CN-122016001-A - Liquid amount measuring method of non-contact high-precision liquid nitrogen generating device

CN122016001ACN 122016001 ACN122016001 ACN 122016001ACN-122016001-A

Abstract

The invention discloses a measuring method of a liquid amount detection device of a non-contact high-precision liquid nitrogen generation device, and belongs to the technical field of low-temperature medium liquid level parameter detection. The device comprises a man-machine interaction module, a liquid nitrogen storage tank, a multi-sensor platform, a damping support frame and an embedded module, wherein the multi-sensor platform integrates a distributed weighing sensor, a temperature and vibration auxiliary sensing unit, a multi-layer grading damping component is arranged in the damping support frame, the method comprises the steps of establishing a reference and a compensation coefficient through multi-dimensional automatic calibration, collecting and preprocessing multi-source data in real time, obtaining liquid nitrogen liquid level height through multi-dimensional interference correction, data cross verification and fusion calculation, and supporting redundancy switching and linkage control by periodically and dynamically calibrating and optimizing precision. The invention is suitable for the real-time monitoring of the liquid amount of the industrial-level and laboratory-level liquid nitrogen generating device, has high detection precision and strong anti-interference capability, is convenient to install, does not need to change the tank body, and ensures continuous and reliable detection and safe operation.

Inventors

ZHONG HUAQIANG
WANG ZHENHUA

Assignees

广东清澜华创新技术有限公司

Dates

Publication Date: 20260512
Application Date: 20260319

Claims (10)

1. The liquid amount measuring method of the non-contact high-precision liquid nitrogen generating device is characterized by comprising the following steps of: acquiring weight, temperature and vibration data by utilizing a plurality of groups of sensing units of a detection device, and executing multidimensional automatic calibration operation on the acquired data to obtain a reference value, a compensation coefficient and an associated model for detection; synchronously acquiring real-time weight data, real-time environmental temperature data and real-time vibration signals of a liquid nitrogen storage tank in the running process of the liquid nitrogen generating device through the plurality of groups of sensing units, and performing preprocessing operation on the acquired real-time data to obtain preprocessed data; according to the reference value, the compensation coefficient and the associated model which are obtained by the multi-dimensional automatic calibration, performing multi-source data fusion calculation operation on the preprocessed data to obtain the liquid nitrogen liquid level height; Performing dynamic calibration operation on the compensation coefficient and the related model parameters according to a set period, and starting redundancy switching operation when the data deviation of the sensing unit exceeds a preset threshold value, so as to ensure continuous operation of the detection process; And performing display operation on the liquid nitrogen liquid level height and related detection data, triggering alarm operation when the detection data exceeds a preset threshold value, and outputting linkage signals to a liquid nitrogen generation device control system.
2. The method for measuring the liquid amount of a non-contact type high-precision liquid nitrogen generating apparatus according to claim 1, wherein, in the course of performing said multi-dimensional automatic calibration operation, Collecting partial weight data of the empty tank and temperature data of a corresponding position through the plurality of groups of sensing units in a state that the liquid nitrogen storage tank is the empty tank and the liquid nitrogen generating device is not operated; Performing correction operation on the empty tank local weight data by using a temperature correction formula, eliminating interference of ambient temperature to the weight data, and obtaining empty tank weight data after temperature correction; Performing calculation operation based on the assumption of uniform stress of the sensing unit in an ideal horizontal state to obtain ideal local weight; Performing calculation operation through the difference value between the empty can weight data subjected to temperature correction and the ideal local weight to obtain a levelness deviation coefficient of the supporting surface; and performing compensation operation on the levelness deviation through a weighting algorithm, generating an empty tank total reference value, correcting an initial weight coefficient, and completing calibration of the empty tank reference value and the levelness deviation.
3. The method for measuring the liquid amount of a non-contact type high-precision liquid nitrogen generating apparatus according to claim 2, wherein, in the course of performing said multi-dimensional automatic calibration operation, The method comprises the steps of filling liquid nitrogen with known mass into a liquid nitrogen storage tank, collecting a plurality of groups of real-time weight data through a plurality of groups of sensing units, performing temperature correction operation on the collected real-time weight data to obtain temperature corrected weight data, combining the levelness deviation coefficient, performing correction operation on the weight coefficient through a least square method to minimize data deviation, and completing consistency calibration of the sensing units; The method comprises the steps of starting a liquid nitrogen generating device, collecting vibration signals within a set time period through a plurality of groups of sensing units, performing feature extraction operation on the vibration signals to obtain vibration feature parameters, establishing a grouping vibration baseline database based on the vibration feature parameters, calibrating directional vibration compensation coefficients of each group of sensing units, and completing calibration of the vibration baseline of the air compressor; And performing feature extraction operation on the vibration signals to obtain random vibration feature parameters, setting a random vibration identification threshold value based on the random vibration feature parameters, establishing a random vibration compensation model and completing random vibration baseline calibration.
4. The method for measuring the liquid amount of a non-contact type high-precision liquid nitrogen generating apparatus according to claim 1, wherein, in the course of performing said multi-dimensional automatic calibration operation, Calculating a temperature average value based on the acquired temperature data, performing modeling operation on the association relation between the liquid nitrogen density and the temperature through an interpolation algorithm, and establishing an association model of the liquid nitrogen density and the temperature to finish density dynamic calibration; The method comprises the steps of keeping a liquid nitrogen generating device in a stop state, executing standing monitoring operation for a set period of time, recording liquid nitrogen volume data and environment temperature data at different moments, executing calculation operation based on the recorded data to obtain a baseline evaporation rate, executing modeling operation on the association relation between the evaporation rate and the environment temperature through a fitting algorithm, establishing an association model of the evaporation rate and the environment temperature, and completing the baseline calibration of the evaporation rate.
5. The method for measuring the liquid amount of a non-contact type high-precision liquid nitrogen generating apparatus according to claim 1, wherein, during the execution of the preprocessing operation on said collected real-time data, Performing screening operation on the real-time data through an outlier rejection algorithm, and rejecting extreme data exceeding a set range; Performing substitution operation on the removed extreme data by adopting adjacent moment data; and carrying out average operation on the data at a plurality of continuous moments through a moving average filtering algorithm, and smoothing high-frequency noise to obtain preprocessed data.
6. The method for measuring the liquid amount of a non-contact type high-precision liquid nitrogen generating device according to claim 1, wherein in the process of performing a multi-source data fusion calculation operation on said preprocessed data, Performing correction operation on the preprocessed real-time weight data by using the temperature compensation coefficient, the directional vibration compensation coefficient and the random vibration compensation coefficient to compensate the interference caused by temperature drift, directional vibration and random vibration, so as to obtain effective local weight; performing real-time monitoring operation on the vibration signals of each group of sensing units by adopting a sliding window method, and calculating a vibration root mean square value and an instantaneous peak value in a window; If the vibration parameter exceeds the random vibration identification threshold value, judging that irregular random vibration exists, triggering dynamic compensation operation and updating a random vibration compensation coefficient; and if the vibration parameter does not exceed the threshold value, keeping the random vibration compensation coefficient reference value unchanged.
7. The method for measuring the liquid amount of a non-contact type high-precision liquid nitrogen generating apparatus as recited in claim 6, wherein after said effective partial weight is obtained, Performing a pairwise difference absolute value calculation operation on a plurality of groups of effective local weights, performing a comparison operation on a calculation result and a preset consistency threshold value, and judging whether slight deviation exists between two groups of sensing units; if the two groups of sensing units are judged to have slight deviation, performing correction operation on the corresponding weight coefficients through a deviation allocation algorithm, wherein the weight coefficients of the rest sensing units are kept unchanged; And performing weighted fusion operation on the effective local weight by using the corrected weight coefficient to obtain the total weight of the liquid nitrogen and the empty tank.
8. The method for measuring the liquid amount of a non-contact high-precision liquid nitrogen generating device according to claim 7, wherein after obtaining the total weight of said liquid nitrogen and said empty tank, Based on the real-time environment temperature average value, performing calculation operation through the density correlation model to obtain real-time liquid nitrogen density; performing calculation operation by combining the total weight and the total standard value of the empty tank to obtain the liquid nitrogen volume without correction evaporation; Performing calculation operation based on liquid nitrogen volume data of a continuous detection period and the evaporation rate correlation model to obtain a real-time evaporation rate; The liquid amount loss caused by evaporation is subtracted to obtain the corrected liquid nitrogen volume.
9. The method for measuring the liquid amount of a non-contact type high-precision liquid nitrogen generating apparatus according to claim 8, wherein after obtaining said corrected liquid nitrogen volume, Based on a volume height correlation function preset by the liquid nitrogen storage tank, performing solving operation through an iterative algorithm to obtain the liquid nitrogen liquid level height; and continuously comparing the liquid level height difference values of two adjacent iterations in the iteration process, stopping iteration when the difference value meets a preset termination condition, and outputting the final liquid nitrogen liquid level height.
10. The method for measuring the liquid amount of a non-contact type high-precision liquid nitrogen generating apparatus according to claim 1, wherein, during the execution of said dynamic calibration operation, Automatically triggering a calibration process at each interval set time length, and executing a re-correction operation on the weight coefficient, the temperature compensation coefficient, the directional vibration compensation coefficient, the random vibration compensation coefficient reference value and the evaporation rate related model parameter by combining the historical detection data; When the data deviation of a certain group of sensing units exceeds a set threshold value, automatically shielding the fault sensing unit, reallocating weights based on the remaining sensing unit data which normally works, and continuously executing liquid amount calculation; when the detection data exceeds a preset threshold value, triggering an audible and visual alarm operation, outputting a linkage signal to a liquid nitrogen generating device control system through an industrial communication interface, and automatically adjusting the running power or the start-stop state of the generating device.

Description

Liquid amount measuring method of non-contact high-precision liquid nitrogen generating device Technical Field The invention belongs to the technical field of low-temperature medium liquid level parameter detection, and particularly relates to a non-contact liquid amount detection technology matched with a liquid nitrogen generating device. Background With the development of low-temperature refrigeration technology, the liquid nitrogen generating device is widely applied to the scenes of industrial production, laboratory scientific research and the like, and liquid quantity and liquid level detection in the liquid nitrogen storage process is a key link for guaranteeing the stable operation of the liquid nitrogen generating device and realizing the dynamic balance of liquid nitrogen supply and demand. At present, the detection of liquid nitrogen liquid quantity is mainly divided into two main flow technical schemes of a weight measurement method and contact type liquid level detection. In the traditional single-sensor weight measurement method, the total weight of a liquid nitrogen storage tank is detected through a single weighing sensor, and the liquid nitrogen liquid quantity in the tank is calculated by combining the fixed liquid nitrogen density. The scheme is not provided with a matched auxiliary sensing unit, the acquired weight signal is easily interfered by external factors such as electromagnetism in the transmission process, and a corresponding compensation mechanism is not provided for vibration generated by the operation of an air compressor matched with the liquid nitrogen generating device, so that the error of weight detection can be directly amplified due to vibration interference. In addition, the scheme needs to manually calibrate the levelness of the supporting surface by using the level meter, the operation process is complicated, the calibration precision is easily influenced by human operation factors, and further, the liquid amount calculation result is deviated. The contact type liquid level detection scheme generally adopts a transparent liquid level indication container to realize liquid level indication by matching with a color-changing indication strip or a buoy component. In the detection process, the detection part is required to be invaded into the liquid nitrogen storage tank, or is enabled to be in direct contact with liquid nitrogen, the detection part is easy to be affected by low-temperature environment to have the problem of corrosion and aging in the long-term use process, and meanwhile, the original sealing structure of the liquid nitrogen storage tank can be damaged through invasive installation, so that potential safety hazards of liquid nitrogen leakage exist. The scheme relies on manual visual observation to finish reading, cannot realize automatic calibration and real-time monitoring of liquid nitrogen liquid quantity, and is difficult to adapt to a use scene of continuous operation of a liquid nitrogen generating device. In addition to the two main flow schemes, the liquid nitrogen liquid quantity detection schemes adopting a single pressure sensor and an ultrasonic sensor are also partially adopted in the prior art. The scheme has the advantages that the problem of limited detection dimension generally exists, the multisource interference factors such as air vibration, ambient temperature drift, local errors of a sensor and the like in the operation process of the liquid nitrogen generating device cannot be covered comprehensively, the detection precision is insufficient, the operation stability is poor, and the detection precision can be obviously attenuated in the long-term use process. Meanwhile, the conventional various detection schemes generally lack redundant design, and the single sensor can directly cause failure of detection function when faults occur, so that the long continuous and high-reliability operation requirement of the liquid nitrogen generating device cannot be met, and the stable application of the liquid nitrogen generating device under complex working conditions is restricted. Disclosure of Invention The invention aims to provide a liquid amount measuring method of a non-contact high-precision liquid nitrogen generating device, which is used for solving the problems of low detection precision, weak anti-interference capability, dependence on manual calibration and complex operation of the existing liquid nitrogen liquid amount detection scheme and improving the liquid nitrogen liquid amount detection precision and operation stability. In order to achieve the above purpose, the present invention provides the following technical solutions: A liquid amount measuring method of a non-contact high-precision liquid nitrogen generating device comprises the following steps: acquiring weight, temperature and vibration data by utilizing a plurality of groups of sensing units of a detection device, and executing multidimensional automatic calibration