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由于流量测量所固有的复杂性,流量检测仪表已成为“过程检测控制仪表”这一大类中品种、规格最庞大的一支,为了对这类仪表有一个总的概念,有必要进行分门别类;但是,流量检测仪表的种类繁多,根据不同的分类原则,可以进行各种分类。在这里我们根据仪表获取流量信号所依据的基本规律来大致地进行分类,有了总的轮廓后再来选型。 (一)力学 1.基于伯努利原理的有: (1)节流装置,是流量测量仪表中应用最广的一类,约占总数的70％,在本世纪三十年代开始大量使用,至今仍然是最常用的流量测量装置。其中包括标准孔板、标准文丘利管,标准喷咀、1/4圆喷咀等。 (2)转子流量计,又称可变面积流量计或恒压降流量计。这一类仪表约占全部流量仪表的5％,历史悠久,应用较广。
Due to the inherent complexity of flow measurement, the flow measurement instrumentation has become the largest and the largest of its kind in the broad category of “process control instrumentation,” and there is a need to categorize it for a general concept of such instrumentation; However, a wide range of flow detection instrumentation, according to different classification principles, can be a variety of classification. Here we roughly according to the basic rules of the instrument to obtain the flow signal to classify, with the overall outline and then to selection. (A) mechanics 1. Based on Bernoulli’s principle are: (1) throttling device, is the most widely used type of flow measurement instruments, accounting for about 70% of the total, began to be widely used in the thirties of this century, It is still the most commonly used flow measurement device. Including standard orifice, standard venturi tube, standard nozzle, 1/4 round nozzle and so on. (2) rotor flowmeter, also known as variable area flowmeter or constant pressure drop meter. This type of instrument accounts for about 5% of all flow meters, has a long history and is widely used.