Abstract: The instant invention is directed to an improved device for mixing liquid reaction components comprising a storage container for each reaction component, a feed pipe leading from each container to a mixing head where the pipe terminates in a pressure controlled injecting jet, and a return pipe containing a shut-off valve, the improvement wherein a pressure adjustable initial stress valve is located in each return pipe. The adjusted initial stress pressure is greater than the solution pressure of the gases or air contained in the reaction components but less than the opening pressure of the injection jet.

Abstract: The instant invention relates to a method and apparatus for measuring the proportion of undissolved gas in a liquid component for the production of foam materials, particularly those based on polyurethanes. The method is based on the equation of state of ideal gases (Boyle-Mariot Law: p.multidot.v = constant) at constant temperatures. The gaseous portion of a liquid component charged with gas increases its volume under expansion according to the above equation. The gas expansion also increases the liquid volume. The differences in the volumes, of the liquid at two differing pressures is therefore a measurement of the quantity of gas present in the liquid. The apparatus consists of a closed graduated measurement vessel being connected to a variable pressure means capable of producing at least two different defined pressures.

Abstract: The two coupled vertical-lift slides of a mixing head for multicomponent plastics are formed with recesses which, in the rest position of the mixing head, form part of the mixing chamber wall so that a stripping rod, whose diameter is greater than the minimum interval between the vertical-lift slides, can be pushed through, preferably perpendicularly of the vertical-lift slides, to scrape out the mixing chamber.

Abstract: The present invention provides a mixing head having vertical lift slides in which the injection pressures can be altered. Each lift slide is provided with a number of injection openings of different diameters arranged in one plane perpendicular to the axis of the slide. The injection pressure is altered by rotating the lift slide to bring a different injection opening into registry with a mixing chamber. The head of each lift slide is provided with a head having change-over detents which mesh with a carrying yoke to facilitate changing injection openings. The lift slides may also be provided with return openings of such diameter that the pressure in the system remains the same whether the slides are in a mixing position or a return position.

Abstract: Foam blocks are continuously produced on a conveyor belt having lateral boundaries, the application zone for the mixture being adjustable in its inclination, and a feed means for the cover sheet of the conveyor belt being provided before the point at which the mixture is applied.

Abstract: The instant invention is directed to a method and apparatus for measuring the proportion of undissolved gas in a liquid component for the production of foam materials, particularly, those based on polyurethane. The method is based on the equation of state of ideal gases (Boyle-Mariot Law: P .sup.. V = constant) at constant temperatures. The gas contained in a liquid component charged with gas increases its volume under expansion according to the above equation. The gas expansion causes expansion of the liquid gas mixture. The difference in the volumetric flow rate of the liquid, at two differing pressures, is therefore a measurement of the quantity of gas present in the liquid. The apparatus consists of one volumetric flow rate measurement unit connected upstream of a pressure drop unit, a second volumetric flow rate measurement unit connected downstream of the pressure drop unit and a differential value indicator connected to the first and second volumetric flow rate measurement units.

Abstract: Continuous foam blocks with rectangular cross-section are produced on a side-limited conveyor band by feeding a foamable mixture to a cover foil travelling with said conveyor band and covering the free surface of the mixture with a bearing layer not earlier than immediately after the supply of the mixture and not later than before the zone in which a skin would be formed on the free surface of the block.