Device for mixing at least two chemically reactive plastics components under pressure, having a mixing chamber, into which the plastics components are injected in each case by way of a component-feeding opening, wherein a reversible control piston is provided for opening and closing the component-feeding openings and for discharging plastics mixture remaining within the mixing chamber, wherein the control piston is connected to an electric drive. Alternatively, in the case of a transfer mixing head, the cleaning piston may be coupled to an electric drive. A method for operating such a mixing head is also disclosed.

A mixing module includes two inlets, an integrator, and a valve member. The integrator has two chambers each having a near end and a far end, and the valve member is movable between two positions. One of the inlets is connected to the near end of one of the chambers and the other inlet is connected to the near end of the other chamber when the valve is in one position. When the valve is in the other position, one of the inlets is disconnected from the chambers and the near ends of the chambers are connected.

The invention relates to a high-pressure mixing, dosing and recirculation head for injection or casting reaction molding, said high-pressure mixing, dosing and recirculation head comprising a head body, a mixing chamber, obtained in the head body wherein a valve element or mixing valve slides and in fluid communication with a supply duct, and a self-cleaning element comprising a scraping portion, said self-cleaning element being structured to slide in said supply duct, as well as comprising an apparatus for controlling and commanding mixing, supply and recirculation comprising a plurality of sensors and transducers mounted on board of the head body and of the components parts of the head connected thereto to detect and transform representative physical quantities of at least one operational status of said high-pressure mixing, dosing and recirculation head into electrical signals and an electronic control and storing system adapted to synchronously control and scan said sensors and transducers and adapted to receive and process said electrical signals indicative of said at least one operational status, at the beginning and during the operational phases of said high-pressure mixing, dosing and recirculation head to compare them with each other and with electrical signals representative of a predetermined reference operational status. The invention also relates to a high-pressure mixing, dosing and recirculation method for injection or casting reaction molding.

A gas mixing apparatus includes: a discharge port of gas provided near conduit space through which the high-viscosity material can flow; a piston pump including a cylinder that can communicate with the conduit space through the discharge port, a piston arranged inside the cylinder, and a drive device for moving the piston between a top dead center and a bottom dead center inside the cylinder; a discharge valve that opens and closes the discharge port; and a suction valve that opens and closes a suction port of the gas into a cylinder space, in which the cylinder forms the cylinder space having a predetermined volume when the piston is located at the top dead center, and in which a tip of the piston approaches the discharge port when the piston is moved toward the bottom dead center.

A mixing module includes two inlets, an integrator, and a valve member. The integrator has two chambers each having a near end and a far end, and the valve member is movable between two positions. One of the inlets is connected to the near end of one of the chambers and the other inlet is connected to the near end of the other chamber when the valve is in one position. When the valve is in the other position, one of the inlets is disconnected from the chambers and the near ends of the chambers are connected.

A mixing module includes two inlets, an integrator, and a valve member. The integrator has two chambers each having a near end and a far end, and the valve member is movable between two positions. One of the inlets is connected to the near end of one of the chambers and the other inlet is connected to the near end of the other chamber when the valve is in one position. When the valve is in the other position, one of the inlets is disconnected from the chambers and the near ends of the chambers are connected.

A cleaning piston for a mixing head of a reaction moulding machine includes a main part which has a cylindrical casing region, and a clearing part. The material and geometry of the clearing part are designed to remove residual material adhering to a channel of the mixing head. The clearing part is at least partly made of non-polar material.

A gas mixing apparatus includes: a discharge port of gas provided near conduit space through which the high-viscosity material can flow; a piston pump including a cylinder that can communicate with the conduit space through the discharge port, a piston arranged inside the cylinder, and a drive device for moving the piston between a top dead center and a bottom dead center inside the cylinder; a discharge valve that opens and closes the discharge port; and a suction valve that opens and closes a suction port of the gas into a cylinder space, in which the cylinder forms the cylinder space having a predetermined volume when the piston is located at the top dead center, and in which a tip of the piston approaches the discharge port when the piston is moved toward the bottom dead center.

A component feed nozzle includes a housing, which has a component inlet and a component outlet, a piston-shaped closing body, which is slidably supported in the housing and which can be moved back and forth axially. The component outlet is closed by the front end of the closing body in a first position and the component outlet is released or opened in a second position. The component feed nozzle has a membrane seal, which is fastened to the rear end of the closing body and to the housing in such a way that the closing body is completely on one face of the membrane seal. The housing and/or the closing body are designed in such a way that the component reaches all surfaces of the closing body and thus the component pressure is applied to the complete effective surface of the membrane.