To separate valve body from touching the media ,all the internal parts such as body ,bonnet and disc are lined ,for example ,the seat are sealed with the integrate polymer ,which can stand well wide temperature and pressure range .The valve has wide material selections ,complete specifications and is the ideal valves for carrying petroleum petrochemical ,chemicals ,raw oil and natural gas ,etc .The stem is of divided style and is connected by the locating clipper ,thus it's convenient for adjusting and maintenance.