Stimuli are signals that trigger the senses. Receptors detect the stimuli and neurons send the signals to the brain where they're interpreted. Each sense organ includes receptors that capture relevant stimuli for transmission to the brain. The receptors in the skin are mechanoreceptors and thermoreceptors.
AWWA Butterfly valves are quick opening valves that consist of a metal circular disc or vane with its pivot axes at right angles to the direction of flow in the pipe, which when rotated on a shaft, seals against seats in the valve body. They are normally used as throttling valves to control flow.
The Post Indicator Valve or PIV, comes in several. types. The PIV is used when the main valve body. in not visible (underground, behind/other side of. wall). These valves are typically used for isolating. sections of piping or hydrants. Yet they can also. be used for sprinkler risers. What makes these valves unique is the window.