Vortex flowmeter is an industrial flow measurement instrument designed based on the Karman vortex principle. It is suitable for flow monitoring of various media such as gas, liquid and steam. Its main principle is that when the fluid flows through a non-streamlined bluff body (such as a triangular prism or a trapezoidal prism), periodic vortices are generated alternately downstream. The vortex frequency is proportional to the flow velocity, and the flow rate is calculated.

I. Core characteristics and technical indicators

1. Working principle and structure

- When the fluid flows through the triangular prism vortex generator, Karman vortices are generated alternately on both sides. The relationship between the vortex frequency ( f ) and the flow velocity ( u ) is:

[ f = rac{Sr cdot u}{d} ]

Where ( Sr ) is the Strouhal number (Reynolds number ( Re_D ) is stable at 0.2 when ( 2 imes10^4 sim 7 imes10^6 )), and ( d ) is the characteristic width of the generator.

- Design without moving parts, reducing mechanical wear and high reliability.

2. Performance advantages

- High accuracy: measurement error ±0.2%～±1.5%, range ratio up to 1:10 (anti-vibration type can reach 20:1).

- Wide adaptability:

- Medium: gas (natural gas, compressed air), liquid (water, oil), steam (saturated/superheated steam).

- Working conditions: temperature range -200℃～+500℃, maximum pressure resistance 42MPa.

- Low maintenance: no pressure pipe, strong anti-pollution, good long-term stability.

3. Function expansion

- Temperature and pressure compensation: equipped with temperature and pressure sensors can directly output standard volume flow or mass flow (key function for steam measurement).

- Output signal: supports 4-20mA, pulse frequency, RS485 communication, compatible with automation system.

2. Application scenarios

- Industrial field: pipeline flow monitoring in petrochemical, electric power, and metallurgical industries (such as boiler steam and compressed air).

- Special requirements:

- High temperature environment: Split design (sensor and meter are separated) to cope with high temperature steam (≤450℃).

- Vibration environment: Anti-vibration type shields mechanical vibration interference through DSP signal processing.

3. Selection and installation points

1. Parameter matching

- Diameter range: DN15~DN3000mm or above, the reduced diameter design can expand the small flow measurement capability.

- Straight pipe section requirements: conventionally require 10D in front and 5D in the back (D is the pipe diameter), and the rectifier section is ≥15D when the reduced diameter is installed.

2. Limitations and countermeasures

- Vibration sensitivity: Avoid lateral mechanical vibration and give priority to anti-vibration models.

- Medium restrictions: solid particles or viscous fluids may cause the vortex stability to decrease.