[Vortex Flowmeters] The straight pipe length from the valve is 20D or longer. Is there any difference depending on the type of valve or how it is used?

The vortex flowmeter should be installed upstream of the valve to prevent the influence of swirling flow caused by the valve. If the vortex flowmeter is installed downstream of the valve, the straight pipe length should be at least 20D upstream and 5D downstream, regardless of the valve type.

Please refer to the tutorial "Required Straight Pipe Lengths for Vortex Flowmeters".