LEVEL DETECTOR Russian patent published in 2023 - IPC G01F23/296 

FIELD: metrology.

SUBSTANCE: devices for measuring the level of liquid media. The level detector includes a housing, a half-wave vibrator attached to the housing using a belt located in the middle of the height of the vibrator, a piezoelectric element acoustically connected to the vibrator, a bandpass amplifier with positive feedback, which includes a piezoelectric element, and an indicator device connected to the output of the amplifier. The first and second resistors and a two-pole switch are introduced into the analyzer, and the indicator device is made in the form of a rectifier, the output of which is connected to the control input of the two-pole switch, while the resistors through the two-pole switch are connected to the feedback circuit of the amplifier in series with the piezoelectric element so that in each position of the switch only one resistor is included in the feedback circuit, and if there is a high level voltage at the output of the comparator, the first resistor is included in the feedback circuit, and the resistance of the first resistor is selected from the condition of disruption of self-oscillations when the vibrator is immersed in liquid to a depth of 2/3 of the vibrator diameter or more, and the resistance of the second resistor is from the condition of maintaining self-oscillations when the vibrator is immersed in liquid to a depth of 1/3 of the vibrator diameter or less.

EFFECT: increased reliability.

1 cl, 2 dwg