In flow measurement, due to the complexity of the measurement medium, there are many kinds of measurement methods, so there are various flow sensors or throttles based on different measurement principles. According to the measurement methods and structures, they can be divided into: differential pressure type, float type, volumetric type, turbine type, electromagnetic type, vortex type, ultrasonic type, thermal type and Coriolis type. According to the installation modes, they can be divided into insertion type, closed pipeline type and open channel type. Weizhanba flow sensor manufactured with advanced technology is a flow sensor designed according to differential pressure working principle and insertion installation method. Its bullet-shaped cross section which fully conforms to the aerodynamic principle, high strength seamless integral structure, low-pressure hole design with its own anti-blocking ability and other technologies are in the leading position in the world.
II. Basic Principles and Structural Characteristics
2.1. Basic Principles
Like other differential pressure flow sensors, such as orifice plate flow sensor, Weizhanba follows Bernoulli equation:
It can be seen that: C is a constant, and K and DP must be determined in order to determine Q.
As shown in the figure: when the fluid flows through the sensor, a high-pressure distribution area forms in the front part of the sensor, and the high-pressure distribution pressure is higher than the static pressure of the pipeline. Furthermore, the velocity of the fluid flowing through the acceleration section of the sensor is accelerated, and a low-pressure distribution area forms in the rear part of the sensor, and the pressure in the low-pressure distribution area is lower than the static pressure of the pipeline. After the fluid flows through the sensor, a part of the vacuum area forms in the rear part of the sensor, and a vorticity occurs in the rear part of both sides of the sensor. The cross-section shape, roughness of the surface and the location of the pressure tap at low pressure are the key factors to determine the performance of Weizhanba flow sensor. The stabilization and accuracy of low pressure signals play a decisive role in the accuracy and performance of Weizhanba sensors. Weizhanba can accurately measure the average differential pressure produced by the average velocity of the fluid. Weizhanba flow sensor arranges many pairs of pressure orifices regularly in high and low pressure areas according to scientific calculation, which makes it possible to accurately and steadily detect the average flow velocity.
2.2. Structural Characteristics
a. Scientific Section Shape
The cross-section of the bullet head shape of Weizhanba receives the minimum traction force, which makes the separation point between the fluid and the sensor fixed.
b. High-Strength Structure
Weizhanba adopts a complete seamless integral structure, which avoids leakage between chambers caused by multi-chip structure of other sensors, ensures long-term accuracy and helps to improve the upper limit of measurement range of sensors.
c. Unique Anti-blocking Design
As shown in the figure, the low pressure tapping orifices are on both rear sides of the sensor and before the separation point between the sensor and the fluid. This not only avoids the influence of vortex on the low-pressure tapping orifices, but also avoids the blockage of the low-pressure tapping orifices. It fully realizes the self-anti-blockage and makes the low-pressure signal more stable and accurate.