Capteur de débit Verabar

Principe de fonctionnement

When the fluid passes the verabar flow sensor, the upstream of the flow sensor will produce a high pressure distribution zone where the pressure is slightly higher than the static pressure of the pipeline. According to Bernoulli equation, the flow velocity will quicken when flowing through the verabar flow sensor, the downstream of the flow sensor will produce a low pressure distribution zone where the pressure is slightly lower than the static pressure of the pipeline. The downstream of the flow sensor will produce some vaccum when the fluid passes the flow sensor, the two sides of the flow sensor will appear swirls, the cross-section shape, surface roughness of averaging pitot-tube and the location of the low pressure tapping are critical factors. The stability and accuracy of low pressure signal depends on averaging pitot-tube’s accuracy and performance. The multiple pairs of pressure tapping holes on the verabar flow probe are distributed at high pressure zone and low pressure zone according to the certain rule, which can accurately detect the average differential pressure so that the flow velocity is measured accurately. 

The design features of verabar flow probe

The cross-sectional shape of verabar flow probe likes bullet (see figure 1), which can produce accurate pressure distribution and a stable fluid separation point. The low pressure tapping holes can produce stable differential pressure signal, and are intrinsic anti-blocking. The integrated structure can avoid signal leakage, in favour of keeping high accuracy in long term.

Product performance

● Accuracy: ± 1%
● Applicable pressure rating: 0 ~ 40 Mpa
● Applicable temperature: -50 ~ 550℃
● Max Range: depending on the flow probe’s strength
● Minimum Range : depending on the minimum pressure difference
> minimum pressure difference for gas: 25 pa;
> minimum pressure difference for liquid: 250 pa;
> minimum pressure difference for steam: 380 pa;
● Range ratio: > 10 : 1
● Applicable pipe size: DN50 ~ DN5000 mm ( Circular pipeline, Rectangular pipeline )
● Applicable process condition: fully filled with fluid, flow in one direction
The viscosity of the fluid (gas, steam or liquid): ≤10 Cp.

Structure diagram of commonly used verabar flow sensor

Insertion type, Model:  HGVB-500	Insertion type, Model:  HGVB-510

Diagram of straight pipe length at upstream / downstream as follow