Problems with the installation of flow meters
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I plan to install a DN10 turbine flow meter on a DN40 pipeline. Do anyone have any opinions or think this is a viable option? I am measuring the flow rate of liquid methanol, and since the flow rate isn’t very high, it’s necessary to use a flow meter with a smaller pipe diameter. Thank you! :)
No problem, it can be installed. If the pipe diameter isn’t reduced to DN10, the flow meter may not function properly, as too low a flow rate will result in significant errors!
Thank you, then I’ll start on the renovation plan
Reduce the pipe diameter from DN40 to DN10, and the straight sections before and after the flow meter must be at least 5D in length; it can be longer! It’s ready to use!
Regarding whether a turbine flowmeter can be installed, the key requirement is that the medium being measured meets certain criteria: it generally should have a low viscosity, typically less than 0.000015 m2/s, and it should be a liquid with low corrosivity. Although turbine flowmeters are available for measuring various types of media, careful consideration must still be given when measuring media with high temperatures, high viscosities, or strong corrosive properties, and appropriate measures must be taken. When the viscosity of the medium exceeds 0.000015 m2/s, the meter coefficient of the flowmeter must be calibrated using actual fluid, otherwise significant errors will occur. Two-phase flow of vapor and liquid, two-phase flow of gas and solid, and two-phase flow of concentrated phase and solid cannot all be measured using turbine flowmeters. If a turbine flowmeter can be used, the uneven flow velocity distribution and the presence of secondary flows within the pipe are important factors that affect the measurement accuracy of the turbine flowmeter. Therefore, turbine flowmeters have certain requirements for the straight pipe sections upstream and downstream. For industrial measurements, a straight pipe length of 20D upstream and 5D downstream is generally required. To eliminate secondary flow, it is best to install a flow rectifier at the upstream end. If a straight pipe section of about 20D can be ensured at the upstream end, and a flow rectifier is installed, the measurement accuracy of the flow meter can reach the accuracy level specified during calibration. This post was last edited by lxq700918 on 2009-3-4 21:13.]
In fact, flow meters must primarily meet the requirements of the manufacturing process; excessive pressure drop resulting from flow measurement can affect production. The chemical industry has certain requirements regarding the selection and installation of flow meters, so it’s worth taking a look if you have the opportunity
If a DN10 flow meter can be used, then the DN40 process pipeline can be considered somewhat a waste.
I agree with what was said on floor 8; a DN25 pipe would be more appropriate, unless it’s an existing pipeline. The flow rate requirements seem to be 5 at the front and 3 at the back
What was said upstairs is pretty clear. For the straight sections before and after, we always use 10 units in front and 5 units behind. Additionally, it’s best not to install it behind the control valve, to prevent gas formation due to pressure reduction, which could cause inaccuracies in the flow meter readings.