Patent GB-1409882-A (GB)
Title: Waste disposal system
IPC: E03F7/10
Filed: 1972-09-19
Abstract: 1409882 Disposal of sanitary waste in engine exhaust systems THERMASAN CORP 19 Sept 1972 [10 Dec 1971] 43361/72 Heading E1C  Sanitary waste, e.g. from a sanitary closet on a vehicle, is disposed of by feeding it from a holding tank 18 into the interior of an exhaust pipe 16 of a fuel-burning engine by operation of a pump 28 the driving motor 30 of which is energised only when; a level-sensing device 36 indicates that the level .of waste in the tank 18 is above a predetermined minimum, and when a further sensor indicative of exhaust gas, temperature indicates that the latter is sufficiently high to destroy odour, and. bacteria in the waste and convert the waste liquid into superheated steam. In the arrangement of Fig 1, two further sensors 38, 40 are provided, the former being a speed-sensing device responsive to speed of the gear box output shaft, and the latter being a vacuum switch in the intake manifold of the engine. The sensors 38, 40 and the level-sensing device 36 all close contacts when the associated predetermined conditions are reached, the contacts being connected in series whereby a circuit is completed to the motor 30 only when all three sensors have operated to close their contacts, A waste injector 26, for injecting waste fed by the pump 28 into the exhaust pipe 16 comprises a tube 46, Fig 3, extending part-way across the exhaust pipe interior and being surrounded by a cylindrical screen 44 for breaking up both the liquid and the solid particles in the waste, the waste solids having been partially broken up previous to entering the tank 18 and having been already filtered by a filter, Fig 5, forming the entrance to waste feed pipe 22. Fig 5 also shows details of the level-sensing device 36 which comprises electrodes 48, 50 and an R.F. module 52 responsive to changes in electrical resistance between the electrodes. A modification of the device 36 (Fig 6, not shown) senses the pressure in a pipe leading from the tank 18, a further modification (Fig 7, not shown) utilising a plurality of vertically spaced sensors. The latter modification is used in the arrangement of Fig 8 (not shown) where the speed-sensing device is responsive to electrical signals from the ignition coil (66) instead of to the speed of the gear box output shaft. In further alternative speed-sensing arrangements (Figs 10-12, not shown), a pilot tube is used, which is placed either in the air stream from the engine cooling fan or in the airstream externally of a vehicle which the engine drives, the pressurevariations in which operate contacts in the electric circuit. In the embodiment of Fig 9, two vacuum switches 68, 70 are responsive respectively to manifold depression and speed of the airstream in the carburettor of the engine, the contacts of the switches 68, 70 and of a level-sensing probe 75 being in series in the circuit of motor 30. In addition, a vacuum switch 76 is responsive to a reduction in pressure in the waste feed pipe 22 caused by a blockage in the pipe or by blocking of the filter in the tank 18, whereupon an independent circuit is completed to a magnet valve causing the latter to admit compressed air via a pipe 80 to the pipe 22 so as to blow back into the tank 18 and thereby clear the blockage. Indicator 34 on the dashboard of the vehicle shows the state of the system in each of the embodiments.  Reference has been directed by the comptroller to Specification 1276448.