US3812795A

US3812795A - Incinerator

Info

Publication number: US3812795A
Application number: US00341305A
Authority: US
Inventors: H Bowles
Original assignee: AUSTRAL INCINERATOR CORP
Current assignee: AUSTRAL INCINERATOR CORP
Priority date: 1973-03-14
Filing date: 1973-03-14
Publication date: 1974-05-28
Anticipated expiration: 1991-05-28

Abstract

An incinerator apparatus for burning waste material wherein a primary chamber is connected to a secondary chamber through an angular duct or passageway of predetermined size and configuration and a nozzle or opening of a preselected size, whereby the velocity of flow of the products of combustion through the apparatus, and particularly through the nozzle or opening, is controlled to maintain the proper draft and the desired dwell time of the combustion products within the apparatus to assure complete oxidation of said products prior to their exit from the usual flue stack. Additionally, a secondary burner is located in such relationship to the nozzle or opening that the products of combustion must pass through the burner flame, and also secondary air inlets for introducing air into the duct are positioned in said duct, all of which substantially increases the efficiency of the apparatus.

Description

United States Patent 1 1 Bowles, Jr.

[ 51 May 28, 1974 INCINERATOR [75] lnventor: Barry L. Bowles, Jr., Houston, Tex.

[73] Assignee: Austral Incinerator Corporation, Houston, Tex.

22 Filed: Mar. 14,1973

211 Appl. No.: 341,305

52 US. Cl. 110/8 c, 110/18 0 51 1m. 01. F23g 5/12 58 Field of Search 110/8 R, 8 A, 8 c, 18 R, 110/18 (3 Y [56] References Cited UNITED STATES PATENTS 3,503,348 3/1970 Dvirka 110/8 3,547,055 12/1970 Zanft 110/8 3,605,654 9/1971 BOWIBS, Jr r 110/8 3,675,600 7/1972 Jones 110/8 Primary Examiner-Kenneth W. Sprague [57] ABSTRACT An incinerator apparatus for burning waste material wherein a primary chamber is connected to a secondary chamber through an angular duct or passageway of predetermined size and configuration and a nozzle or opening of a preselected size, whereby the velocity of flow of the products of combustion through the apparatus, and particularly through the nozzle or opening, is controlled to maintain the proper draft and the desired dwell time of the combustion products within the apparatus to assure complete oxidation of said products prior to their exit from the usual flue stack. Additionally, a secondary burner is located in such relationship to the nozzle or opening that the products of combustion must pass through the burner flame, and also secondary air inlets for introducing airinto the duct are positioned in said duct, all of which substantially increases the efficiency of the apparatus.

12 Claims, 7 Drawing Figures fATENTEDMAY 28 I974

sum

2 or 2 1 INCINERATOR BACKGROUND OF THE INVENTION The invention relates to an incinerator apparatus wherein effective burning of waste material is accomplished with a minimum of residual combustion products escaping through the usual flue stack.

The incinerator disclosed in my prior U.S. Pat. No.

' 3,605,654 is of the same basic design and arrangement and actual use has established that it operates satisfactorily in the burning or destruction of waste material and is capable of meeting flue emission standards for this type of unit. However, such prior structure as well as other prior art incinerators have not recognized that the predetermined sizing and relationship of the primary and secondary chambers, the duct and the openings through which the products of combustion flow is important in achieving maximum efficiency. More par ticularly, there is no teaching in the prior art that velocity of flow through the nozzle or passageway which extends from the duct to the secondary chamber is a major factor in controlling the dwell time of the combustion products which should be such as to effect complete oxidation of combustion products. And finally, it has not been recognized that the size and configuration of a duct connecting the primary and secondary chambers of an incinerator is a controlling factor not only in creating turbulence and mixing therein to assure secondary pyrolysis and oxidation to take place but also in improving precipitation of heavier particulates and fly ash from the main flow stream.

SUMMARY OF THE INVENTION The improvement of the present invention resides in the predetermined or preselected relationship between the primary chamber, the interconnecting duct, the size of the nozzle or passageway which communicates with the secondary chamber, and the size and configuration of the duct. Such relationship properly controls the velocity of the products of combustion passing through the nozzle into the secondary chamber, which, in turn,

controls the velocity of flow and dwell time of said products in the duct. This assures that secondary pyrolysis and oxidation will take place in the duct. The particular configuration and size of the duct, as herein disclosed, improves precipitation of the heavier particulates as the combustion products flow through said duct.

OBJECTS OF THE INVENTION One object of this invention is to provide an incinerator apparatus wherein the size and relationship to each other of the chambers, duct, nozzle and other openings are such thatthe velocity of the products of combustion through the apparatus is controlled to achieve maximum efficiency in burning waste material.

Another object is to control the velocity of the combustion products flowing from the duct through the nozzle into the secondary chamber and to locate a secondary burner in such proximity to the nozzle that the combustion products are directed through the flame of the secondary burner to thereby accomplish more complete pyrolysis and oxidation of said products, said burner also assisting in maintaining the proper draft through the apparatus.

Still another object is to provide one or more secondary air inlets in the connecting duct between the primary and secondary chambers to admit sufficient air for secondary pyrolysis and oxidation of the combustion products within said duct.

Another object is to provide a duct or passageway which interconnects the primary and secondary chambers of the apparatus and which is of a configuration which causes the products of combustion to change direction and at the same time reduce velocity, whereby an improved mechanical separation or settling out of the larger particulates or fly ash is accomplished.

Another object is to provide an apparatus wherein the volume of the connecting duct between the primary and secondary chambers is at least fifteen percent of the volume of the primary chamber, such relationship assuring sufficient dwell time in the duct for secondary pyrolysis and at the same time also accomplishing an efficient mechanical separation or precipitation of particulates from the main stream of combustion products.

Other objects will appear hereinafter.

DESCRIPTION OF THE DRAWINGS FIG. 5 is a transverse, vertical sectional view taken through both chambers and on the line 5-5 of FIG. 2.

FIG. 6 is a transverse, vertical sectional view taken through the interconnecting duct which establishes communication between the primary and secondary chambers and taken along the lines 6-6 of FIG. 2.

FIG. 6A is a view of one of the air inlets having a blower connected therewith to provide a forced air system.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION In the drawings the numeral 10 designates a housing, the walls of which may be constructed of a suitable refractory material or alternately could be a metallic casing combined with refractory insulation. The interior of the housing is formed with a primary burning chamber A (FIG. 4) into which the waste material to be burned is deposited; if desired, grate 11 may be disposed within said chamber. The material may be introduced into the chamber A through an access opening 12 which is closed by a door 13. Any desired type of burners (not shown) are mounted within the chamber A and in general practice are used to initiate burning of the waste material. A clean-out opening 14 normally closed by a door 15 is provided in the lower side wall of the primary chamber A for removingfly ash from said chamber.

The products of combustion exit from the primary burning chamber through a flame port or opening 16 which communicates with one end of an angular duct generally indicated by B. As is clearly shown in FIGS. 1 and 2, the duct B is formed within the housing at one side of the primary chamber and has a relatively short vertical portion 17, a horizontal section 18 and a second elongate vertical section 19. The products of combustion entering the duct through the port or opening 16 are caused to travel upwardly in a vertical direction, then horizontally through section 18 and then downwardly through section 19. As the products flow through the horizontal section 18, they undergo a turbulent and mixing action, this being caused by the undulating path which the products must traverse in travelling from port 16 through said duct. Thus, the duct may also be termed a mixing chamber.

The cross-sectional area or volume of section 19 is greater than that of the horizontal section 18 so that as the products of combustion change direction in passing from section 18 to section 19, their velocity is some what slowed; as will be explained, this results in improving the precipitation or mechanical separation of the heavier particulates so that such particulates, indicated generally by the letter P in FIG. 3, may fall downwardly into the lower portion 190 of the section 19 of said duct. Such lower portion 19a which receives the precipitated matter forms a settling chamber from which the particles may be removed through an access opening 20 which is normally closed by a door 21.

In order to promote and insure secondary pyrolysis and oxidation of the combustion products within theduct B, side openings or inlets 22 through which air may be admitted are formed in the wall of the horizon- I system and in such case, a suitable blower, 23a in FIG.

6Awould be connected to each inlet 22.

The products of combustion flowing through the duct exit therefrom through a nozzle or opening 24 which establishes communication with a secondary chamber C. The secondary chamber is separated from the primary chamber Aby arefractory wall 25 (FIG. 5) and is heated from the heat in said chamber A as well as from the heat in the duct B. As the products of combustion flow through the nozzle 24, their velocity is increased but upon entry into the relatively large volume of chamber C, such velocity is decreased to permit further settling of the heavier particles. From the chamber C the products of combustion flow upwardly and into the lower end of the usual flue stack 26. The area of the chamber C immediately below the flue stack. (FIG. 3), which is designated by the letter 27, is actually an afterburner chamber, and an afterburner 28 may be mounted at the upper portion of this chamber to assure complete combustion of the products escaping through the flue stack. v

. Opposite the nozzle or opening 24 which is located between the vertical section 19 of duct B and the secondary chamber C is a secondary burner29. It is preferable that this burner be directly aligned with the nozzle or opening 24 so that its flame indicated by the dotted lines F is directly, in the path of all products of combustion flowing from the duct B through the opening 24 and into the secondary chamber. This burner may be controlled in its operation by a thermocouple 30 which is disposed in the section 19 of the duct. Whenever the burning of material has progressed within the-duct B to the point where a predetermined temperature is reached, such temperature will act upon the thermocouple 30 to shut off the burner. On the other hand, if the temperature in the duct B falls below that for which the thermocouple is set, then the burner will reignite to provide for a secondary burning action on the products of combustion.

From the foregoing, it will be seen that the waste material is introduced into the primary burning chamber A wherein initial burning takes place. The products of combustion pass from this chamber through the flame port or opening 16 and into the duct 8 and since the walls of the duct are formed of a refractory material. there is sufficient heat generated within this duct to maintain the burning cycle. The duct is arranged so that the products are first directed upwardly a short distance, then their direction is changed to move them through the horizontal section 18 of the duct after which their direction is again suddenly changed as they enter the vertical section 19 of said duct. To assure that there is sufficient air in the duct to maintain secondary pyrolysis and oxidation reactions of the combustion products, the dampers 23 may be properly adjusted to admit such air through the openings 22.

The downward flow of the combustion products through the vertical section 19 of the duct B causes the heavier particulates or matter to drop downwardly into the settling chamber 19a. This mechanical separation or settling is believed to be assisted by the fact that the cross-sectional area of the vertical portion 19 of the duct B is greater than the cross-sectional area of the horizontal portion 18; by reason of this change in crosssectional areas, there is a slight slowing down of the velocity of the products of combustion as the same suddenly change direction, thereby encouraging and assisting in the mechanical separation or settling of the heavier particles. Of course, some of the heavier particles may strike the wall of the vertical portion 19 at its intersection with the horizontal portion of the duct and this too will assist in causing such particles to precipitate.

After passage through the duct B, the products of combustion then flow through the nozzle or opening 24 which functions to increase the velocity of the stream as it passes through said opening. The amount of restriction created by this opening will control the velocity therethrough and will also control the velocity of the products of combustion which are passing through the duct B because of the relationship of the size of opening 24 to the volume of the duct. By controlling velocity, it is possible to control the dwell time of the products within the duct and thereby permit the products to remain in the duct for a sufficient time to permit secondary pyrolysis to take place.

As the products leave the nozzle or opening 24 they are projected into the relatively larger secondary chamber C and a further settling of the heavier particulates or matter may occur. Some of the heavier particles will fall downwardly while it is possible that some of the lighter particles might be projected against the opposite wall of the chamber C and physically knocked downwardly into the lower portion thereof. These settled particles may be removed from the secondary chamber C through an opening 31 which is normally closed by a door 32 (FIG. 3). Upon leaving the secondary chamber C, the remaining products of combustion pass upwardly through the afterburner chamber 27, past the afterbumer 28 and outwardly through the flue stack 26.

Actual experiments have shown that the size of the chambers and their relationship to the size of the duct The size of the nozzle or opening 24 through which the combustion products exit from the duct must be of a size which will control the velocity of the combustion products, not only through this nozzle but also through the duct. As an example, experiments have shown that the total average velocity from the flame port or entry 16 to the nozzle or opening 24 should not exceed 55 feet per second. By maintaining the velocity below this figure, it is assured that the products of combustion will have sufficient dwell time in the duct for secondary pyrolysis and oxidation reactions. Also under these velocity conditions, the heavier particulate matter has the opportunity to mechanically separate or settle out as the combustion products flow downwardly through the vertical section 19 of the duct. It might be noted that actual use of experimental incinerators having a capacity of 300 to 500 pounds per hour function satisfactorily when the total average velocity does not exceed the above mentioned 55 feet per second.

Although the actual velocity through the nozzle or opening 24 may vary over a fairly wide range, the size of this opening must always be related back to the volume of the duct B. Obviously, if the nozzle or opening 24 is too large in relationship to the duct, then the ve locity through the duct is increased and there is not sufficient dwell time of the combustion products in the duct. [f on the other hand, the nozzle or opening 24 is too small in relationship to the duct, then too much back pressure is built up which results in incomplete oxidation of the combustion products, thereby reducing the overall efficiency of the apparatus. Regardless of the relationship between the nozzle opening 24 and the duct and the size of the apparatus, actual use has shown that the total dwell time of the combustion prod ucts in'both the duct B and the secondary chamber C may range anywhere from 0.50 second to L5 second without materially impairing the overall efficiency. Al-

though dwell time in the secondary chamber is referred to, it is not as important as the dwell time within duct B where the secondary pyrolysis and the oxidation of the combustion chamber products occur.

My prior patent indicated that the burner 29 could be mounted at any point in the duct, but it has now been found that to obtain maximum efficiency, it is necessary to locate the secondary burner 29 so that all products of combustion pass directly through its flame. To accomplish this, the burner should be located immediately adjacent and preferably in alignment with the nozzle or opening 24. Such location assures that when the burner is operating, all products of combustion will pass through the flame F of said burner. Additionally, when the burner flame is directed at and through the nozzle or opening 24-, it will function to improve the draft through the entire apparatus.

In summary, the present improvement resides in controlling the velocity of the combustion products through the nozzle or opening 24 by properly relating the size of this opening to the volume of the duct B, which, in turn, has its volume related to that of the primary chamber A. In this way, the velocity of flow of the combustion products through the duct is controlled so as to assure the necessary dwell time for efficient secondary pyrolysis; such secondary pyrolysis is assured by providing the air inlets 22 and regulating the air supply into the duct by means of the damper 23. The increase in volume of the vertical section 19 of the duct B over that of the horizontal portion 18 is believed to improve the mechanical separation or precipitation. By positioning the burner in alignment with the nozzle or opening 24, any remaining products of combustion must contact the flame F of the secondary burner 29 before passing to the secondary chamber where additional settling occurs and the overall result is maximum efficiency in the burning operation, with -a minimum amount of unburned particles escaping through the flue stack 26.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

What I claim is:

1. An incinerator apparatus including,

an insulated housing,

a primary burning chamber in said housing for receiving waste material to be destroyed,

a duct within said housing in flow connection with said primary chamber,

said duct having a horizontal portion and an elongate vertical portion,

a settling chamber at the lower end of the vertical portion of said duct,

a secondary chamber in the housing within which further settling occurs,

means establishing flow communication between the duct and said secondary chamber, said means comprising an opening having a preselected size in relationship to the volume of the duct to thereby control the velocity of flow within said duct to assure ample dwell time of the products of combustion within said duct to effect pyrolysis and oxidation reactions of said products, and

a stack in flow connection with said secondary chamber.

2. An incinerator apparatus as set forth in claim 1, together with a secondary burner located in the duct and having its flame aligned with the opening which establishes flow-communication between the duct and the secondary chamber, whereby when said burner is op- 5 together with air inlets formed in the side wall of the duct, and damper means in said inlets for controlling the air flowing therethrough.

5. An incinerator apparatus as set forth in claim 1, wherein the vertical portion of said duct is larger in crosssectional area than the horizontal portion thereof to effect a slight reduction in velocity of the combustion products.

6. An incinerator as set forth in claim 1, wherein the duct is of a configuration which causes a turbulent mixing flow of the combustion products therethrough to enhance the secondary pyrolysis and oxidation reactions in said duct.

7. An incinerator apparatus including,

an insulated housing,

a primary burner chamber within the housing and having an opening nearer its upper end for escape of the products of combustion,

an angular duct formed within the housing adjacent a portion of one wall of the primary chamber,

said duct having a relatively short vertical portion, a horizontal section and an elongate vertical section, the bottom portion of said vertical section forming a settling chamber,

the lower part of said short vertical portion of the duct communicating with the primary chamber through the opening in its upper end,

a secondary chamber within the housing and having one wall which is also common to the primary chamber whereby heat from said primary chamber will be transferred to the secondary chamber,

said secondary chamber also being adjacent the duct,

means establishing communication between the duct and the secondary chamber, said means comprising a nozzle opening having a preselected size in relationship to the volume of the duct to thereby control the velocity of the combustion products through the duct,

a secondary burner located in the duct and having its flame aligned with said nozzle opening to cause the combustion products to pass through the flame in flowing from the duct to the secondary chamber, and

a stack in flow connection with the secondary chamher.

8. An incinerator apparatus as set forth in claim 7,

together with air inlets formed in the side wall of the horizontal section of the duct, and

damper means in said inlets for controlling the air flowing therethrough.

9. An incinerator apparatus as set forth in claim 7,

wherein the vertical section of said duct is larger in crosssectional area than the horizontal section thereof so that there is a slight reduction in velocity of the combustion products as they flow from said horizontal to said vertical section.

10. An incinerator apparatus as set forth in claim 7,

. wherein the nozzle opening which establishes communication between the duct and the secondary chamber is located substantially mid-height of the elongate vertical section of said duct and above that portion which forms the settling chamber. 11. An incinerator apparatus as set forth in claim 7, wherein a y t y the volume of the angular duct is at least fifteen percent of the volume of the primary chamber. 12. An incinerator apparatus as set forth in claim 7, together with an air inlet formed in the side wall of the horizontal section of the duct, and a blower communicating with said air inlet for forcing air therethrough.

Claims

1. An incinerator apparatus including, an insulated housing, a primary burning chamber in said housing for receiving waste material to be destroyed, a duct within said housing in flow connection with said primary chamber, said duct having a horizontal portion and an elongate vertical portion, a settling chamber at the lower end of the vertical portion of said duct, a secondary chamber in the housing within which further settling occurs, means establishing Flow communication between the duct and said secondary chamber, said means comprising an opening having a preselected size in relationship to the volume of the duct to thereby control the velocity of flow within said duct to assure ample dwell time of the products of combustion within said duct to effect pyrolysis and oxidation reactions of said products, and a stack in flow connection with said secondary chamber.

2. An incinerator apparatus as set forth in claim 1, together with a secondary burner located in the duct and having its flame aligned with the opening which establishes flow communication between the duct and the secondary chamber, whereby when said burner is operating the products of combustion must pass through said flame in flowing from the duct to the secondary chamber.

3. An incinerator apparatus as set forth in claim 1, together with air inlets formed in the side wall of the duct, and damper means in said inlets for controlling the air flowing therethrough.

4. An incinerator apparatus as set forth in claim 2, together with air inlets formed in the side wall of the duct, and damper means in said inlets for controlling the air flowing therethrough.

5. An incinerator apparatus as set forth in claim 1, wherein the vertical portion of said duct is larger in cross-sectional area than the horizontal portion thereof to effect a slight reduction in velocity of the combustion products.

7. An incinerator apparatus including, an insulated housing, a primary burner chamber within the housing and having an opening nearer its upper end for escape of the products of combustion, an angular duct formed within the housing adjacent a portion of one wall of the primary chamber, said duct having a relatively short vertical portion, a horizontal section and an elongate vertical section, the bottom portion of said vertical section forming a settling chamber, the lower part of said short vertical portion of the duct communicating with the primary chamber through the opening in its upper end, a secondary chamber within the housing and having one wall which is also common to the primary chamber whereby heat from said primary chamber will be transferred to the secondary chamber, said secondary chamber also being adjacent the duct, means establishing communication between the duct and the secondary chamber, said means comprising a nozzle opening having a preselected size in relationship to the volume of the duct to thereby control the velocity of the combustion products through the duct, a secondary burner located in the duct and having its flame aligned with said nozzle opening to cause the combustion products to pass through the flame in flowing from the duct to the secondary chamber, and a stack in flow connection with the secondary chamber.

8. An incinerator apparatus as set forth in claim 7, together with air inlets formed in the side wall of the horizontal section of the duct, and damper means in said inlets for controlling the air flowing therethrough.

9. An incinerator apparatus as set forth in claim 7, wherein the vertical section of said duct is larger in crosssectional area than the horizontal section thereof so that there is a slight reduction in velocity of the combustion products as they flow from said horizontal to said vertical section.

10. An incinerator apparatus as set forth in claim 7, wherein the nozzle opening which establishes communication between the duct and the secondary chamber is located substantially mid-height of the elongate vertical section of said duct and above that portion which forms the settling chamber.

11. An incinerator apparatus as set forth in claim 7, wherein the volume of the angUlar duct is at least fifteen percent of the volume of the primary chamber.

12. An incinerator apparatus as set forth in claim 7, together with an air inlet formed in the side wall of the horizontal section of the duct, and a blower communicating with said air inlet for forcing air therethrough.