Waist wheel flowmeter is a high-precision measuring instrument used for continuous or intermittent measurement of flow in pipelines. It has the characteristics of high accuracy, good reliability, light weight, long service life, and easy installation and use, and is a typical volumetric flowmeter.

Working principle of waist wheel flowmeter

The working principle of the waist wheel flowmeter is based on the rotational motion of the waist wheel in the fluid. Specifically, when the fluid passes through the flowmeter, under the action of differential pressure between the inlet and outlet fluids, the two waist wheels (resembling an 8-shaped shape) will rotate in the positive direction. These two waist wheels are controlled on their respective axes and are interconnected through gear connections. As the waist wheel rotates, the fluid is continuously divided into individual volume parts and discharged from the flow meter through the measuring chamber.

The amount of liquid flowing through each pair is four times the volume of the measuring chamber. The number of rotations is reduced through a sealed coupling and a reduction mechanism, and then transmitted to the counter to indicate the instantaneous flow rate and cumulative flow rate of the liquid.

Structural composition of waist wheel flowmeter

The waist wheel flowmeter mainly consists of the following parts:

Shell: protects internal measuring components and provides fluid channels.

Waist wheel rotor component: refers to the internal measuring element, which includes two waist wheels that mesh with each other.

Drive gear: coaxially installed with the waist wheel, used to drive the rotation of the waist wheel.

Counting indicator component: including counters, deceleration mechanisms, etc., used for measuring and displaying flow information.

Application fields of waist wheel flowmeter

The waist wheel flowmeter is widely used for flow measurement of large-diameter gas, liquid, and steam medium fluids in various industries’ industrial pipelines.

Especially in the petroleum and petrochemical industries, waist wheel flow meters are highly favored due to their high precision and reliability. They are mainly used for loading, shipping, oil sales measurement, quantitative delivery, raw material in and out measurement, fuel consumption, and other aspects on oil distribution platforms, docks, and water gas stations in oil depots.
In addition, it is also used for precise measurement of fluids such as petroleum and petroleum products, chemical solutions, etc. in sectors such as power, metallurgy, transportation, food processing, medicine, national defense, and commercial trade.

Waist wheel flow meter purchase points

The selection of waist flow meter should generally be considered from these four points, that is, according to the nature and flow of the measured flow body to determine the flow sampling device and the type and specifications of the measuring instrument, the selection should be fully in line with the instrument conditions provided by the process, considering the accuracy level and economy, and considering the safety of the measurement.
1, according to the nature of the measured flow body and flow conditions, to determine the type and specifications of the waist flow meter
The nature and flow of the fluid determine the form and specifications of the flowmeter. First of all, the selection should consider several key physical and chemical properties of the fluid: the state of the fluid (solid gas or liquid), the conductivity of the fluid, the chemical corrosion of the fluid, and the viscosity of the fluid. Secondly, it is necessary to fully understand the application range of various forms of flow meters. The physical and chemical properties of the fluid should be considered comprehensively in the selection. The fluid in the solid state is generally dust or block strong, and the flow meter selection is only three kinds of impulse flow meters, belt weights and track scales. There are more forms of flow meters for liquid and gaseous fluids, and general flow meters have series and models dedicated to gas measurement, such as the Coriolis force mass flowmeter we use has series models dedicated to gas measurement. If the liquid working condition is relatively poor, it is not exhaled corrosion, conductive, and with solid particles, in this case, it is best to choose an electromagnetic flowmeter. The flowmeters suitable for high viscosity mainly include elliptical gear flowmeters, waist wheel flowmeters, scraper flowmeters, target flowmeters, wedge flowmeters, etc., which are also determined according to accuracy, economic requirements and other actual working conditions. Finally, for the fluid with corrosion, we must pay attention to the choice of liquid material of the flow meter, for example, when the electromagnetic flow meter is used to measure hydrochloric acid liquid, the electrode must use tantalum electrode otherwise the electrode is easily corroded.
2, the choice of waist flow meter should fully consider the table conditions provided by the process.
First of all, consider the static pressure and temperature of the medium, the static pressure and temperature resistance of the flow meter is also an important part of ensuring the service life and accuracy of the instrument, the static pressure of the instrument is the degree of pressure resistance, it should be slightly greater than the working pressure of the measured medium, generally 1.25 times, to ensure that there is no leakage or accident.
The second is the choice of the range range, mainly the choice of the upper limit of the instrument scale. Select small, easy to overload, damage the instrument; The selection is too large, which hinders the accuracy of measurement. The national standard stipulates that the maximum flow does not exceed 95% of the full scale; The normal flow rate is 70% ~ 85% of the full scale; The minimum flow is not less than 30% of the full scale. The last more important instrument condition is the process pipe diameter, some flowmeters do not have a particularly large diameter, some large diameter flowmeters are very expensive, more suitable for large pipe diameter flow meters are flute uniform tube, insert vortex, insert turbine, electromagnetic flowmeter, venturi tube, ultrasonic flowmeter.

3. Consider the accuracy level and economy of the waist flowmeter
   Generally, where the accuracy requirements are relatively high, there are mainly raw material measurement into the factory and into the production device, the finished product measurement of the output device and the factory sales, the measurement of raw materials of the process formula, and the measurement of expensive substances. For the flow rate that is only a general reference in the production unit, cheap flowmeters such as glass rotors and metal rotors are usually selected with relatively low prices. The gas (air, nitrogen, vapor) in the production of public works usually uses vortex flowmeters, and all kinds of water mainly uses electromagnetic flowmeters. These two options are economical and can meet the accuracy requirements.