Abstract: An apparatus for preparing flowable reaction mixtures from at least two flowable reactants in which the components are injected into a mixing chamber by means of injection nozzles, the force of the reactant acting upon the nozzle needle is at least substantially compensated to avoid impairing the mixing ratio during a change-over of the nozzle needle. The rear end of the nozzle needle is provided with a chamber communicating with the component supply line.

Abstract: In the production of a flowable reaction mixture of at least two flowable, also not readily miscible, reaction components which react completely with each other to form solid substance or foam material, a rapid abatement of the mixture flow is achieved with a compact type of construction after causing throttling at the discharge of the mixing chamber.

Abstract: In a fine comminution apparatus arranged downstream of a coarse comminution apparatus, polyurethane foam wastes can be comminuted to the desired particle size for recycling as an additive in the production of polyurethane, in a low-dust and energy-saving manner, by carrying out the fine comminution preferably by repeatedly forcing a mixture of the coarsely comminuted material and one of the reaction components through a nozzle or through a plurality of nozzles.

Abstract: A process and apparatus are described for the production of a flowable reaction mixture from at least two flowable reactive components which may be difficult to mix, which components react with one another to form a solid or a foam material. The components are injected into a mixing zone where the components are mixed in a continuous flow. The mixture flowing from the throttling zone is divided into two sub-streams which flow around a piston and which recombine opposite the division point.

Abstract: In an apparatus for manufacturing molded plastic articles or for manufacturing hollow foamed articles wherein at least two further mold halves are allowed to cooperate alternately with a first mold half, improved accessibility is achieved and a smaller amount of floor space is required by providing a support structure comprising a vertically arranged support axis which has at least one transverse axis on which the further mold halves are pivotably supported by holding devices.

Abstract: In order to guarantee substantially trouble-free operation when manufacturing sandwich elements on a double conveyor belt installation having a downstream cross cutter and cleaning device, the cleaning device disposed on a transport carriage i) is returned to the carriage of the cross cutter to pick up the next sandwich element, is braked and is then re-accelerated to a speed higher than the production speed, ii) is, after reaching a desired distance.

Abstract: In order not to have to rinse, during breaks in production, oscillating mixheads such as are used for the manufacture of free-flowing, plastic-forming reaction mixtures, an exchangeable insert part held in position by means of a clip and preferably consisting of plastic material is provided in the mixhead. The insert has a mixing chamber and an outlet channel. This insert part can be disposable or reusable.

Abstract: In order to guarantee substantially trouble-free operation when manufacturing sandwich elements on a double conveyor belt installation having a downstream cross cutter and cleaning device, the cleaning device disposed on a transport carriage i) is returned to the carriage of the cross cutter to pick up the next sandwich element, is braked and is then re-accelerated to a speed higher than the production speed, ii) is, after reaching a desired distance.

Abstract: A process and apparatus are described for the production of a flowable reaction mixture from at least two flowable reactive components which may be difficult to mix, which components react with one another to form a solid or a foam material. The components are injected into a mixing zone where they components are mixed in a continuous flow. The mixture flowing from the throttle zone is divided into two sub-streams which flow around a piston and which recombine opposite the division point.

Abstract: The present invention is directed to an apparatus for introducing gas into one of at least two free-flowing components which are subsequently mixed to provide a foam-forming free-flowing mixture by transferring the component to have gas dispersed therein from a supply container to a gas loading area, loading the component with gas and returning the component to the supply area, wherein the gas used in the gas loading area is obtained from a gas cushion maintained in the supply container and wherein the gas is compressed to a pressure higher than the pressure in the gas loading area before it is dispersed into the free-flowing component.

Abstract: The invention relates to a nozzle for mixing at least two flowable (and in particular foam-forming) reaction components comprising a housing; component supply pipes leading into the housing; a housing bore arranged in the housing having a coaxial outlet channel in its end face; at least one needle casing arranged coaxially in the housing bore; an injection needle guided coaxially in the needle casing; a first chamber arranged between the wall of the housing bore and the needle casing with one of the component supply pipes opening into said first chamber; a second chamber arranged between the needle casing and the injection needle, with another component supply pipe opening into said second chamber; wherein in the closed state, said injection needle forms a tight fit with the internal end face of the needle casing, and the external end face of said needle casing forms a tight fit with the internal end face of the housing bore; and wherein in the open state, said injection needle frees a coaxial nozzle opening

Abstract: In order to keep the reversing times from circulation of the reaction components to mixing and vice versa as short as possible for the purpose of good mixing in the initial and end phases in the preparation of flowable reaction mixtures by high-pressure mixing, the holding pressure applied to the flow reversing element is maintained by a releasable non-return valve until the full hydraulic reversing pressure has built up on the opposite side, and only then is the non-return valve released.

Abstract: The polygon effect in a double belt conveyor for the continuous production of laminates having a foam core foamed in situ between covering layers is avoided in that the slat belts are provided with guiding rails in the deflection areas, and in that the slat belts are driven by rotating pulling elements. The driving elements of the pulling elements engage on catches which are arranged along the slat belts, only in the sections of straight-line motion of the slat belts.

Abstract: The present invention is directed to a process and apparatus for introducing gas into one of at least two free-flowing components which are subsequently mixed to provide a foam-forming free-flowing mixture by transferring the component to have gas dispersed therein from a supply container to a gas loading area, loading the component with gas and returning the component to the supply area, wherein the gas used in the gas loading area is obtained from a gas cushion maintained in the supply container and wherein the gas is compressed to a pressure higher than the pressure in the gas loading area before it is dispersed into the free-flowing component.

Abstract: The invention relates to a nozzle for mixing at least two flowable (and in particular foam-forming) reaction components comprising a housing; component supply pipes leading into the housing; a housing bore arranged in the housing having a coaxial outlet channel in its end face; at least one needle casing arranged coaxially in the housing bore; an injection needle guided coaxially in the needle casing; a first chamber arranged between the wall of the housing bore and the needle casing with one of the component supply pipes opening into said first chamber; a second chamber arranged between the needle casing and the injection needle, with another component supply pipe opening into said second chamber; wherein in the closed state, said injection needle forms a tight fit with the internal end face of the needle casing, and the external end face of said needle casing forms a tight fit with the internal end face of the housing bore; and wherein in the open state, said injection needle frees a coaxial nozzle opening

Abstract: Closure units for molding tools, in particular those for the production of polyurethane moldings comprising long lifting cylinders arranged between an upper cross head and a movable cross head for lowering and raising the upper half of a molding tool, the movable cross head being mounted on columns connecting the fixed cross head to a base by means of short lifting cylinders having arrestable drag pistons arranged therein, were found to offer advantages in terms of economy of design and operation.

Abstract: A nozzle is used to mix two or more flowable reaction components which nozzle has a force controlled injection needle (7) and a force controlled needle casing (12) guided in a guiding bore (12). One component emerges centrally into an outlet channel (3) while the opening (25,26) of at least one further supply pipe (23,24) lies in the area of a sealing surface (4) which limits one side of the guide bore (2) and which forms a tight fit (18) with an outer sealing surface (17) thereof when the needle casing (12) is in a closed position.

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: In the continuous production of block-foam from liquid reaction components, the danger of over-rolling exists in installations having low throughputs and in installations having high throughputs, which over-rolling results in faults in the finished block. These over-rolling phenomena are avoided by providing a conveyor belt in the mixture charging zone which belt transports on its conveying surface a foil which has trough-shaped indentations which can correspond to trough-shaped indentations in the conveying surface. The reaction mixture is portioned into the indentations of the foil. These portions are only spread out once the reaction mixture has reached the creamy phase.

Abstract: A process and a mixing head for the production of a reaction mixture comprising at least two reaction components, with a high degree of mixing. By this process, reaction components are introduced, at a high pressure into one end of the mixing chamber of the mixing head, these components being deflected by the front of the discharge piston which forms the opposite end of the chamber, a counterflow forming intensive turbulences on the wall of the mixing chamber and on the boundary surface with the incoming flow before this counterflow exits the mixing chamber at the same end through which it entered the chamber, substantially as a radially-directed, laminar flow.