Here’s information on the simplest type of air valve; the 2/2 style.
The first 2 in the 2/2 air valve refers to the number of “working” air ports that are found in the valve body. That is, the number of ports that supply air to the valve, and channel the compressed air to whatever it is that the valve is supposed to do. van điều khiển điện
Most 2/2 valves will have numbers or letters etched, cast or painted near each of their two “working” air ports. If there are numbers near the ports, the number 1 would be the supply port to bring the compressed air to that valve. Port number 2 would be the working port from which air would flow to accomplish whatever task that you wanted that valve to do.
If the port designations are letters, then port ‘A’ would be the supply port and port ‘B’ the working port.
If the 2/2 valve is to be “air operated”, that is an external air signal is to be used to shift the 2/2 valve, there will be another port. That port may not have a designation or it might say ’12’. No, that’s not a twelve, but rather indicates that air will flow from port 1 to port 2 when an external air signal operates that valve.
The second 2 in a 2/2 air valve indicates the number of positions that the internal valve mechanism has. In this case, two. When this valve is operated or actuated, it will either open or close. At rest, that is when the external valve operator has not been activated, the internal valve mechanism will either stay open or closed.
Most 2/2 compressed air valves are classified as NC. NC stands for normally closed. This means that when the valve is not actuated, it’s normal state is closed, and compressed air cannot pass through it.
There are some applications for 2/2 valves where the flow of air through the valve when it is not being operated is desirous. A NO or normally open valve would then be selected. When this type of 2/2 valve is at rest, compressed air will flow through it, and it is only when the valve is actuated that the flow of air will stop.