Measurement issues of intermittent feed flow meters
Thread Content
I would like to ask everyone: Regarding the measurement issues with intermittent feed flow meters, these meters are installed vertically. When the pump stops feeding, the liquid flows back. Although check valves are in place, impurities sometimes accumulate inside them, which still allows the liquid to flow back. Remote control makes it unlikely to use manual valves. Are there any other good methods to prevent this backflow? Thank you!
Firstly, the flow meter must have the capability to measure two-way flow; when set up to measure two-way flow, the total amount of material transferred is simply the forward flow minus the reverse flow. If the problem with the check valve cannot be resolved, then make adjustments to the flow meter. If such a function doesn’t exist, then find a way to prevent backflow.
Add a pneumatic shut-off valve after the flow meter; the valve opens when the pump starts and closes when the pump stops
Both electromagnetic and ultrasonic methods generally have the capability for two-way measurement; if these two options are being considered, check the she’ding parameters and make adjustments accordingly
The flow meter has the capability for two-way measurement, but there is another issue: when the 4–20 MA signal from the flow meter is fed into the DCS for accumulation, both the positive and negative flow rates appear the same on the DCS, making it impossible to distinguish between them. This is unless the flow meter is connected to the DCS in communication mode, allowing the DCS to directly obtain the net cumulative flow rate from the flow meter.
Add a pneumatic on/off valve for isolation, or use a needle-check valve in series.
Hello! I’m not very familiar with the structure of series-connected needle check valves. Can such valves effectively prevent reverse internal leakage? Thank you!
Try using a swing check valve.