Crown-drilling pumping sand:
Drilling type pumping sand is mainly applied to a thick layer of mud conditions, first penetrated by the drill mud layer, and then extract the sand and mud layers below piped to shore, which is mainly aimed at the general mechanical suction dredgers and sand does not work and the development of the site developed a working principle: when the device is working first to drill completely erect, and start driving slowly rotating the drill bit after decentralization, devolution process pumps and pumping sand pump to start playing with the drilling operations, into the sand until the next start Chousha . To be on reducing the amount of sand, then the appropriate drilling depth adjustment decentralization.