| The salinometer is a benchmark instrument for salinity measurement and calibration,providing laboratory calibration for ocean observing instruments such as CTD and occupies a very important position in ocean observation field.At present,the domestic salinometer has a great demand,while the high-end market has long been occupied by the Canadian 8400 B salinometer.Germany OPS salinometer is also actively developing the market.There is an urgent need for a new type of salinometer with high accuracy,high stability and automated measurement characteristics.This paper aims to develop a new type of salinometer based on temperature and conductivity sensor.The principle and implementation method of high precision temperature and conductivity measurement are studied.The measurement method is optimized on the basis of salinometer usage scenarios.In this paper,the reasonable internal structure of the water bath is designed,the temperature control zone is separated from the measurement area,and the joint temperature control of the thermoelectric cooling and stir is realized based on the innovative algorithm.High precision and high dynamic response of the water bath temperature control is realized within ±10? range.Direct measurement of any temperature of the sea water samples can be carried out immediately,avoiding its salinity changes during the temperature pre-balance process.This paper completes the selection of the injection system and the design of the driving circuit to realize the automatic operation of the operation such as flushing,injection and emptying,which overcomes the influence of operation factors and maximizes the consistency and credibility of the measurement results.Salinometer water consumption is less than 20 ml.When near room temperature,the water bath temperature control accuracy is better than 0.001 ?.After calibration,salinity accuracy is better than 0.002.Salinity drift after one week does not exceed 0.0033,satisfying the accuracy and stability requirements. |
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