An Improved Method of, and Means for, Preventing Explosions in Mines by Damaged Electric Lamps and Motors.

摘要

23,344. Palmer, F. Oct. 12. Explosions, preventing in mines and in connexion with electric apparatus.-In devices for preventing explosions in mines due to the damage or sparking of electric cables, motors, lamps, &c., of the kind in which such apparatus is enclosed in air-tight casings and pipes supplied with compressed air, switches controlling the electric supply are adapted to open when the pressure falls and to re-close when the pressure is restored. The lamps 1, Fig. 4, are enclosed in a globe 2, and compressed air is supplied through a pipe 15, enclosing the cables, to a compartment 7, and thence through a tube 14 to a compartment 8 communicating through a perforated base 3 with the globe 2, a flexible diaphragm 12 carrying contacts 13 being thus raised to close the circuit. A lightly-loaded valve 18 allows the escape of any air leaking into the compartment above the diaphragm. Fig. 2 shows a switch-box containing a pivoted double-pole switch 40 controlled by means of a spring 42 and a pneumatic piston 39. Compressed air is supplied to a compartment 26, and thence through a tube 36 to a compartment 28, a valve 44 permitting the escape of any air leaking into the central compartment 27. The casings surrounding the motors are provided with a vent, in order to ensure a gradual change of air.