When using a precessing vortex flow meter to accurately measure the total flow, the following issues should be considered:
1. The pipeline flow resistance should be 2×104～7×106. If it exceeds this range, the index of the flowmeter, that is, the Stroha number is not a parameter, and the accuracy reduces.
2. The flow rate of medium must be within the required range, because the precession vortex flow meter measures the total flow based on the frequency. Therefore, the flow rate of medium must be limited, and different mediums have different flow rates.
(1) When medium is vapor, max velocity should be lower than 60 m/s
(2) When medium is steam, it should be lower than 70 m/s
(3) The low-limit flow rate is calculated from the relative curve diagram or formula calculation of the instrument panel based on the viscosity and relative density
(4) In addition, the working pressure and temperature of medium must be within the required range.
The characteristics of the precession vortex flow meter.
1. Key advantages
(1) The calibration index of the meter will not be harmed by the fluid working pressure, temperature, relative density, viscosity and composition change, and there is no need to re-calibrate when disassembling and replacing the inspection components;
(2) The measuring range ratio is large, the liquid reaches 1:15, and the vapor reaches 1:30;
(3) The pipeline specification is almost unlimited, 25-2700 Mm;
(4) Work pressure damage is very small;
(5) Immediately output the electronic signal linearly related to the total flow, with high precision, reaching ±1%;
(6) The installation is simple, the maintenance amount is small, and the common faults are very few.
2. Key defects
(1) The variable flow rate and pulsating beverage flow will endanger the measurement accuracy. There are regulations for the connection section on the upper, middle and lower reaches of the instrument panel (three d upstream and downstream, 1D in the middle and downstream). If necessary, the rectifier should be modified on the upstream and downstream sides;
(2) When the inspection components are dirty, the measurement accuracy will be compromised. The total flow components and the inspection holes should be cleaned with vehicle gasoline, gasoline, ethanol, etc. on time.
3. Installation of precession vortex flowmeter
1. When the flowmeter is installed, it is forbidden to carry out arc welding immediately at the flange of its import and export trade to prevent burning the internal parts of the flowmeter.
2. Try to clean up the newly installed or repaired pipeline, and install the flowmeter after removing the dirt in the pipeline.
3. The flowmeter should be installed in a site that is conducive to maintenance, without the influence of strong magnetic fields, and without obvious damping vibration and radiant heat hazards;
4. The flowmeter is not suitable for places where the total flow is often interrupted and there are obvious pulsating beverage flows or working pressure pulsating beverages;
5. When the flowmeter is installed outdoors, there must be a cover at the upper end to prevent the infiltration of precipitation and sun exposure from harming the life of the flowmeter;
6. The flowmeter can be installed at any angle of view, and the inflow of fluid should be consistent with the inflow marked on the flowmeter;
7. At the pipeline construction site, consideration should be given to installing products or metal bellows to prevent serious pull or rupture of the flowmeter;
8. The flowmeter should be installed coaxially with the pipeline output, and prevent the sealing piece and unsalted butter from entering the inner wall of the pipeline;
9. When using an external switching power supply, the flowmeter must have a reliable grounding device. The grounding wire cannot be used with the weak current system software. During pipeline installation or maintenance, the grounding wire of the arc welding system software cannot be overlapped with the flowmeter steel bar. .