High-pressure mixing device with single-piece delivery duct

A high-pressure mixing device suitable for forming a polymeric mixture resulting from a first and at least a second chemically reactive liquid component, said mixing device comprising:

• a head-body configured with a mixing chamber having an inner cylindrical surface provided with inlet openings and outlet openings respectively for injecting and recirculating the reactive components;
• a delivery duct for releasing and ejecting the resulting polymeric mixture, having an inner cylindrical surface in fluid communication with said mixing chamber and inside which a cleaning member is slidingly movable suitable for ejecting the mixture once a delivery is finished;
• a valve member provided with longitudinal slots for recirculating separately the reactive liquid components and slidingly movable in said mixing chamber between a backward position, in which it leaves said inlet openings exposed, and an advanced position, in which each of said longitudinal recirculating slots puts in communication one respective inlet opening with a respective outlet opening for recirculating the respective reactive component;
• wherein said delivery duct is composed of a tubular element made in a single ne non-jointed piece, having an open upper end communicating with a spacer chamber, and an open lower end for delivering the reactive mixture and,
• a cleaning member or stem reciprocable via hydraulic control in said tubular element between an upper backward position—in which the cleaning member or stem clears, at least partially, the outlet of said mixing chamber into a delivery chamber defined in said tubular element for enabling the outflow of the reacting mixture—and a lower advanced position in which the cleaning member or stem ejects the mixture still contained in said tubular element and scrapes away from the surface of said tubular element the adhered resin;
• said tubular element being a piece distinct from, separated and processed separately from, said head-body and removably insertable into a pass-through hole of said head-body, extending transversally with respect to said mixing chamber, said tubular element being arranged to extend transversally with respect to said mixing chamber and to protrude at the bottom from said head-body longitudinally along an axis of said pass-through hole;
• wherein said tubular element is configured with an intermediate transversal hole placed, in an assembled configuration, so as to extend, with an increased diameter, said mixing chamber which thus extends up until it leads into an inner chamber of said tubular element;
• said intermediate transversal hole having one first diameter greater than a second diameter of said mixing chamber to compensate for, while assembling, mutual geometrical positioning errors and tolerances due to processing tolerances such as to avoid steps and zones interfering with the movement of said valve member inside the intermediate transversal hole, said intermediate transversal hole being configured as an extension of said mixing chamber and conformed for internally receiving a front cylindrical end part of said valve member in said advanced position;
• an elastic or elasto-plastic sealing elements;
• on the surface that delimits said intermediate transversal hole an annular seat being obtained which is conformed for housing said elastic or elasto-plastic sealing element, said sealing element being housed with forced interference and compressed in said seat for exerting an hydraulic sealing function against leakages of reactive components from said longitudinal recirculating slots through said intermediate transversal hole and seats of said tubular element and against leakage of lubricant liquid from the gap defined between a stem of a control cylinder of said cleaning member and said tubular element—towards said longitudinal slots when the end front part of said valve member is in said advanced position;
• said tubular element being configured with an annular shoulder zone placed at a zone distant from said intermediate transversal hole, and
• fixing and orienting elements being provided and configured for removably fixing said annular shoulder zone to a side surface of said head-body transversal with respect to said pass-through hole, for locking in the correct position said tubular element in said pass-through hole,
• between said tubular element and said pass-through hole and in said head-body being defined a clearance gap configured to allow to easily interchange f said tubular element, to ease the insertion into, and the removal of said tubular element from said pass-through hole,
• sealing and centering elements being also provided configured to avoid leakages of polymeric mixture of the reactive components outside said mixing chamber and through said clearance gap and towards said spacer chamber and to avoid any leakage of lubricant liquid from said spacer chamber towards said mixing chamber through said clearance gap.