Abstract: A high-pressure self-cleaning mixing apparatus adapted to mix at least first and second reactive polyurethane-forming components and feed the mixed components to a mold is disclosed. The apparatus includes at least a mixing chamber, first and second feed passages, first and second recycle passages, and a cleaning member having at least first and second longitudinally-extending recycle grooves spaced from each other. The cleaning member is movable between an open position in which the first feed passage radially feeds the first polyurethane-forming component to the mixing chamber and a closed position in which the first longitudinally-extending recycle groove communicates the first feed passage with the first recycle passage to recycle the first polyurethane-forming component instead of feeding the first polyurethane-forming component to the mixing chamber.

Abstract: An apparatus for feeding and metering fluid components to a mixing head, in particular for metering and feeding reactive chemical components to a high pressure mixing head. The apparatus comprises at least a first and second transfer cylinder whose control unit is fed with hydraulic fluid from a single source of constant pressure, and whose component pumping unit is connected to a tank for the component, respectively to an inlet aperture for the component in a chamber of the mixing head, by means of a proportional servo valve which is controlled in relation to the rate of flow of the components so as to keep both the pressure and the flow of the components to be mixed constant.

Abstract: A metering device for feeding liquids, in particular chemical components for the production of polyurethane mixtures in a high-pressure mixing head.The device comprises at least a first and a second metering unit of the type having a cylindrical chamber in which a plunger slides to displace a pre-established volume of liquid during its stroke and to feed it to the mixing head. The plunger is connected to a worm screw control device, in which the worm screw control devices of the metering units are interconnected by a mechanical drive actuated by a driving motor; one or more revolution variators can be disposed in the mechanical interconnecting transmission in order to vary the ratios between the speeds of the plungers and, therefore, the quantities metered in relation to the stochiometric ratios between the liquids to be mixed.

Abstract: The invention refers to a high-pressure mixing device, for at least two chemical components to be mixed, in particular of the type having a movable mixing chamber, in which the mixing chamber communicates with an outlet duct for discharging the mixture therefrom through a lateral passage and in which the component inlet apertures open directly into the mixing chamber but are oriented so as to face away from the lateral passage in a direction which is opposite to the flow of the mixture in the outlet duct.

Abstract: The invention relates to a method for producing insulations of foamed plastic material, in cabinets and doors of refrigerators, freezers and the like.According to the invention, a metered quantity of a foamable mixture is fed into the gaps between the inner and outer walls of a cabinet or door, placed in a foaming jig; the foaming process is controlled by sensing characteristic parameters, for example, the temperature of the jig, cabinet or door, or the pressure of the foaming plastic material, comparing them with reference parameters or data stored in a data processing unit. A control signal is generated to open the foaming jig and to unmold or remove the cabinet or door when at least one of the processing parameters has reached a pre-established value. The metered quantity of mixture fed in each subsequent foaming operation is corrected each time according to the changes in the peak pressure of the foam with respect to the previous foaming operation.

Abstract: A high-pressure mixing head for at least two fluid components to be mixed together.The mixing head comprises a movable mixing chamber, defined by a cylindrical hole whose longitudinal axis is parallel to the axis of an outlet duct; the mixing chamber is provided in a slider movable in a guide channel at right angles to and crossing the outlet duct for the mixture. The slider is movable from a first operative position in which the chamber is disposed on one side of the outlet duct, in correspondence with the nozzles for injecting the components to be mixed, and in which the outlet aperture of the mixing chamber communicates with the outlet duct, to a second position in which the injectors communicate with component recycling ducts, and in which the mixing chamber is axially aligned with the outlet duct and with a sliding cleaning member.

Abstract: A plant for molding articles in polyurethane material; the plant comprises a plurality of motorized mold supporting carriages independently movable along a suspended monorail running along a production line. Each carriage comprises a mold supporting press for opening and closing a mold provided with independent pneumatic control means supported by the same carriage; the control means are connectable to a source of fluid under pressure in pre-established working positions along the production line; each carriage also comprises a drive unit connected to electrical power supply bus bar along the monorail and a peripheral control unit operatively connected to a central logic unit by dialogue conductors provided on the monorail.

Abstract: A mixing method and apparatus for preparing multi-component plastic materials, especially polyurethanes, which are mixed before being fed into a mold. According to the invention, a first and at least a second main component are mixed by feeding them into a limited area of a mixing chamber through lateral inlet apertures symmetrically arranged with respect to a plane comprising the longitudinal axis of the chamber and in which a third or secondary component to be mixed is fed through a channel, opening in the chamber upstream of said inlet apertures and orientated so as to direct the flow of the third or secondary component towards said mixing area in the direction of flow of the mixture. A control member is moved toward an advanced position so that it closes the inlet apertures to interrupt feeding of the first and second main components and a coloring agent through respective inlet apertures after a mixing operation.