Miner's dust-protective helmet - has fan driven by rechargeable batteries with parallel conductors containing resistor and diodes

摘要

The dust-protective helmet is particularly for miners. It consist of a strong protective helmet with a visor, and it has an electrically-driven fan with dust filters and a battery power surface. The source comprises one or more rechargeable batteries in series, cast in a housing with a surface conductivity of at least 10-9 Ohm-1, together with a switch contact and two conductors in parallel leading to one of the poles. One conductor contains one or more resistances, and the other diodes connected in series in the inverse-current direction in relation to the current flow from the source.