音叉型物位感測器之振動分析

Vibration Analysis of Tuning-fork Level Sensor

李泓緯(Hung-Wei Li)

指導教授 ： 張培仁

國立臺灣大學/工學院/應用力學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.02822

摘要

在大型工業如化學工業、石化產業及水泥業等，物料反應前後皆存放於大型儲存槽之中，儲存槽內容物量之監控為一常見之課題。工業界使用儲存槽內部物位感測器來偵側儲存槽內的物位高度，其中以音叉型物位感測器和超聲波型物位感測器最為常見。本研究欲解決現行音叉型物位感測器之偵側誤判問題。觀察發現，音叉型物位感測器之不良品在非感測端發生振動現象時，將會造成感測器之誤判現象。因此，本研究先透過振動分析實驗了解音叉型物位感測器之振動性質，尋找問題發生的可能原因，並利用COMSOL Multiphysics軟體進行有限元素法之分析，藉由不同之幾何形狀設計和邊界條件設定，確定造成音叉型物位感測器誤判問題的成因。進一步將分析結果和模擬結果與製造廠商進行討論和生產，再觀察其振動情況是否改善，以期提高製造商之生產良率。另一方面，本研究透過一連串的振動分析及模擬，建立音叉型物位感測器的評估方式，在往後該產品的生產流程上，能夠更確切了解和掌握不良品發生振動問題的原因並予以改善。

關鍵字

物位感測器 ； 有限元素分析模擬 ； 振動

並列摘要

In chemical engineering and petrochemical industries, how to monitor the material level in a huge storage tank is an important issue. The radar level sensor, ultrasonic level sensor, and tuning-fork level sensor are the common instruments adopted by industries. This work aims at investigating what cause the yield of the tuning-fork level sensor during manufacturing. Through observation, one can find that the defective products show the undesired vibration phenomenon at the non-sensing side. Therefore, the author tries to find out the vibration characteristics of the tuning-fork level sensor via experiment as well as the possible cause of yield. After narrow down the possible causes, to further verify the possible causes, the author adopts COMSOL Multiphysics commercial software to simulate the tuning-fork level sensor with different geometrical design and boundary conditions setting. The simulation results are then discussed with the manufacturer to improve the manufacturing yield. At the end, the author builds the criteria for the manufacturing of the tuning-fork level sensor, and can understand the mechanism more detail.

並列關鍵字

level sensor ； finite element method ； vibration

參考文獻

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