Which flow meters do not require straight pipe sections before and after them?
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I recently had to select a flow meter and have the following questions; I hope experts can help answer them. Thank you~~ 1. Do Coriolis mass flow meters not require straight sections before and after them? Why? 2. Does a thermal gas mass flow meter require straight pipe sections before and after it? Why? 3. Are there any other types of mass flow meters? 4. Are there any other flowmeters that do not require straight sections before and after them?
Mass flow meters do not require straight pipe sections, as it is inherent to their principle. Thermal mass flow meters, on the other hand, need straight pipe sections in order to ensure that the flow velocity is within the designed range and remains stable
Now only the Coriolis mass flow meter does not require a straight pipe section.
Only the Coriolis mass flow meter does not require a straight pipe section
Most of them are needed. A mass flow meter is also advisable.
Quality is also needed, and control valves are essential as well.
Could you explain in detail why mass flow meters do not require a straight pipe section?
Quality also requires straight pipe sections, especially when the pipe diameter changes
I will only answer your first question. Yes, a Coriolis mass flow meter does not require a straight pipe section. Why is it not necessary? It’s because the Coriolis mass flow meter is not a velocity flow meter; most of the flow meters we encounter are velocity flow meters, such as those that use differential pressure, electromagnetic principles, or ultrasound to measure the flow velocity of the fluid, and then calculate the flow rate by multiplying this velocity by the cross-sectional area (with an appropriate weighting factor). When we talk about the flow rate of a medium, in reality the flow velocity varies at different points within the pipe; generally, the velocity is higher in the central part, while it is lower at the edges due to friction with the pipe walls (you can look up more information on laminar and turbulent flow). Only a sufficiently long straight pipe section can ensure that the flow velocity distribution throughout the pipeline matches the distribution specified in the instrument’s design, thereby guaranteeing stable and accurate measurement by the flow meter. Thermal mass flow meters are rather special; from what I remember, they seem to measure kg/s over a certain line, which is also a form of flow rate. If I’m wrong, please correct me – I’m not very familiar with this topic. A Coriolis mass flow meter measures mass and relies on inertia for measurement, so it does not require a straight pipe section. Of course, for liquids that vaporize easily, maintaining a straight pipe section downstream helps to maintain back pressure and ensure that the medium does not vaporize. The above are all my personal opinions; please feel free to point out any mistakes.