Blowing apparatus including piezoelectric valve and optical granular material sorting machine using the blowing apparatus

摘要

The present invention has an object to provide a blowing apparatus wherein a piezoelectric element is unlikely to cause insulation deterioration leading to burnout during use of the blowing apparatus. The blowing apparatus of the present invention blows compressed gas supplied from a compressed gas supply unit through a nozzle hole of a nozzle unit by opening a piezoelectric valve. The blowing apparatus comprises a humidity sensor detecting a humidity of the compressed gas inside a flow path unit, and a humidity control unit comparing a detected value of the humidity detected by the humidity sensor with a set value. If the humidity of the compressed gas inside the flow path unit detected by the humidity sensor is equal to or greater than the set value, the humidity control unit replaces the compressed gas inside the flow path unit with the compressed gas whose humidity is less than the set value and which is supplied from the compressed gas supply unit, before starting to use the blowing apparatus.