Vapor resistant tank level alarm system

Abstract

A tank level alarm system in which all of the electrical components are located in a sealed housing above the tank's upper surface. There is no direct electrical connection between the tank liquid level detector within the tank interior and the alarm electrical components in the housing. A magnetic switch opens and closes based upon the proximity of a magnet mounted to a vertical rod to which a float is attached within the tank. The magnetic switch is positioned electronically in series with a battery and then in parallel with each of a plurality of alarm devices which in the preferred embodiment include a flashing light, an audio generator and a transmitter. When the tank's liquid level is below a selected maximum “safe” level, the magnet mounted to the upper end of a vertical rod is separated from the magnetic switch by a sufficient distance to keep the switch in its “open” state. However, as the liquid rises in the tank, the float connected to the lower end of the vertical rod, begins to rise with the liquid thereby causing the vertical rod to travel upwardly with the liquid. This raises the magnet positioned at the upper end of the rod until it comes sufficiently close to the magnetic switch to close it electronically, thereby connecting the battery to the alarm devices. A normally closed magnetic switch may be used with a chain or other flexible interconnector instead of a rod to serve as a low level alarm instead of a high level alarm.

Dependencies are inferred from the claim text.