Gate Valve Parts Main gate valve parts: body, seat, gate, stem, bonnet and actuator. The main operation mechanism is very simple. When the handwheel is turned, it rotates thestem, which is translated into the vertical movement of a gate via threads. Types of Gate Valves The working principle of manual gate valve: turning the hand wheel, through the thread of the hand wheel and the valve stem, raise or lower the valve plate connected with the valve stem to open and close. Classified by shell/body material, gate valves can be divided into: Metal material valves: such as carbon steel valves, alloy steel valves, stainless steel valves, cast iron valves, titanium alloy valves, Monel valves, copper alloy valves, lead alloy valves, etc. Metal valve body lining valves: such as rubber-lined valves, fluorine-lined valves, lead-lined valves, plastic-lined valves, and enamel-lined valves. Non-metallic materials valves: such as ceramic valves, glass valves, plastic valves. How does the 3 flanged gate valve work? The gate valve is designed to open or close the flow of liquid by restricting or opening the flow with a circular or rectangular wedge. The gate valve can also control the pressure of the liquid passing through the pipe or valve.