Bohrungsgeraet

1,219,185. Boring earth &c. INSTITUT FRANCAIS DU PETROLE DES CARBURANTS ET LUBRIFIANTS. 12 March, 1968 [13 March, 1967], No. 12053/68. Heading E1F. In a well drilling bit adapted for use with flushing fluid and comprising a body 2 having working areas 8, 9, channels 10, 10a having inlets adjacent the areas, a zone 5 connected to the channels, and further channels 6 for the supply of cuttings and fluid to the borehole, cuttings and fluid from the areas are sucked up the channels 10, 10a by a reduced pressure which developes in the zone as a result of supply of fluid during drilling. Part of the fluid from the channels 6 passes downwardly along longitudinal and radial grooves in the body to the channels 10, 10a. The fluid passing downwardly to the working areas may bypass the zone 5 and channels 6 so that fluid not loaded with cuttings is supplied to the areas. The bit may be rotary, percussive or rotary and percussive.