Abstract: Means are utilized to cause deposition of solids from a solution such as sewage. Tube clarifiers are then utilized to settle the solids by gravity whereupon the solids are urged to a sediment discharge by means of an auger thus leaving clarified liquid for separate discharge. The tube clarifier may include stationary or adjustable screens or baffles to trap the solids to assist in the settlement and/or the auger flight may be perforated for a similar reason.

Abstract: A toroidal cylinder is provided with a slot formed around the inner wall. A central shaft carries a sunwheel engaging a set of planet gears which in turn engage a fixed ring gear secured to the cylinder adjacent the slot. A pair of rings are provided carrying sets of pistons running within the cylinder, the edges of the rings sealably running within the slot. Pins on the planet gears engage slotted arms secured to the rings so that opposite pairs of pistons move toward and away from one another in sequence thus providing compression and expansion strokes in the cylinder together with intake and exhaust strokes. A fuel mixture ignited by spark plugs or the like may be used or, alternatively, fuel injection may be utilized and inlet and exhaust ports are formed within the walls of the toroidal cylinder.