초록 ▼

The present electronic multi-purpose material level sensor is based on time domain reflectometry (TDR) of very short electrical pulses. Pulses are propagated along a transmission line that is partially immersed in a liquid, powder, or other substance such as grain in a silo. The time difference of t

The present electronic multi-purpose material level sensor is based on time domain reflectometry (TDR) of very short electrical pulses. Pulses are propagated along a transmission line that is partially immersed in a liquid, powder, or other substance such as grain in a silo. The time difference of the reflections at the start of the transmission line and the air/liquid interface are used to determine levels to better than 0.01 inch. The sensor is essentially independent of circuit element and temperature variations, and can be mass produced at an extremely low price. The transmission line may be a Goubau line, microstrip, coaxial cable, twin lead, CPS or CPW, and may typically be a strip placed along the inside wall of a tank. The reflected pulses also contain information about strata within the liquid such as sludge-build-up at the bottom of an oil tank.

대표청구항 ▼

A sensor for determining the surface or interface level of a material comprising in combination: a transceiver for generating electrical transmit pulses; a guide wire at least partially immersed in the material; a conductor electrically coupling said transceiver and said guide wire; a launcher plate

A sensor for determining the surface or interface level of a material comprising in combination: a transceiver for generating electrical transmit pulses; a guide wire at least partially immersed in the material; a conductor electrically coupling said transceiver and said guide wire; a launcher plate connected to said conductor at said coupling to said guide wire; said transmit pulses being conducted over said conductor to said launcher plate, said launcher plate acting as a transmit antenna ground plane, and helping launch said electrical pulses as near field, guided electromagnetic (EM) waves, and also producing a fiducial pulse back to the transceiver; said EM waves propagating along said guide wire, and being at least partially reflected by the surface or interface; said reflected EM waves propagating back along said guide wire toward said launcher plate, said launcher plate acting as a receive antenna ground plane, and therefrom said reflected EM waves being transmitted as reflected pulses to said transceiver; and said transceiver determining a time delay between said fiducial and reflected pulses, thus establishing the surface or interface level relative to said launcher plate.