Method And Apparatus For Eliminating Smoke Emissions From Incinerators

Abstract

Smoke emissions are eliminated from an incinerator by admitting cool air into a stack arranged to receive smoke from a combustion chamber for inducing a draft in the stack which opposes a natural draft therein. Smoke is carried along by the induced draft and returned to the combustion chamber, so that only gases free of particulate matter are emitted from the stack. The induced draft returning to the combustion chamber as overfire air has sufficient pressure for creating turbulence in the combustion chamber for retaining the smoke in the combustion chamber a time sufficient to ensure complete combustion thereof. The cool air is admitted into the stack by a louvered portion provided in the stack and arranged adjacent the combustion chamber, and, alternatively, one or more louvered elements connected to the combustion chamber and the stack so as to be in parallel with the louvered portion. Ducts are connected to the louvered portion and louvered elements to return smoke to the combustion chamber.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to apparatus for eliminating smoke emissions from incinerators, and, more specifically, to such a apparatus for incinerators primarily intended to burn paper.

2. Description of the Prior Art

Incinerators have long been used to burn trash, and particularly paper, both for large buildings and individual residences. In recent years, however, the problem of air pollution has resulted in the use of such incinerators to be either eliminated by legislation or effectively eliminated by strict emission control standards.

The most objectionable air pollutant normally emitted from an incinerator is smoke. Smoke is gasborne particles resulting from incomplete combustion of the materials being burned. It has long been known that if these particles, or particulate matter, can be either recycled to the combustion chamber or further burned in an additional combustion chamber, they can theoretically be eventually eliminated by complete combustion. In the past, attempts have been made to recycle this particulate matter to the combustion chamber by running a duct from the stack to the middle or lower portion of the combustion chamber so as to employ the draft created in the combustion chamber to draw the particulate matter through the duct and combustion chamber and back to the stack.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved apparatus for eliminating smoke emissions from incinerators. It is a further object of the present invention to provide apparatus which will return smoke laden air through the combustion chamber in the form of overfire air for creating turbulence in the combustion chamber.

It is yet another object of the present invention to provide an incinerator which meets air pollution control emission standards, while remaining simple in construction and inexpensive in cost of fabrication and maintenance.

These and other objects are achieved according to the present invention by admitting cool air into a stack arranged to receive smoke from a combustion chamber for inducing a draft in the stack which opposes a natural draft therein, and returning to the combustion chamber smoke carried along by the induced draft so that only gases free of particulate matter are emitted from the stack. The step of returning includes the steps of returning the induced draft as overfire air and providing sufficient pressure in the induced draft for creating turbulence in the combustion chamber for retaining the smoke in the combustion chamber a time sufficient to ensure complete combustion thereof.

Apparatus for carrying out the method according to the present invention has a stack arranged to receive smoke and with means for admitting cool air into the stack for inducing a draft therein which opposes a natural draft in the stack, and means connected to the stack for returning smoke carried along by the induced draft so that only gases free of particulate matter are emitted from the stack. Container means may be provided having walls defining a combustion chamber. The stack is connected to the container means and arranged in communication with the combustion chamber for receiving smoke therefrom.

In a preferred embodiment of apparatus according to the present invention, the means for admitting is a louvered portion formed in the stack and arranged adjacent the combustion chamber. The means for returning may include a duct connected to the container means and arranged in communication with the combustion chamber so as to provide the overfire air supply for creating sufficient turbulence in the combustion chamber for retaining the smoke in the combustion chamber a time sufficient to ensure complete combustion thereof.

A preferred embodiment of the present invention has at least one louvered element connected to the container means and arranged in communication with the combustion chamber for receiving smoke therefrom, and connected to the stack and in parallel with the louvered portion of the stack. A duct is connected to the louvered element and to the container means for returning smoke from the louvered element to the combustion chamber.

These together with other objects and advantages which will become substantially apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view showing an incinerator according to the present invention.

FIG. 2 is a top plan view showing the incinerator of FIG. 1.

FIG. 3 is a sectional view taken generally along the line 3 --3 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, FIG. 1 shows an incinerator 10 according to the present invention having a stack 12 with a pipe portion 13 and means 14 for admitting cool air into stack 12 for inducing a draft therein which opposes a natural draft in stack 12. Means 16 is connected to stack 12 for returning smoke carried along by the induced draft, so that only gases free of particulate matter are emitted from stack 12.

A container means 18 is provided to which stack 12 is connected. Container means 18 may be a barrel 20 provided with access openings 21, 22 (FIG. 3). Doors 23, 24 are hinged as at 26, 28, respectively, to cover access openings 21, 22, respectively. Hinges 26, 28 may be of any suitable, known type, such as piano hinges. Bar and keeper assemblies 30, 32 are provided to retain doors 23, 24, respectively, in their closed position with respect to access openings 21, 22, respectively. Barrel 20 is provided with a vent 34 in door 23, a vent 36 (FIG. 2) having a pivotally mounted cover member 37, vents 38 and 40, and vent 41 in door 24. Vents 39, 41 are not shown in FIG. 3. Vent 36 is arranged in a top wall 42 (FIG. 2) and vents 38, 40 are arranged in a cylindrical side wall 44. Walls 42, 44 are combined with a bottom wall 45 (FIG. 3) to define a combustion chamber 46 (FIG. 3). Stack 12, by means of being connected to container means 18, is in communication with combustion chamber 46 by means of opening 47 for receiving smoke therefrom.

Means 14 has a louvered portion 48 formed in stack 12 and arranged adjacent combustion chamber 46. Portion 48 is formed by a plurality of fins 50 arranged about the periphery of stack 12. Fins 50 are formed in a suitable, known manner, such as by stamping. Means 16 has a duct 52 (FIG. 3) connected to stack 12 and in communication therewith by means of an opening 54 provided in louvered portion 48, and is connected to container means 18 and arranged in communication with combustion chamber 46 by means of an opening 55 provided in top wall 42. In this manner, the induced draft returning through duct 52 is designed so as to provide an overfire air supply for creating sufficient turbulence in combustion chamber 46 for retaining the smoke in combustion chamber 46 a time sufficient to ensure complete combustion thereof. Duct 52 has an elbow portion 56 connecting same to louvered portion 48 at opening 54. A screen 57 may be arranged at the outlet of pipe portion 13 to catch any ashes or other particles that may allude the induced draft in louvered portion 48 and pass up the stack 12.

Although it is to be understood that an incinerator according to the present invention may have only stack 12 with a louvered portion 48, the particular embodiment shown in the drawings has a pair of louvered elements 58 connected to container means 18 and arranged in communication with combustion chamber 46 via openings 60 formed in top wall 42 and in communication with stack 12 for receiving smoke therefrom. Elements 58 are also connected to stack 12 for communication therewith by means of openings 62. The elements 58 are connected to stack 12 in parallel with louvered portion 48. Fins 50 are also formed in pipe portions 63 of elements 58. A duct 64 is connected to a respective louvered element 58 and is in communication therewith by means of an opening 66. Ducts 64 are also connected to container means 18 and are in communication with combustion chamber 46 by means of opening 68 provided in wall 44 by returning smoke from louvered element 58 to combustion chamber 46. Each louvered element 58 has an elbow 70 and a pipe 72 as a part thereof. Each duct 64 has a pair of elbows 74 and connecting portions 76, 78. A pipe 80 completes each duct 64.

In operation, trash, preferably paper 82, is firmly packed and evenly distributed in barrel 20 by passing same through access opening 21 with door 23 pivoted out of the way (not shown). Paper 82 may be packed into combustion chamber 46 up to barrel ring 84. Vent 36 is left open at all times. Vent 34 is preferably left partially open for regulation of the oxygen required for combustion. After a fire is started in combustion chamber 46, cold air from the atmosphere enters louver portion 48 and louver elements 58 through fins 50 therof. This cold air sets up an induced draft which forces hot air and other gases carrying particulate matter into the return duct 52, 64 and into combustion chamber 46 as overfire air. With proper design, the pressure of the induced draft entering into combustion chamber 46 provides sufficient overfire pressure for creating turbulence in combustion chamber 46 for retaining the smoke in combustion chamber 46 a time sufficient to ensure complete combustion thereof. The arrows in FIG. 3 of the drawings show the various flow paths. Access opening 22 may be used, when door 24 is swung open, for cleaning the residue ash from combustion chamber 46 of barrel 20. Incinerator 10 is intended to reduce the entire composition of paper 82 into ashes. These ashes can be used as, for example, fertilizer which will be beneficial to the environment. When properly operated, incinerator 10 will emit smoke, or carbons, in an amount not to exceed three-quarters of one ringleman - a value taken from a standard Ringleman Chart -- and then only will it emit such an amount for less than 30 seconds.

The cold air will cause the induced draft due to its tendency to settle when mixed with warm air. The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. What is claimed as new is as follows:

Claims

1. An incinerator comprising in combination:

a. a stack arranged to receive smoke, and including means for admitting cool air into the stack for inducing a draft therein which opposes a natural draft in the stack;

b. means connected to said stack for returning smoke carried along by the induced draft, so that only gases free of particulate matter are emitted from said stack; and

c. container means having wall defining a combustion chamber, and wherein said stack is connected to said container means and arranged in communication with the combustion chamber for receiving smoke therefrom, said means for admitting including a louvered portion formed in said stack and arranged adjacent to the combustion chamber, the means for returning including a duct connected to said container means and arranged in communication with the combustion chamber so as to provide an overfire air supply for creating sufficient turbulence in the combustion chamber for retaining the smoke in the combustion chamber a time sufficient to ensure complete combustion thereof, and at least one louvered element connected to said container means and arranged in communications with the combustion chamber for receiving smoke therefrom, and connected to said stack in parallel with the louvered portion of said stack, a duct connected to said louvered element and said container means for returning smoke from said louvered element to the combustion chamber.

2. An incinerator comprising in combination:

a. a stack arranged to receive smoke, and including means for admitting cool air into the stack for inducing a draft therein which opposes a natural draft in the stack;

b. means connected to said stack for returning smoke carried along by the induced draft, so that only gases free of particulate matter are emitted from said stack; and

c. container means having walls defining a combustion chamber, and wherein said stack is connected to said container means and arranged in communication with the combustion chamber for receiving smoke therefrom, at least one louvered element connected to said container means and arranged in communication with the combustion chamber for receiving smoke therefrom, and connected to said stack in parallel with the louvered portion of said stack, a duct connected to said louvered element and said container means for returning smoke from said louvered element to the combustion chamber.

3. A structure as defined in claim 2, wherein the means for returning includes a duct connected to the louvered member, and to said container means and arranged in communication with the combustion chamber.

4. A structure as defined in claim 1, wherein the means for returning includes a duct connected to the louvered member, and to said container means and arranged in communication with the combustion chamber.