SEISMIC EXPLORATION ENERGY SOURCE

摘要

1,245,979. Hydraulic reciprocating motors. TEXAS INSTRUMENTS Inc. Nov.19, 1968 [Dec. 20, 1967], No.54789/68. Heading F1A. [Also in Divisions G3 and H4] The radiating member of a seismic wave generator is reciprocated by the controlled flow action of a fluid whose viscosity is varied by application of a field. A generator for use on land comprises, Fig.1, radiating member 12 which is held against the ground by the weight of a transport truck acting on sprung plate 16. A hydraulic motor for reciprocating member 12 consists of reaction mass 20, cylinder 22, drive rod 18 and four electrostatic valves 30, 32, 34, 36 each comprising a set of concentric cylindrical electrodes. The valves rely on the Winslow effect in certain fluids: when a valve is energized by a voltage from amplifier 42 the field within the valve increases the hydraulic fluid viscosity, thus blocking fluid-flow. The fluid is pumped, under pressure, through cylinder 22 via inlet 24 and outlets 26, 28. Valves 32, 34 are fixed to rod 18, and valves 30, 36 are fixed to cylinder 22, so that by energizing first the valve pair 32, 36 and then the valve pair 30, 34, the rod 18 is reciprocated. A control signal drives amplifier 42, whereby the generator output follows the control signal. The control signal may be programmed by radio command and may be adjusted, to compensate for different earth characteristics, by a feedback loop including an accelerometer 52 and position transducer 54 coupled to rod 18. The hydraulic fluid pressure and temperature are monitored at 76 and 74. In a generator for marine use, Fig.3, the hydraulic motor comprises Winslow-effect valves 136,138 fixed to piston rods 108, 110 and similar valves 140, 142 mounted outside cylinder 102. Piston 106 and rods 108, 110 are reciprocated by energizing valve pair 138, 140 alternately with valve pair 136, 142, thereby varying the volume of a chamber defined by diaphragm 134, plate 128 and flexible annular seal 132. In a modified marine seismic generator, Fig.4, (not shown), valves 136 and 138 are replaced by a second pair of valves mounted outside the cylinder. The various generator embodiments provide little phase shift between the seismic output and the control signal, so that several generators may be used in parallel.