Abstract: A component-feed nozzle for a reaction-mixing head of a reaction injection device includes a housing having a component inlet and a component outlet. Received in the housing is a closing and flow restriction member which is movable by a linear drive between at least two positions. In a first position, the closing and flow restriction member closes the component outlet, and in a second position clears the component outlet, thereby establishing a flow communication between the component inlet and the component outlet. The closing and flow restriction member has at least a first area and a second area, which generate forces in opposite directions, when the component pressure is applied, wherein the areas are sized in such a way that the opposing forces substantially offset one another.

Abstract: The present invention relates to a mould, in which a completely closed cavity can be formed in one operating state, comprising an injector (10) which is at least partially accommodated in the mould (14) and the discharge opening of which opens into the closed cavity. According to the invention, the injector is designed with a material feed duct (30) and a material return duct (34), wherein the two ducts (30, 34) open into a connecting chamber (32) in the region of the tip of the injector (10) and are flow-connected to one another via said connecting chamber (32). In this case, an injector needle (36) can be switched into at least two operating positions, wherein, in one moved-forward operating position, the discharge opening is closed by means of the tip (38) of the injector needle (36) and, in the other, pulled-back operating position, the discharge opening is flow-connected to the connecting chamber, and the injector (10) is therefore open.

Abstract: The present invention relates to a mould, in which a completely closed cavity can be formed in one operating state, comprising an injector (10) which is at least partially accommodated in the mould (14) and the discharge opening of which opens into the closed cavity. According to the invention, the injector is designed with a material feed duct (30) and a material return duct (34), wherein the two ducts (30, 34) open into a connecting chamber (32) in the region of the tip of the injector (10) and are flow-connected to one another via said connecting chamber (32). In this case, an injector needle (36) can be switched into at least two operating positions, wherein, in one moved-forward operating position, the discharge opening is closed by means of the tip (38) of the injector needle (36) and, in the other, pulled-back operating position, the discharge opening is flow-connected to the connecting chamber, and the injector (10) is therefore open.

Abstract: A mixing head for mixing at least two reactive starting materials includes a feed passageway for introduction of a high-viscosity starting material, and a return passageway for the high-viscosity starting material for allowing circulation of the high-viscosity starting material. The high-viscosity starting material can be introduced into a mixing chamber for subsequent mixing with a via at least one injection port. A switchover device is provided for selectively establishing a flow communication between the feed passageway and the mixing chamber and a flow communication between the feed passageway and the return passageway, wherein the flow communication between the feed passageway and the mixing chamber is provided upstream of the at least one injection port.

Abstract: Integrated in the mixing head of a polyurethane apparatus for producing a mixture stream of chemically reactive plastic components, is a cutting arrangement by which natural fibers or fiber strands of soft-elastic and tough consistency can be drawn from a continuous strand and, after cutting into fiber pieces of given length, can be introduced into the mixture stream. The cutting arrangement includes an inner guide tube which receives a fiber strand, drawn from a continuous fiber strand by two feed rollers, and fed via the guide tube and an outer support tube to rotating knife elements. By subjecting the guide tube to a vacuum and applying a compressed gas stream to the end of the outer support tube, the soft-elastic fiber strand is held straight in a manner which is optimal for the cutting process. The cut fiber pieces are introduced together with the gas stream into the mixture stream of chemically reactive plastic components.

Abstract: A closed loop feedback control for a high pressure impingement mixing system. The high pressure impingement mixing device is equipped with a circulation loop containing both a pressure sensor and a flow volume meter. Constant pressure and flow volume is achieved by continuous closed feedback loop monitoring of the pressure and flow volume to effect a change in an adjustable pump setting and servo displaceable nozzle needle. The nozzle needle adjustment allows maintaining the appropriate pressure and volume on a continuous spaces. It also allows altering component ratios and/or flow volumes during a shot in order to affect a change in material or flow characteristics of a produced part.

Abstract: A closed loop feedback control for a high pressure impingement mixing system. The high pressure impingement mixing device is equipped with a circulation loop containing both a pressure sensor and a flow volume meter. Constant pressure and flow volume is achieved by continuous closed feedback loop monitoring of the pressure and flow volume to effect a change in an adjustable pump setting and servo displaceable nozzle needle. The nozzle needle adjustment allows maintaining the appropriate pressure and volume on a continuous spaces. It also allows altering component ratios and/or flow volumes during a shot in order to affect a change in material or flow characteristics of a produced part.

Abstract: A closed loop feedback control for a high pressure impingement mixing system. The high pressure impingement mixing device is equipped with a circulation loop containing both a pressure sensor and a flow volume meter. Constant pressure and flow volume is achieved by continuous closed feedback loop monitoring of the pressure and flow volume to effect a change in an adjustable pump setting and servo displaceable nozzle needle. The nozzle needle adjustment allows maintaining the appropriate pressure and volume on a continuous spaces. It also allows altering component ratios and/or flow volumes during a shot in order to affect a change in material or flow characteristics of a produced part.

Abstract: A piston metering apparatus for the metering of the components of a reaction injection molding machine comprising a metering cylinder (2) the cylinder space of which is surrounded by a cylinder wall, a metering piston (10) sealed in relation to the cylinder wall by means of a sealing unit, a cylinder base (3), component inlet (4) and component outlet lines (5) connected with the metering cylinder (2), and a metering piston (10) coupled with the hydraulic piston rod of a hydraulic drive unit (12). In order to simplify the inspection and maintenance of such a piston metering apparatus, the metering piston (10) is in the form of a plunger piston and the sealing unit is contained in a sealing cartridge (9) releasably fastened to the upper edge of the metering cylinder (2).