There are three types of cover designs for manually welded gate valves. One type is bolt type valve cover, which is designed in this way. The valve body and valve cover are connected by bolts and nuts, and sealed with wrapped gaskets (made of 316 clip flexible graphite). When customers have special requirements, metal rings can also be used for connection. Another design form is the welded valve cover, according to which the valve body and cover are connected by threads and fully welded sealed. When customers have special requirements, full penetration welding can also be used. There is also a type of pressure self tightening valve cover, which is designed in this way. The valve body and cover are connected by threads and sealed with an internal pressure self sealing ring.