An apparatus and method for measuring a liquid level in a vessel using an acoustic wave. Acoustic tubes have first ends disposed vertically along a sidewall of the vessel for each of the liquid levels to be measured, and the tubes communicate with the inside of the vessel. Second ends of the tubes are...http://www.google.es/patents/US6546794?utm_source=gb-gplus-sharePatente US6546794 - Liquid level measuring apparatus and method
