A pneumatic system has several components that do different functions in the system. One of these components is called a flow control valve. Flow control valves come in many different types and are designed to control flow pressure, rate, and the quantity of air moving inside a pneumatic system. These valves are used in many industrial applications and transmit power via compressed air. Some of the applications that use pneumatic valves include diesel engines and power tools that are operated pneumatically. Pneumatic performed ball valves with actuator assembly, proper for helium gas operation is needed for various isolation activities.
Depending on the type of pneumatic system, components of the application, and the type of pneumatic valve, these components may be found in several areas within the system, including the device’s heart.
The post below will explain several types of pneumatic valves used in various industries. We are also going to look at their configuration information and specifications of each type of pneumatic valve. So go on reading to be enlightened about these essential devices.
What Does Pneumatic Valve Mean?
Pneumatic valve is used in two contexts which need to be explained. In the first context, a pneumatic valve refers to a component used to control or regulate inert gas or air flowing through a pneumatic system. A pneumatic valve is a device that is used to manage or modulate the flow of air in a pneumatic operation and also controlling the air or gas at the origin, controlling its passage as required into tubing, pipes. These regulations are made at the source, controlling how air passes through pipes, tubing, or devices found in a pneumatic system.
There are several ways for the actuation component to open or close in a pneumatic valve. Some of them include electrically motorized or solenoid actuators, manually or pneumatically. However, the controlled pressurized gas or air flowing through the pneumatic system’s valve ports should be noted as the key concept.
The other context where a pneumatic valve is applied is when any other media flows through the valve port besides air, but the air is used as the control mechanism on the valve. For example, the following media can be oil, water, or any other fluid. The controlled substance is not air in such a context, but the air is used to control flow in the valve mechanism. Occasionally, such valves are called pneumatically-actuated valves.
In short, the first context involves controlling air, but the valve mechanism used may or may not use air. On the other hand, in the second context, the air is used in the control mechanism, but the controlled substance is not air. Knowing these two pneumatic valve contexts will help you better understand pneumatic valves and their industrial uses.
Let us now explain the types of pneumatic valves as used in the first context.
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Pneumatic Valve Types
Also called directional control valves, pneumatic valves are categorized based on different approaches. Here are some of them:
- The available switching positions or the number of flow paths
- The entry and exit ports found on the device
- How the device opens and closes its ports
- How the valve sits in an un-actuated state
Pneumatic valves inhibit or control the direction of airflow. They belong to multiple types of pneumatic valves used in hydraulic systems in many varying ways. Some of these ways include disconnecting or connecting compressed air from the system or retracting or advancing air that moves as part of the mechanism.
The primary types of pneumatic valves can be classified in four ways:
- Two-Way directional control pneumatic valves
- Three-Way directional control pneumatic valves
- Four-Way directional control pneumatic valves
- Spring offset pneumatic valves
Two-Way Directional Control Pneumatic Valves
These types of pneumatic valves work by passing air in two directions. These two directions can be opened or closed through two ports. No air will flow into the valve if the valve ports are closed. However, air may move from the first port through the valve in the opposite direction or through the second port when the ports are opened.
Three-Way Directional Control Pneumatic Valves
There are three ports found in a directional three-way air control valve. Each of these three ports has a different function. The first one connects the valve to another device or an actuator. The second port is fused to airflow, and the third port acts as an exhauster. The third port is closed while the first and the second ports are opened. This allows air to flow through the valve to the device. The actuator can vents exhaust when the second port is closed and the first and the third ports are opened. Occasionally, three-way valves are paired and connected to double-acting cylinders or connected to actuators in cylinders.
Four-Way Directional Control Pneumatic Valves
There are four ports in a four-way directional valve:
- One is connected to the pressurized airflow.
- Another port acts as an exhauster.
- Two ports are connected to actuators.
The four distinct paths make these pneumatic valves work effectively when reversing the motion of a basic cylinder or motor. That is why they are the most commonly used pneumatic valves used in pneumatic systems. Occasionally, an extra port is added to a four-way control valve. This is normally done to provide dual pressure for the valve to alternate between the two ports by applying one of two kinds of pressure. This is provided based on the application requirements. Another way is using an extra port as a secondary exhauster.
Spring Offset Pneumatic Valves
Pneumatic valve types belonging to this category are classified based on how airflow direction is switched:
- The valve is either closed or opened to allow air to flow or not flow through the valve in a two-way directional valve.
- An actuator positions a valve spool for each port to be either opened or closed.
- A spring is used to release the spool to place the pneumatic valve to its previous position.
A two-way directional valve working this way is also known as a spring offset valve.
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Specifications of Pneumatic Valves
Below are summarized key specifications for pneumatic valves since there are several of them. The mentioned parameters are only meant to guide you as the reader. Valves may be categorized differently by different manufactures and suppliers. Moreover, several factors will determine exact specifications, including desired porting, the valve’s actuation mechanism, and the manifold design.
Operating Medium – This refers to the media type that the pneumatic valve can regulate safely. Compressed air is used most of the time.
Cycle Rate – The cycle rate is the number of valve cycles in a period that can be operated.
Pressure Range/Operating Pressure – This refers to the pressure range or amount that the pneumatic valve can manage (e.g., in Bars, psi, or Pa).
Port Size – This is the physical dimensional parameters on the thread style or the valve that define the port sizes.
Response Time – This is the time taken by the valve to switch positions or states once it’s actuated.
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Conclusion
Pneumatic valves are essential tools for controlling or regulating airflow or other media types that flow. These types of valves come in many different types meant for different application requirements. To effectively benefit from flow control valves, you need to pick the right valve for the right application.
