Vortex flow meter
Thread Content
When the valve is opened to more than 50%, the flow rate reading exceeds the range; when it is opened to more than 90%, the flow rate starts to drop to around 60%. The valve was checked and found to be in good condition, and the same phenomenon occurs when using a valve bypass to adjust the flow rate (nitrogen is present in the pipeline; currently it is being vented, and the high pressure difference causes the reading to exceed the range – under normal operating conditions this does not happen)
It seems that only when the valve opening is below 90% is it considered false flow; it makes more sense that false signals are generated when the valve is not fully open.
Either it’s the increased vibration in the pipeline due to higher traffic volume that causes false signals
It seems that this operating condition is not suitable for vortex flow meters; why not use orifice plates or Venturi meters instead?
What type of flow meter is used here? Is it a differential pressure flow meter?
The flow rate is too high; check to see if that’s the case
Whether to install the valve before or after the meter is a key issue; if there is a control valve upstream of the vortex flowmeter, a straight pipe section 50 times the diameter of the pipe is required between the control valve and the flowmeter. Let’s see if this is the case with you.
If the flow meter is chosen to be too small, all vortex street indicators will show a reverse trend: that is, as the flow rate exceeds the meter’s maximum measurement capacity, the flow rate continues to increase yet the indication from the vortex street sensor decreases.
This phenomenon may be caused by changes in pressure and high flow rates in the pipes; take a look at the selection options