Grado Adroit is a gravimetric batch blender with integrated control, developed by Doteco for extrusion lines; it is the third generation of the Grado range. Unveiled at K 2013, it stands out for its precision, capacity, maintenance, modularity and reliability, all of which have been improved as a result of innovative technological features. The blender is designed to be installed directly on the extruder throat, but it can also be installed on a mezzanine or off-line, on a floor-type hopper, to feed one or more extruders. It is available in four models with four different capacities - S (200 kg/hour), J (400 kg/hour), Q (800 kg/hour) and K (1300 kg/hour) - each of which can be supplied in 5 versions, to process from 2 to 6 ingredients. The semi-spherical mixing chamber with its truncated conical bottom guarantees homogeneous blending and prevents accumulation of material residue. Emptying is facilitated by the presence of discharge spouts with manual slide gates, while the inclined slide gate, connected with the drain spout, guarantees complete draining of the material. The slide-gate unit is easily removed to allow the complete removal of all residual material. The basic 2-ingredient model comes ready designed for expansion to up to 6 ingredients, which is easily and rapidly accomplished thanks to a special kit which does not require the intervention of a specialised technician. The innovative kinematics of the feeding gate in engineering polymer featuring high strength and low inertia, the dual-lip scrapers (also in engineering polymer), the weighing hopper with vibration damping system and the last-generation B&R-X20 electronics all add up to increased precision, accuracy, efficiency and reliability, and therefore to a longer service life and reduced maintenance. The batch blending method requires that each ingredient be fed in sequence, by means of a gate valve, and weighed on a gravimetric hopper feeder, mounted on load cells. Once the set weight is reached, the batch is discharged into the mixing chamber. Grado Adroit uses a semi-spherical loss-in-weight mixing chamber, installed on a load cell which continuously weighs the materials used. The system can measure and control the extrusion throughput or line speed, or, alternatively, can perform the two functions simultaneously. In the case of multi-layer lines, the throughput of each extruder is measured and controlled to ensure that the percentage ratio between the various layers remains constant. The automatic material loading system is controlled by the same PLC and terminal that manage the feeding dispensing system. It is possible to link one or more vacuum pumps with the different pneumatic receivers, with the combinations depending on the specific plant configuration. The loading cycle of the pneumatic receivers, sharing the same vacuum line, is managed automatically by the PLC, on the basis of effective consumption. The option for the active control of the loading phase reduces the amount of residual material at the end of each batch down to a minimum.