Abstract: A sewage system is provided for waste disposal units whose waste is removed by the supply of liquid and subsequent application of partial vacuum, for example vacuum closets. In order to make for the employment of large systems, the units are grouped such that a predetermined maximum partial vacuum transport distance is not exceeded. Each such group is connected to a converter in which the partial vacuum is converted into excess pressure which makes for long distance transport, by the intermediary of an intermediate step at atmospheric pressure. Moreover, the waste can be comminuted and oxygenated in the intermediate step of the converter, at the same time as the requisite partial vacuum is established.

Abstract: A non-return valve has a housing being symmetric with respect to a plane perpendicular to the direction of flow, and having facing inlet and outlet openings with surrounding identical valve seats, and identical bearing means adjacent each opening for holding a reversible valve flap. One flat side of the valve housing forms an inspection cover and, together with the opposite parallel flat side, carries the bearing means. Between the flat sides there extend parallel transverse sides and end sides which make an obtuse angle .alpha. with one transverse side and an acute angle with the other transverse side. One end side defines the inlet opening and the other end side the outlet opening.

Abstract: The disclosure relates to a vacuum toilet apparatus for mobile units, for example trains or buses, having at least one toilet stool from which faeces etc. are conveyed by means of a vacuum to a storage container by the intermediary of a conduit system. A pneumatic ejector is provided for producing the requisite vacuum. The ejector is supplied with compressed air from a compressed air reservoir. The air which is used for producing the vacuum is conveyed further to the storage container for the purposes of oxygenating the liquid in the container. The storage container is under atmospheric pressure and the conduit is connected to the container via a sluice which has a discharge valve in the form of a mechanically balanced flap valve which is opened by the weight of the contents of the sluice.