CA1102626A - Waste disposal system and method - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Disclosed is a portable waste disposal system that is designed primarily for use in marine craft, mobile homes, campers or the like.
The system comprises a macerator until for converting excrement to a liquified effluent, and an incinerator unit for incinerating the effluent.
The macerator unit comprises a holding tank which receives the waste material from a toilet. When the level of the excrement within the holding tank reaches a predetermined level, and maintains that level for a predetermined period of time, the system is activated and the excrement from the holding tank is macerated by a macerator and provided to a feed compartment. A circulation pump then pumps the macerated effluent from the feed compartment through a circulation line to the incineration unit.
The incineration unit comprises a combustion chamber and an additional feed pump which draws effluent from the circulation line and feeds the effluent into the combustion chamber. A crucible is disposed within the combustion chamber for receiving the effluent fed therein.
A burner is provided which introduces a high temperature flame into the combustion chamber to incinerate the effluent in the crucible. The crucible is elevated from the floor and spaced from the walls of the combustion chamber so that the flame from the burner fills the entire combustion chamber and heats the crucible on all sides. The effluent within the crucible is incinerated until all of the liquid is vaporized and the remaining solid waste material is reduced to a fine ash.

The fuel for the burner is reguinted by a pair of fuel valves, one of which is cycled to maintain the temperature of the exhaust gases from the combustion chamber within predetermined limits. In addition, the entire incineration operation is conducted at a sufficiently elevated temperature so that no offensive odor is created. A pot rotator motor is also provided for rotating the crucible after the incineration cycle is complete to dump the remaining ash material to the floor of the com-bustion chamber. A convenient ash removal duct is provided at the rear of the incineration unit for removing accumulated waste material.
The incinerator unit also includes a novel cooling system for dissipating the heat from the combustion chamber, and cooling various critical components to insure the proper operation of the system. The entire system is operated under the control of a solid state control circuit which continuously monitors the system to insure that it is operating within certain critical parameters. As a safety precaution, if various positive checks are not confirmed, the control unit automati-cally shuts down the system, thus eliminating the possibility of an accidental fire.

Description

Bl~C~CGr~OVND ~ND SUI\/IM~RY O:F TI~ 3NTION
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20 `The present invention relates to a portable was:te disposal system that is adapted primarily for use in marine craft, mobile homcs, trailers and the like.
~c to incrcasingly strict ~deral and statc environmcntal re~ulations, it h~s becomc neccssary to avoid thc discharge of un-25 treated scwa~c from boàts and other vchiclcs, as wcll as tl)c ' i ' ~

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indi~:criminate tlisposal of scwaE~c in any cnvironment, cven rcmota and rural arcas. Prescnt day air pollution stalldards havc also madc thc discharge of m~xious odors into the atmosphcrc illc~al in many areas. In addition, a gencral increased concern ovcr the cnvironment has made the disposal of raw sewagc and tile discharge of oifensive - odors extremely undesirable.
Many procedures have been proposed ior the disposal o sewage under such difficult conditions as e~ist where the sanitary - .
iacilities are carricd by vehicles. The use OI heat to vapori~e the liquid eîfluent from the source OI sewage, or from an intermediate septic tank, has been proposed. In some instances; waste hcat from an internal combustion engine or other heat source carrled by the vehicle has been employed. Boilers and vaporization chambers have also been utilized into which the sewage or liquid efIluent is directly introduced. E~owever, with such systems, the minerals and organic solids in the efnuent eYentually form a caked deposit on the internal walls of the boilers or vaporization chambers, thus acting as a hea~
ins~liator, and greatly r~ducing the volume of the boiler and the effi-ciency of the heat transfer to the boiler ~ZvallsO Consequently, the boiler is no longer capable of operating at optimum eîEiciency, and may also be incapable of ~aporizing waste matcrial at the required ,~ rate. The reduced operating temperature can also result in ihe crea-tion of noxious odors in greater quantity.
1~ typicai wastc disposal systcm currently used in many marine craft simply compriscs an incincrator unit locatcd dircctly bcneath the toilct for rccciving thc wastc matcrial. The systcm ~s opcrated s;mply ,~ ' ' ,' ' ~ ' . . .

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:, . ' , ' by closing a hatch located at the top of the unit and activating a burner which :Lncinerates the excrement for a predetermined period of time. After several operations of the ; system, the incinerator must be cleaned through the same hatch;
which can be a very unpleasant and tedious task.
The present invention seeks to Overcome the disadvantages of these prior art systems by providing a portable waste disposal system that operates completely automatically~
generates no offensive odors, requires infrequent cleaning and is easy to clean. In addition, the present system is adapted to incinerate the waste material as completely as possible so that a minimum amount oE solid waste material is left unconverted. In particular, the present invention is adapted to produce only approximately 15 grams of solid matter for every gallon of excrement disposed. Consequently, on the average, clean out of the system is required only every 14 days when continuously in use. In addition, the system can dispose of approximately one gallon of excrement every hour, which is sufficient to accommodate the excrement o-f as many as 8 adults on a continuous basis when a flush efficient marine type toilet is used.
The problems of the prior art are overcome by the present , invention which broadly provides, in a waste disposal system for disposing of excrement including an incinerator having a ~, burner and a first fuel valve for supplying a minimum amount . ~
of fuel to the burner and a second fuel valve for supplying an additional amount of fuel to the burner, the method oE
disposing of excrement including the steps of converting the - ~ excrement to a substantially liquified effluent, igniting ::
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the burner, feeding effluent into the incinerator, regulating the second fuel valve in response to exhaust gas temperature to boil away the liquid in the effluent at a first average fuel-to-air mixture, terminating the feeding of effluent into the incinerator, and regulating the second fuel valve in response to the exhaust gas temperature after the liquid has been boiled away to incinerate the remaining waste material at a second lower average fuel-to-air mixture.
Apparatus for carrying out the above method may be seen to provide in a portable system for disposing of excrement comprising a coversion unit for converting the excrement to a substantially liquified effluent and an incineration unit for incinerating the effluent, the improvement wherein the incineration unit includes a combustion chamber, a burner for p introducing a high temperature flame into the combustion chamber, feed means for feeding effluent into the combustion chamber, and fuel means for supplying fuel to the burner in accordance with the temperature of the exhaust gases from the combustion chamber including first valve means for supplying a minimum amount of ; 20 fuel to the burner and second valve means for regulating ~he ~` supply of additional fuel to the burner in accordance with the temperature of the exhaust gases.
More particularly, the present system utilizes a macerator -~ unit for converting the excrement to a liquified effluent, and an incinerator unit for incinerating the liquified effluent.
The macerator unit comprises a tank that is divided into a ~ holding compartment and a feed compartment. Excrement is -~ supplied through a waste inlet into the hold1ng compartment from where it is macerated and provided to the feed compartment.
liquid circulation pump draws the effluent from the feed a-~, : . , . -, . :
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compartment and pumps the effluent to the incinerator unit, which may be located at a point on -the craft or vehicle quite remote from the macerator unit.
The incinerator unit essentially comprises a combus-tion chamber having a crucible disposed therein for receiving the effluent. Controlled amounts o~ effluent are supplied to the cc~bustion chamber by a feed pump which draws effluent from the circulation line supplied by the liquid circulation pump from the macerator unit. A high temperature burner is mounted on the top of the combustion chamber that is adapted to generate a downwardly directed flame which engulfs the entire combustion chamber. The fuel for the burner is provided by a fuel pump and is regulated by a pair of ~uel valves. The primary fuel valve is adapted to proYide a minimum amount of fuel to the burner, and the secondary fuel valYe is cycled between its open and closed position in accordance with the temperature of the exhaust gases ~rom the combustion chamber. In this manner, the temperature of the incineration process can be controlled within preselected temperature parameters to optimize the incineration ~"
~o process and prevent the ~roduction of offensive odors. The ,~:
effluent within the co~bustion chamber i`5 incinerated un~il all , r of the liquid has been yaporized and the remaining solid matter s~ has been reduced to a fine ash. The latter part of the incinera-'I
tion cycle, or burn-out cycle, is conducted with a r~duced fuel-to-air mixture so that the remaining solid waste matter is completely oxidized. In this manner, only a minimum amount of solid waste matter is completely oxidized. In this manner, only :;~
;~ a minimum amount of solid waste matter remains after the com-pleted incineration cycle. In addition, by completely oxidizing the csm~

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colid mnttcr to a finc ash, thc crucil)lc can be rcadily empticc3 of tha remainin~ ash matcrial simply by rotatin~ the crucil~lc to dump the material to thc floor Or thc chamber. l~rom therc, the ash matcriial i~i easily removcd from the unit via a convenient ash removal duct located at the rear of the unit. In this manner, the continuous build-up or caking of the effluent within the incinerator unit is avoided, The incinerator unit is co~cd by a pair of forccd draft fans which circulate ambient air through a pair of cooiing chambers w~ich completely surround the combustion chamber. The air from the cool-ing chambers is then mixed with the e~haust gases îrom the combustion chamber to cool the exhaust gases b,_Iore being expelled from the in- -cinerator lmit. In addition to providillg cooling or the combustion chamber, the fans also serve other cooling functions. In l)articular, the primary cooling fan draws ambient air through the control com-partment to dissipate the heat from the electronic control unit, and . i . . . . .
also directs cooling air along the shait connecting the pot rotator motor to the crucible within the combustion chamber. In this rnannerJ the ;; motor is protected from the intense heat o~ the combustion chamber whicl would otherwise be transmitted along the s~alt and cause the 2û motor to overheat.
Sirnilarly, the combustion fan, in addition to drawing ambient air around tlle combustion cllamber, providcs thc air supply Ior thc~ ;
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~; ~ burner, and also supplies cooling air along the cfIluent fced line into ~ ~ the combusilion chambcr to cool tbc fced linc and prevcnt t~1c heat from ; ~ 25 tl-c combustion chamber Irom causi1lg thc efflucnt to cakc witllin thc fecd linc! i .

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, The entire ~aste disposal sys-tem is operated and controlled by a solid-state electronic con~ol uni-t ccmprising a d.c.
battery powered logic and timing unit and a hi~h current, high voltage transistor switchin~ panel supplying d.c. generator or rectified a.c. power to the various mechanical components.
In addition to controlling the entire sequence of events which occur during the system's operation, the control circuit continuously performs various safety checks to insure that the system is operating within specified critical parameters. If at any time a condition arises which does not fit within these parameters, the control circuit automatically enters an emergency shutdown sub-routine which effectively deactivates the entire system, except for the fans, which continue to operate until the system has cooled to a sa~e leyel.

,~1 BRIEF DESCRIPTION OF THE_ DRAWl:NGS
; Other objects and advantages of the present invention will become apparent from a reading of the following detailed ~-;
description of the preferred embodiment which makes reference ` 20 to the following set of drawings in which:
,'~ Figure 1 is a block diagram of a typical application of the present invention;
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.:. . .: , 1~2~6 Fi~ure 2 is a plan view of the macerator unit of the present invention;
l~igus~e 3 is a dia~rammatieal view of the ;neinerator unit of the present invention;
F'igure 4 is another view of the incinerator unit illustrated in ~igure 3; ;
Figure 5 is a plan Yiew of the componeDt compartment o:E the .
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il~einerator unit;
Figure 6 is an illustration of the take-off fro~ the circu}ation 10 line to the ineinerator unit;
Figure 7 is a partial vi~w o~ the incinerator unit; .
Figure 8 is another partial view of the incinerator unit;
Figure 9 is a bloek diagram of the electronic control eireuit of the present invention; ' -Figllres 10 through 17 are block diagrams which represent .
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-~ ~ . the sequence of events which occur during the operation of the present - invention; and Figure.s 18 through 26 are circuit diagrams of the electronie . . . .
;~ . eontrol unit of the present invention;

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0 DETAIL~3D D13SCRIPTION OF TH:E~ PREFERR~ MBODIMENT
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~eIerring to FiL~ure 1, a general bloclc diagram illustratin~ - ;
a typical applieation of the present waste disposal system 10 is s]lown. t The eomplete waste disposal systcm cornprises thrce Sasic units, tho m~cerator unit 14, the incincrator unit lG, an~l the elcctronic control ~5 unit 1 B. Each of tllc tllree units may be loc'~te~l sepa;~aLe from the other .
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two units, although in thc prcfcrrcd cmbodi~ncnt tlle con~rol unit 1~
is locatedwithin tllc samc cnclosure that houscs thc incincrator unit il;o ' , ' . ~ , , Generally speakin~, the maccrator unit 14 is adapted to re-ceive excrement directly from a toilet 12 which may be located on a marine craft, mobilc home, camper trailer, ctc. The rnacerator unit 14 rnacerates or liquifies the excrement into an effluent which is provided to the incinerator unit 16. The illcinerator unit 16 is adapted . .
to dispose of the effluent by incineration at temperatures preferably lû in excess of 1000 F. When incinerated at these elevated temperatures, the majority of tlle elfluent evaporates in the form of water vapor and the remaining solid waste matter is reduced to a fine ash.
Both the macerator unit 14 and incinerator unit 16 are oper-ated under the control of a completely solid state electronic control 15 unit 1~, The control unit 18 essentially controis and monitors the .:, , .
~ ~ ~arious sequence of events which takes place during the system's oper-: ` ation; In addition, the control unit 18 continuously performs various .,, .
safety checks to insure that the system is operating within certain specified critical parametcrs.
Practically spealcing~ the present waste disposal system 10 has thc capacity to dispose of cxcremcnt at a rate of approximately onc gallon pcr l-our. CorrcspondinL~ly, the prescnt sysLcm can accom- ;
modate the cxcrcment of ci~ht adult individu;lls on a continuous basis wlJcn a flusll cfficicnt marine typc toilct is uscd. In addition, tl~c systcm ~! 25 - produccs only approxim.l~cly 15 ~rams of solid wastc matlcr for a~rcry ~allon Or cxcrcmcnt di6poscd Accoràin~ly, sincc t]lC disposal of .. . . . ... .. . . . . . ........ ......
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excrcmcnt ia e~o complctc, thc prcscnt systc~n lQ clil~inateY ~lC nc-ccsaity of frcqucnt clcaning'.
Loolcing to Figuro 2, a plan view of the macerator unlt 14 according to the prcscnt invention is shown. Thc maccrator unit 14 5 comprises a rectangular shaped tank 20 having a feed compartment22 and a holding compartmcnt 24 separated by a partition 26 disposed within the tank 20 parallel to its cnd surIaces. .An overflow 25 is pro- ' ' ~ided in the partltion 26 to lim,it the amount oî cffluent that can be stored in the feed compartment 22. In addition, it will be noted that the overflow, pipe 2S is designeci to prevent the unmacerated excre- ."p, .: , men in the holding compartment 24 from entering the feed compart .
ment 22 when the excrement in the holding compartment 24 is sloshed about by the roclcing of the vehicle or marine craft on which the dis-:~ posal system is located. The partition 26 is preferably located so that ~he volume of the holding compartment 24 is appro~imately three : to four times greater than that of the leed compartment 22. ~3xcremellt ,~
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is fed into the holding.compartment 24 through a waste inlet 28 located at th`e top of the tank 20. The waste inlet 28 also serves as a vent through whlch gases from the holding compartment 24 are expelled.
~' 2û ' Mounted to the top of the tanli 20 over the partition 28 is the macerator pump and motor 30. The intak,c to the macerator 30 is pro-vided through a Iar~e diametcr pipe 32 that extends through an op~ning ;n thc top of thc tanlc 20 to tl-e bottom of the llolding compartmcnt 2~. , ~.
I'}lc dischargc from thc maccrator 30 is dircctcd out of a smaller diamcter pipc 3~ into both tl~c fccd and holding comp~rtmcnts, 22 and a~ rca})cctivcly. Thc maccrator discllarGc pipc 3~ cxtcnding into thc ' ' : ' ' . ' . .
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holdin~ comp~rtmcnt 2g contains all ~dditional lcn~tl~ of pipc 3G formin~
a T~joint ncar thc l~ottom of thc hol~lin~ compartmcnt 2~, as shown, The openin~s at eithcr cnd of thc pipc 36 arc substantially rcstricted so as to form nozzlcs 38. In this manner, thc effluent dischargcd îrom the macerator 30 is expelled into the holdin~ compartment 24 at an increased velocity to facilitatc mixing oi the eiiluent and waste material . ,. . .
Also mounted to the top of the tank 20 of the macerator unit 14 is a liquid circulation pump 40 which circulates the macerated effluent through a circulation line 48 that extends from the macerator unit i4 to the incinerator unit 16 and back to the macerator unit 14, The liquid circulation pump 40 is operated by a motor 42 which drives r the pump via a gear box 44. The liquid circulation pump 40 draws . ~
;j,, effluent irom the feed compartment 22 thro~gh an opening in the top oi the tank 20. The eMluent is then circulated through the circulation line 48 that runs to the incinerator unit 16 and back to the feed com-.
partment 22 of the macerator unit 14O The liquid circulation pump 40 circùlates thc eifluent at a relatively high velocity so that the solid .
; ~ waste particles in the eiiluent do not settle and clog the circulation ~0 line 48. In addition, since the maGeratOr unit 14 may be located quite remote ~om tl e incineration unit 16, thc liquid circulation pump 40 is requircd to transport thc efflucnt irom thc macerator unit 14 to ,~
-thc incincrator unit lGo It is important to notc that thc liquid circula-tion pump 40 ~nust bc of thc revcrsible typc so that thc direction of cfflucnt iloiv in thc circulation linc g8 can bc rcvcrscd aftcr thc in~
cincration cyclc ;s complcted, ~s will subscqucntly bc cxplaincd .~ ~ ' . ', ~ ' .

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in ~reatcr dctail, this cnablcs the circulation linc 4~ to bo clcared .. . .
of cfflucnt bcfore tl~c systcm is deactivated so that thc circul~tion line ~B does not bccome clo~gcd irom the accumulation of sta~nant ~Yastc mattcrO Note also, that whereas the inlet pipc 46 of thc liquid circulation pump extcnds to tlle bottom of thc feed compartment 22, ` ' the return circulation'line 48 from the incinerator unit 16 does I~Ot ' ~
extend below the overflow 25 in the partition 26 hetween the two com- ' . .
partments. Accordingly, when the direction of the liquid circulating .pump 40 is reversed after ar~ incineration cycle, effluent from the îeed compartment 22 is no~ drawn into the return circulation line 48 to ,4 - ' . ' prevent the clearing of the line.

' ' Optionally, a stirrer or agitator 50 may be provided to cir-culate the macerated efnuent within the feed compartmen1: 22 during ~: ~he operation of the system to prevent solid waste particles from settling to the bottom of the tank.
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ln operation, when the waste material in the holding compart ' gi ' ment 24 reaches a predetermined level, a liquid level switch (not shown) disposed within the holding compartment 24 is activated initiating the c~peration of the system. As w~ll subsequentl~ be e.Yplained in greater detail in connection with the description of the control circuit 18 of the present system, the liquid circulation pump 40 is then activated to ~ -circulatc cfïlucnt to thc incincrator unit lG. For prcselected pcriods ~;

.durin~ Ule opcration of thc system, tl~ macerator pump and n~otor 30 ArC opcrated to maccratc thc wastc from the holdin~t compartrncnt 24 ~5 and disc~ar~c thc liquificd cfflucnt into tl;c fced compartmcnt 22 and ~acl; into thc lloldin~ compartmcnt 2~. Sincc thc maccrator 30 can : , ' . ~ ' .: .

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' ` ' macerate WastC matcrial substanti~lly fast~r than thc incinerator unit 16 ean dispose of it, thc fced compartment 22 is always lilled witl~
e~fluent. In particular whercas thc incincrator unit lG can only convcrt appro~imatcly a fourth oî the capacity of the Ieed compartment 22 at a time the macerator 30 can fill the feed compartment 22 with macerated excrement from the holding compartment 24 in approx-i~nately 1 minute. Thus it will be und~rstood tbat the ef~luent that is drawn from the feed compartment 22 and supplied to the incinera~or unit 16 comprises waste material that was macerated during the pre-~0 vious op~rating cycle of the waste disposal system.
Referring to Figure 3j the general structure of the inc;nerator unit 16 ~IJill now be explained. The incinerator unit 16 is contained ~ithin 2 rectangular shaped cabinet having a front door panel 52 that is fastened to the main body of the unit by a piano hinge The incin-erator unit 16 essentially comprises three separate compartments the incineration compaFtment the component compartment whioh is separated from the incineration compartment by a fire wall 54 and the control compartment which- is located on the inside of the front door panel ~2 and houses the electronic control circuit 18.
~ocated witMn the incincration compartment is tl~e combustion chambcr 56. The combustion chamber 5G comprises cylindrically shaped inncr and outcr shells 5~ and 60 rcspectiYcly tl~at are sep-arated by a laycr of insulation ~2. As can bcst be scen in Fi~ure 7 the combustion cllambcr 56 is clcvatcd from the lloor of the incincrator unit 16 by support;n~ mcmbcrs 6~, and spaccd from t]lc walls of tbe compartmcllt so as to dt finc an .lir sp~cc comp~ctcly sllrroundin~ tl-e r-13-:: . , : :
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cornbustion cl~ambcr. This air spacc compriscs thc primary coolinL~
chambcr 6~ for thc incincratox un;t 16 ;lnd is utilizcd to dis~;ipatc rnost of thc hcat ~encratcd within thc combustion chamber S6, Disposcd within the combus~îon chambcr 56 is a cruciblc 70 comprised of 3 hcmisphcrically shaped pot, l~le crucible 70 is suspendedwithin the combustion chamber 56 on opposing sides by a paîr of aligned shafts 68-arld G9 supported by the u~alLs 5~ and 60 of the chamber 560 Shaft 68 extends through the fire wall 54 into the component compart-- ment oi the incinerator unit 16 and is connected to a pot rotator motor 72 and electrical clutch 74 which are utilized to rotate the crucible ~"
70 within the combustion chamber 56, as will subsequently be des-cribed, As is best shown ir. Figure 8, mounted to the top of the com-bustion chamber 56 is a high temperature burner 76, which ma~ be oi1 fired, or operated with any other suitable l;quid or gaseous fuel.
The burner 76 utili7ed in the preferred ernbodiment herein ;s manu~ac-tured by Stewart-Warner Corporation. model number 10530-A2~ heater, although comparablc burners can, cf course, be employed. The present burner 76 is adapted to operate off the same fuel that is used in the engine of tlle vehicle or c~aft. In this manner, the nced for an alter-native filel supply is eliminaLed, The dischar~e of the burner 76 has a truncatcd coi~ical shape as shown, that is adapted to direct a flame , . downwardly into the con~bustion chambcr 56. During operation, the namc from thc hurncr 7G is of such ma~nltudc that thc entirc combus-tion chambcr 56 is cngulfcd in iilamc. In conncction tllcrewit]~, it i9 lmport;lllt that thc cruciblc 70 bc suspcndcd from tl~c floor and Gp~ccd ;

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:, ,, . : :-6~6 ~rom thc walls of thc combustion chambcr 5Go In this manncr, thc ~larnc from thc burncr 7~ is deflcctcd off thc wall~ and Iloor of thc combustion chambcr 56 so that heat is dircctly ;lpplied to all sides ~f the crucible ?0. As will be apprcciated by thosc slcilled in the art, S this ~:auses a more complcte burning of the ~I~luent, which in ~urn pIevents the efiluent from caking inside the crucible 70 aftcr repeated operations of the system. Accordingly, the ef~iciency of the inciner-ation unit 16 is maintained over prolonged periods of use.
Located inside the burner 76 adjacent the burner head 77 is an ignitor or glow plug 78. The glow plug 78, which is analogous to the cigar lighter in an automobile, is adapted to be energized prior to ignition of the burner 76 to provide the "spark" that ignites the burner 76. Once it is fired, the burne. 76 can independ~ntly sustain its flame and the glow plug 78 can be deenergized.
Mounted above the cylindrical air intake 8~ of the burner ?6 ~.
is a forced draft combu~tion fan 80 The combustion fan 80 is connec-- ted to an adaptor plate 82 which is provided to conform the rectangular-~hapèd discharge nozzle of the fan 80 to the circular-shaped air intake .
84 of the burner 76. The combustion fan 80 provides the cxpress air required to support the high temperature flame of the burner 76.
Coupled to the cylindrical air intake 84 of tlle burner 76 and ~xtendiJ1g radially therefrom is an air duct 86 which ties into the cxhaust unit 88 of the incineration unit 16. As ~,rill subsequently bc chplaincd iJI con-ncction with the dcscription of ~i~urc 3, thc air duct ~ blceds a por-tion of thc air dischar~cd by thc coinbustion ~n 82 into an cxllaust, mixin~ ch~ml~cr l0~ whcrc ;t is rnixcd witll tllc exh~u~st ~,ascs from thc : 15 . . .
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combustion chaml~cr 56 to cool the exhaust gases bcfore they are ~x~
pelled from thc incincration unit 16, Also extcnding throuGh the ceilin~ of the combu$tion chamber 56 abo-/c the crucible 70 is the effluent îced line 90 whiçh is mounted normal to the top surface of the combustion chamber 56 alongside the burner 76. ~he effluent feed line 90 cxtends from the combustion chamber 56 through an opening in the fircwall 54, as shown in Figure 5, and is connected to the outlet of the feed pump 120 located in tbë
component compartment of the incmeration unit 16, The termination 10 ~ of the eifluent feed line 9C within the combustion chamber 56 is of necessity relatively close to the burner 76 so that the effluent from the feed line will be dispensed into the crucible 70 suspended below.
Although the burner 76 is completely surrounded by a layer o insul- -ation 62, the feed line 90 adjacent the burner 76 is still exposed to . a significant amount of the heat. If left unattended, the heat from ,~
the burner 76 could result in a sufficient heating of t`ne feed line 90 to ca~use the effluent within the feed line 90 to cake and create a block-age in the line. In order to prevent this from occurring, another bleed line ~2 is coupled to the cylindrical air intal;e 84 oî the burner 76 and connectcd to a conduit 94 which jackets the feed line 90 adjacent the - ~ burner 76. In this manner, a stream of cooling air is bled from the combustion fan ~0 and dirccted around tl-c fced linc 90 to preYcnt the heat radiating from the burncr from hcating the efflucnt within the ~eed li~c ~û. Thc cooling oî thc fced linc.90 thus insurcs a smooth ~5 flow of cfflucnt into the combustion chambcr 5G cvcn whcn thc burner . .
7G is at opcratin~ tcmpcrature.
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i26 ~c~erring spccifically to l~igures 3 and 7, thc cxl~au~3t from the combustion chambcr 5G is dircctcd out an opening ~)6 in the wall near the floor of the coml~ustion chambcr 56 and into an cxhaust stack 9~O ~s bcst shown in Figure 3 the cxhaust stack 98 extcnds sli~htly S above the top surface of the combustion cllamber 55 so that the exhaustgases expelled from the top of the exhaust stack 98 are mixed with the -cooling air frorn the primary cooling chamber 66 in a first exhaust mixing chamber 102 The mixed exhaust a;r is then directed into a ~econd mixing chamber 104 where the gases are mixed agaili with the secondary cooling air that is bled from the combustion fan B0 through the air duct 86 previously described. The top of the exhaust unit 88 is eovered by a counter-weighted exhaust cap 106 which opens when the cooling and combust.on fans are activated.
Located at the base of the exhaust sl-ack 9~ is an ash removal duct 100. The duct 100 provides access to the combustion chamber 56 ~rom the rear of the incineration unit 16. By removing the access cover (not shown) that fits on the outside rear panel of the unit con-~enient acccss is provided to the ~loor of thc combllst;on chamber 56 Ior remoying the ash that is dumped from the crucible 70. I-Iowever, since only approximately 15 grams oî solid waste material is generated Ior ever~; gallon of cxcremcnt disposed ti~c cornbustion chamber 56 requirc.s infrcquent cleaning.
Referring now to Fi~ure 5 a plan vicw of thc componcnt com-~artmcnt of the inc;n~rator unit 16 is s?lown. Tho componcnt compart-mcnt houscs thc various mechanical coml>oncnts of tl~c incincr;ltor unit 16 whicll arc opcratcd ur~dcr tllc control of tllc clcclronic conlrol unit lB

.

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.
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v Tlle transIormer 110 located at tl~c b~se of thc compartmcnt is pro-vided ~;o that the systcm may bc opcrated under conventional 115 volt .outlat current, which is typ;cally available for hoolc-up at docks and campsites. A fuel pump 112 mounted to the lirewall 5~ draws fuel . îrom a remote tank and pumps the iuel through a fucl filter 114 to the burner 76 located on the opposite side of the firewall 54. ~s previo~sly mentioned, the burncr 76 used in the preferreci embod;ment is adapted to operate with ordinary automotive fuel. Accordingly, the fuel line' to the fuel pump 117 ~ill Lypically be routed to the fuel tank of the - 13 Yehicle. The amount of fuel supplied to the burner 7G is regulated by a pair oî fuel ~ralves 116 and 118. Each valve is adapted to provide approximately one half of the total allowable fuel flow. As'will subse-quently be explained in greater detail, the primar~ iuel val~Te 116 is .
a~ways open while the burner 76 is operating, and the secondary fuel Yalve 118 is cycled between its opened and closed positions under the eontrol of the electronic control unit 1~ in accordance with the temper- ature of the exhaust gases from the cornbust~on chamber 56.
`\ .As stated previously, effluent is pumped from the macerator unit 14 to the incinerator unit 16 by the liquid circulation purnp 40 2~ located on the macerator unit 14. ~owever, the liquid circulation pump 40 does not pump emuent dircctly into thc combustion cl-amber 56 of the incincralor unit 16; This i~ primarily due to the fact tllat the macerator unit 1~ will frcqucntly.be located quite remote from tl~e in- . ,^
cinerator unit lG. 'rhus, it ~nay rcquire a Iini~c perio~l of time for the ~:
liquid circulation pump ~0 to pump the effluent fl~orn tl~e macerator unit 1~ to the incinerator ~nit lG, l~ecordin~ly, it can bo appreciated . .

.,.
, , . . : ; :

2~, that it would otherwise be extremely difficult for the control unit 18 to accurately control the amount of effluent that i5 fed into the combustion chamber 56~ In addition, when the macerator unit 14 is located a significant distance from the incinerator unit 16, it becomes desirable to pump the effluent through the lengthy circulation line 48 at a relatively high velocity so that the solid waste matter in the effluent does not settle and clog the line. Consequently, in such a situation, the rate of effluent flow through the circulation line 48 is too rapid to safely dispense the effluent from the circulation line 48 directly into the crucible 70.
Accordingly, the present invention utilized an addi-tional.feed pump.l20.whIch draws effl~ent from the circulation line 48 and feeds it into the crucible 70 w.ithin the combustion chamber 56. Referring specifically to Figure 6, a T-joint 122 is inserted in the circulation line 48 outside the incinerator unit 16, and the branch from the T-joint 122 is connected through a feed line 90 to the feed pump 12Q. Thus, ~hen it is desired to feed effluent into the ~busti~n chamber 56, the feed pump 120 is activated and effluent is dra~n off the circulation line 48. It should be noted, that only a fraction of the effluent that is circulated past the T~joint 122 through the circulation line 48 is drawn into the feed line 90 by t~e feed pump 120. In particular, the rate at which effluent is fed into the combustion chamber 56 is determined by the capacity of the feed pump 120. As will subsequently ~e described in greater detail, during the operation of the system, ~he liquid circulation pum~ is continuously activated so that effluent from the macerator unit 14 ~ill al~a~s be present at the T-joint 122 as required. In -- lg --: : . , :
:

this ~nanner, the amount cf ef~luent fed into the crucible 70 witl~in the eombustion ellamber SG ean be accurately eontrolled by eontrollin~
the aetivation of the ~eed pump 120.
Onee the efIluent within the erucible 70 has been eompletely ineinerated to a iine ash it is desirable to remove the ash from the erueible 70. To accomplish this ~ pot rotator motor 72 and eleetrie clutch 74 ~Flgure 7) are eonnected to the shaft Gû from whieh the erucible 70 is suspended within the combustion ehamber 56 ~îter eompletion of the incineration eycle the control unit 18 is adapted to automat~cally activate the pot rotator motor 72 ard cluteh 74 to .
rotate the crucible 70. Accordingly the waste material remaining in the erucible 70 is dumped to the floor of the combustion ehamber 56.
This not only prevents the accumulation of waste matter in the crucib~e 70 but also serves to dispense the waste material to a location where t5 - it ean more readily be removed from the incinerator unit 16. Speeifie-ally the floor of the eoml~ustion chamber is easily cleared of t]-e dumped waste material simply by inserting a suction hose through the ash removal duct 96 located at the rear of the ineinerator unit 16 .As can best be seen in Figure 7 a microswitch 75 is also 20 . provided which is mounted adjacent to the shaft of the motor 72 so as to be aetuable by a camming surfacc inte~ral to the sl~aft as a means of indicatin~ the upright positioli of the crucible 70. Speeif~cally the electronie control unit 18 is adal~tcd to deactivate the clutch 74 to eease rotation of thc crucible 70 whcn thc micros~vltcl~ 75 indicates . . .
that a eomplete revolution has occurred. In thi~ manner it is assured that tl~e erucible 70 is in the proper upri~l~t poqition at the termination .
. i . , ... .. ., .... .. ,. . ... .... =_ .
. ... , .. , , -, ., .~ . 1' . ~ :. . .:: :

of the sy.stem's oper~tionO
Tho iinal comp~nent located in tl~e comp~nent compartment of the incinerator unit 16 is the primary cooling fan 12~. The primary eooling ian 12~ comprises a forced draft cooling fan ~imilar to the eombustion fan 80 mo~lnted within the incinerator compartrnent al)ove the combustion cliamber 5~. q'he air from the primary cooling fan 124 is discharged through an opening in the fire wall 54 into the pri-mary cooling chamber 66 which completely surrounds the combustion ehamber 56. As will be more fully explained in connection ~l~ith the description of Figures 3 and 4, the air discharged by the primary eoolir~g fan 124 is circulated through the primary cooling chamber 66 to dissipate the heat irom the combustion chamber 56, and then mixed ~ith the exhaust gases from the combustion chal~lber 56 before being expelled from the exhaust unit 83 of the incinerator 16, . As can also be seen from Figures 5 and 7, a bleed line 126 ,~
is provided from the discharge of the primary cooling fan 12~ to the sha~t of the pot rotator motor 72 where it is coupled to the shait 68 extending through the fire wall 5~. As will also be explained in con-neetion with the d~scription of ~igure 3, the discharged air bled from the pril~lary cQo]ing fan 12~ is utilized to cool the shaft of the pot rotator motor 72 to prevent the heat fro~n the combustion chamber 5G
from bcinct conductcd alon~ the shaft (;E~ and o~terlleatin~ the motor 72.
Due to the cxtremcly l-igh temperatures at which the prcsent ~YaStC disposal system opcratcs, the mcmner in whic)l the incineration unit 1 G is cooled constitutes ~n important part of tho present invention.
Rcferr~nL~ to Fi~urecJ 3 and ~, ti~e cntirc coolin~ Or the incincratiQIl unit . ` - ' ~ 1 , .

- ~ .

... ..

o ~2~Z6 lG is pcrformcd by two fans; tho coolin~ fan 12~ and tho combustion f~n ~0. 13ach fan, howcvcr, pcrforms multiplc cooling functions. l`hc dischargc from the primary coolin~ fan i9 provided dircctly tllrough an opening in tlc fircwall 5~ into thc primary cooling chambcr 66, as explained, Tlle primary cooling chamber 66 comprise,s thc air spacc bctween thc outer sheli 60 OI the combustion chamber 56 and the com~
.
bustion chaml)er housing 65. As the Fi~ures illustrate, the primary coo~ing chamber 66 completely surrounds the combustion chamber S6.
This is important from the standpoint that it prevents e~cessive heat buildup in any one area of the combustion chamber 56. In addition, ", it will be noted that the primary cooling chamber 66 also completely æurrounds the exhaust stack 98 at the rear of the combustion chamb~r : 56, In this manner, the forced air from the primary cooling fan 124 dissipates the heat from the e~haust stack 98 as well. As best shown in Figure 3, the primary cooling chamber 66 extends slightly akove lhe e~aust stack 98 of the combustion chamber 56 to pro~ide a chamber ,~j;
102 wherein thc coolin~ air from the primary cooling chamber 66 can mix with the exhaust gases ~rom the combustion cha~ber 56 to cool the e~haust gases bcIore tliey are cxpelled fror,1 the incineration unit 16, l~n additional function performed by the primary cooling fa~l 124 is the cooling of the shaft of the pot rotator motor '72. Ill partic-~- ular, a blccd line 126 i~: providcd îrom the discllar~e sidc of the coolin~ ;
fan 124 to Ihc output shaIi of thc pot rotator motor 72 whcrc it couples - to thc sllaît GU cxtcnding from thc combustion chambcr i5G, ~ portion of thc disch;lrgcd air from thc cooling fan 12~1 i9 dircctcd throu~h the .
biccd linc 12G Qlong thc sllaft oî thc moto~ 72 nn~l throllgl~ nn opcnin~

-~2-:

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in t]lC firewall 54 into thc. primar,y cooling chaml)cr GG. From therc, thc air flo~vs around the combustion charnbcr 5G ancl is discharg~d through the exllaust mixin6 chambcr 102 of the exhaust unit 88 as pre-viously described. The cooling of the shaft of thc pot rotator motor 5 . . 72 is important to prevent the motor from overheating. Specifically, due to the direct mechanical con3lection between the pot rotator motor 72 and the crucible 70 ;vitl-in the combustion chamber 56, the thermal conduction along the shaft 68 would, absent the cooling means provided, ~e sufficient to damage the motor 72. Accordingly, by cooling the shaft e~
of the pot rotator motor 72, significant heat flow from within the cor;l-bustion chamber to the pot rotator motor 72 is avoided.
Finally, it will be noted that the suction side of the primary cooIing fan 12'L dra~s ambient air through the lou~ers 130 located at the top of the outside front panel 52 of the incinerator unit 1~, and through the control compartment containing the electronic control unit 18. As will be explained in connection with the description of the control unit l8, the electronic control circuit includes a high power switchin~
panel that is mounted within the control compartment. As those skilled in the electronics art will appreciate, the switching panel generates a ~0 . substantial amount of heat. Thus, by drawing ambient air over the control compartment, the primary cooling fan 12~ serves to dissipate the heat from tlle control unit 18 as wcll.
The combustion fan 80 locatcd dircctly above the burncr 76, also scrves scvcral important cooling functions. Spcciîically, in ~5 addition to provitling cxprcss combustion ~ir for tllc burncr 7~ a por-tion of thc disch;lr~ed air from tllc fan ao is providcd throu~h an a.ir duct -~23- .

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2~i . .
8~ to a sccond CXh.:lUSt mi~nn~ chambcr 104 whcrcin thc a;r from the combustion fan 80 is combincd witll thc exhaust ~ases aDd prim~ry coolin~ air rnixture. Thus, thc exhaust gases from tho combustion chamber 56 are m;xed twice with cooling air before beinç~ dischar~ed . from the incinerator unit 16.
The d;scharge from the combustion fan 80 also serves to cool the part of the effluent feed line 90 that extends into the cornbustion chamber 56. As previously explained, a bleed line 92 located prox-.
imate the discharge nozzle of the combustion ~an 80 is joined to a pipe ,~"10 g4 which jackets the length of feed line 90 adjacent the burner 76, as ~hown in Figure 8. In this manner, a portion of the air discharged from the combustion fan ~0 is directed into the pipe jacket around the effluent feed line 90 and down into the combustion chamber 56. ~y directing cooling air along this part of the feed iine 90, the effluent within the line is prevented from getting excessively hot due to the ~ ,~
heat from the combustion chamber 56. This is irnportant since the - feed line 90 is of necessity located within close pro~;imity to the burner and therefore is otherwise apt to become e~tremely hot. If the feed line 90 is allowed to get hot, the effluert inside will froth and cal;e to the sidcs of thc feed line 90, thereby inhibitin~ the flow of emuent.
Eventually, this would cause the ieed line 90 to become complcteIy clog~cd and all flow would bc termillated. ~ccordin~ly, it can bc sccn that thc cooling air blcd from tl~e combustion fan ~0 ancl dircctcd around .
the fced linc 90 is ncccssary to insure that thc cfflucnt flows smoothly into thc combustion chambcr 5~, ~: . -.

..;
.. . . . _ .... ~ . . . . . , .. . . .. .. , .. _ -~
' ' ' , ~ i ' r ' ' ~ . '~ ` ', .

.. .. . ..

Finally, the suction side of the combustion fan 80 performs an overall secondary cooling function by drawing ambient air through openings 108 in the bottom of the incinerator unit 16 and circulatin~ the ambient air around the entire combustion chamber 56.
~ Specifically, as best illustrated in Figure 4, the ambient air - drawn through the openings 108 in the bottom of the incinexator unit 16 is directed between the combustion chamber housing 65 and the inner housing panel 140 of the incinerator unit 16. Thus, it can be seen that a secondary cooling chamber is provided that completely surrounds the primary cooling chamber 66 to further dissipate the heat from the b~ustion chamber 56.
In addition, the normal gravity flow of air causes ambient ; air to flo~ through the louyers 136 at the ~ottomof the outer housing side panels 142, up the space between the inner and outer housing panels 140 and 142 respectively, and out the louvers 134 at the top of the outer housing side panels 142. Accordingly, radiant heat from the combustion chamber 56 that passes through the insula-tion layer 62 bet~een the inner and outer combustion shells, 58 and 60 respectiyely ! iS cooled b~ th.ree separate air flows before ~o passing outs~de the incinerator unit 16. Thus, it will be appre-ciated that the outer walls of the incinerator unit 16 remain ; remarkably cool even at the peak. operating temperatures of the unit.
As previously stated, the operation of the entire system is controlled by an electronic control unit 18 which, in the preferred embodiment herein, is located inside the front door panel 52 of the incinerator unit 16. The.control unit 18 utilized in the preferred embodiment comprises a completely solid state circuit.
However, as will be readily apparent to those skilled in the .
` - 25 -~: csm/' ; , ,. :
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electronics art, a control unit u-tilizing a microprocessor pro-grammed to perform the same functions as the present solid state control unit 18 can also be employed. The control unit 18 is essentially adapted to control the various sequence of events which occur during the disposal system's operation, and continuously monitor the system to insure that it is operating within certain critical parameters. If at any time a condition arises which does not fall within these parameters, the control unit 18 is adapted to automatically remoye power from all mechanical compon-ents, except the fans, until the system has cooled below 300F, ; and then completely shut down the system. Under such a situation, a trouble light on the front of the incinerator unit 16 or a remote control panel is illuminated to indicate that the unit must be serviced before it can again be safely operated.
Referring to Figure 9, a block diagram of the electronic control circuit 18 is shown. The control circuit itself is operated under the d.c. power from the battery of the marine craft or other yehicle on which the disposal system is locatedO The mechanical components of tha syste~ however are preferably operated under alternative power sources, either rectified a.c. or the output fro~ an alternator or d.c. generatoE, if available. As an initial precaution, the control unit 18 is adapted to determine whethex adequate power is present. If adequate power is not present, the system will remain inoperative. In addition, if at any time during the system's operation, all non-battery power is lost, the control unit 18 will automaticall~ deactivate the entire system/ except for the fans, which will continue to be operated under battery . ...

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power until the entire unit has coolcd bclow 300~ I;`. This function is provic1cù by a buss power sclect circuit 150 whic)l csscntially detcr mines whether or not rectificd a. c. power or auxiliary d. c. po~er from an alternator or g~nerator is present. If the power select eir-, cuit 150 is satislied that adequate power is available, an enable si~-nal is provided on line 152 to the event register 154 and lhe timing eirc~it 156. The enabIe signal permits the system to shift out of the standby mode, or event zero. In addition, the buss power sclect cir-euit 150 routes pc>~er to the power switching circuit 158. The power switching eircuit 158 comprises a plurality of relatively high current switching transistors and associated circuitry that are adapted, when appropriately enabled by control signals from the logic control center 160, to direct current to the various mechanical co~r~ponenis individually controllf~ d.
The heart of the electronic control unit 18 is the logic control eenter 160. The control center IG0 essentially comprlses a plurality of logic circuits that provide instructional signals to the power switching eircuit 158 and failsafe circuit lÇ2 pursuant to analytical clecisions that are made in accordance with information provided to the logic center 16û. In particular, the logic control center lGû recciives input primarily from three sourccs; the event re~ister 154, the temperature detector circuit lG2, and the timing circuit 156. The event re~;stcr 154 is adaptcd to kcep track of l)~e current "location" of thci systcm and pro vide a si~nal to the lo~ic control ccntcr lG0 idcntifyin~ t1~c cvent in w1-ich t~c systcm is eurrently opcratin~O Wl~cn all Or Ille rcquired oper~tions for tlut cvcnt havc bccn pcrformcd, the lo~ic control center - ' '' . ' ' ,: ~

;

` ` ~L~Z6~Ç; l lG0 provides nn advancc signal lncrcmcnting thc cvent rc~istel~ 154 to thc next evcnt, The timin~ circuit 15G is adaptcd to providc various incremental timing signals to the lo~ic coritrol ccntcr lG0 which tho control center utilizes to ùetermine whcther or not certain time periods . have e~iplred. Speciîically, the timing circuit 156 providcs one second, one minute, two minutcs, four minutes, eight minutes, and sixtecn mlnutes signals which tl~e logic control center 160 uses to calculate all of the required time interYals encourtered during the operation oI
the system. The control center 160 is Iurther adapted to control the initiation of the timing circuit 156 so that the various timersi can be reset when desired to me~sure the appropriate time periods.
The logic control center 160 receives temperature inp~t froIn the temperature detector circuit 162. The temperature detector 162 in turn receives information from the temperature amplifier and pro-cessor circuit 16~. The temperature amplifier and processor circuit . ,~;;
164 is adapted to convert the electrical signals received Irom the exhaust stacl; and pilot thermocouples 166 and lG8 respectively, to analog si~nals that are proportional to the temperature readings taken.
The analog signals from the temperature processor lB~ are then pro-vided to thc temperature detector circuit lG2 which compares the temp-erature readings of the thermocouples to various predetcrmined temp-crature vaiues and in~orms the logic corltrol center 160 of the results of thc comparisons. In particul~r, tlle logic control ccntcr 160 m~y, ~or examplc, "ask" thc tempcratllrc dctector circuit 162 ~vhcthcr or - not the stacli tcmpcraturc i5 abovc 10001?. ~rl-c tcmpcralurc dctcctor c~rcuit lG2 will rcspolld l~y providin6 a lo~ic sigllal to thc lo~ic control 2~

, .,, , ,, ~,}~, . ,,., .,, ;
... . ...... .... .. ~

: :, . :
- , : , .
: -~26~6 center 160 indicating either a "yesi' or "no" answer.
Finally, the failsafe circuit 162 is provided which is adapted to monitor and confirm the occurrence of certain critical operations of -the system. For example, if the logic control center 160 directs that the macerator pump is to be activated, the fail-safe circuit 162 determines if in fact power has bèen applied, and whether or not the componen-t is properly connected. The fail~
safe circuit 162 accomplisheis this by checking the impedance characteristic of the line. If a high impedance is present, ~0 indicating the lack of a proper ground, the failsafe circuit 162 directs the buss power select circuit 150 to blow the links. The buss power select circuit 150 will, in turn, reset the event register 154 to event zero by removing the enable signal, and the system will re-enter the standby mode. Similarly, if, for example, either of the fan pressure switches do not close after the logic control center 160 has instructed that the fans be activated, the failsafe circuit 162 will instruct the buss power select circuit 150 to blow the links and apply battery power to the fans.
It is to be understood, that under all failsafe conditions, the 0 control circuit 18 is adapted tc continue to operate the fans, under d.c. battery power if necessary, until the system has cooled below 300F before the entire system is deactivated and the trouble light illuminated.

Referring to Figures 10-17, the overall sequential operation of the system will now be explained. In the standby mode, or Event zero 7 ~ r ~ 29 -. , .

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~ `z~

the event re~ister is set to zero. The output from the event rc~ister i~ provided to an LEl~ display whicll appcars on the front pancl of the ineinerator unit 16 to provide a visual indication of the event in which the system is eurrently operating. While in the standby mode, the `
eontrol circuit 18 eontinuously monitors the exhaust stack temperature of the incineration unit 16 to insure that it is below 400 F. If, for example, resiclual heat from the previous operation of the system eauses the temperature of the unit to iDcreaSe above 40û F; the eon-trol eircllit 18 will first ebeck for a source OI available power and then automatically activate the cooling and combustion fans until the stack temperature falls below 300 F.
It is to be noted at this point that there is disposed at the dis-eharge nozzle of both fans, an air switeh that isadapted to close wllen air is being clischarged from ihe ~an and open when the fan is off. Thus, throughout the operation of the system, wheneYer the control cireuit 18 has instructed that the fans be either activated or deactiYated, the eon-ditions of the air switches are always checlced to confirm the stattls of the fans.
Once the eontrol eircuit 18 is satisfied that the temperature of the e~;haust staclc is at a safe level, the availability of aclequate power is eonfirmed and the standby li~llt located on the front panel of the inein- ;
erator unit 16 is turned on. If adequate power is not present, the sys-tem will not shift out of the standby mode. Durin~ the standby mode, the eontrol cireuit 1~ cheeks the liquid level sensin~ switch loc:~tc~ in ~` 25 the holcUn~ tanl; of the maceration unit 1~ to detcrminc if tl-e switell has been closed for tl~e previous two minute period. 'l'l~e system will r em;~in :- ` ' . '~' 30~ ~
.: ` .
... . ... ... . . .
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`

in thc standby modc, also continuously monitorin~ tllc cxhaust staclc tcmpcraturc, until thc holding tanlc of thc maceration unit 1~ is fillcd ~o thc appropriatc levcl. Thc two minutc closure rcquirc~ncnt is inclu-ded to insurc that the liquid lcvel switch has not closed merely because S of the e~crement "sloshing" wit]lin the holding tanl; caused by thc rocl;-;ng of the vessel or vehicle.
When the control circuit 18 senses that the liquid lev~l switch has b~en closed for two minutes, it again checlcs to insure that adequate power is available before shifting out oi thc standby mode. If power is not available at this pointJ a ~varning light on the front of the inciner-ator unit 16 is turned on. As an additional precaution, the control circuit 18 also confirms the t~Yo minute period by checking a bacl;up timer T2 beforc proceeding to Event 1.
Event 1 consists essentially of activating the combustion and ~5 cooling fans and chec'~iing for positive thermocouple sensing. Only ~i ~en the fans have been confirmed turned on and the thermocouplcs proven good will the control circuit 1~ advance to Event 2, During ~3vent 1, the control circuit 18 loads into a pair of regîsters thc pre-established over temperaturc andunder-temperature values, to ~e subsequcntly dcscribed, and checlis to insure that the ignition timer is set to zcro. To confirm positive thermocouple scnsing, thc control circuit 1~ compares the currcnt reading of the e~haust staclc thcrmo-- couplc ~ith the ncwly loadcd ovcr-tcmpcraturc and undcr-tcmpcrature valucs. Since thc incincration cyclc has not yet bc~l1n, tllc thcrmo-couplc rca~ should bc lcss than both thc ovcr-tcmpcrnt-lrc all~l u~-~lcr-tcmpcrnturc ~,ralucs, If thcsc conùitions arc satisfic~l! tllc control circuit ~ ~ , ~-31-.'~' ' ' ' i . .

,~
:. i . . . . . . . .

`

62~;
.
l~ supplic~ po~YCr to thc coc~lin~ and combustion fans and confirms activatic>n of the f3ns by C]~CCkiDg thc condition of thc air switchos.
Upon confirmalion~ the standby li~llt is extin~uishcd and thc control circuit 18 proceeds to 13vent 2.
~ vent 2 essentially compriscs a 60-second purge cycl~ which is included to remove, prior to incineration, any resiclual fbmes ~rhich may have accumulated in the incineration unit lG. While the fans ar~
operating, the contrvl circuit 18 activates the liquid circulation pump on ~he maceration unit and starts the agitator motor lo~ated in the holding tank. The control circuit 18 then waits 60-seconds and pro-ceeds to Eyent 3, :Event 3 begins the ignition cycle. Power is applied to the glow plug, or ignitor, and the fans are reduced to hali speed to decrease the cooling rate of the incinerator unit 16 and allow a heat buildup ~or the start of ignition. The control circuit 1~ then initiates the ignition and backup timers, and waits 30 seconds to permit the glo~lr plug to heat~up. Once this prehcat cycle is completed, power is appl;ed t~ the fuel pump and to the primary fuel valve. .A load checlc is then performed to conirm both operations. It will be recalled, that the primary ~el valYe proYides approx~mately onc half the total fuel flow capacity to thc l>urncr, Tbc control circuit 1~ con~irms ignition l~y clleclcin~ thc pîlot tllermocouplc to determinc whctllcr the tempcrature at tllc burncr has rcacllcd ~00 F, If thc tompcr;~turc Or thc burncr docs not rcach ~00~
~vithin 3 mim~tcs from thc timc fucl is initi;llly supl)licd, thc cmcr~cncy hutdowll routillc is itnitiatcd, If tllc 4G0 tcmpc~atulo l~ ;~tt.llnc(l wltllin . . ' . ' ` .

the allotted timc, t]lC control circuit 1~ additionally checlcs tllc c~haust stack therrnocouplc to detcrmine if thc tcmperaturc of thc cxi-aust has reachcd 150 F. II this condition is not also satisficd, thc cmer~ency 6hutdown routinc is entcred. IJpon confirmation of burncr ignition, the systern procecds to Event ~.
During 13vent 4, the combustion chamber is brought up to oper-ating temperature. The secondary fuel valve i5 opened to provide max-imum fuel flow to the burner, the glow plu~ is turned off, and full power is reapplied to the fans. The system is then given 45 minutes to reach an operating temperature of 1100 F, as measured by the e~haust stack thermocouple. If the proper operating temperature is ~ot attained within the 45 minute period, the emergency shutdown routine is entered.
Otherwise, the system proceeds to Event 5.
Once operating temperature has l~een attained, the incineration cycle i5 initiated. The effluent eed pump on the incineration unit 16 is activated and a 16 minute incireration timer is initiated. To confirm tbat effluent is being fed into the combustion chamber, the control cir cuit 18 checks the condition of a feed pressure switch disposcd in the feed linc betwcen the feed pump and the combustion chamber. The feed pressurc switch is adapted to dctect tlle flow of cffluent thro~ 1 the feed linc by sensin~ tlle pressurc differential in thc linc. Howcver, othe~
types of sensors can be cmployed. ~t ihis point, the llquid circulation ~; pump of thc maccrator unit 1~ should have had sufficicnt timc to pump cfflucnt throug]l thc circulation linc to thc incincrator unit 1~. J~owcvcr, a tllrcc minutc lccway is providcd within which t]lC fccdin~,~ of cfflucnt into t)lc comb-lstioll ch~l~l)cr must bcLin bcforo thc cmcr~,~cncy ~:hutdown . - - . .
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routinc is entcred. If tllc feed prcssure switcll is closcd within tl~e tl~rcc minutc period the systcm procecds to 13vcrlt 5O
lt ~houlci be notcd tllat tho chcck of thc fced pressllre switch serves seYcral irnportant additional functions. By indicatin~ that cff}u-S ent is properly being fcd into the combustion chamber the feed pressure switch also conlirms the absence of leakcs or breaks in the circulation a~d feed lines the propcr functionin~ of the Ii~ùid circulation pump and the proper functioning of the macerator which liquifies the excre-ment and fills the feed compartment permitting the efflilent to be pumped through the feed lines. ~ccordingly if the feed pressure switch does not close within the allotted three minute period any OI the above factors could be the cause of the manfunction.
Once the incineration cycTe Event 5 is initiated the control circuit 18 is adapted to continuously monitor the exhaust stack temp-erature to insure that it never falls below the under-temperature set-ting of 800 F or increases above the o~er-temperature setting of 1325 iF The under-temperature value o 90û F represents the min-i~nu~n temperature at whicll no odor is produced by the burning process.
The over-temperature value of 1325 F is selected merely as a safety factor. If the exhaust staclc temperaturc ever falls outsicle of these limit5 thc sy5Lcm will automatically enter the cmergency sl~utdown -~ routinc and blow the links.
Durin~ thc incincration cycle it is desirable to maintain thc .:
ex2-allst stacli tcmpcraturc bctwecn 1000 F ancl 1?00 F In order to maiht~in thc exh~ust st~iclc tcmpcraturc within tl)csc limit.; the sccond;lry ~ucl valvc is cycled bctwccn its opcned and closccd positions in accordQI~ce :~, . . .

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witll YariatiOnS in tllc staclc tcmpcr~ture. Spccifict~lly, whcn tho cxhaust stack tcmpcraturc falls bclow 1000 F, the sccondary fucl valvc is opcn-ed and whcn lhe c~;haust taClC tcmpcraturc increascs ahovc 1200~ F, the E:econdary fucl valvc is closcd.
The incineration cycle comprises two sixteon minute phascs.
During the first, or feed phase, effluent is fed into the combustion chamber of the incineration unit 16 During the second, or burn-out phase, the ef~luent feed pump is turned off and the ef~luent within the combustion chamber is completely incinerated. For tlle first 14-minutes of the ~eed phase of the incineration cycle, the logic circuit 18 contin-uously monitors the condition of the feed pressure switch to insure that the feed pump is operatinç~ properly. 1~ at any time the ~eed pres-sure swltch opens~ the emergency shutdown routine is entered. Four-teen minutes into the feed phase of the incineration cycle, the macer-. 15 ator pump and motor and the pot rotator motor are activated Tlle macerator and pot rotator motor remain on for the rcmaining two min-utes of the 16 minute feed phase. The macerator is operate~ at tl~is point of the c~rclc primariiy due to the power requirements of the pump and motor. Specifically, the current draw ol the macerator is such that it can only be opcratcd for relativcly short periods of time.
addition, since the maccrator can mact:rale substantially more waste ;`, in hvo minutcs than the incincrator can dispose of during the entire incincration cyclc, tllerc is always an adcquatc amounl of cfflucnt in tl~e ~ccd tanlc of thc maccration unit to supply tllc incincralor. Thus, the prccisc timc durin~ t]~c opcration of tl~c systcm tl)al thc maccrator i,s ncti~tc~i i5 val iablc~ hccor~in~ly, othcr ft~CtDl`g ~:ltCI~ n~ tl)c po-YCr ~ j -9i5 .
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requirements of the system and design convenience can be considered. Note also, that the crucible within the combustion chamber does not rotate at this time, although the pot rotator motor is turned on, because the clutch is not engaged.
The only reason for activating the pot rotator motor at this time is that design consideratlons make it convenient to connect the pot rotator motor and maceratox in parallel so that both units are operated simultaneously.
Upon completion of the 16 minute feed phase of the incineration cycle, the timer is reset to zero and the system enters the 6 minute burn-out phase of the cycle. In particular, a timer flag is switched from a L0 logic state to a HI logic state indicating the completion of the first 16 minutes of the cycle, and the beginning of the burn-out phase. After the timer flag is switched, the feed pump is turned off and the feed pressure switch checked to confirm deactivation of the pump. The feed pressure switch is given three minutes in which ta o~e~;
If the switch does not open within the time the emergency shutdown routine is entered.
During the burn-out phase of the incineration cycle, the control circuit 18 continues to monitor the exhaust stack~temperatt~re'~nd ~ycle the secondary fuel valve to maintain the stack temperature between 1000 F, and 1200 F. ~owever, ~ since the effluent is no longer being fed into the combustion chamher the temperature ; ~'0 at the exhaust stack will begin to rise with the secondary fuel valve open.
- Accordingly, approximately 7 minutes into the burn-out phase of the cycle, the secondary fuel valve will have to remain closed for substantially the balance of the cycle in order to maintain the stack temperature below 1200 F. With the secondary fuel valve closed for a greater percent of the time, the increased air-to-fuel csm/ lii`

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ratio in the cornbu~tion chamber causes the remaining waste rnaterial in the crucible to be burned to a fine ash. This secondary burning of the waste material is an important feature of the systexn because it results in the complete oxidation of the effluent. In this manner ~he waste material is prevented from caking inside the crucible over numerous operations of the system. In addition compiete oxidation of the effluent insures that no odors will be exhausted when the unit begins operation after a shutdo~vn period or during its current shutdown period.
Fourteen r~inutes into the burl~-oul phase of the incineration ;cycle, the macerator pump and motor and poL rotator ~notor are again turned on for two minutes Fifteen minutes into Lhe burn-ollt phase or one minute after the pot rotator ~notor is startetl po~er is momentarily applied to the~ electric clutch thereby causing the crucible inside the eor.~bustion cha~ er to slowl~ rotate one complete reYoliltion; The microswitch mounted adjacent U~e shaft of the motor is then checlied to ~, - insure that the pot is stopped in lhe upright position If t]~e pot is not upri~ht at the end of the illcineration cycle the emergency shutdown routiile is entered Upon complction of the incint ration cycle tl~e control circuit 1~
a~ain c1-ecks t1~c liquid lcvcl switch in t]~e holdin~ tan1i of the maccration u~it to dctcrmine whctl)cr Lhc switc]l has bccJ1 open for Ihc prcvlous two minutc period. If t1-c liq~id ].cvcl s~iritcll is still closcd Ll~c systcm entcrs ~ ne~ inc;ncr.~tion cyclc and thc fccd pump is oncc aC;3il~ Lurncd on. IIo~r-2~ evcr, if t1~c liquid lcvcl 5wiLch l~;lS l~ccn opcn for Lhc prcvious two minu~-e.s~
tho systcm, ~vanccs to ~?vcn~ G.
1~VCnt ~ l~cl~jin.3 thC sl~11tt1()wl1 ~lnd sccurc scq1~cncc; T}~c m;~ccr;ltor ~7 .. _ . . . .. . .. ..
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pllmp ~ntl molor J>ot rot:ltor motor liquid circulatiQn pump ~nd n~it.3tor motor nrc all turncd ofI l~dditionally ii tllc fccd pump i~
not already off it also is dcactivatcd and t]lC îecd prcssurc switch checked to confirm tl~c a~scncc of emucnt flo~v The sccondary a~ld primary fucl vzlvcs are then closed and the fucl pump dcacti~rated.
After a del~y of five scconds the liquid cil culation pump is activated in the reverse direction to clear the circulation line of eIIluent. This feature is particularly impt,rtant to the proper operation of the system ~: since the feed lilles will eventually become clogged if effluent is per-14 mitted to remain stagn~.nt in the feed lines after the system is shut down.. The liquid circulation pump is opera.ted in the reverse direction or three minutes afl:er which time the system ad~ances to Event 7 ..
. wherein the liquid circulation pump is turned off and the cooldo~n period is initiated. During ~vent 7 both tbe co~nbustivn and coolin~ fans remaill on at full pov~rer for a 30 minute period. If after 30 ~inutes the e~haust saack temperature has not fallcn below 300 ~ the fans will - c~ontinue to operate. When the e~haust staclc temperature cools to 300 ~, ~ the Ians are turned off and the fan swilches chccked to confirm dcactiva-tion of the fans. The systcm thell returns to the standby mode Whel1ever a condition arises ~vhich c'.au.5c.s tl~c coDtrol circuit 18 to cntel~ tlle emergcncy shutdo~n sc~uence ~l-e circuit iniaially w aits for a 15 sccond pcriod to allow the condition wl~ich caused entry into t}~e cmcr~cncy slllltdown scqucncc to corrcct il:self. If t]~c condition ~!
contimics ~o pcrsis~: aflcr 15 sccol~ds the trou)~lc li~l-t is tllrned on ~nd 2~ ~hc a c. linlcs arc l~lo~n. BoL3l lllc coml)uslion an(i coolin~ fans rlrc tllen .
~pcratc~ n(lcr l~aat(:ry l~owt!r for n 30 ~nilllltc pcriotl to ins-1rc t]~at ~l)c ~ ,'' , . . .

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system is cooled before the control circuit 18 automatically shuts down the entire system.
While the above description CQnStitUteS the pre.ferred embodi-ment of the invention, it will be appreciated that the invention is sus-ceptible.to modification, variation and change without departing from the proper scope or fair meaning of the a.ccompanying claims ' '' . ' ' , . . ~

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Claims (51)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a waste disposal system for disposing of excrement including an incinerator having a burner and a first fuel valve for supplying a minimum amount of fuel to said burner and a second fuel valve for supplying an additional amount of fuel to said burner, the method of disposing of excrement including the steps of:
converting the excrement to a substantially liquified effluent;
igniting said burner;
feeding effluent into said incinerator;
regulating said second fuel valve in response to exhaust gas temperature to boil away the liquid in said effluent at a first average fuel-to-air mixture;
terminating the feeding of effluent into the incinerator;
and regulating said second fuel valve in response to the exhaust gas temperature after said liquid has been boiled away to incinerate the remaining waste material at a second lower average fuel-to-air mixture.

2. The method of Claim 1 wherein said excrement is converted to a substantially liquified effluent by macerating said excrement.

3. The method of Claim 1 wherein said effluent is incinerated in a crucible disposed within said incinerator, and further including the step of dumping said crucible of said ash after said incineration process.

4. The method of Claim 1 wherein said second fuel valve is regulated so that said incineration process is conducted at temperatures that will maintain the temperature of said exhaust gases above a predetermined minimum level.

5. The method of Claim 4 wherein said predetermined minimum level is 900°F.

6. The method of Claim 1 wherein said second fuel valve is regulated so that said incineration process is conducted at temperatures that will maintain the temperature of said exhaust gases within a predetermined temperature range.

7. The method of Claim 6 wherein said temperature range is between 900°F and 1325°F.

8. The method of Claim 6 wherein said incineration process is conducted for a predetermined period of time.

9. The method of Claim 8 wherein the feeding of effluent into said incinerator continues during said incineration process for a predetermined portion of said predetermined period of time.

10. The method of Claim 9 wherein said predetermined portion is approximately half of said total predetermined period of time.

11. The method of Claim 1 further including the step of bringing the temperature of said incinerator up to a preselected temperature prior to the feeding of effluent into said incinerator.

12. The method of Claim 1 wherein said incineration is located remote from a conversion unit in which said converting step is performed, said conversion unit being connected to said incineration by a feed line; said feeding step includes the feeding of effluent from the conversion unit through the feed line to the incinerator; and the flow of effluent in said feed line is reversed following said terminating step so as to return unincinerated effluent in said feed line to said conversion unit.

13. The method of Claim 12 wherein said excrement is converted to a substantially liquified effluent in said conversion unit by macerating said excrement.

14. In a portable system for disposing of excrement comprising a conversion unit for converting the excrement to a substantially liquified effluent and an incineration unit for incinerating said effluent, the improvement wherein said incineration unit includes:
a combustion chamber, a burner for introducing a high temperature flame into said combustion chamber, feed means for feeding effluent for supplying fuel to said burner in accordance with the temperature of the exhaust gases from said combustion chamber including first valve means for supplying a minimum amount of fuel to said burner and second valve means for regulating the supply of additional fuel to said burner in accordance with the temperature of said exhaust gases.

15. The system of Claim 14 wherein said second valve means is adapted to increase the supply of additional fuel to said burner whenever the temperature of said exhaust gases descreases below a first predetermined temperature and to decrease the supply of additional fuel to said burner whenever the temperature of said exhaust gases increases above a second predetermined temperature.

16. The system of Claim 15 wherein said first predetermined temperature is 1000°F.

17. The system of Claim 15 wherein said second predetermined temperature is 1200°F.

18. The system of Claim 15 wherein said second valve means continues to maintain the temperature of said exhaust gases within the limits defined by said first and second predetermined temperatures for a predetermined time period after said feed means has ceased feeding effluent into said combustion chamber.

19. The system of Claim 18 wherein said predetermined time period is sufficient for said burner to boil away the liquid in the effluent fed into said combustion chamber and reduce the remaining solid waste material to an ash.

20. The system of Claim 15 wherein said first valve means is adapted to supply said minimum amount of fuel at all times during the operation of said burner and said second valve means is adapted to supply said additional fuel in accordance with the temperature of said exhaust gases relative to said first and second predetermined temperatures.

21. A portable marine waste disposal system comprising a macerator unit for converting excrement to a liquified effluent and an incinerator unit for incinerating said effluent, said macerator unit including a hold tank for storing said excrement, macerator means for macerating said excrement into a liquified effluent, and pumping means for circulating said effluent through a circulation line from said macerator unit to said incinerator unit and back to said macerator unit, said incinerator unit including a combustion chamber, a crucible disposed within said combustion chamber so as to be spaced from the floor and walls of said chamber, feed means operatively associated with said circulation line for drawing a portion of the effluent circulating therein and feeding said effluent into the crucible within said combustion chamber, burner means for introducing a high temperature flame into said combustion chamber so as to boil away the liquid in said effluent and incinerate the remaining solid waste matter to a fine ash, fuel means for supplying fuel to said burner in accordance with the temperature of the exhaust gases from said combustion chamber including first valve means for supplying a minimum amount of fuel to said burner and second valve means for regulating the supply of additional fuel to said burner in accordance with the temperature of said exhaust gases, and means for dumping said ash from said crucible.

22. The system of Claim 21 wherein said pumping means is adapted to reverse the flow of effluent in said circulation line after the desired amount of effluent has been fed into the crucible within said combustion chamber, so as to clean said circulation line of effluent.

23. The system of Claim 21 wherein said burner means is adapted to incinerate the effluent within said crucible at temperatures sufficient to maintain the temperature of the exhaust gases from said combustion chamber above 900°F.

24. The system of Claim 14 wherein said conversion unit includes:
a holding compartment for storing said excrement;
a second compartment for storing said effluent;
macerating means for converting said excrement to said effluent, said macerating means drawing excrement from said holding compartment and discharging the macerated effluent into said second compartment, and overflow means connecting said second compartment to said holding compartment for permitting macerated effluent above a predetermined level in said second compartment to flow back into said holding compartment, but preventing excrement in said holding compartment from entering said second compartment.

25. The system of Claim 24 wherein said macerating means is further adapted to discharge macerated effluent into said holding compartment at an increased velocity so as to mix the excrement in said holding compartment.

26. The unit of Claim 24 wherein said macerating means includes a discharge tube extending into said holding compartment and having a restricted opening for increasing the velocity of the macerated effluent discharged into said holding compartment.

27. The system of Claim 24 wherein said holding compartment and second compartment comprise adjacent volumes within a single tank separated by a partition.

28. The system of Claim 27 wherein said overflow means comprises a tube having a 90° bend therein, with one end of said tube being fitted over an opening in said partition and the other end extending downwardly into said holding compartment.

29. The system of Claim 28 wherein the capacity of said holding compartment is substantially greater than the capacity of said second compartment.

30. The system of Claim 24 further including agitator means disposed in said second compartment for preventing the solid matter in said macerated effluent from settling to the bottom of said second compartment.

31. The system of Claim 14 wherein said conversion unit includes:
a tank comprising a holding compartment and a feed compartment, a waste inlet for introducing excrement into said holding compartment, a macerator pump mounted to said tank for converting said excrement to a macerated effluent, a macerator intake extending into said holding compartment for supplying excrement to said macerator pump, a first macerator discharge extending into said feed compartment for providing macerated effluent to said feed compartment, and a feed pump mounted to said tank for drawing macerated effluent from said feed compartment and pumping said effluent through a feed line to said incineration unit.

32. The system of Claim 31 wherein said conversion unit further includes a second macerator discharge extending into said holding compartment for returning macerated effluent to said holding compartment.

33. The system of Claim 32 wherein said conversion unit further includes overflow means connecting said feed compartment to said holding compartment for permitting effluent above a predetermined level in said feed compartment to flow back into said holding compartment, but preventing excrement in said holding compartment from entering said feed compartment.

34. The system of Claim 31 wherein said feed pump is adapted to pump said effluent through said feed line at a velocity sufficient to prevent substantial settling in said feed line of the solid waste material in said effluent.

35. The system of Claim 31 wherein said conversion unit further includes agitator means disposed within said feed compartment for preventing the solid waste matter in said macerated effluent from settling to the bottom of said feed compartment.

36. The system of Claim 14 wherein said incineration unit includes:
a crucible disposed within said combustion chamber for receiving the effluent fed into said combustion chamber, said crucible being elevated from the floor and spaced from the walls of said combustion chamber so that the effluent in said crucible is heated on all sides by the flame from said burner.

37. The system of Claim 36 wherein said crucible is mounted on a horizontal rotatable shaft that is connected to rotation means located external of said combustion chamber for rotating said crucible at least one full revolution after said effluent has been fully incinerated to remove any solid waste material remaining in said crucible.

38. The system of Claim 37 wherein said incineration unit further includes means for providing access to the floor of said combustion chamber from external of said incineration unit so that said solid waste material can be removed from said combustion chamber.

39. The system of Claim 37 wherein said rotation means comprises an electric motor.

40. The system of Claim 39 further including means for cooling said rotatable shaft so that the heat from said combustion chamber is not conducted along said shaft to said motor to an extent detrimental to said motor.

41. The system of Claim 14 wherein said feed means includes a feed line extending into said combustion chamber;
and wherein cooling means are provided for cooling said feed line so that the effluent in said feed line will not become heated to an extent that will impair the flow of said effluent into said combustion chamber.

42. The system of Claim 41 wherein said cooling means includes a fan mounted adjacent said burner and means for directing at least a portion of the discharged air from said fan along said feed line.

43. The system of Claim 42 wherein said fan is further adapted to provide combustion air for said burner.

44. The system of Claim 43 further including exhaust means for directing the exhaust gases from said combustion chamber external of said incineration unit and means for directing another portion of the discharged air from said fan into said exhaust means to mix with and cool said exhaust gases.

45. The system of Claim 14 wherein said incineration unit includes:
a first inner housing defining a first cooling chamber between said combustion chamber and said first inner housing;
a second inner housing defining a second cooling chamber between said first inner housing and said second inner housing;
first cooling means for causing ambient air to circulate through said first cooling chamber to dissipate the heat from said combustion chamber;
second cooling means for causing ambient air to circulate through said second cooling chamber to further dissipate the heat from said combustion chamber; and exhaust means for directing exhaust gases from said combustion chamber and cooling air from said first and second cooling chambers external of said incineration unit.

46. The system of Claim 45 wherein said exhaust means is adapted to mix at least a portion of the cooling air from said first and second cooling chambers with said exhaust gases from said combustion chamber to cool said exhaust gases before said exhaust gases are expelled from said incineration unit.

47. The system of Claim 45 further including an outer housing defining an air space between said second inner housing and said outer housing, said outer housing having openings formed therein through which ambient air is permitted to enter and exit said air space.

48. The system of Claim 45 wherein said first cooling means comprises a forced draft fan adapted to draw ambient air into its suction side and discharge said ambient air into said first cooling chamber.

49. The system of Claim 45 wherein said second cooling means comprises a forced draft fan adapted to draw ambient air through said second cooling chamber into its suction side and discharge at least a portion of said cooling air into said exhaust means.

50. The system of Claim 49 further including means for directing a substantial portion of the cooling air discharged from said fan into said burner.

51. The system of Claim 50 wherein said burner means is adapted to heat said combustion chamber to a level sufficient to maintain the temperature of the exhaust gases from said combustion chamber above 900°F.