What are Valves? Valves are mechanical devices that open, close, or partially obstruct the flow of water to control, direct, and regulate it. They can be made of various materials such as bronze, PVC, brass, and so on. D Chel Valves is India's leading Valves Manufacturer. Ball Valves are a popular product in the Metal Market. Valves are used to direct flow, shut off water access, prevent backflow, and adjust water pressure in residential and commercial buildings, water supply systems, wastewater treatment plants, and chemical plants.