Method and high-pressure mixing apparatus with self-regenerating seal

A method for forming a self-regenerating seal into a mixing chamber of a high pressure mixing apparatus, comprising the steps of:

• feeding a first and at least a second polymeric component to the mixing chamber through injection holes, to form a reactive polymeric mixture, to be dispensed by a delivery conduit, in which a slidable valve member is reciprocable in the mixing chamber between a retracted position, and an advance position to open and respectively close the injection holes and the mixing chamber in respect to the delivery conduit;
• providing at least one annular seat for housing an annular sealing element on an inner surface of the mixing chamber in a sealing zone downstream of the injection holes;
• providing an annular sealing element in said at least one annular housing seat by a polymerisable resin;
• and
• automatically regenerating worn and/or torn parts of the annular sealing element, by allowing the reactive mixture to fill up and polymerize into the worn and/or torn parts of the sealing element, inside the annular housing seat.