How to water seal the drill bit of a down-the-hole drill rig video

DTH technique was used in well drilling exclusively to dig, accurate, vertical bores, and rotary drilling was used to turn the hole. The Directional DTH system, patented by Atlas Copco, was first used. [pdf]

Twin screw water-cooled air compressor seal

Though the oil free type compressor design method is used for twin-screw steam compressor, the bearings and synchronous gears still need lubrication by pressured lubricating oil. If steam leaks into the l. [pdf]