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.
Ball Valves. Ball valves are a common variety of pool valve found on pool plumbing. Relatively inexpensive to purchase, and simple to use. Good replacement valve for old brass gate valves.he handles on ball valves tend to break rather easily, and they can also be somewhat difficult to turn, especially if installed in an awkward position. Their advantage is their cost ($10 - $15), and ball valves tend to be easier to understand for novice pool operators than the three way type valve.