Method and apparatus for preparing and dispensing a mixture obtained by mixing chemically reactive components, at least one of which containing a filler material

Method for verifying the dimension of, and monitoring possible damage to, particles that make up a filler material contained in a second chemically reactive component intended to be mixed with a first chemically reactive component for preparing and dispensing a mixture, the method providing for performing a special verification cycle with the help and application of a position transducer and the use of a position control by using a control servo valve coupled with an interception and supply device of said second chemically reactive component, in which said special verification cycle includes the steps of:

• supplying said second chemically reactive component, at a set flowrate, to said interception and supply device, after closing a re-introduction circuit for redelivery to a respective tank,
• positioning, by driving respective mechanical or hydraulic member, a plug shutter element included in said interception and supply device with respect to an associated calibrated supply nozzle so as to define therebetween a controlled annular passage section for the second chemically reactive component,
• reducing gradually the distance between said plug shutter element and said supply nozzle and
• monitoring continuously the pressure of the flow of said second chemically reactive component upstream of the interception and supply device during reduction of the passage section and, in case of sudden pressure peaks,
• detecting the position of said plug shutter element to obtain the dimension of the passage section for the second chemically reactive component and
• comparing this dimension with the data corresponding to the whole non-worn filler material so as to determine, by comparison, the degree of damage to the filler material contained in the second chemically reactive component.

Apparatus for preparing and dispensing a mixture, comprising

• a high pressure mixing device provided with a mixing head in which a mixing chamber is obtained for mixing at least one first chemically reactive component with at least one second chemically reactive component containing a filler material,
• in said mixing head a slide-valve being housed and slidably movable that is provided with longitudinal slots for recirculating said at least one first chemically reactive component and said at least one second chemically reactive components to respective storage tanks,
• a pumping arrangement connected to a delivery line and configured to withdrawn, from a respective tank, a quantity of said chemically reactive second chemically reactive component containing the filler material and dosing in a controlled and settable manner said second chemically reactive component towards said delivery line to the mixing head;
• a sectioning valve configured to interrupt the fluid communication between said pumping arrangement and said respective tank,
• an interception and supply device or injector configured to permit/prevent the supply of said second chemically reactive component to the mixing chamber or the corresponding recirculating slot obtained on the slide-valve of the mixing device,
• a re-introduction circuit configured to redeliver said second chemically reactive component, in a low pressure and low speed condition, to the respective tank bypassing the mixing head,
• a diverter valve, placed upstream of the interception and supply device or injector, configured to deviate the circulation of said second chemically reactive component from said delivery line to said re-introduction circuit.