Assume that a control valve regulates stream flow to a process and that high temperature makes the reaction hazardous. The usual pneumatically operated control valve utilizes the following action for fail-safe operation
A. Air to open
B. Air to close
C. 3 psi (20 kpa) to fully open
D. 15 psi (100 kpa) to fully close
Answer:A
Assume that a control valve regulates stream flow to a process and that high temperature makes the reaction hazardous. The usual pneumatically operated control valve utilizes the following action for fail-safe operation
A. Air to open B. Air to close C. 3 psi (20 kpa) to fully open D. 15 psi (100 kpa) to fully close