Valves The primary purpose of a valve is to direct the flow of fluids by starting, stopping, and throttling flow to make modern processing possible. Valves are designed to withstand pressure temperature, and flow, and can be found in homes and industry across the world. The most common valves found in the manufacturing industry are gate, globe, ball, check, butterfly, plug, needle, three-way, diaphragm, relief, angle, and multiport. All valves are selected for a specific purpose. Valves are classified by flow control elements, function, and operating conditions, such as pressure, flow, or temperature. The most common way to classify valves is by the valve’s flow con