1、 Product features and main technical parameters
● Simple structure with no movable parts inside
The detection component does not come into contact with the detected medium
● Stable performance and long service life
The same sensor can measure liquids, gases, and vapors
Within the specified Reynolds number, the instrument coefficient is not affected by changes in fluid temperature, pressure, viscosity, and composition.
This instrument is suitable for the Reynolds number range:
2X104-7X106 (DN25-DN100) 4X104-7X106 (DN150-- DN300)
The ordinary type of product can achieve instantaneous and cumulative display
Temperature and pressure compensation type can automatically calculate and display standard flow rate and operating flow rate, temperature and pressure parameters, etc
The steam temperature and pressure compensation type can calculate and display parameters such as mass flow rate, temperature, pressure, density, etc. by itself
Work pressure: 1.6-4.0MPa
● Medium temperature: -40 ℃~+200 (integrated type) -40 ℃~+300 (separated type)
● Environmental temperature:- 25℃～+60℃
Relative humidity: 5% to 95%
● Atmospheric pressure: 86-106KPa
Type of fluid being tested: liquid, gas, vapor
Accuracy: Level 1, Level 1.5
● Output signal:
Analog output: (fully isolated two-wire system 4-20mA) remote transmission distance 1000m
Pulse output: (fully isolated three wire system VH -3V) remote transmission distance 500m
485 output: (fully isolated 485 output Modbus protocol, can be directly connected to PLC and computer configuration software, no need to write drivers, can carry 256 loads) Remote transmission distance of 1200m
Wireless output: (fully isolated wireless output Modbus protocol, can be directly connected to PLC and computer configuration software, no need to write drivers, can carry 256 loads) Remote transmission distance 4500m

2、 Working principle
When a non streamlined cylinder (vortex generator) with a vertical flow direction is inserted into a fluid, two rows of internally rotating vortex columns are alternately generated on its downstream side, called "Karman vortex columns".
Within a certain range of Reynolds numbers, the frequency of vortex release f is related to the fluid velocity V and the width of the vortex generator face d as follows:
　　2
F=st * v/d (1)
In the formula: St： Strouhal number (infinite steel constant)
From the above equation, it can be seen that as long as the frequency f of the vortex is detected, the flow velocity V of the fluid can be measured, thereby achieving the measurement of the flow rate Q of the fluid in the pipeline
V=f * d/St (2)
Q=v * S=f * d/St * S (3)
In the formula: cross-sectional area of S pipeline
D/St * S is a constant, let 1/K=d/St * S, then
Q=f/k (4)
In the formula, the instrument coefficient of K-flowmeter (pulse number/liter) is usually calculated using actual flow tests.
Due to the alternating generation of vortices on both sides of the vortex generator, the vortex force acts on the detection body, causing it to generate alternating stress. This stress acts on the piezoelectric element, generating an alternating charge signal with the same frequency as the vortex. After processing by a converter, it outputs a pulse signal with the same frequency as the vortex or a 4-20mADC signal proportional to the flow rate.