The invention discloses an underground ventilation
system which comprises a main air duct, a plurality of
branch air ducts, first-stage throttling
orifice plate structures, first-stage
differential pressure detection devices, second-stage throttling
orifice plate structures and second-stage
differential pressure detection devices. Each
branch air duct is provided with a plurality of air openings;the first-stage throttling
orifice plate structures are arranged between the main air duct and the
branch air ducts, and each first-stage throttling orifice plate structure is provided with at least one first-stage throttling orifice; the first-stage
differential pressure detection devices are used for detecting the differential pressure of the front sides and the rear sides of first-stage throttling orifice plates; the second-stage throttling orifice plate structures are arranged between the air ports and the branch air ducts where the air ports are located, and each second-stage throttling orifice plate structure is provided with at least one second-stage throttling orifice; and the second-stage differential
pressure detection devices are used for detecting the differential pressure of the front sides and the rear sides of second-stage throttling orifice plates. The throttling orifice plate structures are easy to
machine, low in cost, easy and convenient to install, free of quick-wear parts, reliable and durable in structure and long in service life, the
airflow distribution accuracy can be guaranteed, and
air volume distribution in the underground ventilation
system can be monitored in real time.