US1929880A - Process of incinerating and equipment therefor - Google Patents

Description

@ch M3, 11%30 w. A. @ARRAH PROUESS OF INCINERATING AND EQUIPMENT THEREFOR Filed May 26, 1928 ,M jg figure Za Patented Oct. 1 0, 1933 PROCESS OF INCI'NERATING ANDEQUIP- MENT THEREFOR William A. Darrah, Chicago, Ill.

Application May 26, 1928, Serial No. 280,901 5 claims. (01.110-14) 5 this invention is to provide a process and equipment which may be used to incinerate garbage with the production of a minimum amount of odor. Another object of this invention is to provide apparatus which will operate Without being seriously aected by the presence of waste foreign material. Another object of this invention is to provide equipment and a process which will,

completely consume the organic material leaving mainlyv the so-called ash or non-combustible material. YOther objects of this invention will appear from a consideration of the specications, claims and drawing which form a part herein, and include high thermal eiciency.

Referring to the drawing: i

Fig. I shows a side elevation partly broken away illustrating one form of my equipment, while;

Fig. II shows a vertical transverse section also 'partly broken away showing further details of my device.

Referring to the drawing, 1 indicates a substantial shell or-drum which is provided with tires 2 and 3 arranged to roll on trunnions 4 and 5 when driven by gear 6 which mesheswith pinion 7 which in turn is driven by pinion 8 on motor 9. Obviously other means of driving this equipment may be applied the form shown being selected for purposes of simplicity and clearness. The trunnions are mounted on supports or foundations 10 and 11 while motor 9 is for purposes -of convenience mounted on a support or foundation 12 Within shell l I may if desired provide a layer of insulation 13 or this may be eliminated depending upon operating temperatures, capacity, desired economy and other obvious factors. I have provided within drum 1 a series of laterally extending flights as shown diagrammatically by 14. In addition I nd it convenient to arrange the housing -of the drum, so that, it is inclined slightly from the horizontal, the direction of inclination being toward the furnace end.

A burner 15 is shown ring into combustion chamber 16 which is lined with refractory 17 and communicates with theopening 18 Ain drum 1. For a portion surrounding opening 18, I have provided a refractory lining 19 within drum 1 and may if desired provide insulation as shown at 20 to retain the heat within drum 1. 'In orderto provide a large space within the hot end of the drum (adjacent point 18) I have enlarged 27. The discharge from fan 26 is connected the shell of drum 1 as shown by 21. A space is provided at the lowerjunction between combustion chamber 16 and end 18 of drum 1. This is shown in Fig. I as the space indicated at 22. On the sides this space is suitably enclosed by housing 23 which connects to spout 24 discharging over slide or grizzly 25. At the opposite end of drum 1 is located a fan 26 which may be driven in any suitable manner as for examplevby motor to stack 28 and the intake of fan 26 is connected 65 by conduit 29 to bonnet 30 at the end of drum 1. The bonnet 30 and pipe 29 of course are stationary while drum 1 rotates maintaining at all times a close contact with bonnet 30. A blast gate 31 is provided in conduit 29 to control the volume of gases drawn through drum 1. A hopper 32 connected by chute 33 with vapor bonnet 30 serves to introduce the material to be treated into drum l. A damper 34 is provided near the 75 hot end of drum 1 making it possible to introduce outside air in order to dilute the products of combustion of burner 15. In the drawing I have shown damper 34 arranged in the upper portion of combustion chamber 16, but I do not wish to be limited to this exact location;

It will be apparent that many modifications of this equipment are possible Without departing 'from the essencev of my invention. Many mechanical expedients can be substituted for the arrangement shown as substantially all features are intended to be taken in a diagrammatic sense.

In the operation of my equipment the material to be treated is delivered into hopper, 32. This may be arranged by conveyors, elevators or desired equipment and the mechanism employed forms no part of this invention. From yhopper 32 the material passes through chute 33 entering vapor bonnet 30 and thus into rotary drum 1. As drum'l rotates the material which is usually moist and may contain such foreign material as cans, bottles, rocks, etc., is lifted and dropped continuously by means of the flights 14. With each interval of lifting and dropping as the drum rotates, the material will progress slightly toward l the combustion chamber end of drum 1. As'the material is thus lifted and dropped it is exposed to the action of the heated gases travelling through drum 1 under the action of fan 26. It will of course be apparent that if desired, I may replace fan 26 by a stack only and depend upon the so-calle'd draft of the stack to produce the desired circulation through the drum. I prefer, however, in most cases to obtain afpositive circulation in the manner outlined. no

The action of the material being lifted and end of the drum. I usually nd it' advisable to add an excess of air at end 18 of drum 1, thus somewhat diluting the hot products of combustion and at the same timel providing a greater volume of circulating gases in shell 1, thus more effectively drying the material being treated.

When properly operated this equipment may deliver the garbage to the enlarged portion 21 of drum 1 in a condition, such that it is substantially free from moisture. Under this condition the dry material burns readily giving very little smoke and substantially no odor. The additional air supply at end 18 of drum 1 naturally favors the complete combustion of the dried material in hot zone 18 of drum 1.

As drum 1 continues to rotate the ashes and non-combustible material travel continuously toward housing 23 and eventually pass out through spout 24. The larger particles such as bottles, cans and waste material will slide along grizzly 25 collecting in chamber 35 Where they may be removed as desired. The finer ash will fall directly through grizzly 25 into chamber 36 where they may be removed by a conveyor 37 or in any other desired manner.

It will'be apparent from the above description that the equipment which I have invented offers means of first drying garbage or foreign material and second burning the dried garbage. The equipment provides means for carrying out this operation automatically and continuously up to the capacity of the equipment, the apparatus also accomplishes this result without interference by such foreign material as cans, bottles, etc.

If the operation of this equipment is compared with the operation of present commercial types of incinerators it will be noted that many advantages exist. In the first place present commercial incinerators ordinarily are constructed with a substantial vertical brick stack and a grate on which coal or other fuel may be burned in the lower portion of the stack.` In actual operation present types of incinerators have a tendency to arch and jam when loaded. In order to overcome this difiiculty it is necessary to more or less continuously shake or poke the present equipment. Under these conditions it usually happens that large quantities of wet garbage are delivered into the hot grates with the result that very objectionable odors are given off. The odors thus produced result ordinarily from the fact that the combustion of the garbage is arrested before being completed. 'I'he partially burned vapors which result causes the objectionable odors. The combustion is arrested in present commercial incinerators because of the chilling effect of the large masses of cold wet garbage which are'suddenly added to the hot zone.

In order to reduce as far as possible the other objectionable odors which arise from present installations, it is customary to build large stacks which are unsightly and expensive and which are not uniformly effective under all weather conditions. It will be apparent that with my equipment the difliculties outlined are completely eliminated and many other advantages obtained.`

It should be understood that this equipment may operate to advantage on ordinary municipal garbage, on sewerage sludge, on waste paper or other waste products and also in the roasting or combustion of such materials as vcertain ores,

slag or trade wastes. I, therefore, do not wish this invention to be limited to any special class of material.

It will further be apparent that with my equipment the heat liberated by the combustion of the dried material in zone 18 serves in turn to further heat and, therefore, dry the incoming material thus making the process cumulative and reducing the heat requirements to a minimum.

As an example of the economy of such an arrangement I have found that in the case of garbage containing around 30% of moisture and '70% of carbohydrates and fats, suiiicient heat is liberated to carry on the operation in many cases without the burning of extra fuel.

It should be understood that burner 15 is used in a diagrammatic sense and I may employ as a source of heat, gas, oil, coal, coke, wood or anydesired fuel.- I may of course substitute a grate for burning solid fuel in place of burner 15 which would be adapted for burning pulverized, liquid or gaseous fuel.

Having now fully described my invention, what I claim as new and Wish to secure by Letters Patent in the United States, is as follows:

1. In an apparatus for incinerating combustible materials and the like, a rotating drum arranged to rotate integrally therewith, a drying chamber in one end of said drum, means for feeding material into said drying chamber, a combustion chamber in the opposite end of said drum, a stationary combustion chamber adjacent and communicating with said rotary combustion chamber, a fuel supply device in said stationary combustion chamber, means for discharging the material from the rotary combustion chamber, positive mechanical means for producing a positive draft through said drum, and a valved inlet in said stationary combustion chamber for admitting atmospheric air at room temperature directly to the upper portion of said stationary combustion chamber to be drawn over the combustion zone by said draft means to mix with and cool the products of combustion prior to their entry, into said drying chamber.

2. In an apparatus for incineratingcombustible materials and the likea rotary drum, a drying chamber in one end of said drum, means for feeding material into said drying chamber, a combustion chamber inthe opposite end of said drum integral therewith and arranged to rotate with said drying chamber, a stationary combustion chamber adjacent and communicating with s'aid rotary combustion chamber, means for discharging material from the combustion chambers, mechanical means for producing a positive draft through said drum, a controlled air inlet in the upper portion of said stationary combustion chamber for admitting atmospheric air directly thereto at room temperature lto be drawn over the combustion zone by said draft means to mix with and thereby cool said products of combustion prior to their entry into the drying chamber. f

3. The method of incinerating wet material which consists in drying the material to be treated, lifting and dropping said material during thev drying operation', burning said material without materially reducing its temperature after drying, adding contrlled quantities of atmospheric fair to the products of combustion previously produced, thereby cooling said products of combustion and causing said mixture of productsof combustion and atmospheric air to pass over said material while being dried, without scorching same.

4. The method of continuously incinerating `wet material which consists in drying the material to be treated while strongly agitated and subjected to a rapid current of hot gases, burning said material after drying without substantial reduction of temperature, reducing the temperature of the products of combustion resulting from said burning operation by the admission of cooler gases and causing said mixture of cooled products of combustion to pass over another portion of said material while being dried under conditions such that scorching is prevented.

A. DARRAH.

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