canvas ventilation of invoice especially for ventilation in underground mines and the way there wentylowania groundwater kopaln

摘要

An improved brattice cloth construction comprising a reticulated back or supporting web referred to for convenience as the substrate, a batting or mat of textile staple fibres in dense, tightly needle-punched engagement with the substrate, and a fire resistant chemical impregnant, in sufficient amount to impart to the assembly of batting and substrate an acceptable flame resistance; and a method of utilizing the same in the ventilation of underground mines. IMAGE