，与其他差压流量计一样，都是基于密闭管道中能量相互转化的伯努利定律，即在稳定流场情况下，管道中的流速与差压的平方根成正比。 V-cone flowmeters , like other differential pressure flowmeters, are based on Bernoulli's law of the mutual conversion of energy in closed pipes, that is, under the condition of stable flow field, the flow velocity in the pipe is proportional to the square root of the differential pressure. This measurement principle is widely used.
现场安装不规范主要可能有下面几个方面：工艺管道前后直管段不足，造成流体的不稳定，影响测量精度；检查V锥流量计正压引压管路的问题，要做到，引压管的畅通。 The irregular installation of V-cone flowmeters in the field may mainly have the following aspects: insufficient straight pipe sections before and after the process pipeline, causing instability of the fluid, affecting the measurement accuracy; checking the problems of the positive pressure impulse pipelines of the V-cone flowmeters, and , The impulse pipe is unobstructed. Check for leaks and plugs, because if such a problem occurs, the differential pressure transmitter is subjected to unidirectional pressure, which will cause the above-mentioned negative pressure phenomenon. When measuring steam, the condensing device will not cool down completely and the installation height will be unreasonable. The V-cone flowmeter must be equipped with a differential pressure transmitter for normal use. Therefore, the performance and installation of the differential pressure transmitter directly affect the overall accuracy of the V-cone flowmeter. Pay attention to the anti-corrosion of the differential pressure transmitter, and open the drain regularly. When measuring high-pressure or corrosive media, pressure leaks or joints often leak, causing pressure loss and differential pressure deviation. The solution is to conduct inspections on time and plug the loopholes.
作为新型节流装置，近年来被炒之过热。 As a new type of throttling device, the V-cone flowmeter has been overheated in recent years. Low pressure loss and high accuracy are the key points of its call compared to other standard throttling devices. But does the V-cone flowmeter really have such a high measurement advantage as it is said now? The following are the technical characteristics of the mutual restriction of the V-cone flowmeter summarized by the author with reference to relevant data and field installation experience. 1. I should have read the V-cone technical manuals of many manufacturers on the site. The β value above may not be of much concern to you. Many manufacturers' labels are in the range of 0.4-0.9. But in fact this and the low requirements of the straight section are contradictory. After a long-term experiment in our factory, if you want to meet the high-precision measurement requirements under the lower requirements of straight pipe sections, the β value must meet the range of 0.45-0.6, but then there is another problem If the diameter of the cone is in this range, the pressure loss is only 90% of that of a standard orifice plate, so the statement that the pressure loss is small is lost. And as suggested by some manufacturers, the value is more than 0.8. In this case, the pressure loss can be reduced to half of the standard orifice plate, but the rectification effect is lost, and the characteristics of low straight pipe requirements on the site are also lost. 2, is the rationality of taking the pressure point. Everyone who has used the V cone knows that the positive pressure is directly the pressure of the on-site pipeline. Although the V cone itself has a rectifying function, it can only be intimidating to the positive pressure. Therefore, if the requirements of the straight pipe section in front of the site are not enough, the positive pressure can not take the representative static pressure. Therefore, no matter what kind of flowmeter, it is definitely not a panacea, and it can only adapt to certain areas and obtain better measurement results.