| 摘要 |
The unit transmits measurements taken downhole during drilling, through the drilling fluid, back to the surface has a long casing which is lowered down the interior of the drillstring to a predetermined location and is fixed in a set angular orientation and eventually withdrawn. In the casing, a hydromechanical transmitter includes a stator fixed to the casing, which has passages, through which drilling fluid flows. A rotor adjacent to the stator is mounted in bearings, along the casing axis and has passages corresponding to those of the stator. The stator can be rotated to an open position, where the passages coincide, allowing flow, or a constricting position in which they do not, hence impeding flow. The rotor is turned and forth by a motor, to translate the measured data, in accordance with a standard coding, into corresponding positive pressure impulses, at controlled intervals. Original features include location of the signal transmitter (4) at the lower end o f the casing (2). The stator is a cylindrical casing (5) open at the lower end, the rotor is a cylindrical shell (6) within and coaxial to the bore of the stator casing, and having an open lower end. Slots in stator and rotor are diametrally opposed, and extend axially to form the radial passages (19, 21). The drilling fluid flows in from outside, though the stator and rotor, into and down the central passage, to leave below.
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