Apparatus and process for mixing granules and/or powders and/or liquids in rubber production plants

A process for mixing at least one chosen from granules, powders, and liquids in rubber production plants, comprising the steps of:

• providing:
• —a mixer/extruder device configured for production of a basic heterogeneous mixture;
• —a plurality of distribution lines operatively connected to said mixer/extruder device to supply the mixer/extruder device with at least one chosen from a powdered product, a granulated product, and a liquid product;
• —said mixer/extruder device configured for mixing the at least one chosen from the powdered product, the granulated product, and the liquid product to obtain said heterogeneous mixture;
• wherein at least one of the distribution lines carries the powdered product and includes a pre-mixer arranged upstream of said mixer/extruder device to mix said powdered product with the liquid product to form a mixture;
• wherein said pre-mixer comprises:
• —a hopper for containing the powdered product and including on an external surface of the hopper, a manifold defining a respective duct in fluid communication with an interior of the hopper;
• —a blower member operatively connected with the duct for delivering a mixing flow of the powdered product inside the hopper;
• said blower member comprising:
• a hollow element defining a duct to pass a flow of gas between an inlet section and an outlet section;
• a shutter contained in the hollow element and an actuator connected with the shutter to adjust a maximum stroke thereof, the actuator moving the shutter along a translation axis from a closed condition to a maximum opening position along a translation axis thereof;
• a lateral supply duct defining the inlet section and flowing into a chamber in a direction incident to the translation axis of the shutter;
• the shutter presenting a shape of a plunger comprising an elongated stem and a frustoconical head portion;
• a stop element, having at least one frustoconical internal stop surface arranged in opposition to the shutter;
• the at least one frustoconical internal stop surface being counter-shaped to the head portion of the shutter to define at least one hermetically sealing configuration of the outlet section;
• and an injector of said liquid product to supply the flow of gas with said liquid product and to make said mixture of liquid product and powder;
• the injector comprising an oil supply nozzle, engaged in an auxiliary duct of the hollow element extending from an opposite side of the lateral duct and in an incident direction to the translation axis of said shutter further including, upstream of the hopper, an injector of the liquid product to supply the mixing flow with the liquid product prior to entering the hopper to make the mixture of the powdered product and the liquid product;
• —distributing the at least one chosen from the powdered product, the granulated product, and the liquid product to an interior of the mixer/extruder device;
• —mixing the at least one chosen from the powdered product, the granulated product, and the liquid product in the mixer/extruder to obtain the basic heterogeneous mixture;
• pre-mixing the powdered product with the liquid product prior to the step of distributing the at least one chosen from the powdered product, the granulated product, and the liquid product to the interior of the mixer/extruder device.