▎ 摘　　要

NOVELTY - The method involves providing a head with a chamber (46) for mixing the components. A slide-valve (5) is provided with longitudinal recirculation slots (6) for recirculating the components to the storage tanks (7A). The second component containing the filler material is re-circulated through the recirculation slots of the slide-valve for a very short time with respect to a recirculating step of the first component through the recirculation slots, so as to avoid the accumulation of damaged filler material in the dosage circuit, recirculating line and tank. A quantity of the chemically reactive second component containing the filler material is withdrawn from a tank, by pumping arrangement connected to a delivery line of the component to the mixing chamber. The second component is prevented from flowing back directly from the pumping arrangement to the tank. The filler material is chosen from expandable graphite, hollow glass microspheres, montmorillonite, peelable clay or graphene. USE - Method for preparing and dispensing mixture obtained by mixing first chemically reactive component by high pressure mixing device. ADVANTAGE - The damage to the filler material dispersed in the resins and accumulation of damage are reduced significantly, that results in higher quality and in better performance of the objects and products obtained by molding by reaction and in particular by foaming by reaction. The wear and erosion is reduced significantly that the latter is subjected to in the high-pressure mixing process in particular minimizing and counteracting the damage that the graphite suffers during the step of high pressure circulation, during the circulation through the injectors, the slots of the slide-valve, the dosing pumps and conduits in general. DETAILED DESCRIPTION - INDEPENDENT claims are included for the following: 1. a method for verifying dimension of particles and monitoring possible damage to particles that make up filler material; and 2. an apparatus for preparing and dispensing mixture DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of the apparatus for preparing and dispensing mixture. Apparatus for preparing and dispensing mixture (1) Slide-valve (5) Longitudinal recirculation slot (6) Storage tank (7A) Chamber (46)