After the nominal diameter of the vortex flowmeter is selected, the large pressure loss of the vortex flowmeter should be calculated based on the diameter of the large flow meter and the fluid density under working conditions.
For gas and steam, the large pressure loss should be lower than the pressure loss value proposed by the customer. For liquids, especially volatile liquids, low back pressure without cavitation should be accounted for.
If the actual working pressure is higher than the low working pressure that does not produce cavitation, cavitation will not occur; if it is lower, cavitation may occur. To this end, the following measures must be taken:
(1) Increase the measuring pipe diameter appropriately, reduce the high flow rate, and reselect the meter;
(2) After increasing the pipe diameter, if a small flow cannot meet the requirements, it should adjust the flow range;
(3) Increase the working pressure in the pipeline;
(4) Choose a vortex flowmeter with a small damping coefficient.
Calculate whether the pressure loss has an impact on the processing pipeline, calculated by the following formula:
DP=1.2r × V2(Pa)
Where: DP: pressure loss (Pa)
r: density of the medium (Kg/m3)
V: Average flow velocity in the pipe (m/s)
When the measured medium is liquid, in order to prevent vaporization and cavitation, the liquid pressure of the sensor should meet the requirements of the following formula:
P≥2.6DP + 1.25P1 (Pa absolute pressure)
Where: DP: pressure loss value (Pa)
P1: The vapor pressure of the fluid (Pa absolute pressure)