取样流量仪表概述

Overview of Sampling Flow Meters

近二、三十年来，”插入式”流量仪表在我国工程实践中已得到广泛应用，其命名也被某些专著采用。本文介绍了其原理、类型、应用和发展中的问题。作者建议按测量原理划分，这类仪表应称为取样流量仪表（Sampling Flow Meter），以利于准确地反映它的特性与利弊。文章还强调了要用好这类仪表，这不仅取决于流速的准确度，而且还取决于管道的截面积及流速分布。后二者与千变万化的应用条件密切相关，而这些却往往是厂商有意或无意回避的。对于如何用好这类仪表，作者提出了一些建议。涉及这类原理的仪表很多，本文着重介绍的是应用较多的差压式。

In the recent twenty to thirty years, ＂Insert-type＂ flow meter has been widely used in the engineering practice in our country and its nomenclature has also been adopted by a few of monographs. This paper introduces its principle, types, applications and the issues in the development. The author puts a proposal in which such kind of instruments should be called sampling flow me- ter as per the partition of measuring principle, so that facilitates to exactly reflect its characteristics and advantages as well as disad- vantages. The paper also emphasizes that should use this kind of instruments well, it not only depends on the accuracy of flow velocity but also the pipeline＂ sectional area and its velocity distribution. These last two are closely related with the daedal applied conditions; however these often are avoided on purpose or unintentionally by the manufacturers. The author proposes some suggestions of how to use this kind of instruments well？ There are a number of instruments that involve this principle, but the widely used differential pres- sure flowmeter is introduced in emphasis in this paper.