Abstract: The invention relates to a pneumatic conveying system, comprising an apparatus for gravimetric solids metering, wherein a readily fluidizable material to be conveyed is fed to a conveying line, culminating with a mixer into which the fluidizable material is conveyed from the conveying line. A degassing screw located between the gravimetric solids metering system and the mixer allow for transfer of conveyed solids into the mixer without pressure buildup and without altering the weight ratio of the filler to product.

Abstract: A three-stage process for the continuous preparation of RTV-1 compositions comprises, in a first step, preparing a raw mixture of &agr;,&ohgr;-dihydroxypolydiorganosiloxane, filler and, if desired, further constituents, in a second step, freeing the raw mixture of gas inclusions under reduced pressure and, if desired, mixing it with further constituents and, in a third step, mixing the degassed raw mixture with a crosslinker, a condensation catalyst and, if desired, additional constituents not yet added in the first and second steps.

Abstract: The organopolysiloxane compositions are prepared by(1) organopolysiloxanes, and(2) prehydrophobicized oxidic stiffening fillers being blended and kneaded in a kneading machine 1 having at least two kneading chambers 2 which are arranged in series next to one another, each contain two axially parallel kneading tools 3 drivable so as to corotate or counterrotate, and communicate with one another via openings 5 through which passage is possible transversely to the axes 4 of the kneading tools 3, the first kneading chamber 2 having a charging port 6 and the final kneading chamber 2 having a discharge port 7.