，主要用于工业管道流体介质的流量测量，如气体、液体、蒸汽等多种介质。 LUGB series vortex flow transmitters are mainly used for the flow measurement of fluid media in industrial pipelines, such as gas, liquid, steam and other media. It is characterized by small pressure loss, large measuring range and high accuracy. It is hardly affected by fluid density, pressure, temperature, viscosity and other parameters when measuring volume flow under working conditions. No moving mechanical parts, so high reliability and low maintenance. The meter constant can be stable for a long time. The plug-in instrument is installed at the insertion port of the pipeline, and the ball valve can be continuously loaded and unloaded. For regular cleaning and maintenance while operating in dirty media. This instrument uses a piezoelectric stress sensor with high reliability and can work in the operating temperature range of -20 ° C to + 250 ° C. It has analog standard signals and digital pulse signal output. It is easy to be used with digital systems such as computers. It is a relatively advanced and ideal flow meter.
Vortex Flow Transmitter Features
The output signal is not affected by the temperature, pressure, and density components of the fluid, and is proportional to the fluid flow rate.
The sensing element is not in contact with the medium and has high reliability.
No moving parts, simple and firm structure.
Wide measuring range and high accuracy.
Small pressure loss and significant energy saving.
工作原理 Working principle of vortex flow transmitter
When a columnar resistance body is inserted vertically in the fluid, vortices are alternately generated on both sides, and as the fluid moves downstream, a vortex train is formed, which is called a Kaman vortex street, as shown in Figure 1. The resistance body that generates the vortex street is called a vortex generator. The experiment proves that the frequency of the vortex is proportional to the flow velocity and can be expressed by the following formula:
The experiment proves that when the distance h between two rows of vortices and the distance L between two vortices in the same row satisfy the formula L / h = 0.281, the asymmetric vortex train can maintain a stable state. When the Reynolds number of the fluid is in the range of 5000-150,000, Sr is basically unchanged, so when d and Sr are constant values, the frequency f of the vortex generator is proportional to the average flow velocity of the fluid, that is, proportional to the volume flow rate Q. It has nothing to do with parameters such as pressure, temperature and density.
When a vortex is generated on both sides of the cylinder, the sensor is induced by an alternating lift perpendicular to the flow direction. The change frequency of the lift is the vortex frequency. The sensor sends the signal to the converter to amplify and shape it to obtain a pulse proportional to the flow rate. The signal is directly output or converted into a 4-20mA standard signal output. The relationship between the flow rate Q and the frequency f is as follows: