초록 ▼

A fluid level sensor for determining the amount of liquid in a container. Thin metal plates are placed parallely adjacent each other to form a capacitor cell coated with a non-hygroscopic film. The plates are mounted on the walls of the container containing fluid. As the fluid covers more surface ar

A fluid level sensor for determining the amount of liquid in a container. Thin metal plates are placed parallely adjacent each other to form a capacitor cell coated with a non-hygroscopic film. The plates are mounted on the walls of the container containing fluid. As the fluid covers more surface area of the capacitor plates, the dielectric properties of the fluid increase the capacitance of the cell proportionally. The plates are connected to an oscillator whose output frequency varies with the change in container fluid levels. By monitoring these frequency changes, the container fluid levels of the fluid in the container can be controlled.

대표청구항 ▼

An apparatus for sensing the level of liquid in a container comprising: first and second parallel metal plates having opposingly facing flat surfaces and providing a capacitance; means for supporting said plates inside said container; insulating spacing means, attached to said first and second plate

An apparatus for sensing the level of liquid in a container comprising: first and second parallel metal plates having opposingly facing flat surfaces and providing a capacitance; means for supporting said plates inside said container; insulating spacing means, attached to said first and second plates for maintaining a constant spacing between said first and second plates; and means electrically coupled to said plates for detecting said capacitance and for generating in response to said capacitance a signal indicating the level of liquid in said container; wherein said first and second parallel metal plates are shaped to support said detecting and signal generating means.