US3067433A - Self-contained sewerage system - Google Patents

Description

De@ 11, 1952 J. w. DlE'rz Erm. 3,067,433

SELF-CONTAINED SEWERAGE SYSTEM Filed May 20. 1959 4 Sheets-Sheet 1 eos FlG-I 'I W ls lz 209| IN VEN TORS JOHN w. DIETz,

BY DONALD J. MAcFAoel-:N a NEAL c. BossEMl-:YER

ATTORNEYS De- 11, 1962 .|.w.D1E-rz ETA. 3,067,433

sELF-coNTAINEn sEwERAGE SYSTEM Filed May 20. 1959 4 Sheets-Sheet 2 lumi uml FIG-2 H5 150 INVENTORS f f DJoHu w. DIETz, BY NALD J. mFADGEN a NEAL c. BossEMEYER www? ATTORNEY Dec'. 11, 1962 J. w. Dlr-:Tz ETAL 3,067,433

SELF-CONTAINED SE'WERAGE SYSTEM Filed May 20. 1959 4 Sheets-Sheet 3 2W FIG 9 140 FIG-I4 a r/zzz 205 /ZZZ 209 OZ 208 l5 303 21o 216 f fZZS 0?'k :l l zw F Fraz? lz? me 200 f l 128 l Ei :No 21s I Il l l Il 198 i 2| I a Il l ZIO i zie g I 192,194'96 IN V EN TORS JOHN W. DIETZ,

BY DONALD J. MAOFADGENB NEAL C. BOSSEMEYER DW' 11,' 1962 .,I. w. DIETz ETAL 3,067,433

SELF-CONTAINED SEWERAGE SYSTEM Filed May 2o. 1959 I 4 sheets-sheet 4 305 FIG I5 |IT,TIT2TQ\3OO P I 1 I I /Ez MOTOR IT 2) I CURCUIT :Th D I I I D] I I L- I I 74a 5' IT I 74 *il I o C 1 I /Cl I T 75h l I II c2 SEAT d l--I I I c3 IswITcI-I 745 l l 325 II-IL 50* I I- IsoLENoID I" d I II :CIRCUIT Isa 3W* I i Y li r I l I I MAIN I ITIMER I IcIRcuIT I I I I I I I PUSH :BUTTON I TIMER START I I I I I I L :T/ENTORS FORWARD JOHN W. DIETZ,

BY DONALD J. MAGFADGENB NEAL C. BOSSEMEYER MM ATTORNgg @litio Filed May Zit, 1959, Ser. No. 814,554 6 Claims. (Cl. 4-78) This invention relates to self-contained sewerage systems, particularly to such systems operating with a flush bowl.

There is an increasing demand for improved, sanitary, self-contained sewerage systems which lve a wide variety of uses. These systems are needed, for example, in aircraft and other vehicles where all waste must be stored in the system and cleaned out at some appropriate station. Such systems operating with a flush bowl are, generally speaking, cleaner, more desirable, and more satisfactory from the viewpoint of the user. In such a flushing system the flush bowl is connected to and discharges into a tank having initially a quantity of a solution which is essentially water with chemical additives for disinfectant, wetting and deodorant purposes. The ushing system uses this liquid solution for flushing purposes, generally by means of a pump which withdraws a substantial quantity of liquid from the tank and transfers the liquid under relatively low pressure to a flushing manifold which directs the liquid over the interior surface of the bowl, from whence it is discharged, together with any refuse or waste in the bowl, back into the tank. Obviously, after a number of uses, the quantity of liquid within the tank will increase, by reason of waste liquids added to the system and also solid or semi-solid sewage material will be transferred into the tank and will tend to collect therein, primarily about o the bottom, although fine solids may remain at least partially in suspension.

The flow path between the tank and the pump generally contains a lter which operates to prevent passage of solids through the pump and into the flushing system. Since the use of the system is spasmodic, the solids may tend to collect on the exterior surface of the filter exposed to the contents of the tank, and after a time such collected solids may impede the ow of liquid through the filter to such an extent that the flushing system becomes ineffective in its operation, and the entire system must be shut down.

The space occupied by the entire system, and its weight, are also important considerations, particularly where such systems are to be installed in aircraft where all space and weight is at a premium. Compact lightweight construction is therefore most important, but must be obtained with a view toward ease of maintenance and longevity of operation. Also, ease of servicing is an important consideration, since the sewerage systems are most conveniently serviced from the exterior of the vehicle, which may be, as in the case of aircraft, considerably above the ground level and somewhat difficult to reach from scavenger carts or the like. Therefore, it is desirable to provide readily operable connections between the sewerage systems within' the vehicle and service apparatus on the exterior, such that the units may be serviced entirely from outside the vehicle.

The primary object of this invention is to provide an improved self-contained sewerage system having a flush bowl and including apparatus for clearing the filter in the flushing circuit prior to each flushing operation, and thus to maintain effective flow of flushing liquid over an extended operation time, regardless of the frequency with which the system is used.

Another object of the invention is to provide such an improved self-contained sewerage system wherein a re- 3,067,433 Patented Dec. 11, 1962 ice versible pump is used to transfer flushing liquid from the tank to the flushing manifold in the bowl, and wherein the pump is controlled to operate in reverse and thus to force liquid outwardly through a lter connected between the pump and the tank for clearing solids which may have collected on the ilter prior to forward operation of the pump to supply flushing liquid to the bowl.

A further object of this invention is to provide such a system wherein the pump preferably is operated to wet the tlush bowl at the beginning of each use, prior to actual flushing of the bowl.

Another object of this invention is to provide an improved construction for a self-contained sewerage system wherein the flushing bowl is mounted directly upon the top of the tank, with the lower end of the bowl extending partially into the top of the tank, and having a lateral discharge from the lower end of the bowl which opens into the tank substantially at the top thereof to provide a compact system.

An additional object of the invention is to provide an improved construction for a self-contained sewerage system wherein the flush bowl, pump, timing mechanism, filter and other parts of the flushing apparatus are mounted on a removable cover which may be supported in sealed relation over a top opening in the tank, such that the entire operating mechanism may be removed without removing the tank from its mounted position.

Another object of the invention is to provide an improved drive for the ushing pump wherein substantially all of the operating parts of the drive, such as gears and the like, are supported away from possible contact with liquids in the tank.

A further object of the invention is to provide an improved drainage and servicing arrangement for such systems, including particularly a novel drainage control valve which may be opened from a remote position, and which, when open, provides a large unobstructed ilow path for removal of material from the tank.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings:

FIG. l is a top View of the system in accordance with this invention;

iFIG. 2 is a section taken on line 2-2 of FIG. 1;

FIG. 3 is a section online 3 3 of FIG. l;

FG. 4 is an enlarged sectional view through the ush bowl, taken in the same direction as FIG. 3;

FIG. 5 is a detail view of the bowl discharge conduit and the control flap valve therefor;

FIG. 6 is a detail section showing the connection and seal between the bowl and tank cover;

FIG. 7 is a broken detail view of the solenoid operator for the flap valve shown in FIG. 5;

FIG. 8 is an enlarged detail section showing the connection and seal .between the tank cover and the tank body;

FG. 9 is an enlarged view, partially in section and partially in elevation, showing details of the pump, iilter, and drive therefor;

FIGS. l0 and ll are detail views of the iilter shown in FIG. 9;

FIG. l2 is a partial view similar to FIG. 9 showing a different type of lter;

FlG. 13 is a view on an enlarged scale taken on line 13-13 in FIG. l2;

FIG. 14 is an enlarged sectional view of the tank cleanout and remote control valve therefor;

FIG. l5 is a wiring diagram; and

FIG. 16 is a diagram showing the timing sequence for a complete operating cycle of the system.

Referring to the drawings, and particularly to FIGS. l-S, the self-contained sewerage system provided by this invention is constructed as a compact unit having a tank 1@ with an open top, normally closed by a cover 11. The cover is secured to the top of the tank by a number of bolt fasteners 12 which extend through peripheral openings in the cover (FlG. 8) with suitable spacers 14 between the inturned top flange 1 5 of the tank. Inwardly from the peripheral part of the cover is a seal receiving bead 17 in the .form of a downwardly opening concave configuration which extends entirely around the edge of cover 11 spaced inwardly from the bolt receiving periphery thereof. The seal is in the form of a compressible hollow tube 18, formed of rubber or other resilient exible material and contained within bead 17, compressed to the cross-sectional configuration shown in FIG. 8 when the cover is secured in sealing relation over the top opening of tank 11i.

The cover is designed to support substantially all of the operating parts of the system so that they may easily be removed for maintenance purposes. Thus, referring to FIGS. 2, 3 and 4, the flush bowl is constructed of corrosion resistant sheet metal or the like, for example stainless steel, to include a main bowl portion 2t) having an annular channel-like configuration 22 about the top thereof. A mainfold ring 23 is fastened in suitable manner, for example by welding, within the inward facing portion of the channellike part 22, to define a manifold 25 having a plurality of inwardly faced openings 26 through which liquid may pass into the bowl. A defiector ring 28 also is secured within the upper periphery of bowl member Ztl, preferably fastened permanently at its upper edge to the ring 23, and spaced about its lower periphery from the ring and/ or bowl surface to define an annular opening 29 through which liquid issuing from the manifold may pass downwardly over the surface of bowl member 211.

The lower portion of the bowl preferably is formed as a separate cup shaped unit 30 having an integral beadlike flange 32 which is permanently secured about its entire edge to the opening in the bottom of the main bowl member 2d. The member 32 is formed at its outer edge to provide a supporting flange 34 (FIG. 6) having bolt receiving apertures 35 through which bolt and nut fasteners 37 may pass to secure the bowl to lid 11. A cornpressible seal member, preferably in the shape of a hollow tubular resilient seal 33 is received within the bead-like part 32 of the lower bowl portion to provide a permanent seal between the bowl and the lid.

As will be noted particularly in FiGS. 2, 4 and 5, the major portion of the lower bowl part 3@ is suspended within the top of the tank, and a discharge conduit or spout dit extends substantially laterally therefrom, opening at its one end into one side of the bowl part 3i?, as shown in FIG. 1. This conduit may carry at its outlet edge a flap valve 42 hinged upon the pin 43 which is carried by the ears 44 at the top of conduit dil. An ear or lug d projects from the fiap valve adjacent the top edge thereof to be engaged by the armature rod 43 of a solenoid operator 5G (FIG. 7).

The operator includes a casing 52 supported within a depression 53 in the lid 11. The armature shaft 48 includes a central guide or push rod 54 fastened thereto and biased downwardly, in a valve closing direction, by a spring 55 which engages a pressure plate 56 at the top of rod 54. Surrounding the armature rod 4S is the solenoid coil 57 which, when energized, Will draw the armature rod 4S upward, as viewed in PIG. 7, to release the fiap valve for opening, by reason of its own weight and pressure of any liquid from within the bowl, to an open position shown approximately by the dotted outline in FIG. 5. The iiap valve and operator are not necessary to operation of the system, but may be desirable in many installations.

An outward casing or closure 60 extends about the flush bowl and rests at its lower forward edge 62 upon a ledge formed by bracket 63 at the front of tank 11i. rfhe enclosure of? includes an opening aligned with the top opening to the fiush bowl, including a depending rim 65 (FIG. 4) which rests upon a gasket 66 supported on the top of the deiiector ring 28. The cover or outer enclosure extends somewhat rearwardly of the bowl and includes an upwardly and rearwardly projecting liange o3 (FlGS. l and 3) which may be aligned with the walls of the room in which the unit is installed to provide a complete decorative enclosure for the system. The bowl is provided with the usual oval shaped seat 7i) and hinged lid 72, carried on a conventional hinge 73 which is fastened to the enclosure 6d as shown in FIG. 3. A normally open switcA 7d is positioned beneath seat '76, and adjusted to be closed only when the seat is depressed, by weight of a person sitting thereon.

The iiushing apparatus for the bowl includes a pump indicated by the general reference numeral 75, and having a conduit 77, including an enlarged reservoir 75 attached thereto and connected, preferably through a flexible elbow 79 to the inlet fitting E50 for manifold 25. Thus, during normal forward operation of the pump liquid is supplied under pressure to manifold 25 and passes through the multiple openings 2-5 against the back side of defiector ring 28, which directs the liquid in a susbtantially continuous iiow pattern about the inner surface of the bowl. An overflow tube S2 is connected through an upper opening 84 to the interior of the bowl, and opens downwardly through the cover 11 as shown in FIG. 3 to provide a protective overflow discharge for the bowl, in the event that for some reason the flapper valve 42 should fail to function or the normal discharge conduit de should be clogged for some other reason.

Pump 75 is supported in suspended relation from cover 11 by a drive housing 85 which is bolted or otherwise secured in sealed relation over an opening 86 in the cover. A drive motor @d is supported on the housing 85, and drives a pinion 92 meshing with a pump drive gear 93 keyed to the drive shaft 95. This shaft rotates within a tubular housing 96 depending from the housing 3S, supported by ball bearings 97 and surrounded at its lower end by a rotary seal 93 through which the lower end of shaft 95, of reduced diameter, extends to the pump impeller 101i which is keyed or otherwise secured to the lower end of shaft 95. The lower tubular housing member 102, which is secured in depending relation from the housing tube 96, includes the pump outlet opening 165 which is connected to the reservoir 73, and at its lower end the housing 102 opens into the interior of a filter which includes a top plate 11?. supported in rotating relation upon a ring 113 carried on the outside of tube 102, slightly above the lower end thereof.

The self-cleaning filter is of a known construction, including the top plate 112 and a bottom plate 115 connected by through bolts 116 which carry a stack of filter elements therebetween. These filter elements include alternate ring members 11d having inwardly extending generally U-shaped parts 119, preferably three in number, which receive the through bolts 116. Between successively stacked rings 18 are U-shaped fingers or spacer members 129, as shown in the exploded diagrammatic View in FIG. ll. The tips of these finger members cooperate with stationary wiper plates 122 which are in turn spaced properly by spacing plates 123, all of these plates being mounted in stacked relation by supporting bolts 125 which extend between a stationary top mounting cup 127 (and radially extending fingers 128 thereon) and the bottom supporting ring 129.

The stacked filter members are rotatably driven by a gear 130 fastened to a driving sleeve 132 which is in turn fixed to the top plate 112. This gear is driven by a pinion 132 carried on a counter shaft 133 mounted within one side of a housing 135 and is supported at its upper end within a bearing 137 and rotary seal 138. At its upper end shaft 133 is secured to the output gear 146 of a reduction gearing unit, having an input gear 142 in mesh with a drive pinion 144 keyed to the pump drive shaft 95. In this manner, whenever the pump impeller 100 is operated the filter stack is also rotated at a substantially lower speed, and in coresponding forward or reverse direction, with the wiper plates 122 functioning to clear collected solids from between the adjacent filter rings 113.

The above described construction provides a pump and filter unit which is mounted in mounted suspended relation from the tank cover 11, with the lower filter plate 115 extending into slightly spaced relation above the bottom of a sump portion 150 in the tank. Substantially all of the driving structure is enclosed within the housings above the rotary seals and directly coupled to the motor, which only the gears 130 and 132 open to contact with liquid in the tank. Such a construction substantially reduces maintenance problems in the pump and filter drive.

An alternate filter construction is shown in FIGS. l2 and 13, including an upper filter plate 160 secured in driving relation to the drive sleeve 132 and connected by bolts and tubular spacers 162 to a closed bottom plate 164. The annular space between these plates is enclosed with a perforated' filter band 165, and on the outside of this band there is a fine mesh filter screen 167. At spaced points about the screen-are depending wiper blades 170 (FIG. 13) which are supported by carrier bolts 172 depending from the stationary cup 127 and radially projecting fingers 128 at the lowerend of the supporting housing, as previously described. The drive to this modified filter unit is exactly the same as that shown in FIG. 9 and above described, and in operation the filter unit rotates at susbtantially lower speed than the pump impeller, with the fingers 170 scraping the surface of filter screen 167.

As mentioned at the beginning of this specification, once the system has been used sufficiently to fill tank 10, it is placed out of operation, and the tank must be cleaned out and the system provided with a fresh quantity of flushing liquid. The manner in which this is done is well known in the art, and forms no specific part of the present invention, apart from the improved tank drainage control which is described in detail below. For replenishing the system, and also for cleansing the tank, a spray ring in the form of a perforated tube 180 (FIG. 2) is mounted to extend immediately beneath the top of the tank, in suspended relation from cover 11. This ring has an external supply connection 182 which may lead to a coupling on the external surface of the vehicle (where the system is used in a vehicle) for coupling to a supply source. Drainage from the tank is provided by a drainage opening formed in the bottom surface of the tank, preferably as a pressed opening 185 (FIG. 14) forming an annular valve seat 186 flush with the lowest surface of the tank bottom. A drainage tube 188 may extend from this opening, being secured about the end of the opening 185, for example by welding thereto. The seat and opening are of no less cross-sectional area than the bowl discharge conduit, so that any material passed into the tank from the bowl can be drained out.

This opening is controlled by a drainage valve in the form of a cup-shaped resilient member 190 formed of suitable material which is also substantially inert and thus impervious to corrosive action of liquid in the tank. A retainer cup 192 extends within the center of the valve member 190 and carries a fitting 194 which extends through the valve member and is connected by a cross pin 196 to a valve control tube 198. This tube extends upwardly through a stationary guide tube 200 and is secured to a top fitting 2 by a cross pin 203, with this fitting in turn being secured to the end of a control cable 205.

The guide tube 200 is carried within a valve mounting 207 which is secured in sealing relation, over a gasket 208 surrounding an opening in the top of tank 10, by the bolt and wing nut fasteners 209. This opening is in the I upper corner of the tank (FIG. 1) where the lip 15 thereof extends substantially inward, such that the mounting 207 is independent 'of the tank cover 11. A valve control spring 210 extends between an upper seating disk 212 surrounding the stationary guide tube 200, and the upper surface of the fitting 194. This spring acts normally to bias valve 190 into seated sealed relation with the valve seat 186. Independent adjusted tightening of the fasteners 209 will cause the mounting 207 to cant slightly on the tank, and in this manner the valve head can be aligned with the seat.

For protection of the valve operating structure within the tank it is preferable to surround the control tube and guide tube and the spring with a flexible expandable protective cover 215, for example in the form of a length of flexible tubing, which is secured in conventional fashion by snap rings 216 at the lower end to the valve member 19@ and at the upper end to the mounting 207.

Control cable 205 extends upwardly and thence over a pair of spaced guide pulleys 217 which are mounted on a stationary bracket 220 extending upwardly from the mounting 207. The cable there is connected to a quickdetach coupling 222 which in turn is connected to a further cable 225 extending through a tube 227 which projects vertically through the tank, from top to bottom, being permanently sealed thereto and providing a passage for the control cable 225 by which the cable is guided out at the bottom, where it connects to a coupler 22S which may be engaged with a suitable control on the exterior of the vehicle. Thus, if the coupler 228 is pulled and held valve member 190 will move to an open position Yagainst spring 210, leaving a free discharge opening unobstructed by flanges, valve seats, or the like. If it is desired to remove the Valve assembly for maintenance purposes, then the quick-detach coupler 222 may be manipulated to separate the connection between cables 205 and 225, and the enlarged head of coupler sleeve 222', being larger than the cross-section of tube 227, will support cable 225 in position when it is so detached from the valve mechanism.

Referring to FIGS. 1, 2 and 3, a Ventilating conduit 230 extends over the tank to a position beneath the housing 60, where it is attached to an inlet fitting 232. The other end of conduit 230 may be secured to a vacuum source, for example the throat of a venturi which is supported in the air Stream on the exterior of the vehicle, to withdraw offensive fumes or the like from the area of the system.

Referring to FIGS. 15 and 16, which show the Wiring diagram 'and timer cycle diagram for the system, the operation of the system is as follows. Assuming that the system has been serviced, and is ready for operation, a quantity of liquid will be in the tank approximately to the level shown by the dot-dash line 270 (FIG. 2), and pressure upon the seat 70 will cause the seat switch 74 to close. This initiates the first or pre-use operation of the system.

In a preferred construction, the flush bowl is constructed of polished stainless steel or similar non-corrosive', relatively light-weight (as compared for example with porcelain) material. This steel should be wetted before use, to assure a proper and complete cleansing thereof during the flushing operation. The liquid in the tank, in addition to its germicidal and deodorant additives, also includes a quantity of wetting agent which provides for proper wetting of the bowl surface, a function which plain water ordinarily cannot perform satisfactorily. Thus, when the seat switch 74 is closed the timer control is energized to operate pump motor first in a reverse direction, such that the impeller forces liquid from reservoir 78 radially outward through filter 110.

For the first use of the system this operation has no particular significance, but thereafter, especially if there is considerable time between uses, this backward flow of liquid through the filter serves to clear the external sur.-

face of the lter elements, i.e., those exposed to the contents Iof the tank, of any collection of solids, for example bits of tissue or the like, which may adhere to the surface either during previous liushing operations or due to settling about the filter, and tend to reduce ow through the pump. Thus, at the beginning of each use of the system the filter is irst cleared. The motor 90 is then operated in a for- Ward direction -for a short period of time and the solenoid 50 is energized to open ap valve 42, passing a relatively small quantity of liquid over the bowl surface, and back into the tank, for wetting the surface.

When the pump motor stops at the end of the wetting operation, the system is readied for use. The actual iiushing of the bowl, after use, is caused by manual operation of a ush control button which will initiate `operation of the pump and timer to carry out the actual flushing cycle.

Referring particularly to FIG. 15, the wiring diagram illustrated is for use with three phase 400l cycle A.C. supply, as commonly used in aircraft. The supply is represented by the plug 300 from whence four lines extend, the common ground line T0, and the power lines for the three separate phases, T1, T2 and T3, each of which is customarily at the same potential with respect to Til as the others, but 120 out lof phase therewith. These lines all extend to the timer mechanism, which is represented with- :in the dotted line in closure 3435. This timer may be supported upon the top of lid 11, for example in the location shown in FIG. 1.

The timer is provided with control cams A, B, C, D, E, and F, respectively, mounted for rotation by a common drive shaft shown schematically at 303 and driven by a three-phase timer motor 310. The seat switch 74 actually operates three separate normally open switches 74a, 74,5, 74C which are connected through a plug unit 312 to the timer circuits, as will presently be described. The solenoid 5@ is connected through plug unit 313 into the timer circuit, and the main push button control 31S, which actuates the flushing operation, is connected to operate three normally open switches 315a, 315b and 315C, which are connected into the timer circuit through a plug member 317.

The timer cam A controls three start control switches A1, A2 and A3. The input to these switches is, respectively, from the lines T1, T2 and T3 such that closing of 'these switches connects each of the power lines of the three phase supply source to the proper windings of timer motor 310, with the common point of these windings being connected to line T0 as shown. These three switches provide the push button start timer circuit as follows. Pressure on the control push button 315 will close the switches 315a, b, c, and this will complete a circuit through the back contacts of switches B1, B2 and B3, which are under the control of the timer cam B, and which are normally connected to the lines T1, T2 and T3, respectively, when the cam follower is in the notch of cam B as shown. Thus, a circuit will be completed through each of the diodes 320 to energize the coil of a solenoid 322 which is connected to close switches A1A2 and A3 when energized. Preferably, a permanent magnet latching device 323 is also connected to control all three of the A switches, to hold them in the closed position and assure energization of timer motor 312 through these switches if pressure on push button 315 is not maintained sufficiently to permit the timer motor to start up and rotate the cams.

The double throw switches B1, B2 and B3, their controlling cam B, and appropriate wiring connections to the timer motor constitute the main timer circuit. The seat 'switch circuit includes the switches 74a, b and c, and the three normally closed switches C1, C2 and C3 which are controlled concurrently by cam C. Each of the sets of switches operated by cams A, B or C are connected to control energization of the ap valve solenoid 50 through the diodes 325 such that Whenever the seat switch circuit is completed, or the main timer circuit switches Bl, B2 and B3 are shifted .t0 their forward c-ontacts, or the timer start switches A1, A2 and A3 are closed, solenoid 50 will be energized to permit opening of ap valve 42.

Finally, the timer includes cams D, E and F which together provide the three phase motor control circuit for the pump motor 90, while the cams E and F also are included in a reversing circuit for that motor. Thus, line T0 is connected to the common connection of the windings W1, W2 and W3 of motor 90. Line T1 is connected to winding W1 through normally open switch D1, which is controlled by cam D. Line T2 is connected to winding W2 through switch E2, and line T3 is connected to winding W3 through switch E1, both of these switches being normally open and controlled together by cam E. Cam 'F controls normally open switches F1 and F2. Switch F1 when closed serves to connect line T2 to winding W3, and switch F2 when closed will connect line T3 to winding W2, bypassing the switches E1 and E2 respectively. It will be obvious from the drawing, and the configuration of cams E and F, that these cams close their respective switches alternately, so that there is no danger of short circuiting through the reversing circuits.

Operation of the circuit during use -of the system is according to the following cycle. Pressure on the seat 70 will close the switches 74a, b and c, and since the cam switches C1, C2 and C3 are normally closed, this will energize timer motor 310 to rotate in a counterclockwise direction, as shown, and also energizing solenoid 50 to open the ap valve. As the timer begins to rotate cam D will close switch D1 and cam F will close switches Fl and F2, causing motor to rotate in its reverse direction for approximately two seconds (24 of rotation on the cycle diagram of FIG. 16) and thus causing the impeller 106 to force whatever fluid is in the standpipe and pump outwardly through the lter to clear it.

Cam F will then open the switches F1 and F2, and cam E will close the switches Eil and E2, the interval between these operations requiring about two seconds to permit the pump motor to come to la stop. As the switches El and E2 close, motor 9d will run in a forward direction for approximately two seconds to supply suficient liquid through the manifold 25 of the Hush bowl to wet the surface thereof. At this time cam C will have rotated so that the follower switches C1, C2 and C3 will have been released to open these switches and the timer motor 3l@ will stop, since cam B has not as yet reached the follower for switches Bl, B2 and B3. At the same time, cams D, E and F will permit the switches controlled thereby to open to stop the motor 9i);

Then, when it is desired to flush the system, push button l5 is depressed to close switches Sla, b and c. This energizes solenoid 322 through the back contacts of switches Bl, B2 and B3 and the diodes 32% to close switches A1, A2 and A3 (the starting switches) against the opening spring bias thereof. The magnetic keeper 322 will retain these switches closed if the button 315 is depressed only for an instant. This starts timer motor 310 for the second time and its rotation causes cam A to engage the follower for switches A1, A2 and A3 and open these switches against the magnetic keeper, and to hold them open for the remainder of the cycle. Thus, even though the button 315 be depressed for a long time, its contacts are a part of the circuit for only a short duration. This provides protection against burn out of the switch contacts. At the same time, cam B shifts switches B1, B2 and B3 to their forward contacts and holds them there to complete the running circuit to the timer motor through the end of the cycle.

Switches Cl, C2 and C3 remain open during the rest of the operating cycle. At the same time, forward energization of motor 9i? is again initiated by cams D and E closing the switches D1 and El, E2, and this continues for approximately fourteen seconds of the cycle, with the pump motor thus supplying a considerable volume of filtered liquid to the iiush bowl for thorough cleansing thereof. The solenoid Se is maintained energized through diodes 325 because of the connection thereof with the front contacts of switches B1, B2 and B3. Approaching the end of the cycle, cams D, E and F permit their respective switches to open and motor 90 is stopped for approximately two seconds, and then switches D1 and F1, F2 are closed by their associated earns to operate motor 90 in reverse, for the purpose of clearing the filter again at the end of the cycle. Finally, the follower for cam B reaches the opening position thereof shortly after cams D, E and F again permit their respective switches to open, stopping the pump motor 9d and timer motor 3.10, at which time the cycle of operation is complete.

It will be appreciated from the foregoing description that the reversed tiow through the filter at the beginning and the end of each use of the system serves to keep the exterior of the filter, exposed to the tank contents, cleared sutiiciently to permit adequate iiow through the pump and supply manifold circuit for a thorough iiushing of the bowl after each use, and in spite of the increase in contents of the tank. Since the iiush bowl is of the dry type, i.e., it does not normally contain a pool of water, the prewetting operation prevents material from sticking to the otherwise relatively dry surface of the bowl and thus promotes a thorough liushing of the bowl.

In the event that for some reason the bowl discharge should become clogged, or the ap valve should fail to open, the overflow conduit 82 will serve to prevent an undesirable overiiow of the ush bowl by conducting the liquid as it reaches this level into the tank. As will be appreciated, after the system has been used a number of times the level within the tank will reach a position where in the system must be placed out of order until it is scavenged and regenerated. in actual operation this system has been designed to provide for approximately one hunderd uses without attention. When the system must be shut down, however, any suitable signaling and/or cut-oit` device can be employed to show that the system should no longer be used, and to prevent its use by cutting off the power supply thereto in any conventional and suitable manner. The system may be scavenged, rinsed, and regenerated completely from the exterior of the vehicle through the above described connections, or in different types of installation the entire system, tank and all, may be removed when full and transported as a unit to apparatus for performing the scavenging and regenerating operation.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. A self-contained sewage system comprising in combination a closed tank, a bowl mounted on top of said tank and having a discharge opening therefrom projecting directly into said tank and extending laterally within the top of said tank, manifold means extending substantially around said bowl adjacent the top thereof for directing a flow of flushing liquid downwardly over the interior of said bowl and thence into said tank, a motor driven pump having an inlet connected to withdraw liquid from said tank adjacent the bottom thereof, a self-cleaning filter surrounding said inlet of said pump and driven therewith to cause cleaning action thereof concurrently with operation of said pump, said pump being connected to discharge directly into said manifold, a drainage opening formed in the lowest portion of the bottom of said tank including a valve seat flush with the bottom of said tank, a resilient remotely controlled valve head cooperable with said Valve seat to control said drainage opening, means normally biasing said valve head into closed position on said valve l@ seat, a spray device mounted interiorly of said tank adjacent the top thereof, and means forming a connection for supplying a cleansing liquid to said spray device from the exterior of said tank to cleanse the interior thereof with said valve head in open position.

2. A self-contained sewage system comprising in combination a closed tank, an open top flushing bowl mounted on the top of said tank and having a discharge opening therefrom directly into said tank including a spout eX- tending laterally within the top of said tank, manifold means in said bowl adjacent the top thereof for directing a flow of flushing liquid over the interior of said bowl carrying waste material with such liquid through said spout and into said tank, a pump having an inlet connected to withdraw liquid from said tank adjacent the bottom thereof and having an outlet connection directly to said manifold means, selectively operable motor drive means for said pump, an annular self-cleaning lter surrounding said inlet of said pump, wiper parts in said filter, rotating parts in said filter connected for driving by said motor drive means concurrently with said pump and contacting said wiper parts to wipe waste material from said filter and thus to maintain an adequate flow path for liquid to said pump inlet, a drainage opening formed in the lowest portion of the bottom of said tank including a valve seat flush with the bottom of said tank, a remotely controlled valve head cooperable with said seat to control said drainage opening, and means normally holding said valve head in closed position on said valve seat.

3. In a self-contained sewage system as defined in claim 2, a timer control connected to govern the operation of said motor drive means, and a circuit including a manually operable switch operatively connected to said timer control for initiating operation thereof.

4. In a system as delined in claim 2, means defining an overflow opening in said bowl substantially above the bottom thereof, and an overflow tube connecting said overiiow opening directly to said tank to conduct flushing liquid into said tank in the event of clogging of said spout and thus to prevent overflow through the top of said bowl.

5. A system as deiined in claim 2, including a reversible motor incorporated in said drive means, a timer control for said drive means, a manually operable switch connected to initiate operation of said timer control, and connections between said timer control and said reversible motor for initially operating said motor in reverse to force liquid backward through said filter to effect a clearing of said filter and subsequently to operate said motor in a forward direction for a predetermined timed interval supplying flushing liquid from said tank through said manifold means.

6. A system as defined in claim 5, including a normally closed motor operated valve means controlling flow from said spout, and a connection between said valve means and said timer control for opening said valve means to maintain a direct opening through said spout from said bowl to said tank when flushing liquid is supplied to said manifold.

References Cited in the file of this patent UNITED STATES PATENTS 1,415,701 Priestman May 9, 1922 2,224,868 Houck et al. Dec. 17, 1940 2,280,930 Reeves Apr. 28, 1942 2,858,939 Corliss Nov. 4, 1958 FOREIGN PATENTS 742,519 Great Britain Dec. 30, 1955 1,145,442 France May 6, 1957

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