Why can V-cone flowmeters have such excellent technical performance? The most basic reason is the simple and scientifically reasonable structure and the throttling mode formed by it.
It should be said that the conical tube is a further development of the technology of the annular orifice plate and the classic venturi tube. It combines the excellent performance characteristics of the annular orifice plate, the classic venturi tube, the wear-resistant orifice plate, and the tapered inlet orifice plate. The measurement performance defect of the orifice plate is eliminated, so that it forms a new type of throttling flow measuring instrument with the characteristics of "selective genetic hybridization". The main measurement performance defects of standard orifice plates:
① During use, it is very easy for the sharp edges of the throttle to be abraded and contaminated, resulting in a gradual change in the outflow coefficient, resulting in difficult to control flow measurement errors.
② In the middle and low Reynolds number measurement area, the outflow coefficient varies greatly with the change of flow conditions, resulting in systematic measurement errors.
③ The requirements for the installation of straight pipe sections are too high, and the strict specifications of the orifice plate installation are difficult to meet the standards, which often results in a large additional error in the installation and installation, which is often difficult to quantitatively evaluate.
④ Large pressure loss
V cone flow metering situation advantages:
(1) There is sufficient test data to show that it has a very strong ability to remove non-axisymmetric velocity distribution caused by flow interference from the upstream, and has low requirements for the straight pipe section of the inlet.
(2) There is no fouling of throttling parts, and mixed-phase flow can be measured.
Metrological performance advantages of classic Venturi:
(1) The requirements for the straight pipe section of the inlet are relatively low.
(2) Fouling is small and pressure loss is small.
(3) Mixed phase flow can be measured.
Measurement performance advantages of wear-resistant orifice plate and conical inlet orifice plate:
(1) There is no sharp edge abrasion, and the outflow coefficient is relatively stable.
(2) A small Reynolds number can also be measured with a conical inlet orifice.