LUB pulse vortex flowmeter

The LUB pulse vortex flowmeter is a new type of flowmeter developed based on the Karman vortex principle and has international advanced level. Due to its unique advantages that cannot be achieved by other flow meters, it has developed rapidly since the 1970s. According to relevant data, the proportion of smart vortex flow meters used in developed countries such as Japan, Europe, and America has increased significantly and has been widely applied in various fields. It will dominate in future flow meters and be an ideal substitute for orifice flow meters.
The LUB pulse vortex flowmeter is suitable for measuring the mass and volume flow rates of superheated steam, saturated steam, compressed air, and general gases, water, and liquids.
2、 Characteristics
The structure is simple and sturdy, with no movable parts, high reliability, and very reliable for long-term operation.
★ Easy to install and very convenient to maintain.
★ The detection sensor does not directly contact the measured medium, with stable performance and long lifespan.
The output is a pulse signal proportional to the flow rate, with no zero drift and high accuracy.
★ Wide measurement range, with a range ratio of up to
★ Less pressure loss, lower operating costs, and more energy-saving significance.
Within a certain Reynolds number range, the output signal frequency is not affected by the physical properties and composition changes of the fluid. The instrument coefficient is only related to the shape and size of the vortex generator, and there is no need to compensate when measuring the fluid volume flow rate. Generally, there is no need to recalibrate the instrument coefficient after replacing accessories.
★ Wide application range, capable of measuring the flow rates of steam, gas, and liquid

3、 Working principle
When a LUB pulse type vortex flowmeter is vertically inserted into a measuring tube, the fluid alternately generates regular vortices on both sides of the column (as shown in the figure below), which is called a Karman vortex street. The release frequency of Karman vortex street is related to the flow velocity of the fluid and the width of the column, which can be expressed by the following equation: f=St · v/d
In the formula: the release frequency of f-Karman vortex street
St coefficient (also known as Strouhal number)
V-flow rate
Width of D-pillar
The release frequency f of the Karman vortex street is directly proportional to the flow velocity v, so the instantaneous flow rate can be calculated by measuring the release frequency of the Karman vortex street.
Strouhal number is an important coefficient of vortex flowmeter. In the flat part of the curve where St ≈ 0.17, the release frequency of the vortex is proportional to the flow velocity, so the detection frequency f can be used to obtain the flow velocity v, and the volume flow rate can be calculated from v.
The vortex release frequency of the LUB pulse type vortex flowmeter is detected by the piezoelectric element inside it, which alternately acts on the stress of the detection sensor (probe) by vortices.