Introduction to Industrial Automation

5.6.2   Speed of Piston’s Translation

The speed that the piston is translating in a pneumatic cylinder is a function of multiple param-

eters, resulting from the manufacture of the cylinder itself, or the control unit (valve). The mean 

speed value for classical cylinders varies from 0.1–1.5 m/s. For a fixed load (force F), a fixed diam-

eter of the cylinder and a fixed inlet valve, the maximum speed of the piston is also defined.

5.7   Pressurized Air Flow Control Valves

The operation of pneumatic cylinders requires the utilization of specific control equipment called 

valves. With the term “valves”, we refer to all control devices that could be used for selecting the 

flow direction of pressurized air, to apply control signals like START and STOP, to regulate the 

pressure and volumetric flow, etc. Valves in general can be categorized based on their functionality 

as follows:

  1. Directional valves

  2. Non-return or check valves

  3. Pressure control valves

  4. Flow control valves (volumetric)

  5. Isolation valves

In the following subsections of Section 5.7, the operation of the directional valves will be further 

analyzed, since they affect directly the logic of an electro-pneumatic automation system design.