【Beginner】How to determine the measurement range of a flow meter?
Thread Content
Knowing the maximum flow rate and normal flow rate of a flow meter, how can one determine its measurement range? For example, if the maximum flow rate is 900 and the normal flow rate is 750, can the measurement range be 1500? How can one determine it when there is only normal traffic sometimes? I’m asking the experts for help
There is no fixed rule for this; different people have different opinions. Generally, a range of 1.1 to 1.5 times the maximum flow rate is acceptable. If only operational conditions are available, the selection should be at least twice the value of those operational conditions. It’s a matter of convention – there’s no set rule, it depends on judgment. In short, just cover a bit more of the maximum flow rate
What was said upstairs is correct; it’s possible to find several options with suitable diameters. A larger diameter results in less pressure drop, so generally a larger diameter is chosen. It is necessary to take the process requirements into account.
It also depends on the flow meter you choose. If the flow meter has a narrow measurement range, such as an orifice plate, it is recommended to set the scale to a value slightly lower than 120%. If you use a flow meter with a wider measurement range, such as a vortex flow meter, then the scale can be set to 150%.
Thank you, Master, for your guidance. However, there’s one thing I’m not quite clear about: what exactly are the operating conditions? . What exactly is the concept?
Thank you for your guidance. Um, does that mean that based on the calculations I’ve done, there are two possible pipe diameters: one is 25 and the other is 50, and both meet the requirements? In that case, if the pipe diameter is 25, it’s better to choose the 25 mm option； If the pipe diameter is 50, then should 50 be chosen?
Thank you for your guidance. In other words, the basic value should be greater than the maximum flow rate, but by how much depends on experience and similar factors; it’s just important not to make it too high, right?
Generally, a diameter smaller than that of the pipe is chosen; it cannot be larger. If there are many options when the diameter is smaller than that of the pipe, it’s better to choose a larger one. For example, if the pipe has a DN50 diameter, and based on the conditions specified in the process along with relevant calculations, it turns out that flowmeter diameters of DN25 and DN40 both work, then DN40 should be chosen
Is it an electromagnetic flowmeter? Generally, the range is set at 1.3–1.5 times the maximum flow rate. If there are specialized calculation tools available, and the diameter of the flow meter is determined based on those calculations, it is best to choose the flow meter according to those results; otherwise, the accuracy will be significantly affected
The operating condition refers to the flow rate range under normal operating conditions (which are generally the design conditions)
I just made it up on the spot; as long as it can handle the maximum traffic volume, that’s fine.