Underwater rock core sampling device and method of use thereof

Claim 1

A hard rock corer for obtaining rock samples at depths down to 6,000 feet comprising: a closed tubular housing having a handle secured thereto in sealed relationship at one end and receiving in sealed relationship a hollow drill shaft at the other end, said housing compartmented to receive in succession in individual interconnected chambers an electric motor, a reducing gear, a universal joint and a piston; said chambers sealed at said piston from the environment and containing a pressure-compensating oil having selected dielectric characteristics for electrically insulating the device from the environment; a drive shaft extending from said universal joint and connected in succession to a rotary water pump and said hollow drill shaft, said piston slidably mounted on said drive shaft in sealing engagement therewith and with the interior surface of said tubular housing to separate the oil on one side thereof from water at ambient pressure on the other side; an opening in said shell intermediate said piston and said pump for admitting water under ambient pressure to the portion of said piston chamber remote from said oil; a pump inlet disposed in said piston chamber and a pump outlet disposed in an end chamber intermediate said pump and said other end of said housing; said drill shaft having an opening in said end chamber and a core receptacle at its remote end, a passage connecting said opening and said receptacle; a hard rock core drill secured to the remote end of said drill shaft; and an electric power supply externally disposed with respect to said housing and means connecting said power supply and said electric motor, whereby during drilling said pump will direct water past the cutting bits, flushing away loose pieces and mud, and during retrieval the core sample will be held in said receptacle by the suction created by reversing said electric moTor.

Claim 11

The method of obtaining a rock core sample from extreme depths by an electrically driven rock core drill comprising the steps of: surrounding the electric motor of said drill with a sealed pressure-compensating oil having suitable dielectric characteristics; admitting seawater at ambient pressure into a free-flooding cavity adjacent the motor cavity; applying water at ambient pressure to said pressure-compensating oil through a free-floating piston forming a portion of said cavity; pumping water from said free-flooding cavity through a hollow drill shaft to a core receiving receptacle at the end of the drill shaft to flush away mud and particles during drilling; and reverse pumping water from said receptacle to said free-flooding cavity after a core sample has been broken free to hold the sample by suction in the receptacle until the sample has been recovered.

Claim 12

The method of obtaining a rock core sample from extreme depths by an electrically driven rock core drill comprising the steps of: surrounding the electric motor of said drill with a sealed pressure-compensating oil having suitable dielectric characteristics; admitting seawater at ambient pressure into a free-flooding cavity adjacent the motor cavity; applying water at ambient pressure to said pressure-compensating oil through a free-floating piston forming a portion of said cavity; pumping water from said free-flooding cavity through a hollow drill shaft to a core receiving receptacle at the end of the drill shaft to flush away mud and particles during drilling; and reverse pumping water from said receptacle to said free-flooding cavity after a core sample has been broken free to hold the sample by suction in the receptacle until the sample has been recovered.