초록 ▼

A down-hole signal generator for a mud-pulse telemetry system comprises a flow constrictor defining a throttle orifice for the mud passing along a drill string, a throttling member displaceable with respect to the throttle orifice to modulate the mud pressure for the purpose of transmitting measurem

A down-hole signal generator for a mud-pulse telemetry system comprises a flow constrictor defining a throttle orifice for the mud passing along a drill string, a throttling member displaceable with respect to the throttle orifice to modulate the mud pressure for the purpose of transmitting measurement data up the drill string, and a turbogenerator. The turbogenerator incorporates an annular impeller surrounding a casing and arranged to be driven by the mud passing along the drill string, and a rotatable magnet assembly disposed in a mud-free environment within the casing. The impeller includes an electrically conductive drive ring and the rotatable magnet assembly includes rare earth magnets, so that, when the impeller is rotated by the mud flow, eddy currents are induced in the drive ring by the magnetic field associated with the magnets and the magnet assembly is caused to rotate with the impeller by virtue of the interaction between the magnetic field associated with the magnets and the magnetic field associated with the induced currents. In this manner torque may be imparted to an electrical generator within the casing without a rotating seal having to be provided between the impeller and the generator.

대표청구항 ▼

A down-hole signal transmitter for a mud-pulse telemetry system, comprising a flow constrictor defining a throttle orifice for the mud passing along a drill string, a throttling member displaceable with respect to the throttle orifice to vary the throughflow cross-section of the throttle orifice, co

A down-hole signal transmitter for a mud-pulse telemetry system, comprising a flow constrictor defining a throttle orifice for the mud passing along a drill string, a throttling member displaceable with respect to the throttle orifice to vary the throughflow cross-section of the throttle orifice, control means for displacing the throttling member to modulate the mud pressure, and a turbogenerator having an impeller arranged to be driven by the mud passing along the drill string and an electrical generator disposed in a mud-free environment within a casing, the impeller being magnetically coupled to the electrical generator to impart driving torque thereto.