Draw a 5/2 air valve;
step by step.

Draw a 5/2 Air Valve; if you have had a moment to visit and read the other pages on this site about drawing air valves, then moving up to drawing the 5/2 compressed air valve should be pretty easy. If you haven't, here are the links to those pages. You may want to start with the 2/2 and work your way up.

Start by drawing a 2" (or so) square on your paper. If you have been drawing valves right along with reading the other pages, you can probably do this in your sleep by now!

It's always good to use graph paper, and keep your pencil sharp and your eraser handy.

Once you have drawn the basic box, which represents the valve body, you will insert the lines as shown in Fig. 51.

As always, the first number in a valve designation, in this case a five, indicates the number of working air ports a valve will have. The second number, in this case a two, indicates how many positions a valve will have. Therefore, a 5/2 air valve will have five air ports and two positions.

Fig 51 shows the flow paths of this 5/2 valve when it is in one of it's two positions.

Note the supply of air (depicted by the black circle) flowing through the valve to one of the two cylinder ports. The other cylinder port is open to one of the two exhaust ports in the typical 5/2 air valve. On the left, the other exhaust port is closed.

Each of the two positions will be represented by a box like that in Fig. 51, and each will show that one valve in one of it's two positions.

Fig. 52 shows the same 5/2 valve but it has now been shifted, and in this second of it's two positions, the flow paths change as shown.

In a 5/2 air valve the supply port never gets shut off. The supply line simply alternates between one cylinder port and the other as the valve is shifted.

With the supply line alternately flowing from actuator port to port, you can see how this would effectively supply a double acting air cylinder or double acting rotary actuator.







You can also see that the air that is exhausting from the air cylinder alternately flows through each of the exhaust ports.

Each of the cylinder ports "has" it's own exhaust port, which allows the 5/2 air valve to have two exhaust flow controls installed, each controlling the speed of the cylinder in one direction. This is one of the significant benefits of selecting a 5/2 valve rather than a 4/2 to control a double acting air actuator.

To finish drawing the one valve, we simply bring the two drawings together as shown in Fig. 53.

When the "right side" of the valve is in control, the compressed air path will be as shown on the right side of Fig. 53. When this valve is shifted, and the "left side" is in control, the flow paths will change. The actual ports don't change, just the flow of air through the valve does.

It is customary to draw a valve in the position that it will be at rest, when the valve in not being acted upon by an exterior actuator or the position that the valve will be in when the air circuit that the valve is part of has stopped functioning.

Sometimes when an air circuit completes it's cycle and stops, one or some of the valves may be deliberately left in an actuated position. The supply line may be drawn on the left in these circumstances. The circuit schematic will show the details if that is the case.

Without the valve actuators being shown in the above valve schematic, and since it's not in an actual valve circuit, a viewer cannot tell where this valve should be when it is at rest. In that case the supply circle is drawn on the right side of the valve schematic.

To complete the schematic of this 5/2 valve, it will need valve actuators. Here's how to draw them.







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