A valve is a device that regulates the flow of liquids, gases or fluids. This is made possible by opening, closing or partially obstructing passageways. In an open valve, the fluid will flow in the direction where pressure is lower. They have many applications in the home and in industry. The most common application in our home is the use of valves in plumbing.

There are many different types of valves; we will describe only a few. A ball valve is applicable for on/off control without pressure drop and is ideal for quick shut-offs. Butterfly valve is often used for flow regulation in large pipe diameters. The closing mechanism is a disk. This type of valve is favored because of their lower cost and lighter weight. Another type of valve is the check valve also called the non-return valve. It allows fluid to flow in one direction only.