The Research On Pressure Balance Device Of Piston And Pressure Sensor Under The Condition Of Deep Ocean

For the detecting of the deep sea pressure, it can not only both withstand and measure great pressure from deep sea, but also can measure small pressure changes. It is a difficult issue that must be faced when using maritime pressure sensor to commit large measuring range and high sensitivity. The paper does the following research aimed at this issue.Firstly, the piston pressure balance device is an important means to balance the great pressure in the deep-sea exploration equipment, it uses the piston-type pressure balancing device to make pressure sensors withstand great pressure. In order to analyze the phenomenon of piston crawling, physical model and mechanical piston crawling process is put forward, the factors of impacting piston crawling need to be summarized. Based on the condensability of liquid, analyze the various factors of impacting oil fluid compression, to identify the relationship between them and the volume of oil compression and finally calculate the working volume of the piston pressure balancing device.Secondly, based on the condensability of the liquid, the relationship among the working-depth of equipment, the volume change of the compensator fluid of piston and the pressure difference between inside and outside of equipment was deduced. At the same time, the calculation method was also put forward. The static and dynamic analysis of the force sensor can provide reference for design and calculation of piston used for pressure balance. The relationship among the creeping phenomenon of piston used for oil-filled deep-sea pressure sensor, the O-ring cross-sectional diameter, the rate of pre-compression, the friction coefficient and the piston quality was analyzed. And figure out their best optimal combination by designing orthogonal experiment, finally summarized the structural design principles of piston pressure balance.Then analysis the stress and strain of the sensitive diaphragm under pressure. Considering the effect of binding strain, a sensitive diaphragm was designed which can measure the slight pressure change. By providing a pressure sensitive diaphragm on the sensor to solve the problem of measuring small changes in pressure.Finally, based on the combination of piston pressure balancing devices and sensitive diaphragm, we present the structural design of a deep-sea sensor of piston and describing the working principle and structure characteristics. For dynamic analysis of pressure sensor, we can get the fact that the pressure sensor can not only measure great pressure but also measure small pressure changes in seawater, and the pressure sensor calibration method is proposed.