Patent ID: 7431081

Claim:
An apparatus for removal and filtration of drilling fluid during top hole drilling, wherein a suction module ( 10 ) comprises an elongated pipe-formed body ( 30 ), which is open at the top and is arranged to an ocean-bottom penetrating pipe, through which is led a drill stem for drilling of the top hole, and the pipe-formed body ( 30 ) comprises a filtration device with through openings, where said openings are arranged to let through to at least one outlet passage ( 32 ) in the pipe wall, filtered return drilling fluid containing dispersed material, such as swelling clay or stones, wherein filtered return drilling fluid from the bore hole is exported to a pump module ( 12 ) through the at least one outlet passage ( 32 ) in the pipe wall, the material in the drilling fluid being of a size less than the diameter of a inlet pipe of the pump or openings of the pump, the upper part of the pipe-formed body ( 30 ) is arranged to contain return drilling fluid, which is not fed to the pump module ( 12 ), and where a volume of said drilling fluid stands as a “plug” above the outlet ( 32 ) of the suction pipe ( 22 ) of the pump and is sealed against the drill stem (l 6 ), and the level of return drilling fluid in the pipe-formed body ( 30 ) being adjusted by regulation of the capacity of the pump ( 12 ).