Monitoring of Impulse Line Blockage Using Phase Difference Between Upstream and Downstream Pressures of Orifice
Monitoring of Impulse Line Blockage Using Phase Difference Between Upstream and Downstream Pressures of Orifice
复制标题
利用孔板上游和下游压力之间的相位差监测脉冲管路堵塞
DOI：
10.1115/power2008-60058
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Y. Yuuki
中科院分区：
文献类型：
--
作者：
J. Eino;A. Uehara;T. Wakui;T. Hasizume;N. Miyaji;Y. Yuuki
组合使用差压变送器、孔板和脉冲管线来生产流量计，广泛应用于过程工业。由于该流量计使用中最常见的问题是脉冲管线堵塞，因此需要在线堵塞检测系统。在之前的工作中，作者开发了一种脉冲管线堵塞指标，称为堵塞指数，它基于压力波动。虽然堵塞指数能够有效地检测堵塞，而不受流量和压力变化的影响，但随着管路压力变化率的增加，它无法检测堵塞。此外，在某些应用中，管线压力会发生连续且频繁的变化。因此，本研究的目的是即使在管线压力变化率如此之高以致于堵塞指数无法检测到堵塞时也能检测到脉冲管线堵塞。在本文中，作者详细介绍了堵塞引起的压力传输延迟，并利用孔口上下游压力的相位差作为新的堵塞指标来定量评估延迟。此外，通过选择具有高功率谱密度的频率，新指数变得足够灵敏，可以在更快速的管线压力变化期间检测堵塞，而以前的堵塞指数在这种情况下失效。版权所有 © 2008 ASME
The combination use of a differential pressure transmitter, orifice and impulse line to produce a flowmeter is widely used in the process industries. Since the most frequent problem encountered in the usage of this flowmeter is impulse line blockage, an online blockage detection system is required. In previous works, the authors developed an indicator of impulse line blockage, called the blockage index, which is based on pressure fluctuations. Although the blockage index is able to detect the blockage effectively without being affected by the change in the flow rate and pressure, it can not detect the blockage as the rate of line pressure change increase. In addition, there are continuous and frequent line pressure changes in certain applications. Hence, the objective of this study is to detect impulse line blockages even when the line pressure change rate is so high that the blockage index is unable to detect the blockage. In this paper, the authors present details on the delay in the pressure transmission caused by the blockage, and evaluate the delay quantitatively by using the phase difference between the pressure upstream and downstream of the orifice as a new blockage index. In addition, by selecting frequencies with high power spectral densities, the new index becomes sensitive enough to detect the blockage during the more rapid line pressure changes under which the former blockage index failed.Copyright © 2008 by ASME