Research And Experiment On The External Pressure Characteristics And Seawater Compensation Technology Of Deep-Sea Pipeline Gate Valve

With the continuous development of modern industry,human demand for oil and gas is also increasing,in such a rapid development of industrialization,land and coastal resources can no longer meet the needs of human development.Human beings realize that deep-sea oil and gas exploitation has good prospects,so they turn their attention to the development of equipment suitable for the exploitation of deep-sea oil and gas resources,because deep-sea oil and gas need to be transported from the deep sea to the land or offshore platform through pipelines to be used by humans,valves will inevitably be used in the process of transportation,so the analysis of the external pressure characteristics of deep-sea gate valves and the design of pressure compensation devices are of great practical significance and value.First of all,this paper studies several failure forms of external pressure vessels,then elaborates on the design methods of several external pressure vessels that are widely used in the world,and then compares and analyzes several external pressure vessel design methods from the overall structure,safety factor and scope of application,etc.,combined with the complex shape structure of the deep-sea gate valve and the characteristics of high-pressure working conditions,and finally selects the selected ISO international standard for theoretical analysis and calculation of the external pressure characteristics of the gate valve.Secondly,according to the selected external pressure vessel calculation standard,the minimum wall thickness of the valve body is calculated by using the calculation formula of the wall thickness in the ISO international standard pressure vessel design standard,so as to preliminarily determine the wall thickness of the valve body;then consult the flange design standard to design the connection flange in the gate valve,and design the sealing pair inside the gate valve according to the working environment and working pressure of the gate valve;and then design the valve body and valve cover of the gate valve in accordance with the pressure vessel design standard in the ISO international standard pressure vessel design standard 3.The sealing place and the valve body and the valve seat are consistent with the theoretical verification,and then the finite element software is used to conduct finite element analysis of these components,and the anti-deformation structure design is carried out according to the analysis results,and the finite element analysis is carried out on the position where the deformation of the valve body and the valve seat are large,and the reinforced structure is then analyzed by finite element.Third,according to the special structure of the valve stem cavity,as well as the highpressure working conditions of the valve stem in the deep sea,the bellows pressure compensator is designed,the designed bellows pressure compensator is carried out for finite element analysis,and then the valve stem cavity equipped with a bellows is analyzed by finite element,the deformation of the bellows is obtained,and then the theoretical calculation formula is used to calculate the allowable displacement of the bellows,and the calculation results of the two methods are compared and analyzed,and then the structure of the bellows is improved.Finally,by building the physical model of the gate valve and the bellows pressure compensator,the sealing of the gate valve and the sealing tank is first detected,and then the compensation effect of the bellows pressure compensator installed on the gate valve is compared and analyzed,and the pressure compensation effect of the bellows pressure compensator can play a certain role in the gate valve is obtained through experimental analysis.