Directional control pneumatic valves are a necessity in your machine. With their applications, various control valves regulate the rate and amount of air that can flow through the machine, which in turn determines output. If a valve isn’t working, then air pressure won’t be consistent and the actuator will fail to generate power.
How do you choose the right type of pneumatic valve for a certain application? You simply need to know which models to use for differently structured systems. Once you do, then you can choose the right one. We go into some of the most common types of functional directional control valves, and their various purposes.
Valve Types
Solenoid Valves
Solenoid valves are designed to open and close in response to an electric signal. They control airflow in a pneumatic system and liquid in a hydraulic one. You can get either a valve with a spool or poppet arrangement.
Generally, solenoid valves are used with industrial workplaces, for manufacturing. The reason is for the valve to work properly, it needs a consistent temperature. If you want one to work in a constantly changing atmosphere, the valve must handle temperature extremes so as not to short out.
An example of the latter would be in a car, where it’s used to start the ignition. When you turn your key, an electric signal is sent to open the valve and start the engine. The valve has to handle the emergence of heat from the engine and any cold from unfavorable weather conditions.
Other applications of solenoid valves include irrigation systems and dishwashers when referring to how they are used with fluids. They control the flow of water to allow for regular waterings of fields or cleaning your cups and plates, respectively. People value these models’ versatility and durability.
Air Operated Valves
Air-operated valves from a design standpoint are shaped similarly to those used in solenoids. Instead of receiving an electric signal, however, they respond to air pressure applying force to a piston or diaphragm.
You will see air-operated valves in environments that demand a high output but don’t want to rely on electricity, and who wish to use them remotely. They are thus used in chemical factories and fertilizer manufacturing facilities Regarding the former, chemicals if exposed to the wrong substances can induce combustion and endanger their operators. In the latter, people are kept far from potentially noxious nitrogen compounds.
Mechanical Valves
Mechanical, or hand-operated valves, use manual power. You may see them in operations where electricity would be dangerous or impractical for the tasks at hand. As with solenoid valves, they can be used for either air or liquid flow.
Usually, you apply energy to these valves using your hand or feet to move them. The operator would need to apply a push-pull motion, or to simply press a button with their palm. Other types of mechanical valves are powered by lever arms, or with the power of friction. These days, mechanical valves have to be a larger size to handle a higher flow rate.
An example of a mechanical valve would be those used to help people with heart disease. They assist in helping ensure that blood and oxygen flow through the human body. While such artificial hearts risk blood clots, they increase a person’s lifespan with durable models.
Another would be a manual valve used in an older machine, that has no electrical connection. Consider how old-fashioned sewing machines and spinning wheels would work by the user pressing a pedal; the energy would be transferred in a circular motion. They would use rudimentary pneumatics.
Factors That Determine Types Of Pneumatic Valves
Additional ports can determine the type of valve that you use. Ports are the pathway within the valve itself through which the air flows. They determine the direction in which air flows, and how strong the force is.
Within a two-way directional valve, the ports are closed when the machines aren’t in use, and they open when power is connected. The former is called the closed resting state.
Having three or four valves means that air doesn’t solely flow in one direction, and in the former, at least one port is left open. You can have airflow directed through different actuators, and dual pressures. This paves the way for more complex systems, which in turn can lead to more output.
The assembly of the valve is also another key factor. You can either have a spool or a poppet design for a valve. As mentioned, solenoid valves come in one or the other.
In a spool assembly, the valve has a series of O-rings within a shaft, as well as a barrel. The O-rings open and close in rhythm with the shaft, which in turn allows for the air to flow. In a poppet assembly, a spring moves the valve, which has a hollow orifice and a sealed surface. The valve lets air flow through when the sealed surface is lifted thanks to an actuator sequel.
A spring offset value is the most likely factor that determines your type of valve. This term refers to how airflow is switched during or before operations. While the actuator moves the valve so that the ports are opened, using its spool to do so, a spring resets the valve to its original position when the machine is not operating. A spring offset valve can also be used to refer to a two-way valve, due to its simplicity in controlling airflow.
Refine Your Compressed Air With SMC Pneumatics
SMC Pneumatics is ready to help you choose the right types of pneumatic valves for our machines. Our experts know which types will help you stay connected to the actuators for the long haul. Whether for air brakes, dental drills or more, we know how to keep you all connected.
Contact us today to order your parts and get advice on your pneumatic system. Our experts will know exactly how to optimize your output and help your system last longer. Find the best valves to create good air pressure.