The Design On Combination Seal Of Piston And Its Application Research In Underwater Pressure Sensor

As the pressure measurement to pressure sensor will be influenced by great pressure of sea water under the deep-sea environment, the piston pressure balancing technology is a reliable way to solve the difficultly, whose key point lies in how to make sure of movement flexibility and seal reliability when the piston is in the process of pressure balancing process. Therefore, this article focuses on the combination of the piston seal, and based on studies for the piston pressure equilibrium technology design a deep-sea pressure sensor that could overcome the great pressure effect from seawater.First of all, a theory that the leak tight structure design of piston is important to movement flexibility and seal reliability was obtained through the analysis to the balance mechanism of piston pressure equilibrium technology. We clarified the current research status to reciprocating motion seal, the structure of combined sealing device and its sealing principle.Then, we established a mechanical and finite element model for combined sealing device of piston and summed up basic design principles for combined sealing device of piston by calculating its contact stress, analyzing the effect of its traveler thickness, the diameter, pre-decrement and internal & external pressure difference for O- shape seal ring on the sealing property. Meanwhile, as it is impossible to make sure of absolute seal during the reciprocation motion, we through the analysis to the equilibrium mechanism of piston pressure balancing technology derived the leakage rate formula(during piston’s pressure balancing process) by applying an inverse solution to Reynolds equation.Next, we established a theoretical mechanics model to the crawling movement, and made a static& dynamic property analysis to piston pressure balancing device, then got know of the effect of static & dynamic friction coefficient,piston quality and O-shape pre-decrement on piston’s creeping phenomenon. We also summarized basic design principles for reduction of this kind of phenomenon.Finally, we designed piston pressure balancing device and deep-sea pressure sensor based on foregoing studies to piston pressure equilibrium.