Introduction to Industrial Automation

5.7.2   Manual Actuation of a Valve

The manual actuation of a valve takes place throughout a mechanism that can be adapted on a 

valve and can be realized in the form of a button, a lever, a pedal, or any other form of actuation 

presented in Figure 5.12a. These mechanisms constitute the pneumatic equivalent of electrical 

buttons and switches. For example, the flow of current throughout an electrical contact is equiva-

lent to the pressurized air flow throughout the airways of the valve. The symbols in Figure 5.12a 

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Elements of Electro-Pneumatic Components 

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