit mainly underground, the danger of explosives is minimized.

Fire pit 10 includes a rear wall 22 on the exterior of which are mounted oil tanks 23. It is also provided with a clean out door 24 which may be availed of when it is desired to charge the fire pit with a large object such as a wrecked automobile. Lines 25 extend from oil tanks 23 to the interior of pit 10 where oil is injected into the burning mass of waste. Above oil tanks 23 are fire doors 26. Extending across rear wall 22 just below its upper edge are three cooling doors 27 which may be selectively opened as occasion demands.

Side walls of pit 10 are shown at 28 in FIG. 3. Each wall 28 is formed with a charging opening 29 and communicating with each opening 29 is a chute 30. Each of the latter is provided with a vertically reciprocating safety gate 31.

A roof 32 covers fire pit 10 and mounted thereon is structure 33 constituting plenum 12 of FIG. 1. The bottom of plenum structure 33 opens onto the interior of fire pit 10.

3,668,833

Referring now to FIG. 4, plenum structure 33 includes an open side in which filter assembly 13 is mounted. Assembly 13 comprises two coarse filters 34 which preferably are mechanical.

After burner station 14 is shown as provided by a module 35 which houses electrodes 36 which generate arc 37.

The electrostatic precipitator at 15 is also constructed as a module 38. Suspended in the latter are a plurality of precipitators 39 which receive electric current at a potential of 140,000 volts.

Station 16 for the alkaline water wash is provided by a module 40. Housed in the latter are spray heads 41. An electrometric pH meter 42 is preferably mounted on the exterior of module 40.

Module 43 is similar in structure to module 40 and houses the spray heads which perform the plain water washing at station 17.

A module 44 houses filter assembly 18 and the fan represented diagrammatically in FIG. 1 at 20. It is believed to be desirable that one of the filters of assembly 18 be mechanical and the other chemical. Thus, filter 45 is a mechanical filter and filter 46 is chemical.

A motor 47 is mounted on module 44 and drives fan 20. A conduit 48 connects module 44 to stack 21.

As illustrated in FIG. 2, plenum structure 33 is built as a module. This module, like modules 35, 38, 40, 43 and 44 are formed with flanges 49 which facilitate their assembly as illustrated in FIG. 4. Normally the assembled modules are supported by a foundation 50.

The manner in which the apparatus of FIGS. 2, 3 and 4 function is believed to be obvious from the description of the method as set forth above in conjunction with FIG. 1.

While a preferred specific embodiment of the invention is hereinbefore set forth, it is to be clearly understood that the invention is not to be limited to the exacts steps, constructions and devices illustrated and described because various modifications of these details may be provided in putting the invention into practice.