Theory and Performance

BOOCCA Averaging pitot flow sensor work principle

BOOCCA Averaging pitot flow senor, complying with Bernoulli equation, share the same principle with other differential pressure flow sensors as follow:

Where：Q=volume flux of inner pipeline

K= flux coefficient

C= flux constant

DP=differential pressure value

Since C is constant, once calculate Q, you have to confirm K and DP first.

When fluid flows past the sensor, it not only generates a high pressure area which is higher than the static pressure of the pipeline in front of the sensor; but also produces a low pressure area in the rear of the sensor which is a little lower than the static pressure of the pipeline.

After the fluid flows past the sensor, a small vacuum space will be produced in the rear of the sensor and many vortices are generated in the rear two sides of the sensor too.

BOOCCA Averaging pitot flow sensor configuration feature

Scientific cross-section shape
Cross-section shape of bullet warhead reduces the pressure drag furthest and fixes the fluid separation point between fluid and probe.

Particular low pressure tapping location
Low pressure tapping ports are located on the rear two sides of sensor, forward to the fluid separation point and turbulent wake area. This avoids the infection by vortex shedding and clogging by dirty medium. It virtually realizes the anti-blocking ability and makes the signal more stable and accurate.

Special distribution of pressure tapping ports

Adopt special procedure to make the low pressure tapping ports not asymmetric to high pressure tapping ports in same cross-section. This increases the anti-impact strength greatly and reduces the possibility of crack when measuring high velocity and other special medium.

Structure of our sensor

General type: The structure of integrative metal cavity, made by one-off casting processing technology, increases the thickness of the probe body and enhances the strength of the sensor greatly.

Strengthened type: With special processing technology, drilling low and high pressure tapping ports and chambers in solid stainless steel, our flow sensors’ strength doubles and are more suitable for measuring high temperature, high pressure, high velocity and corrosive mediums. Furthermore this structure avoids the leakage and crack aroused by multi-piece structure or welding processing in other averaging pitot tube flow sensors. The entire body strength of flow sensor ensures the long-term accuracy and increases the upper limit of the range.

Roughness processing and grooves in contrary-flow surface

Making the frontal surface of the sensor with even roughness processing and grooves equals to a turbulent generator which ensures stable turbulent boundary layer on both sides of the sensor. The rough surface of the sensor applies the same principle as Golf balls surface. The separation angle between the flow direction and fluid separation points is 120 degree. but it is just around 80 degree if the surface is without roughness processing. Under this situation, the pressure drag is further larger than the former. Due to less pressure drag, the fluid can run a more accurate and stable track. The lower limit of flow velocity which our sensors can measure increases by 30% than other sensors at least.

Multi-group pressure tapping ports
The sensor goes through the entire section with multi-group tapping ports. The location of the tapping ports are derived from the calculation by area-integral method, and the signal measured is a real reflection of average velocity. Even if the straight pipe is not enough or fluid fluctuates largely, they can also get flow signal accurately and measure true flow rate. The accuracy of other flow sensors with single-point tapping is just ±10% in practical application.

High accuracy flow coefficient

The coefficient of our flow sensor retains a constant and linearity (different from that of orifice plate and venture tube which varies with the Reynolds value) and can not be influenced by Reynolds value or throttling area in a considerable range.