A gate valve is a type of valve used to control the flow of liquids or gases in a pipeline. It operates by raising or lowering a gate within the valve body, allowing for full flow when open and complete blockage when closed. This design makes it ideal for applications where a straight-line flow and minimal pressure drop are required. Gate valves are commonly used in various industries, including water supply, oil and gas, and chemical processing. They are typically made from materials like cast iron, stainless steel, or brass, depending on the specific application and the type of fluid being controlled.