초록 ▼

A fuel tank alarm system comprises three density sensors disposed at different heights within a fuel tank. An electrical density signal produced by the lowest sensor is subtracted from the corresponding signals from the upper two sensors to produce two density-difference signals which are then compa

A fuel tank alarm system comprises three density sensors disposed at different heights within a fuel tank. An electrical density signal produced by the lowest sensor is subtracted from the corresponding signals from the upper two sensors to produce two density-difference signals which are then compared with a reference signal. When an inverse density gradient of dangerous proportion exists in the fuel tank, one or both of the density-difference signals exceeds the reference signal in magnitude and an alarm circuit is actuated. The alarm circuit can automatically start a pump to circulate fuel in the tank and reduce dangerous density inversion of fuel therein.

대표청구항 ▼

A system for indicating an abnormal density variation in a mass of liquid contained within a storage tank, comprising: at least two density sensing means mounted in said tank at different respective heights for producing respective density output signals proportional to the density of the liquid at

A system for indicating an abnormal density variation in a mass of liquid contained within a storage tank, comprising: at least two density sensing means mounted in said tank at different respective heights for producing respective density output signals proportional to the density of the liquid at each respective height when said density sensing means are immersed in said liquid, at least one density gradient sensing means connected to two of said density sensing means, for comparing the density output signals of the two density sensing means and for producing a density gradient output signal proportional to the density gradient in the liquid between the two density sensing means, and alarm means connected to said density gradient sensing means, for producing an alarm indication when said density gradient output signal indicates an inverse density gradient in the liquid exceeding a predetermined value.