device maetning foer of nivaan of a in a behaallare existing fluidum

摘要

PCT No. PCT/SE90/00019 Sec. 371 Date Jun. 6, 1991 Sec. 102(e) Date Jun. 6, 1991 PCT Filed Jan. 11, 1990 PCT Pub. No. WO90/09599 PCT Pub. Date Aug. 23, 1990.A device for gauging the level of a fluid in a container with a microwave signal is described. The device comprises a vertical tube (1) mounted in the container, and a transmitter and a receiver and an electronic unit for determining the level based on the reflex position of the microwave signal. The device is characterized particularly by a calibration device in the form of a polarization means (6, 7) for polarizing the microwave signal in two polarization planes separated from each other and at least one reflecting reactance (10) in the tube (1) arranged to give a substantially stronger reflex of the microwave signal in the first polarization plane than in the second.