Design And Research Of Pressure-retaining And Pollution-preventing Sampler At Deep-sea

Seawater is rich in information.Analyzing and studying the physical and chemical properties of water samples is of great significance for exploring deep-sea mineral resources,understanding the characteristics of Marine microorganisms,and understanding the natural laws of the earth's interior.On the market,the existing deep-sea pressure-maintaining samplers generally have the problem of sample contamination.In view of this situation,this paper proposes a new type of pressure-maintaining and pollution-preventing sampling cylinder structure which can be used in ten thousand meters of deep sea,and its key technologies is studied.The main contents are as follows:The sampling principle and structural characteristics of the advanced deep-sea sampler at home and abroad are investigated,and the design technical difficulties of the deep-sea sampler,such as sample anti-pollution,ultra-high pressure seal,sample pressure retaining scheme,overall compact structure,are sorted out and analyzed,providing technical background for the design of new sampling device.Aiming at the problem of sample pollution,a new type of cylinder structure with sewage collection function is proposed,which is separated from sample chamber,sewage chamber and energy storage chamber by pistons with cross section difference.Regarding the sealing reliability of the key sealing parts at the end of the sampler under different conditions of sea depth,the reinforced composite right angle sealing ring was selected,and the nonlinear simulation was carried out based on the finite element software ANSYS.Through the analysis of the contact status of the seal ring,it was found that the contact status between the baffle ring and the end mating surface was the key point of sealing success,and the conclusion of the contact pressure of the baffle ring verified the reliability of the selected composite right angle seal ring at various sea depths,providing a reference for the subsequent mechanism design.Aiming at the limitation of pre-charging pressure and the calculation of pressure holding rate of the new sampling cylinder structure,the principle of sample sampling and energy storage is analyzed,and the limitation conditions of pre-charging pressure under different sea depths are obtained.The mathematical model for calculating the final pressure drop of the sample is deduced by combining the cylinder deformation equation with the state equation of seawater and gas.The calculation verifies that the basic dimensions of the selected cylinder meet the requirements of the sampling principle and the condition of the final pressure drop of the sample.The dimensions of the key parts such as cylinder,piston and thread sleeve are calculated for the structure of the pressure maintaining sampler.Then,the finite element software AN SYS was used to analyze the connection structure,and the stress concentration was reduced by optimizing the rounded parameters at the contact point between the tetrahedral ring and the end of the cylinder and the groove end of the thread sleeve.The simulation verified the rationality of the structure of the sampler.