Digital capacitive liquid level measuring system

Abstract

The invention discloses a digital capacitive liquid level measuring system. In a liquid rocket engine test, the steady permeation flux of a low-temperature propellant (such as liquid hydrogen, liquidoxygen and liquid methane) is an important parameter of engine design. At present, a sectional capacitive liquid level meter developed independently by out institute, a matched capacitance transducer,a collecting device and a computer are utilized to form a flow measuring system, and high-precision steady permeation flux measurement and real-time liquid level monitoring in hydrogen-oxygen enginehigh-altitude simulation testing and calibration testing can be achieved. In order to improve the precision and reliability of the capacitive liquid level meter, the performance of a transmitter is improved, and a digital liquid level measurement device based on an FPGA is developed so that a sectional liquid level sensor, the digital liquid level measurement device and the computer can form a complete solution, and intelligentization and digitalization of an instrument are achieved.

Description

technical field [0001] The invention relates to a liquid level measuring instrument and an upper computer acquisition software, in particular to a liquid level measuring system applicable to low-temperature medium, and belongs to the technical field of instruments and meters. Background technique [0002] In liquid rocket engine tests, the steady-state flow of cryogenic propellants (such as liquid hydrogen, liquid oxygen, liquid methane, etc.) is an important parameter for engine design. At present, the Beijing Institute of Aerospace Experiment Technology uses the self-developed segmented capacitance liquid level gauge and supporting capacitance converter plus acquisition equipment and computers to form a flow measurement system, which can realize the high-altitude simulation test and calibration test of the hydrogen-oxygen engine. High-precision steady-state flow measurement and real-time liquid level monitoring. [0003] As far as the sensor (segmented capacitance liquid ...

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Problems solved by technology

[0003] As far as the sensor (segmented capacitance liquid level gauge) is concerned, the technology is mature, but the supporting capacitance converter has the defects of low stability, low precision, and low intelligence. Because it is a pure analog circuit inside, Each of the signal processing links needs to be realized by adjusting the potentiometer. There are dozens of potentiometers in the circuit. Once a certain potentiometer is accidentally touched, the pre-adjusted circuit will change, resulting in output signal distortion.

This method of analog circuit plus adjusting potentiometer is relatively primitive, and some problems have been exposed in the application of the test bench of Beijing Institute of Aerospace Experiment Technology

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