How can the water flow rate in a partially filled pipe be measured? What type of flow meter is suitable for this purpose?

Add a U-bend to the pipeline, but be sure to meet the requirements for the straight pipe section required for the flow meter.

At present, for pipes of this diameter, flow meters designed for measuring flow when the pipe is not fully filled are available only at the inlet, with prices exceeding 750,000. Moreover, since the condition of measuring flow when the pipe is not fully filled occurs very rarely in practical use, there are few actual application examples both domestically and internationally. Imported non-full-bore flow meters incorporate a capacitive level sensor within the pipe of the flow meter itself to measure the cross-sectional area of the fluid. Capacitive sensors have slightly lower relative accuracy, weaker interference resistance, and lower reliability in use. Therefore, we propose making a separate opening in the pipeline and installing a guided-wave radar to measure the liquid level of the medium inside the pipeline. Guided wave radar performs better than capacitive level sensors in terms of accuracy and reliability. The liquid level measured in this way can be used to calculate the actual cross-sectional area of the medium. Flow rate measurement is a challenge in partial-flow measurement. Since the medium cannot fill the pipeline, it is more susceptible to the conditions within the pipeline, such as bends, pump sources, and sudden fluctuations in liquid level. All these changes will cause instability in the flowing medium, generating a large number of false and noisy signals in the sensor’s magnetic field; such false and noisy signals significantly affect the accuracy of measurements. Therefore, to ensure relative accuracy in measurements taken in non-full-pipe conditions, the following requirements must be met: (1) The straight pipe sections before and after the flow meter should be at least 10D in length ahead of it and 5D behind it (this ensures that the fluid flows past the flow meter in a smooth manner, without significant turbulence or air bubbles, thereby improving the accuracy and stability of the measurement). ⑵ The fluid medium in the pipeline must ensure that more than two-thirds of the pipeline is filled. (When the fluid medium does not meet this requirement, it is easy to experience very large fluctuations and significant measurement errors, because the two electrodes of the electromagnetic flowmeter are installed horizontally opposite each other at half the diameter of the flowmeter; only when the fluid medium covers the electrodes and reaches more than two-thirds of the pipe’s interior can accurate measurements be taken.) ⑶ The fluid medium inside the pipeline is continuous and relatively stable. (Rapid and drastic changes in liquid level should not occur; of course, stopping the operation after it has been running for some time should also be avoided.) Because this can easily cause ripples inside the pipe, leading to large fluctuations in the measurements). ⑷ Try to avoid large differences in the fluid medium inside the pipes between day and night; of course, the fluid level in the pipes at night must also be at least two-thirds full. ⑸ It is best not to install the flow meter in water (although the electromagnetic flow meters produced by our company, with an IP68 protection rating, can remain submerged in water for extended periods, the fact that measurement is carried out in a non-full-bucket condition means that the better the working conditions on site, the better the measurement results will be). ⑹ Since measurement in a non-full-bucket condition inevitably has an impact on accuracy, the precision of measurements under such conditions can only be guaranteed at around level 2. The electromagnetic flowmeters of large diameter (DN600 and above) produced by Chuanyi Flowmeters achieve a measurement accuracy of grade 0.5 when the pipe is full; however, in cases where the pipe is not full, there are too many factors that interfere with the measurement, so such accuracy cannot be achieved. At the current level of technology, there are no electromagnetic flowmeters for non-full-bore measurement that can achieve an accuracy level of above grade 1. ⑺ The installation location of the electromagnetic flowmeter should be as far away as possible from motors and pumps, as being too close to them may cause large fluctuations in the output of the electromagnetic flowmeter. ⑻ The medium under test must not contain large sediment particles or uneven fluid density. (Larger sediment particles can cause significant fluctuations in the measurements when they strike the detection electrodes; moreover, uneven fluid density can also lead to fluctuations in the readings.)

1. People upstairs really know how to make things up~~~~~~~~~~~~~~···· 2. The poster should specify what the diameter of the pipe is – whether it’s 5 mm, or 500 mm, or 2 meters or 5 meters in length; otherwise, the pipes might not be big enough

Please provide your company’s detailed information and operating conditions; perhaps I can help you design a solution, as I possess patented technologies

Please provide your company’s detailed information and operating conditions; perhaps I can help you design a solution, as I possess patented technologies

Basically, all flowmeters require that the pipe be filled completely during measurement. I am also somewhat interested in this topic, and I hope to get some brief introductions to actual application examples

If your requirements aren’t high, you can consider a water meter.

There are many methods of measurement: 1. In an open environment, use channel flow meters, ultrasonic devices, electromagnetic sensors, or various types of volume flow meters； 2. In a sealed environment, method 1 can also be considered, or vertical installation, necking, U-tubes, etc., can be used to fill the pipe over a certain length. Is it inspiring?

Depending on the operating conditions, appropriate measuring instruments can be used: contact-type open-channel partial-full flow meters (with sensors installed on the bottom supports), or non-contact level gauges (which require penetration of the pipe for installation)

Non-full-bore electromagnetic flowmeters can be used