An introduction to pneumatic valves
Pneumatics are used in a wide variety of industrial settings, with pneumatic valves one of an array of components that control the amount, pressure and rate of air as it moves through a system. Pneumatic systems depend on the force of compressed air to transmit power and create mechanical movement across countless automated processes. Continue reading our helpful guide to find out everything you need to know about pneumatic valves.
Pneumatic valves explained
Pneumatic valves are one part of a pneumatic system and can be found in various industrial flow applications. While pneumatic machines come in a wide array of forms, most pneumatic valves work the same way.
Pressurised air is held in a reservoir and, as air is fed into the reservoir through a compressor, it pushes against the walls of the area. Once the pressure is strong enough, it compresses beneath the reservoir and pushes the diaphragm down, causing the valve stem to press down and close the valve.
When the air exits the diaphragm, the springs uncoil, moving the valve stem up and opening the valve. When this is done, the pressure is controlled, making the movement fluid.
Pneumatic valve types
Pneumatic valves can be classified using different approaches, which include:
- Number of entry and exit ports they possess
- Number of flow paths or switching positions
- Mechanism that is used to open and close ports
- Position of the valve when in un-actuated state
Pneumatic valves can also be known as directional control valves, and those that control the direction of airflow, or inhibit flow, are a large type of pneumatic valve that houses multiple variants. These devices can be used in various ways to connect or disconnect the main compressed air from the system, or to advance air cylinders that move as part of the machine or process for which the pneumatic system was created.
The primary types of pneumatic valves are:
- 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
A two-way directional pneumatic valve passes air in two directions. The air passes through two ports, which can be opened and closed. If the valve is closed, no air can flow through. If it’s open, air flows through the first port and can move either through the second port or in the opposite direction.
Three-way directional control pneumatic valves
The three-way directional pneumatic valve has three ports, which all have their own jobs to do. The first port connects the valve to an actuator or another device. The second port is connected to the airflow, and the third is used as an exhaust exit.
When the first and second ports are open, and the third is closed, the air flows through the valve to the device. When the second port is closed and the other two are open, the actuator can vent exhaust. Three-way pneumatic valves are often connected to actuators in cylinders, or used in pairs and connected to double-acting cylinders.
Four-way directional control pneumatic valves
A four-way pneumatic valve has four ports, with two connecting to actuators, one that’s used as an exhaust pathway, and another that connects to a pressurised airflow.
This type of pneumatic valve is among the most commonly used valves used in pneumatic systems because the four paths allow the valve to reverse the motion of a motor or basic cylinder.
An additional port can often be added to a four-way valve, which makes it a five-ported four-way valve. A four-way pneumatic valve with an extra port is used to provide dual pressure. This means that the valve can apply one of two kinds of pressure and alternate between the two, depending on what the application requires. The valve can also use the other port as a secondary exhaust port.
Spring offset pneumatic valves
A spring offset pneumatic valve refers to the manner in which the airflow direction is switched. In a two-way directional valve, the valve is either open – which enables airflow – or closed. To control this, an actuator moves a valve spool into position.
In a spring offset pneumatic valve, when releasing the valve spool and returning the pneumatic valve to its previous position, a spring releases the spool.
Pneumatic valves at Matara
Matara works hard to deliver an unbeatable range of pneumatic and linear automation products, backed by technical expertise and market leading value.
From our headquarters in Gloucestershire, our team manufactures and supplies to a wide range of customers across all sectors of industry. From automotive to aerospace, food to pharmaceuticals, our reputation has grown as the partner of choice for service, delivery and peace of mind.
As a privately owned business, we are able to operate on a more flexible basis than others in our sector. We know that our clients appreciate this as they see the direct benefit in areas such as pricing policies, relationships with key personnel and management, and short and effective lines of communication.
For any more information, do not hesitate to contact us.