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U.S. Department of Energy
Office of Scientific and Technical Information

Apparatus for signalling within a borehole while drilling

Patent ·
OSTI ID:6359220
A down-hole signal transmitter for a mud pulse telemetry system comprises a flow constrictor defining a throttle orifice for the mud flow, a throttling member displaceable to vary the throughflow cross-section of the throttle orifice, and a pump for displacing the throttling member against the mud flow in order to modulate the mud flow. The displacement of the throttling member is controlled by a hydraulic amplifier, comprising a main pressure relief valve and a subsidiary control valve, and a solenoid to which the output signal of a measuring instrument is supplied. When the main valve is close, the pump displaces a ram, coupled to the throttling member, upwardly. However, when the signal supplied to the solenoid is such as to magnetically attract an armature, the control valve is opened to conduct a small flow of oil between the pump input and the pump output, and this in turn causes the main valve to open thus conducting a much larger flow of oil from the pump input to the pump output and allowing the throttling member to be displaced downwardly by the pressure of the mud flow. The power required to modulate the mud flow with this arrangement is very low and is easily provided by a down-hole electrical generator.
Assignee:
NL Sperry-Sun, Inc.
Patent Number(s):
US 4535429
OSTI ID:
6359220
Country of Publication:
United States
Language:
English