Types of Valves Based on Function, Ports and Operators
When a liquid, semi-solid material, steam, or air moves along piping to be used in an application, the flow of the materials needs to be regulated. Too much of the materials could be unwanted for the applications, cause damage to the system, or be dangerous for workers. Also, workers must have a way to close off the flow of materials entirely for specific reasons, such as to perform maintenance on equipment or to halt operations if there is a problem with processes. A mechanism called a valve is used to regulate the flow of materials.
Valves come in many types based on the materials it regulates and what systems it is used in. Pneumatic valves are found in pneumatic systems to control the amount of compressed air that reaches operations as well as the air pressure and rate. There are numerous types of pneumatic valves available based on how the valve operates, the number of ports on the valve, and how the valves are powered.
Types of Valves by Function
Spool valves are valves that have a large spool inside a sealed chamber that will have multiple ports. The spool will move back and forth through the chamber, allowing some ports to be open and other ports to be closed as air passes through the open channels. The spool moves using an actuator powered either by a lever, a button, or by using electrical means.
Poppet valves operate by having a ball or plug and a seat. The valve will seal the port closed by sitting the plug into the seat as the materials are able to pass through to other open ports.
Types of Valves Based on Ports
Directional Control Valves
The name directional control valve is often used interchangeably with pneumatic valves. These valves control the direction of air flow or may inhibit air flow entirely. The valves may be placed in a wide range of areas in a compressed air system, such as along the compressed air supply to either connect or disconnect it from the rest of the system, or along the air cylinders to retract or advance them. To turn the flow of air on or off, an actuator is used to move a spool in the path of the airflow.
Directional control valves come in multiple port configurations: two-way directional, three-way directional, four-way directional, and so forth. Each port will be given a distinct function. For example, a three-way directional control valve will have one port connected to the pressurized airflow, another port connected to the actuator, and the third port for the exhaust.
Types of Valves Based on Operator
Solenoid valves refer to how the valves are powered by using electricity. They may be used in both hydraulic and pneumatic systems. These valves must work in the right temperatures or they may malfunction or short circuit.
Mechanical valves are manually operated as a worker must use either their hands or feet to operate them. Mechanical valves are usually found in operations where electrical-powered valves cannot be used.
Air-operated valves work by responding to air pressure. The air pressure places the right amount of force onto a diaphragm or piston to shut the port. When the air pressure is removed from the diaphragm or piston, the valve opens.
Spring Offset Valves
For spring offset pneumatic valves, these are biased valves based on how the air flow moves in a specific direction and then becomes switched to a new direction. The valve will either open or close the port as an actuator moves the valve spool into the appropriate position. A spring is used to release the spool so that it may return to its previous position.
Selecting the Right Valve for Operations
The right valve to use in operations will depend on what materials are flowing through the systems, the number of ports that are required, environmental factors, and how you plan to power valve operations. The number of valves available on the market is vast, and many manufacturers create custom valve assemblies for operations to ensure that these mechanisms will work as specified by the customer, so they have productive work environments.
If you are looking for more information about valves, contact JHFoster today.