A sail switch, vane switch or flow switch is a mechanical switch that is switched on or off in response to the flow or non-flow of a fluid such as air or water. A sail switch typically operates through the use of a paddle which gets displaced due to the force of fluid moving past it. Sail switches find application in the detection of fluid flow and measurement of fan speeds. A sail switch might be used to protect a central heating system electric heating element from being energized before the air flow from the blower is established. Sail switches might also be used to alarm if a ventilation fan in a hazardous location fails and air flow has stopped.
Famous quotes containing the words sail and/or switch:
“Undoubtedly if we were to reform this outward life truly and thoroughly, we should find no duty of the inner omitted. It would be employment for our whole nature.... But a moral reform must take place first, and then the necessity of the other will be superseded, and we shall sail and plow by its force alone.”
—Henry David Thoreau (1817–1862)
“Children ... after a certain age do not welcome parental advice. Occasionally, they may listen to another adult, which is why perhaps people should switch children with their neighbors and friends for a while in the teen years!”
—Marian Wright Edelman (20th century)