Abstract: Hydraulically coupled injection nozzles (5,28) and return nozzles (15,38) are used in an apparatus for producing a reaction mixture of fluid components forming foam or a solid material. These nozzles (5,15,28,38) comprise control pins (11,20,34,43) which are designed to be inserted into the openings (6,17,29,40) of the nozzles (5,15,28,38). The ratio between the distances which the control pins (11,20,34,43) travel outside and inside the orifices (6,17,29,40) is adjusted in such a way that, when the nozzles (5,15,28,38) are switched from "mixing" to "circulation" or vice versa, there is a time interval during which all the nozzles (5,15,28,38) are closed.

Abstract: The invention relates to a method and a device for producing a solid-forming or foam-forming flowable reaction mixture by metered injection of flowable reaction components into a mixing zone from which the finished reaction mixture is discharged.

Abstract: The instant invention is directed to a process for filling a cavity with a flowable reaction mixture through an inlet opening located at the bottom of the cavity. The process broadly comprises injecting a relatively small amount of reaction mixture into the cavity to cover the inlet opening with reaction mixture. The injection process is then briefly interrupted. Thereafter, the remaining amount of reaction mixture is injected into the cavity. The invention also relates to apparatus useful in performing the above-described process.

Abstract: The invention is directed to a device for the discontinuous production of block foam comprising a mixing unit, a means for moving the unit approximately vertically into and/or out of a mold with the unit having reaction component feed lines, a stirring means, and a mixing container having a plate with feed openings for the reaction components characterized in that(A) a distributing device is arranged below the feed opening for one of the components and(B) the mixing container comprises a bottomless cylindrical shell, the lower rim of which can be placed on the bottom of the mold.

Abstract: The instant invention broadly relates to a process and apparatus for filling a cavity with a reactive mixture. More particularly, the invention relates to a process for filling cavities, particularly mold cavities, with a reactive, flowable mixture which preferably forms foam, wherein at least two reaction components are brought into a mixing zone, where they are mixed and then brought into the cavity, the improvement wherein at the beginning of the filling process, during a limited time interval, the reaction mixture is fed into the cavity under low flow velocity until the mixture has reached a certain level in the cavity, and subsequently the remaining mixture to be injected, is fed in under increased flow velocity.

Abstract: The instant invention is directed to a process for the continuous production of block-shaped foam and to the equipment used therefore. The process of the invention broadly involves the heating of the bottom film prior to application of the foamable mixture. In this way, the undesirable crust generally formed on the bottom of the foam blocks is substantially reduced and/or eliminated.

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.

Abstract: The instant invention is directed to an improved device for the continuous production of foam blocks of rectangular cross-section, comprising an endless conveyor belt with side walls, means for supplying a covering sheet to the upper surface of the upper rim of the conveyor belt and the side walls, a charging device for supplying a foamable reaction mixture to the upstream end of the said upper rim of the conveyor belt, and a plurality of mold covers which are placed along the foaming area and each of which is suspended from a guiding device, the improvement wherein each guiding device comprises first and second links secured to mounting means, a diagonally extending rod pivotally connected at its lower end to the mold cover, a first lever pivotally connected at one end to the first link and pivotally connected at its opposite end to a point on the rod intermediate its ends, and a second lever pivotally connected at one end to the second link downstream of the pivotal connection between the first lever and th

Abstract: The instant invention relates to an apparatus for the continuous production of foam plastic blocks of a rectangular cross-section, in particular based on polyurethane. The apparatus generally comprises an endless conveyor belt whose upper run is provided with side walls, an unwinding device for a bottom and side sheet to cover the upper run of the belt and the side walls, a levelling device in the form of a roller or a doctor, which extends transversely in relation to the conveyor, a mixture application device and an unwinding device for a sheet to cover the mixture applied.

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.