Improvements in Remote Station for Oceanographic Data Sensing

摘要

1,167,365. Measuring temperature, electrically. GENERAL ELECTRIC CO. Oct.25, 1966 [Nov.26, 1965], No.47788/66. Heading G1N. Temperatures at predetermined depths in the oceans are measured by a plurality of thermistors disposed at predetermined intervals along a cable corresponding to the depths, the cable being suspended by one end from floating buoy, and signals corresponding to temperatures sensed are transmitted by radio to a receiver base. Each thermistor is successively connected, via leads of predetermined length, and a rotating switch to a Wheatstone bridge Fig. 2 (not shown). The otherwise logarithmic resistance/temperature characteristic of each thermistor is linearized by the provision of a resistor in parallel while a resistor in series with each thermistor shifts the characteristic to within the operating range of the read out device. The potential drop across a thermistor and its associated leads and calibrating resistors is compared in the bridge with that across a reference resistor and the reference resistor is automatically adjusted by a servo to rebalance the bridge. The voltage across the tapped portion of the reference resistor is thus proportional to the thermistor resistance and to the temperature sensed, and, is transmitted by radio to a distant receiver. As shown Fig.1 thermistors 7 are disposed along a cable 1 and are connected by a respective pair of conductors 6 to the measuring bridge and calibrating network on the buoy. The cable also includes a stainless steel rope member 2 wrapped with tar impregnated jute 3 to provide thermal insulation, a plurality of conductors 4 which may connect pressure transducers to the read out device, for accurately determining the depths, a heat conducting layer of aluminium tape 8, and an outer sheath 9 of polyethylene.