Air Preparation Valves allow metered flow of fluid in one or both directions. Many of them allow for free flow in one direction and reduced or metered flow in the reverse direction. They are used in pneumatic circuits to regulate the rate of activation or exhaust of cylinders and other pneumatic devices. Air valves can be configured in-line or at right angles. In an in-line configuration, the input and output ports are on the same axis. In a right angle configuration, the input and output ports are perpendicular. Flow control choices for air valves include unidirectional, bi-directional or three-way. In a one-way configuration, the valve permits metered flow in one direction and free flow in the reverse direction. In a two-way configuration, the valve provides for metered flow in both directions. In a three-way configuration, the control provides flow control in three directions.

Air Pressure Amplifiers can be as low as 5 psi or as high as thousands of psi. Shop air helps for the amplifiers so they require no electricity, cooling water or lubrication. The boost ratio is based on the supply air pressure.

An air pressure-reducing valve is an automatic control valve. It is designed to reduce a higher inlet pressure to a lower constant outlet pressure regardless of fluctuating flow rates and/or varying inlet pressure. It is a pilot controlled, hydraulically operated, diaphragm actuated globe valve in either the oblique (Y) or angle pattern design. Valve differential pressure powers the diaphragm actuator open or closed. The lower control chamber is connected through a fixed orifice to the downstream pressure, which serves to cushion the closing of the valve.