Vortex FlowmeterYK-LUGB

Suitable Medium

Steam and compressed air, coal gas and other medium and high velocity gases

Unsuitable Media

Low flow rate liquid gas

The YK-LUGB vortex flowmeter measures the volume flow of gas, steam or liquid, the volume flow of standard conditions or the volume flow of mass flow according to the Karman vortex principle. It can also be used as a flow transmitter in applications and automation control systems. The instrument uses advanced differential technology, with isolation, shielding, filtering and other measures to overcome the problems of poor vibration resistance and small signal fuzziness of similar products, and adopts special sensor packaging technology and protective measures to ensure product reliability . The product has two forms: basic type and composite type. The basic type measures a single flow signal, and the composite type can uniformly measure temperature, pressure, and flow. Each form has an integral and split structure to suit different installation environments.



If a non-streamline vortex generator (bluff body) is installed in the fluid, two rows of regular vortices are alternately generated from both sides of the vortex generator. This type of vortex is called the Karman vortex street, as shown in Figure (1).


Figure (1)

   vortex array is arranged asymmetrically downstream of the vortex generator. Suppose the frequency of the vortex is f, the average velocity of the measured medium is V, the width of the front face of the vortex generator is d, and the diameter of the surface body is D. According to the principle of Karman vortex street, the following relationship is expressed:


   Where: f-Carman vortex frequency generated on one side of the generator

   St-Strohal number (dimensionless number)

  V-The average flow velocity of the fluid

  D-The width of the vortex generator

   It can be seen that the instantaneous flow can be calculated by measuring the separation frequency of the Karman vortex street. Among them, the Stroghal number (St) is a dimensionless unknown number,

   Figure (2) shows the relationship between St. Rohal number (St) and Reynolds number (Re).


Figure II)

   In the straight part of the curve table with St=0.17, the release frequency of the vortex is proportional to the flow velocity, which is the measurement range of the vortex flow sensor. As long as the frequency f is detected, the flow velocity of the fluid in the tube can be obtained, and the volume flow rate can be obtained from the flow velocity V. The ratio of the measured pulse number to the volume is called the meter constant (K), see formula (2)


   Where: K = instrument constant (1/m³).

  N = number of pulses

  Q=Volume flow rate (m³)



    1. No moving parts, long-term stability, simple structure, easy to install and maintain

    2. The output of the sensor is pulse frequency, its frequency is linear with the actual flow of the fluid being measured, the zero point has no drift, the performance is very stable, the structure is diverse, and there are pipeline plug-in flow sensors.

    3. The accuracy is high, usually the measurement accuracy of liquid is ±1%; the measurement accuracy of gas is ±1.5%

    4. Wide measuring range, up to 1:20 within the Reynolds number of 2×10⁴~7×10⁶

    5. The pressure loss is small (about 1/4~1/2 of the orifice flow meter), which is an energy-saving flow meter

    6. The installation method is flexible, according to the different process pipelines on site, it can be installed horizontally, vertically and inclinedly at different angles

    7. It adopts noise cancellation circuit and anti-vibration sensor head, which has certain anti-environmental vibration performance

    8. Using ultra-low power consumption single-chip microcomputer technology, one 3V10AH lithium battery can be used for more than 5 years

    9. The non-linearity of the meter coefficient is corrected by the software to improve the measurement accuracy

    10. Use EEPROM to protect the accumulated flow from power failure, and the protection time is more than 10 years


    Vortex flowmeters can be widely used in large, medium and small pipelines for water supply and drainage, industrial circulation, sewage treatment, oil and chemical reagents, as well as compressed air, saturated and superheated steam, natural gas and various medium flow measurement.


Executive standard

Vortex flow sensor (JB/T9249-1999)

Nominal diameter


15, 25, 40, 50, 65, 80, 100, 125, 150, 200, 250, 300, (200~1000 plug-in type)

Nominal pressure 


1.6MPa, 2.5Mpa, 4.0Mpa (others can be customized)

Conditions of Use

Medium temperature: -40℃-+250℃, -40℃-+350℃

Ambient temperature: -20℃-+60℃

Relative humidity: 5%-90%

Atmospheric pressure: 86kpa-106kpa

Output signal function

Pulse signal, 4-20mA

Communication output function

RS485 communication output, HART protocol, etc.


Pipeline type: liquid ±1%; gas or steam ±1.5%, ±1%

Plug-in type: liquid ±2%; gas or steam ±2.5%



Supply voltage

A. External power supply: 24VDC±15%, ripple ≤±5%, suitable for 4-20mA output, pulse output, RS485, etc.

B. Internal power supply: 1 set of 3.0V10AH lithium battery, the battery voltage is normal when the battery voltage is 2.0-3.0V

output signal

Square wave pulse (not including battery-powered type): high level≥5V, low level≤1V; current: 4~20mA

Pressure loss coefficient

Comply with JB/T9249 standard  Cd≤2.4

Explosion-proof mark

Intrinsically safe type: ExiaⅡ CT2-T5, flameproof type: ExdⅡCT2-T5

Protection level

Ordinary IP65

Applicable medium

Gas, liquid, steam

Transmission distance

Three-wire pulse output type: ≤300m, two-wire standard current output type (4~20mA): load resistance ≤750Ω

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