Electrode cylinder support structure for large-diameter capacitive liquid hydrogen density sensor

Abstract

The invention belongs to the technical field of capacitive sensors and provides a support structure for a capacitive sensor component used in a large-diameter low-temperature fluid transportation pipeline. The support structure is formed in a manner of combining a stainless steel framework and a polytetrafluoroethylene material and is composed of a large circular ring (1), a plurality of wire arranging troughs (2), a plurality of supporting ribs (3), a small circular ring (4), a positioning pin hole (5), a wire passing hole (6), an insulating piece (7), an insulating trough (8), a plurality of stainless steel projections (9), and a polytetrafluoroethylene ring (10). The support structure not only can bear high-speed impact from a low-temperature fluid but also can satisfy insulation requirement between a capacitor and an electrode. The wire arranging trough can prevent a signal wire from being impacted due to low-temperature and high-pressure liquid and gas, thereby reducing generation of stray capacitance. Through a multi-time and long-period test, the support structure is proved to be capable of adapt work environment of 1.6 MPa and 20 K. The support structure has reliable performance and can be used as a method of supporting an electrode cylinder of a low-temperature capacitive sensor.

Description

technical field [0001] The invention belongs to the technical field of low-temperature capacitive sensors, relates to a supporting structure of sensors, and relates to a supporting method for capacitive sensor elements used in large-diameter low-temperature liquid delivery pipelines. Background technique [0002] At present, there are mainly two methods for measuring the density of liquid hydrogen propellant in liquid rocket engines: one is the temperature-pressure method (abbreviated as P-T method), and the other is the capacitance density meter measurement method. The P-T method is to measure the pressure and temperature of liquid hydrogen at a certain position in the pipeline, and then use the manual of liquid hydrogen thermophysical properties to find out the density of liquid hydrogen under the corresponding pressure and temperature conditions. The accuracy of temperature and pressure measurement directly determines the density measurement. The accuracy of the results, ...

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Problems solved by technology

[0004] The outer dimension of the sensor matches the diameter of the liquid hydrogen delivery pipeline. For the small-caliber liquid hydrogen density sensor, the bracket supporting multiple stainless steel cylinders is generally made of polytetrafluoroethylene, which can meet the requirements of support and insulation at the same time. However, for large-caliber capacitive density sensors, if polytetrafluoroethylene is still used as the bracket, its strength cannot meet the requirements, and it cannot meet the requirements of high-speed gas purge replacement before filling and large-flow ultra-low temperature liquid hydrogen impact. At the same time, since the cross-sectional area occupied by the support structure and the electrode cylinder of the capacitive density sensor should not exceed 15% of the cross-sectional area of ​​the measured liquid in the pipeline, otherwise it will have a great impact on the density measurement value, so it cannot be simply In order to meet the strength requirements by greatly enlarging the geometric dimensions of the PTFE support frame, we can only find higher-strength support materials or improve the support structure to meet the use requirements of large-caliber liquid hydrogen density meters.

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