US3724401A - Controls for incinerator - Google Patents

Abstract

A solid waste incinerator having a control system responding to predetermined conditions that exist within the combustion chamber thereof during a normal burning operation. The usual system of complex temperature and pressure sensors is replaced by a simple controller that operates in response to a predetermined set of average values independent from those at that time in the combustion chamber.

Description

United States Patent [191 Krumm 51 Apr. 3, 1973 [54] CONTROLS FOR INCINERATOR [75] Inventor: Eugene D. Krumm, Wellsville, N.Y.

[73] Assigneei The Air Prehenter Company Inc.,

Wellsville, N.Y.

221 Filed: July 16,1971

[21] Appl. No.: 163,198

7/1956 Short et a1. 10/1968 Flowers, Jr. 12/1971 Stockman et al ..1 10/8 Primary Examiner-Kenneth W. Sprague Att0mey--Wayne H. Lang et al.

[57] ABSTRACT A solid waste incinerator having a control system responding to predetermined conditions that exist within the combustion chamber thereof during a normal burning operation. The usual system of complex temperature and pressure sensors is replaced by a simple controller that operates in response to a predetermined set of average values independent from those at that time in the combustion chamber.

7 Claims, 2 Drawing Figures [56] References Cited UNITED STATES PATENTS 3,323,475 6/1967 Melgaard ..l l0/l8 PATENTEDAPR 3 ma u o a a J o o q o e n INVEN TOR.

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nef/vr CONTROLS FOR INCINERATOR This invention relates to combustion controls for an 5 incinerator that arebased upon hypothetically or experimentally determined conditions that occur in an incinerator during a typical burning operation rather lers that respond to actual conditions that prevail during combustion within the combustion chamber of the incinerator.

SUMMARY OF THE INVENTION In the field of waste incineration more effective co'mbustion may be obtained if the supply of air to the chamber in which combustion is being carried out is varied to meet current demands within the combustion chamber. This is particularly true in an incinerator of 2 the starved air type as defined in U. S. Pat. No. 3,491,707 of Lubertus' 'Bakker granted on Jan. 27, 1970, wherein waste material is distilled in a primary chamber under controlled conditions having a deficiency of oxygen to produce a combustible gas, and the gas so produced is then burned in a secondary chamber under near stoichiometric conditions until only inert ash from the primary chamber and non-combustible gas from the secondary chamber remains.

The supply of combustion air and/or fuel to the primary and secondary combustion chambers is varied throughout the combustion process to produce effective combustion and complete elimination of the wastes in accordance with the curves shown in FIG. 1 of the drawing. Thus, while a deficiency of oxygen may be required in the primary combustion chamber to produce gas under conditions of pyrolosis using starved air principles, stoichiometric conditions or even a slight excess of air may be required in the secondary chamber to provide for complete combustion of 4 the gaseous products so produced. Moreover, the quantities of fuel and air required continuously vary in accordance with the degree of combustion within the primary and secondary combustion chambers of the incinerator in the manner shown by the curves of FIG. 1. However, a precise but varying relationship between the air and the fuel required to produce the desired degree of combustion withthe temperature required in the respective combustion chambers may be derived for a bum using a predetermined type and amount of 5 fuel and being effected in a given length of time.

An obvious method of combustion control would be to modulate air and fuel flow to the primary and to the secondary combustion chambers in accordance with the arrangement of U. S. Pat. No. 3,491,707. Such a system of control usually requires various thermocouples or other sensors in each combustion chamber to sense the temperature, and then it requires cooperating controllers responsive'to conditions in the respective chambers to actuate the air or fuel supply valves and regulate the air and fuel flowing thereto.

The arrangement of this invention makes unnecessary the use of thermocouples or other complicated and expensive sensing apparatus within the several cornbustion chambers that respond to existing conditions produced therein to actuate the valves which supply the air or fuel thereto. Instead my system uses a controller that varies the air and/or fuel supply valves according to a predetennined standard denoted by a particular shape of a cam in a cam-timer arrangement, or the particular pattern of holes on a punch card, tape or the like. When a charge of fuel is placed in the incinerator to be burned, a controller having a sequence of operation based upon an average of experimental or otherwise predetermined conditions is thus prothan upon the more extensive and expensive control- 10 grammed to operate the air or fuel supply valves leading to the primary and/or secondary combustion chambers in an optimum sequence that produces the gas in v the primary chamber and then burns it effectively and completely in the secondary chamber.

BRIEF DESCRIPTION or THE DRAWING FIG. 1 is a graph showing a typical temperature- DESCRIPTION OF THE PREFERRED EMBODIMENT In an incinerator constructed according to my invention, I provide a standard combustion vessel having a fixed head 12 at one end thereof and an access door 14 pivotally supported on hinges at the other that encloses a primary combustion chamber 15. At the top of the fixed head is an outlet port 19 for the exhaust of gaseous products of combustion generated therein.

The bottom of the vessel 10 enclosing the primary combustion chamber is adapted to receive one or more tubes 22 having apertures 24 through which air is supplied from a source 26 by means of an inlet pipe 28. As in all apparatus of the starved air type, air in less than stoichiometric proportions is supplied to the primary combustion chamber so that conditions of pyrolosis exist and a combustible gas is distilled therefrom to be exhausted through outlet port 19 to the secondary combustion chamber 32 where the combustible constituents are completely burned.

The secondary chamber 32 receives a supply of air through inlet pipe 34 from source 26 sufficient to provide for complete combustion of the gas produced in the primary combustion chamber whereby only carbon monoxide and water vapor remain to be exhausted from the stack 36 into the atmosphere. A slight excess of air may on occasion be supplied to the secondary chamber to produce complete combustion and some cooling compatible with the integrity of the material used in construction of the stack 36.

An independent supply of fuel 38 may be supplied through pipe to the secondary combustion chamber 32 whereby the combustion process therein is not completely dependent upon the gas produced in the primary combustion chamber 15. supply of the seconan elevated temperature necessary to complete combustion of the gas therein.

Many waste products, especially those of high BTU content, cannot be burned in conventional incinerators having either a single combustion chamber or a primary and a secondary chamber not subject to combustion control. However, by continuous modulation or control of combustion within the several combustion chambers it is possible to burn many types of waste products including those of high BTU content.

This modulation would normally be effected by regulatingthe temperatures within various sections of the primary and secondary chambers of the incinerator in accordance with the desired conditions. Means for regulating the temperature would logically include thermocouples or other sensors along with their respective controllers for the primary and the secondary chambers. Moreover, such apparatus would include valves, actuators, and other related control and safety devices in the lines supplying air and fuel thereto. Although such an arrangement is effective, its complex nature makes it extremely costly to assemble and maintain, and difficult to operate so that the widespread use of such apparatus is necessarily curtailed. I provide a simple, low cost control device that can control the air' and/or fuel valves to the primary and to the secondary combustion chambers of the incinerator. The control device does not include the usual complex and expensive circuitry, sensors, actuators and related control equipment, but it does include a simple controller based upon predetermined characteristics noted during a previous burning cycle. Inasmuch as all characteristics of combustion are substantially repeated for each burning cycle during the incineration of a given type and quantity of a material asshown in the graph of FIG. 1, the positioning of the valves controlling the air and fuel flowing to the incinerator may be similarly repeated to obtain these same conditions during a subsequent burn.

Thus a cam 44 is slowly rotated by a timer mechanism 46 operates the valve 48 permitting air to flow into the chamber and provide combustion therein in accordance with predetermined conditions.

Simultaneously, a cam 52 similarily operated by a timer mechanism 54 actuates valve 56 to supply air for combustion to the secondary combustion chamber 32 sufficient to completely burn the gas produced in the primary combustion chamber.

While the cam 44 is adapted tov actuate valve 48 to supply less than stoichiometric amounts of air to the primary combustion chamber 14, cam 52 is adapted to actuate valve 56 to provide adequate air in stoichiometric or more than stoichiometric amounts for complete elimination of the gas in chamber 52.

When it is desired that a different type or quantity of waste material be incinerated in the incinerator it is only necessary to replace the cams 44 and 52 with those that have been cut according to experimental or hypothetical conditions desired in the primary or secondary combustion chambers. Thus a set of cams may be made available for a variety of differing conditions so it is only necessary to plug-in the proper cams to produce the desired combustion conditions.

. By this arrangement temperature sensing apparatus responsive to current conditions is eliminated completely although a simple thermocouple with off-on I controls may be used to provide the signal for an emer-' gency or safety shut-down to close all air and fuel valves when the operational temperature exceeds a predetermined value.

While this invention has been disclosed with reference to a cam-type actuator,'the apparatus could which would sense various codes as indicated on a tape or chart in accordance with current control devices. It is to be understood therefore that the details of the incinerator has been described by way of illustration only and the limits of the invention are to be determined by the scope of the appended claims.

I claim:

1. An incinerator for the combustion of waste material therein comprising a housing enclosing a primary combustion chamber having an inlet for waste material and an outlet for the exhaust of products of combustion therefrom, a source of air for combustion, an air supply duct feeding air for combustion from said source into said combustion chamber, valve means in the air supply duct regulating the flow of air to said combustion chamber, an actuator for said valve, and means controlling movement of said actuator vin response to predetermined conditions whereby the valve moves to sequentially vary the air flow theret hrough from the source to the bustion chamber.

2. An incinerator for the combustion of waste material of the type defined in claim '1 wherein the actuator controlling movement of the valve in the air supply duct comprises a movable cam.

3. An incinerator; for the combustion of waste material of the type defined in claim 1 including a secondary combustion chamber having an inlet and an outlet, duct means connecting the exhaust outlet of the primary combustion chamber to the secondary combustion chamber, an air supply duct connected to the secondary combustion chamber, secondary valve means regulating the flow of air to the secondary combustion chamber, and an actuator for said secondary valve means movable in response to a series of predetermined values. I v

4. An incinerator for the, combustion of waste material of the type defined in claim 3 whereby the predetermined values controlling air flow to the secondary combustion chamber are sensed by control means independent from that controlling air flow to the primary combustion chamber.

5. An incinerator for the combustion of waste material therein comprising a housing enclosing a primary combustion chamber having an inlet for waste material and an outlet for the exhaust of products of combustion therefrom, a secondary combustion chamber having an inlet and an outlet duct, duct means connecting the outlet for exhaust from the primary combustion chamber to the inlet to the secondary combustion chamber, a source of air for combustion, a supply duct feeding air from said source to the primary combustion chamber, duct means for the supply of air for combustion to the secondary combustion chamber, valve means regulating the flow of air to the primary and to the secondary combustion chambers, and control means for said valve means including a timing primary comand to the secondary combustion chambers.

7. An incinerator as defined in claim 6 wherein the contours of the camming means controlling the air flow to the primary and to the secondary combustion chambers differ one from the other.

Claims (7)

1. An incinerator for the combustion of waste material therein comprising a housing enclosing a primary combustion chamber having an inlet for waste material and an outlet for the exhaust of products of combustion therefrom, a source of air for combustion, an air supply duct feeding air for combustion from said source into said combustion chamber, valve means in the air supply duct regulating the flow of air to said combustion chamber, an actuator for said valve, and means controlling movement of said actuator in response to predetermined conditions whereby the valve moves to sequentially vary the air flow therethrough from the sourCe to the primary combustion chamber.

2. An incinerator for the combustion of waste material of the type defined in claim 1 wherein the actuator controlling movement of the valve in the air supply duct comprises a movable cam.

3. An incinerator for the combustion of waste material of the type defined in claim 1 including a secondary combustion chamber having an inlet and an outlet, duct means connecting the exhaust outlet of the primary combustion chamber to the secondary combustion chamber, an air supply duct connected to the secondary combustion chamber, secondary valve means regulating the flow of air to the secondary combustion chamber, and an actuator for said secondary valve means movable in response to a series of predetermined values.

4. An incinerator for the combustion of waste material of the type defined in claim 3 whereby the predetermined values controlling air flow to the secondary combustion chamber are sensed by control means independent from that controlling air flow to the primary combustion chamber.

5. An incinerator for the combustion of waste material therein comprising a housing enclosing a primary combustion chamber having an inlet for waste material and an outlet for the exhaust of products of combustion therefrom, a secondary combustion chamber having an inlet and an outlet duct, duct means connecting the outlet for exhaust from the primary combustion chamber to the inlet to the secondary combustion chamber, a source of air for combustion, a supply duct feeding air from said source to the primary combustion chamber, duct means for the supply of air for combustion to the secondary combustion chamber, valve means regulating the flow of air to the primary and to the secondary combustion chambers, and control means for said valve means including a timing mechanism, camming means moving in response to said timing mechanism, and actuating means for said valve responding to said camming means to provide a sequential actuation of said valve.

6. An incinerator as defined in claim 5 wherein independent cam means regulates air flow to the primary and to the secondary combustion chambers.

7. An incinerator as defined in claim 6 wherein the contours of the camming means controlling the air flow to the primary and to the secondary combustion chambers differ one from the other.

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