振動式料位計之靈敏度分析與改良

Sensitivity Analysis and Improvement of Vibrating Probe Level Meter

林資凱(Chi-Kai Lin) ； 徐茂濱(Mau-Pin Hsu) ； 黃偉晟(Wei-Chen Huang)

《中華民國振動與噪音工程學會論文集》 2013 (2013/06) Pp. 283-289

摘要

本論文以實驗方式探討現有料位計之缺失，並針對這些缺失進行改良，最後將改善方式發展成一個能偵測多種物料與液體之水位的分析流程。流程中首先對料位計進行實驗模態分析，以瞭解料位計的固有特性（自然頻率、模態阻尼等）；接著擷取料位計上的工作頻率、電壓訊號及作ODS（Operating Deflection Shapes）分析，藉此瞭解料位計之工作頻率及工作時的動態行為，再分析兩者的相關性，以瞭解料位計之阻尼大小及料位計的激振頻率是否接近共振頻率。研究結果指出，現有的料位計因激振頻率較遠離自然頻率且阻尼過大，使得料位計無法感應到水位的變化，因此本研究利用低阻尼材料設計料位計，並用接近共振頻率的激振頻率激振料位計，以提升料位計之感應靈敏度，最終可使得料位計偵測到原本無法感應到的水位變化。

關鍵字

振動式料位計 ； 實驗模態分析 ； 振動 ； 共振 ； 阻尼

並列摘要

This research investigated the faults existed in some current vibrating probe level meters. After thorough analysis, modifications were made and improvements were experimentally verified. In the end, the whole analysis procedure was incorporated into a flow chart, which helps developing such a level meter capable of detecting levels of various materials or liquids.In this study, modal testing was first performed on the target level meter to obtain its characteristics such as working frequency and operating deflection shapes were measured to find the relationship with the meter's characteristics.Experimental outcome indicated that not only the working frequency is too far away from resonance frequency but also the damping in the level meter is too strong to be sensitive enough to detect the levels of some low-density materials. After appropriate countermeasures were taken, the modified level meter can finally detect the levels of water and other liquids and hence meet the predetermined goal.

並列關鍵字

vibrating probe level meter ； modal testing ； vibration