US3698331A - Apparatus and method for the disposal of liquid waste material - Google Patents

Abstract

An incinerator and method for the disposal of liquid waste material containing a substantial amount of water. The incinerator comprises a hollow shell having an inclined elliptically shaped thermally conductive baffle plate having a plurality of openings therethrough. The baffle plate is mounted at an oblique angle inside of the shell, dividing the latter into two portions. Liquid waste material is sprayed through a nozzle onto the upper surface of the baffle plate while a fuel-fired flame is directed against the lower surface of the baffle plate. Water is rapidly evaporated and combustible components of the liquid waste material are burned, the water vapor and combustion products passing into the atmosphere through a flue.

Description

United States Patent [151 3,698,331 Rohr et a1. Oct. 17, 1972 [5 APPARATUS AND METHOD FOR THE 3,572,265 3/1971 Stockman ..110/18 DISPOSAL OF LIQUID WASTE MATERIAL Primary Examiner-Kenneth W. Sprague [72] Inventors: Alton J. Rohr, Framingham; Cor- Attorney Harry Saragovltz et 11:22:: J. McKeown, Natick, both of [57] ABSTRACT [73] Assignee: The United States of America as n incinerator and method for the disposal of liquid represented by the Secretary of the waste material containing a substantial amount of Army water. The incinerator comprises a hollow shell having an inclined elliptically shaped thermally conductive Flledi J y 1971 baffle plate having a plurality of openings [21] Appl No ;163,794 therethrough. The baffle plate is mounted at an oblique angle inside of the shell, dividing the latter into two portions. Liquid waste material is sprayed 1 Cell. ..110/7 2 2510512: through a nozzle omo the upper surface of the harm ll. g It f fi fl td inst th paew eaue e aes rece aga e [58] held 8 8 Is 18 C lower surface of the baffle plate. Water is rapidly References Cited evaporated and combustible components of the liquid waste material are burned, the water vapor and combustion products passing into the atmosphere through a flue.

10 Claims, 3 Drawing Figures PAIENTEDnm 11 m2 SHEET 1 [IF 2 kwezaaons: damn I B0718 JMaKeowra; .W, 7% M M 6.

PATENTEDnm 11 m2 SHEET 2 OF 2 liwezii'om: damn J. 1807247 'coameww J. Mal'feowzw,

APPARATUS AND METHOD FOR THE DISPOSAL OF LIQUID WASTE MATERIAL back of the front lines. They require sanitary facilities for these groups, such as batteries of shower baths, lavatories, and latrines to service groups of up to about 250 men. This poses a problem of disposing of up to about 100 gallons of urine per day and, with an equal quantity of flushing water added, a total of up to about 200 gallons per day of diluted urine for a group of 250 men. Without sewage disposal plants, such as are common in most developed areas, it has become important for military operations in the field that sanitation facilities be provided including equipment for disposing of liquid waste materials, such as urine, substantially as fast as it is accumulated in storage tanks connected to the latrines.

Accordingly, an object of the invention is to provide an improved incinerator for the disposal of liquid waste material containing a substantial amount of water.

Another object is to provide a method for sanitarily disposing of liquid waste material containing a substantial amount of water.

Other objects and advantages of the invention will become apparent from the following description of the invention, and the novel features will be particularly pointed out in connection with the appended claims.

In the accompanying drawings:

FIG. 1 is a side elevation of the incinerator of the invention;

FIG. 2 is a vertical section through the incinerator along the line 2-2 in FIG. 1 looking toward the end of the incinerator in which a burner is mounted, and showing a baffle plate mounted in the incinerator; and

FIG. 3 is a plan view of the baffle plate looking at the upper surface thereof.

In the illustrated embodiment of the invention, the incinerator 10 comprises a hollow shell 11 in which the liquid waste material 12, which is sprayed into the shell by spray nozzle 13, is evaporated and burned. The liquid waste material in fine spray form impinges on the upper surface of baffle means 14, most of the spray striking the top portion of the baffle means because of the upward tilt of the spray nozzleJHowever, a portion of the spray also strikes the inside surface of the top of the shell between flue stack 15 and the baffle means to prevent the top of the shell from being overheated by the flame 16 produced inside of the shell by fuel-fired burner 17, which is preferably fired with oil.

Baffle means 14 is preferably a thermally conductive plate made of corrosion resistant material, such as a corrosion-resistant metal or alloy, having a plurality of spaced openings 18 passing therethrough from the upper surface to the lower surface thereof for the flame from the fuel-fired burner to pass through on its way to flue stack 15. The baffle plate is preferably elliptical in outline shape. This enables tilting of the baffle plate so that an included angle of about is formed between the upper surface of the baffle plate and the top of the shell. Thus the interior of the shell is divided into two distinct portions by the baffle plate, namely a burner portion 19 and a nozzle portion 20. The baffle plate is supported by a pin 21 mounted in the top of the shell against which the baffle plate rests, a rod 22 mounted horizontally in the shell about midway between the top and bottom of the shell, the rod preferably being welded at each end thereof to a sidewall of the shell, and a bracket 23 releasably held against the lower end of the baffle plate by a wing bolt 24 which is screwed into nut 25, the latter being welded to the bottom of the shell. The baffle plate is readily removable from the shell for purposes of cleaning out the incombustible ash that drops to the bottom of the shell. This is accomplished by unscrewing the wing bolt 24 and lifting the baffle plate out of the shell through the nozzle portion thereof after removal of the end plate 26 from the shell which is made possible by unscrewing bolts 27.

As illustrated by FIG. 3, the elliptically shaped baffle plate has an angle iron 28 welded to the upper surface of the baffle plate along the long axis of the baffle plate. This angle iron provides support to the baffle plate to prevent its being warped by the approximately 2,000F. temperature developed in he baffle plate by the flame. The fine spray of liquid waste material impinging on the baffle plate is rapidly heated by the baffle plate as well as by the flame and combustion products from the oil burner which pass through the spaced openings in the baffle plate and deliver heat to the droplets in the fine spray of liquid waste material in the nozzle portion of the shell adjacent to or in the vicinity of the baffle plate. Rapid evaporation of the water in the liquid waste material occurs, the water vapor being conducted into the flue stack 15 and any extension thereof by the hot combustion products and thence into the external atmosphere. Any combustible solids present in the liquid waste material are burned, contributing additional heat and combustion products to those derived from the fuel. Any incombustible materials, such as salts and metal oxides, drop to the bottom of the shell and must be cleaned out periodically, as described above.

The baffle plate for use in the disposal of urine may be made of any of a large number of corrosion resistant metals or alloys, among which are the Hastelloys. However, it is preferably made of Inconel 600, l 1 gage (0. l 25 inch thick), having six one-fourth inch diameter openings per square inch therethrough, the openings being on 7/ 16-inch staggered centers, with an open area of about 30 percent of the total area of each of the upper and lower surfaces of the baffle plate. A metal plate product manufactured by Ferguson Perforating & Wire Co., Providence, R]. has these characteristics. If the baffle plate were constructed of appreciably heavier gage material, it would be possible to dispense with the angle iron 28, which gives support to the baffle plate. However, this would appreciably increase the cost of the baffle plate, which must be constructed of corrosion-resistant material because of the corrosiveness of urine, particularly at elevated temperatures.

The angle at which the baffle plate is inclined with respect to the top of the shell is selected so that any of the liquid waste material that impinges on the baffle plate in the liquid state will flow by gravity along the solid portions of the upper surface of the baffle plate and will not drop off the baffle plate into the bottom of the shell. It is preferred that this angle be about 60. If the angle is much greater than 60, the spray of liquid waste material is likely to pass through the openings in the baffle plate to too great an extent and cause the flame to be extinquished by too rapid cooling of the fuel vapors. If the angle is much less than 60, the liquid waste material which impinges on the baffle plate may flow down through the openings in the baffle plate and drop off before the water has absorbed enough heat to cause evaporation thereof.

The openings through the baffle plate are of such diameter and spaced apart so that it is very unlikely that the spray of liquid waste material will pass through the baffle plate and cool the fuel vapors to such an extent as to extinquish the flame.

The rate of flow of fuel and the rate of flow of the liquid waste material must be maintained within close limits if efficient disposal of the liquid waste material is to be accomplished. It has been found to be better to use too much fuel rather than not enough since in the latter case liquid waste material will not be heated fast enough and will flow by gravity down the baffle plate to the bottom of the shell and will, therefore, necessitate too frequent cleaning out of the incinerator. Furthermore, the cleaning of the incinerator will be much more difficult if large amounts of the liquid waste material have been allowed to flow down or drip off of the baffle plate to the bottom of the shell. On the other hand, if a large excess of fuel is used over that required to evaporate and burn the liquid waste material as rapidly as it is sprayed into the incinerator, the incinerator will become overheated, creating problems of distortion of the metal parts thereof. it has been found to be desirable to incinerate diluted urine at a rate of about 8 gallons per hour employing a back pressure of about 18 to 20 p.s.i. ln order to do this, it has been found best, when using fuel oil in the fuel burner, to operate the burner at a flow rate of about 1.5 gallons of fuel oil per hour and not to allow the fuel oil to impinge on the baffle plate. When the supply of urine in the storage tank (not shown) decreases to a predetermined low level, the burner ceases to operate but the urine pump (not shown) continues operating for about 20 seconds, forcing urine into the incinerator. When the urine flows into the storage tank and reaches a predetermined level, the burner is started again to preheat the incinerator. After about 50 seconds, the pump is turned on and spraying of urine into the incinerator is resumed, both fuel oil and urine being pumped at the above-described flow rates. The urine pump is permitted to continue operating for a short time after the burner is shut off to provide cooling of the incinerator. The burner is started before the urine pump after a shutdown in order to avoid accumulations of unevaporated and unburned urine in the bottom of the incinerator shell.

In general, a high temperature in the incinerator is desirable in order to maintain the temperature of the exhaust gases in the flue stack at a high level since the escape of odors into the surrounding atmosphere is minimized under these conditions.

If it is desired to vary the rate of fuel flow, it is necessary in order to obtain the best results to vary the positioning of the baffle plate. The higher the flow rate of the fuel, the farther removed the baffle plate should be from the burner nozzle; vice versa, the lower the flow rate of the fuel, the nearer the baffle plate should be to the burner nozzle.

The spray nozzle for spraying urine on the baffle plate is preferably a model H2B Spraco nozzle, manufactured by Spray Engineering Co., Burlington, Mass. This type of nozzle produces a hollow cone-shaped spray pattern, the droplets being quite fine. However,,it is best not to use a nozzle which produces too fine a spray since, in such a case, some of the extremely fine droplets of urine are carried out the flue stack without evaporating and burning.

In order to keep the incinerator of the invention operating as smoothly as possible with a minimum number of interruptions, it has been found that the addition of about 1 pint of 5 percent hypochlorite bleach solution to the supply of urine in the storage tank twice a day eliminates plugging of the filter and the building up of a precipitate of calcium magnesium phosphate on the pump impeller to such an extent as to cause jamming of the pump. The calcium magnesium phosphate results from the action of microorganisms on the urine. Thus, the hypochlorite keeps in check the growth of microorganisms in the urine and eliminates the precipitation of calcium magnesium phosphate in critical parts of the liquid waste disposal apparatus.

The incinerator and method of the present invention are very useful in disposing of liquid waste materials, such as urine, by evaporation of the water therein and combustion of the combustible components thereof and elimination of the evaporated components and combustion products into the atmosphere. This avoids contamination of streams in the vicinity of concentrations of troops in military operations where normal sewage handling facilities are not available. Advantages include better sanitation since the high temperatures employed in the incinerator destroy all microorganisms present in the liquid waste material.

It will be understood that various changes in the details, materials and arrangements of parts which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention.

We claim:

1. In an incinerator for the disposal of liquid'waste material containing a substantial amount of water comprising a hollow shell wherein said liquid waste material is evaporated and burned, the combination of a burner means for directing a fuel-fired flame into said shell from a first end thereof, a spray nozzle means for directing a fine spray of said liquid waste material into said shell from the other end thereof, a flue means for conducting evaporated components and combustion products from said liquid waste material and said flame out of said shell, and a baffle means positioned in said shell between said burner means and said spray nozzle means, said baffle means comprising a thermally conductive plate having a plurality of spaced openings therethrough and being disposed within said shell to provide an inclined upper surface facing said spray nozzle means such that liquid waste material impinging on said upper surface will flow by gravity along said upper surface, said spray nozzle means being adapted to direct said fine spray of liquid waste material upon the inclined upper surface of said baffle means, said burner means being adapted to direct said flame against the lower surface of said baffle means, whereby the heat from said flame is transferred to said liquid waste material on and in the proximity of the upper surface of said baffle means to evaporate the aqueous portions of said liquid waste material and to burn the combustible portions of said liquid waste material.

2. A combination as set forth in claim 1, wherein said shell is in the form of a cylinder, the central axis of said cylinder being in a substantially horizontal plane.

3. A combination as set forth in claim 2, wherein said baffle means is a generally elliptically shaped plate conformed to substantially completely divide the interior of said shell into two portions.

4. A combination as set forth in claim 3, wherein the included angle formed between the upper surface of said baffle plate and the top of said shell is about 60.

5. A combination as set forth in claim 3, wherein said spaced openings are generally circular and spaced apart substantially equidistantly, the total areas of said openings being about 30 percent of the total surface area of said upper surface and of said lower surface of said baffle plate.

' 6. A combination as set forth in claim 4, where said spray nozzle means is adapted to produce a hollow cone-shaped spray.

7. A combination as set forth in claim 6, wherein said spray nozzle means is directed upward from the horizontal to direct said spray toward the top portion of the upper surface of said baffle plate and toward the internal surface of the top portion of said shell adjacent to the upper surface of said baffle plate.

8. In a method of disposing of liquid waste material containing a substantial amount of water which is characterized by spraying said liquid waste material into the interior of a shell and directing a liquid fuelfired flame into said interior of said shell to evaporate the aqueous portions of said liquid waste material and to burn the combustible portions of said liquid waste material, the improvement which comprises spreading said liquid waste material on a first surface of a perforated baffle plate and directing said flame on the surface of said perforated baffle plate opposite to said first surface, whereby the heat from said flame is more efficiently transferred to said liquid waste material than in the absence of said perforated baffle plate.

9. In a method as set forth in claim 8, wherein said spreading of said liquid waste material on said first surface of said perforated baffle plate is carried out by spraying said liquid waste material on said first-surface of said perforated baffle plate.

10. In a method as set forth in claim 9, where said spraying of said liquid waste material is carried out at a flow rate of about 8 gallons per hour at a back pressure of from about 18 to about 20 pounds per square inch and said flame is produced by fuel oil at a flow rate of about 1.5 gallons per hour.

Claims (10)

1. In an incinerator for the disposal of liquid waste material containing a substantial amount of water comprising a hollow shell wherein said liquid waste material is evaporated and burned, the combination of a burner means for directing a fuelfired flame into said shell from a first end thereof, a spray nozzle means for directing a fine spray of said liquid waste material into said shell from the other end thereof, a flue means for conducting evaporated components and combustion products from said liquid waste material and said flame out of said shell, and a baffle means positioned in said shell between said burner means and said spray nozzle means, said baffle means comprising a thermally conductive plate having a plurality of spaced openings therethrough and being disposed within said shell to provide an inclined upper surface facing said spray nozzle means such that liquid waste material impinging on said upper surface will flow by gravity along said upper surface, said spray nozzle means being adapted to direct said fine spray of liquid waste material upon the inclined upper surface of said baffle means, said burner means being adapted to direct said flame against the lower surface of said baffle means, whereby the heat from said flame is transferred to said liquid waste material on and in the proximity of the upper surface of said baffle means to evaporate the aqueous portions of said liquid waste material and to burn the combustible portions of said liquid waste material.

2. A combination as set forth in claim 1, wherein said shell is in the form of a cylinder, the central axis of said cylinder being in a substantially horizontal plane.

3. A combination as set forth in claim 2, wherein said baffle means is a generally elliptically shaped plate conformed to substantially completely divide the interior of said shell Into two portions.

4. A combination as set forth in claim 3, wherein the included angle formed between the upper surface of said baffle plate and the top of said shell is about 60*.

5. A combination as set forth in claim 3, wherein said spaced openings are generally circular and spaced apart substantially equidistantly, the total areas of said openings being about 30 percent of the total surface area of said upper surface and of said lower surface of said baffle plate.

6. A combination as set forth in claim 4, where said spray nozzle means is adapted to produce a hollow cone-shaped spray.

7. A combination as set forth in claim 6, wherein said spray nozzle means is directed upward from the horizontal to direct said spray toward the top portion of the upper surface of said baffle plate and toward the internal surface of the top portion of said shell adjacent to the upper surface of said baffle plate.

8. In a method of disposing of liquid waste material containing a substantial amount of water which is characterized by spraying said liquid waste material into the interior of a shell and directing a liquid fuel-fired flame into said interior of said shell to evaporate the aqueous portions of said liquid waste material and to burn the combustible portions of said liquid waste material, the improvement which comprises spreading said liquid waste material on a first surface of a perforated baffle plate and directing said flame on the surface of said perforated baffle plate opposite to said first surface, whereby the heat from said flame is more efficiently transferred to said liquid waste material than in the absence of said perforated baffle plate.

9. In a method as set forth in claim 8, wherein said spreading of said liquid waste material on said first surface of said perforated baffle plate is carried out by spraying said liquid waste material on said first surface of said perforated baffle plate.

10. In a method as set forth in claim 9, where said spraying of said liquid waste material is carried out at a flow rate of about 8 gallons per hour at a back pressure of from about 18 to about 20 pounds per square inch and said flame is produced by fuel oil at a flow rate of about 1.5 gallons per hour.

Images