초록 ▼

An elongated cable has a length equal to the height of the silo, whereby, when the cable is disposed in the silo, it extends from the top end to the bottom end of the silo. An electric generator for generating an AC electric signal is automatically and continuously swept through a preselected freque

An elongated cable has a length equal to the height of the silo, whereby, when the cable is disposed in the silo, it extends from the top end to the bottom end of the silo. An electric generator for generating an AC electric signal is automatically and continuously swept through a preselected frequency range. The generator means being connected to the top end of the cable to thereby transmit the generated signal along the cable. Thus, when the generated signal is transmitted along the cable and the frequency of the generated signal is automatically and continuously swept, peak voltages will occur at frequency intervals, the frequency intervals being a function of the level of material. The frequency intervals are detected whereby to determine the level of material. Interference signals are eliminated by an adjustable impedance device at the bottom end of the cable.

대표청구항 ▼

Apparatus for determining the level of material in a silo, comprising: elongated cable means having a length equal to the height of said silo and being disposed in said silo and extending along the length thereof, whereby the cable extends from the top end to the bottom end of said silo; generator m

Apparatus for determining the level of material in a silo, comprising: elongated cable means having a length equal to the height of said silo and being disposed in said silo and extending along the length thereof, whereby the cable extends from the top end to the bottom end of said silo; generator means for generating an AC electric signal, said generator means including means for automatically and continuously sweeping the frequency of the generated signal through a pre-selected frequency range, said generator means being connected to the said cable means to thereby transmit said generated signal along said cable means; whereby, said generated signal is transmitted along said cable means and the frequency of the generated signal is automatically and continuously swept, so that peak and null voltages will occur at frequency intervals, said frequency intervals being a function of said level of material; means for detecting said frequency intervals; means for determining said level connected to said means for detecting; said generator means and said means for detecting being connected at the top end of said cable means and a portion of said signal transmitted along said cable means being reflected at the top surface of said material to provide signals proportional to said level, the remainder of said signal being reflected at the bottom end of said cable means to cause interference signals; said cable means including means for eliminating said interference signals comprising an adjustable impedance device at the bottom end of said cable means; and means for adjusting the impedance of said adjustable impedance device to equal the impedance of the portion of the cable means submerged in said material during operation of the apparatus.