属于均速管流量范畴里面，它的基本结构是中间一根中空的金属管，在迎向流体流动的方向有钻有成对的测压孔，在现场使用的时候，阿牛巴流量计垂直于工艺管道轴线插入安装，当流体通过时，能起到标准孔板节流产生压差的效果。 Annubar flowmeter belongs to the category of uniform velocity tube flow. Its basic structure is a hollow metal tube in the middle. There are pairs of pressure measuring holes drilled in the direction facing the fluid flow. The Nubar flowmeter is inserted and installed perpendicular to the process pipeline axis, and when the fluid passes through, it can play the effect of standard orifice plate throttling to produce a pressure difference.
Annubar flowmeter distinguishes other pipeline flowmeters:
1. Simple installation. The installation of Annubar flowmeter is very simple. Just open a small hole in the process pipe, weld the joint body, then insert the flowmeter and screw it down. 2. The length of the straight pipe section is low. When Annubar flowmeter is installed on site, the straight pipe section before and after is only 1/3 of the throttling device such as standard orifice plate, which greatly reduces the investment on site process pipeline. 在工艺系统不停产的情况下拆除和安装，大大减少了仪表维护人员的工作量。 3. It can be disassembled and installed without stopping. This feature is not available in other pipeline flow meters. Annubar flowmeter is removed and installed without stopping the process system, which greatly reduces the workload of instrument maintenance personnel. 4. Significant energy-saving effect. After measurement, the pressure loss of Annubar flowmeter is very small. In the same situation, it is only less than 5% of the throttling devices such as standard orifice plates. Therefore, using Annubar flowmeter greatly reduces the power Consumption, with significant energy saving effect
安装 Annubar flowmeter installation
1. The mechanical size of Annubar flowmeter is tailored according to the size of the installed pipeline, and its measurement range is calculated and calibrated according to the flow data provided by the process. When selecting, be sure to provide the manufacturer with the correct flow data and pipe size. The pipe size includes the outer diameter and wall thickness. The flow meter must be installed in accordance with the standard to ensure that the measurement error of the entire measurement system is within the allowable range.
2. The front pipe of the detection rod sensor must ensure a straight pipe length of 7D-9D (this data varies from manufacturer to manufacturer, all from 3D to 30D) in order to make the liquid, gas (vapor) body in the large pipeline. The flow velocity should be distributed on the axis as symmetrically as possible. Only in this way, the measured flow velocity can be used to estimate the flow through the entire cross-section. Otherwise, the flow velocity distribution of the liquid and gas (steam) in the large pipeline will be complicated, and the fluctuation of the flow coefficient K will be large, which cannot guarantee the measurement. Accuracy. However, it is impossible to guarantee a long straight pipe in the actual process design.
3. The total pressure hole of the detection rod sensor must face the flow direction, and the deviation is not greater than 7 °. The detection rod should be inserted to the end along the diameter of the pipeline. For vertical pipelines, the detection rod can be installed at any position along the pipeline's circumference 360 ° along the pipeline horizontal plane. The high and low impulse pipes should be on the same plane; for horizontal pipelines, they should be installed at an oblique downward direction during measurement.
Whether the flowmeter can accurately measure and its service life is directly related to whether it is installed correctly. Once the flowmeter is installed, system errors that affect the accuracy of the flowmeter will always be accompanied and it is difficult to eliminate from the software. The correct installation method can refer to the installation specification of the differential pressure flowmeter, which is not repeated here.
4. The detection rod is fixed on the pipe through the joint. After the joint is tightened, the detection rod must not be loose or leak. Pipe vibration and fluid shock will loosen the fixed head of the detection rod, cause the detection rod to break and damage, affect accurate measurement and cause economic loss.