Abstract: The invention relates to a process for the continuous preparation of polyether alcohols by reacting H-functional initiators with alkylene oxides using basic catalysts, wherein at least one initiator is metered with at least one alkylene oxide continuously into a back-mixing reactor and the reaction product is removed continuously from the back-mixing reactor.

Abstract: The invention provides a process for continuously preparing polyether alcohols using DMC catalysts, which comprises, in a first step, in a continuous reactor, adding alkylene oxides onto H-functional starter substances and transferring the output of this reactor to a second step in a reactor which is divided by closed trays into mutually separate sections, known as compartments, which are connected to one another by external pipelines, in which the output of the reactor from the first step of the reaction passes through the compartments in succession.

Abstract: In a method of measuring the fill level of a reactor in continuously operated polymerization processes using measurement of the respective phase interface in the reactor by means of ionizing radiation, at least one measuring unit comprising a radiation source which emits ionizing radiation and a corresponding detector is brought to the phase interface in the reactor and flexibly installed there, with the fill level of the reactor being measured by determining the phase interface by means of the radioactive backscattering measurement.

Abstract: A process and apparatus for the measurement of parameters in reactors having moving stirrers which contain probes in the reactor interior, wherein at least two probes connected via a multiplexer to a sensor signal amplifier by connecting cables located in the moving stirrers are installed on the surface of the moving stirrers, and the measurement data obtained by the probes are passed via the connecting cables to a sensor signal amplifier and from thence are passed on to an electronic evaluation unit by non-contact, inductive signal transmission by means of a contactless sensor tap.