What is the difference between a normally open and a normally closed 3 Way Air Solenoid Valve?

Hey there! As a supplier of 3 Way Air Solenoid Valves, I often get asked about the difference between normally open and normally closed 3 Way Air Solenoid Valves. So, I thought I'd write this blog to clear things up for you.

Let's start with the basics. A 3 Way Air Solenoid Valve is a type of valve that controls the flow of air in a pneumatic system. It has three ports - an inlet, an outlet, and an exhaust. The valve uses an electromagnetic solenoid to open and close the valve, allowing or blocking the flow of air.

Now, let's talk about the difference between normally open and normally closed valves.

Normally Open 3 Way Air Solenoid Valve

A normally open 3 Way Air Solenoid Valve is, as the name suggests, open when there is no electrical power applied to the solenoid. In this state, air can flow freely from the inlet to the outlet. When electrical power is applied to the solenoid, the valve closes, blocking the flow of air from the inlet to the outlet and diverting it to the exhaust port.

This type of valve is commonly used in applications where you want air to flow continuously unless there is a specific need to stop it. For example, in some industrial processes, you might want air to be constantly supplied to a certain part of the system, and only stop the flow when a particular event occurs.

One of the advantages of a normally open valve is that it provides a fail-safe mode. If there is a power outage or a problem with the electrical system, the valve will remain open, allowing air to continue flowing. This can be crucial in applications where a continuous supply of air is necessary to prevent damage to equipment or ensure safety.

Normally Closed 3 Way Air Solenoid Valve

On the other hand, a normally closed 3 Way Air Solenoid Valve is closed when there is no electrical power applied to the solenoid. In this state, there is no air flow from the inlet to the outlet. When electrical power is applied to the solenoid, the valve opens, allowing air to flow from the inlet to the outlet.

Normally closed valves are often used in applications where you want to start the flow of air only when a specific event occurs. For example, in a pneumatic control system, you might want to activate a cylinder or a tool by supplying air to it only when a switch is turned on.

The main advantage of a normally closed valve is that it can prevent unwanted air flow when the system is not in use. This can help save energy and reduce wear and tear on the equipment.

Applications

The choice between a normally open and a normally closed 3 Way Air Solenoid Valve depends on the specific application. Here are some common applications for each type:

Normally Open Valves

• Air supply systems: In some industrial air supply systems, a normally open valve can be used to ensure a continuous supply of air to a particular area. For example, in a paint spraying booth, air needs to be constantly supplied to keep the environment ventilated.
• Safety systems: In safety-critical applications, such as emergency shutdown systems, a normally open valve can be used to allow air to flow to a safety device, such as a fire suppression system, in case of a power failure.

Normally Closed Valves

• Pneumatic actuators: In pneumatic control systems, normally closed valves are often used to control the movement of cylinders and other actuators. The valve can be opened to supply air to the actuator, causing it to move, and closed to stop the movement.
• Process control: In industrial processes, normally closed valves can be used to control the flow of air to specific parts of the system. For example, in a chemical processing plant, a valve can be opened to supply air to a reaction vessel at a specific time during the process.

How to Choose

When choosing between a normally open and a normally closed 3 Way Air Solenoid Valve, there are a few factors to consider:

• Functionality: Think about the specific function of the valve in your system. Do you need air to flow continuously or only when a certain event occurs?
• Safety: Consider the safety requirements of your application. If a continuous supply of air is necessary in case of a power failure, a normally open valve might be the better choice.
• Energy efficiency: If you want to save energy by preventing unwanted air flow when the system is not in use, a normally closed valve might be more suitable.

As a supplier of Air Solenoid Valve 3 Way, I can help you choose the right valve for your application. We also offer a range of other solenoid valves, such as explosion proof 5 way pneumatic valve and 24vdc Pneumatic Solenoid Valve, to meet your specific needs.

If you're interested in purchasing any of our products or have any questions about 3 Way Air Solenoid Valves, feel free to get in touch with us. We're here to help you find the best solution for your pneumatic system.

References

• "Pneumatic Systems Handbook" by David W. Croll
• "Solenoid Valve Handbook" by Peter J. Schneider