Selling Cheap Valves in Jakarta. A valve is a device or object that functions to regulate, direct, or control the flow of fluid (gas, liquid, fluidized solids) by opening, closing, or blocking part of the entryway. Valves are part of a fitting, but are usually discussed as a separate category. In an open valve, fluid flows in the direction from high pressure to low pressure. There are various types of valves that are commonly used, namely: Check Valve, Ball Valve, Gate Valve, Butterfly Valve, Control Valve, Globe Valve and others.