Duct series that is difficult to leak air.

The leakage air volume is almost "zero" for the positive pressure duct "Non-Leak Duct" and for the negative pressure duct "Pita Joint Duct" used in high-pressure ventilation systems such as long-distance shields.

■Non-Leak Duct (for Positive Pressure) ●Non-Leak Duct (Packing Type) (Patent Application No. 2015-38261) Measured value φ2500 at 8kPa with a maximum leakage rate of 0.1m³/min (per one fastening connection point) Available in standard length of 10m for φ800 to φ2500 ●Small Diameter Non-Leak Duct (Patent No. 4917069) This is a duct for positive pressure. Air leakage is almost zero. With a leakage rate of 1/3700 compared to conventional ducts, it is an excellent air duct for long-distance small cross-section shield and tunnel ventilation. Available in standard length of 10m for φ300 to φ700 ■Pita Joint Duct (for Negative Pressure) This is a duct for negative pressure. Air leakage is almost zero even at -80kPa. With low friction resistance and excellent long-distance air delivery characteristics, it allows for significant energy savings and enables the use of a smaller blower. Compared to conventional steel pipes, the outer diameter of the joint section is smaller, allowing for space-saving installation. It offers excellent cost performance for methane gas exhaust, long-distance shields, small cross-section tunnel mechanical excavation, TBM, etc.

Ventilation and Exhaust