Systems and methods for remotely measuring a liquid level using time-domain reflectometry (TDR)

摘要

A remote pulse TDR liquid level measurement system and method may include inserting a probe into a body of water. The probe has a probe/air interface, and the body of water includes an air/water interface. A narrow pulse is remotely transmitted to the probe via a coaxial cable. A first impedance mismatch is received from the probe/air interface in a form of a positive reflected pulse, and a second impedance mismatch is received from the air/water interface in a form of a negative reflected pulse. A time between the positive reflected pulse and the negative reflected pulse is calculated, and the time is converted to a distance, the distance being indicative of the water level.

主权项

1. A system for measuring a water level, comprising:
a probe including a conductive rod and insulating spacers within a conductive tube, the conductive rod arranged coaxially within the conductive tube, the conductive rod extending through the insulating spacers, the conductive tube including perforations exposing the conductive rod and the insulating spacers within; a head connector connected to the probe; a coaxial cable connected to the head connector, the coaxial cable including an inner conducting wire within an outer conducting shield and separated by an inner insulator, the inner conducting wire and the outer conducting shield of the coaxial cable being in electrical communication with the conductive rod and the conductive tube of the probe, respectively, via the head connector; a pulsing unit connected to the coaxial cable, the pulsing unit configured to transmit a narrow pulse to the probe and to receive a positive first reflected pulse and a negative second reflected pulse therefrom via the coaxial cable, the positive first reflected pulse being from a head connector/air interface, the negative second reflected pulse being from an air/water interface of the water level, the pulsing unit configured to calculate a time between the positive first reflected pulse and the negative second reflected pulse and to convert the time to a distance that is indicative of the water level; and a calibration cable connecting the head connector to the coaxial cable, the calibration cable having an impedance that is higher than the coaxial cable but equal to that of the head connector, the calibration cable having a length less than that of the probe.