引導式控制閥特性分析及於定壓差之應用

引導式控制閥，具有成本低、自備回饋與放大的功能及堅固可靠的優點，不像電子式控制閥，會有受電源及環境影響的缺點。然而此類閥卻少有人研究，為能在工業界推廣，建立使用技術，本論文即以分析引導式控制閥之作動特性及如何應用此類閥組於定壓差管路系統，做為研究主題。本研究分為二部份，第一部份是引導式定壓差控制閥，穩態及動態的數學模式推導及穩態的VisSim模擬；第二部份是實際量測之驗證，包含撰寫PC based的人機介面程式，並經由LabJack信號卡，即時抓取壓差與流率的數據，再經由線性迴歸分析，以找出引導式定壓差控制閥之特性，建立工業界使用此閥於管路系統中的技術。研究結果顯示此類閥可成功應用於須要定壓差的管路系統中，這種應用可簡分為兩種，一種是控制閥與泵並聯，以維持泵出入口定壓差，另外一種是控制閥與負載串聯，穩定負載之壓差。在兩種應用中，本研究提出了穩壓線來取代原泵浦的性能曲線，並成功的應用穩壓線來解說，控制閥全開與全關的條件，以及控制閥之子閥及針閥的調整，如何影響系統的壓差與流量。總而言之，本研究在藉由數學推導、模擬與實驗，探討引導式控制閥的特性，建立使用及調整技術，這研究結果應對此類閥的推廣有甚大的幫助，也對閥的製造與設計，提供必要的基礎。

關鍵字

引導式控制閥；控制閥特性係數；泵浦特性曲線

並列摘要

Pilot-operated control valves have the advantages of low costs, self-provided feedback and amplification functions. They are also tough and reliable and do not have the disadvantages of electronic control valves, liable to be influenced by power and environment. However, these valves are seldom revealed in research literatures. In order to popularize their application in the industry, this thesis is aimed to analyze the characteristics of pilot-operated control valves and establish their application techniques in the field of constant pressure difference. This research is divided into two parts. The first part is to derive steady state and dynamical mathematical models and VisSim simulation of steady state case. The second part is actual experiments for verification. This includes writing a man-machine interface program on PC and collects the data of pressure differences and flow rates via LabJack signal card in real time. After that, linear regressive analysis is applied on the experimental data in order to find out the characteristics of pilot-operated control valves. The result of this work shows that this kind of valves can successfully apply in pipeline systems which need constant pressure difference. The applications can be categorized into two kinds; one is to connect the control valve and pump in parallel in order to maintain a constant pressure difference of pump’s discharge and suction. Another one is to connect the control valve and load in series in order to maintain a constant pressure difference of the load. In two applications, this work proposes a constant pressure line to replace original pump characteristic curve. This can successfully explain the turn-on and shut-off of the control valve. The adjustment of pilot and needle valves can also be interpreted on how the adjustment influencing the system pressure and flow rate. In summary, this research investigates the characteristics of pilot-operated control valves through deriving their mathematics, simulation and experiment. The established adjustment technology should be very helpful in popularization of this kind of valves. The knowledge on the thesis also offers an essential foundation for valve manufacturer and designer.