How are Pneumatic Valves Classified?
Properly chosen pneumatic valves can reliably and efficiently control the amount and direction of air flow from source to final system application. The wrong pneumatic valve, however, can lead to poor actuator performance, sticking or corroded valves, or possibly hazardous unintentional venting. These events result in production slow-downs and costly repairs.
The best way to avoid potential problems is to choose the correct components in the first place. This article reviews how pneumatic valves are classified, to help you choose the most effective parts based on more than just considering applications.
How To Classify Each Type of Pneumatic Valve
Sometimes called directional control valves, pneumatic valves are classified using different approaches, mostly based on their application.
Ports: Some valves are classified by the number of entry and exit ports which they possess. Each port serves a unique purpose, such as intake and exhaust, or connection to an actuator:
- Two-way Directional Valve: Air passes in one direction, through two ports. These ports can be closed or open.
- Three-way Directional Valve: This valve has three ports, which each serve a different purpose. The first port connects the valve to an actuator. The second port is connected to the incoming air or air inlet. The third port is used for exhaust. The addition of the exhaust port allows the downstream air to exhaust when the inlet air port is closed.
- Four-way Directional Valve: This valve has four or five ports. Two ports connect to actuators, one connects to the incoming air or air inlet, and one or two ports are for exhaust.
Switching Positions: Two-way 2 position valves are used for basic on/off functions; when the valve is closed, airflow cannot flow through it. Three-way 2 position valves work similarly to 2-way 2 position valves but they have an exhaust port.
For four-way five-port 2 position valves have the ability to extend and retract a cylinder and have two exhaust ports. In one position the air will flow through to extend a cylinder; in the other position, air will flow through a different port to retract the cylinder. Four-way 3 position valves can extend and retract a cylinder like four-way 2 position valves but also have a center position which can be used for additional control of the cylinder when the valve solenoids aren’t energized.
Actuation Mechanism: The mechanism that is used to open and close the ports may be electric, mechanical, manual or air-operated. Some pneumatic control valves have a spring mechanism that is used to close or open ports. These spring offset valves often work to return the valve to its prior position in 2 position valves or move the valve to the center position in 3 position valves.
How to Find the Right Pneumatic Valve for Your Job
Issues with pneumatic valves can lead to costly problems all over the system, but choosing the right pneumatic valve and the right pneumatic valve manufacturer can dramatically reduce valve problems. Specifications to highlight when working with a manufacturer include:
- Operating environment where the valve will be used.
- Pressure range the valve will be expected to handle.
- What medium will the valve be used to control – compressed air or other?
- Flow capacity required.
- Cycle rate required.
- Response time needed to switch positions after actuation.
- Port size requirements.
The experts at JHFoster work with clients from any industry you can imagine. We have provided everything from pneumatic valves and integral components to entire system configurations. This experience gives us insights you need to find the perfect pneumatic valve to overcome inefficiencies and cut unnecessary costs.
Headquartered in Eagan, Minnesota, John Henry Foster provides a wide range of reliable pneumatic valves for an array of applications. The JHFoster team can be your partner in choosing the right components, in the right systems, for the right applications every time. Contact us online, request a quote, or call 855-688-0043 today to discuss your pneumatic valve needs.