Reed switches in Petrol and Diesel Pumps
Petrol and diesel pumping stations are explosive environments where a minor mistake could cause a great big fire. Reed Switches and Reed Sensors, being hermetically sealed off from the atmosphere are one of the very few devices that are safe for use in such areas. Petrol and diesel pumps use reed switches to sense if the nozzle has been placed in the holster properly so that the last volume filled display can be reset to zero. A tiny magnet embedded in the nozzle handle is made to activate a reed sensor mounted inside the holster. Reed Switch based flow sensors, when used with very low level sensing loads such as 10V/10mA can operate up to a billion operations. These encoder type flow sensors that consist of a multi-pole magnet that rotates along with a paddle wheel in the pipeline gives square wave output which is used by the microprocessor to translate into the actual volume of petrol or diesel being pumped, and this is displayed on digital panels along with the day’s fuel prices.