Proportional powder dispensers prevent damage caused by limestone and rust in new plants. In old ones, they create a protective film around the pipes to prevent corrosion due to years of erosion by water. Thanks to the Venturi system, the dosage of the polyphosphates is proportional to the flow of the water supplied, ensuring a precise introduction of the product. Microdosing of the polyphosphate neutralises the precipitation of calcium and magnesium carbonate up to a temperature of 70-75°C. The MIDI dispenser can be installed on horizontal, vertical or oblique tubes. Its small size allows it to be placed in small spaces while ensuring broad operating autonomy.