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专利名称：CORE BIT申请号：AU7652774申请日：19741217公开号：AU484907B2公开日：19760617
摘要：1494413 Boring earth &c WALLIS GEOCHEMICAL DRILLING CO PTY Ltd 18 June1975 [17 Dec 1974] 25949/75 Heading E1F A core sampling drill includes a drill bit 11having a series of cutting surfaces, e.g. tungsten carbide members 13, disposed around acentral core passage 14, the upper end of the bit 11 being screw threaded so that it canbe attached to the lower end of a drill stem section 12. A core tube 16 is positionedconcentrically, with its lower end within the drill bit, to provide an outer annular passage17. At the inside of the wall of the bit 11 is formed an annular recess 15 of arcuate crosssection so that air passed downwardly through the outer annular passage is turned anddirected upwardly into the core tube 16, material cut by the drill bit being entrainedtherein. Preferably, the lower end of the core tube 16 is flared, as shown.
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