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 are quarter-turn, straight-through valves that have a round closure element with matching rounded seats that permit uniform sealing stress. The valve gets its name from the ball that rotates to open and close the valve. Ball valves are used in situations where tight shut-off is required. ball valve can be used to stop and start as well as throttle or regulate the flow or movement of media through a system. The shape of the valve determines how many directions of flow the valve will have. The number of ports can range from one to four.