How to choose the installation location of ultrasonic flowmeter

　　In recent years, a large number of new varieties of ultrasonic flowmeter have emerged, which are increasingly widely used in petrochemical, pharmaceutical, environmental protection and other fields, and become one of the main varieties of new flowmeter. It can effectively solve the problem of non bubble and corrosive medium under the condition of high pressure and non corrosive. For the clamped ultrasonic flowmeter, because the pipe size has nothing to do with the price, it is widely used in large pipe and large flow measurement.

　　Principle and measurement method of ultrasonic flowmeter

　　Ultrasonic flowmeter is based on the information of fluid velocity when ultrasonic wave propagates in the flowing fluid. For example, the propagation velocity of downstream and countercurrent is different due to the superposition of fluid velocity. Therefore, the flow rate of the fluid can be detected through the received ultrasonic wave, which can be converted into flow. Ultrasonic flowmeter consists of ultrasonic transducer, electronic circuit and flow display and accumulation system. The ultrasonic transmitting transducer converts electric energy into ultrasonic energy and transmits it into the measured fluid. The ultrasonic signal received by the receiver is amplified by the electronic circuit and converted into an electrical signal representing the flow, which is supplied to the display and integration instrument for display and integration. In this way, the flow detection and display are realized.

　　When selecting the installation point of ultrasonic flowmeter, the following factors must be considered: full pipe, steady flow, scaling, temperature, pressure, interference, etc.

　　1. Full pipe: select the pipe section filled with fluid with uniform and dense material and easy for ultrasonic transmission, such as vertical pipe section (fluid flowing upward) or horizontal pipe section.

　　2. Steady flow: the installation distance shall be a straight pipe section with an upstream diameter greater than 10 times the straight pipe diameter and a downstream diameter greater than 5 times the straight pipe diameter without any elbow, reducer and other uniform components. The installation point shall be far away from the interference sources such as valves, pumps, high-voltage electricity and frequency converters.

　　3. Avoid installation on Zui high points of the piping system or vertical pipes with free outlets (fluid flowing downward)

　　4. For open or half full pipe, the flowmeter shall be installed at the U-shaped pipe section.

　　5. The temperature and pressure at the mounting point shall be within the working range of the sensor.

　　6. Fully consider the scaling condition on the inner wall of the pipe: Although the pipe without scaling is selected for installation, if it cannot be met, the scaling can be considered as the lining for better measurement accuracy

　　7. The two sensors must be installed in the horizontal direction of the pipe shaft surface and within ± 45 ° of the horizontal position of the shaft surface, so as to prevent the phenomenon of insufficient pipe on the upper part, bubble or precipitation on the lower part from affecting the normal measurement of the sensor. If it cannot be installed horizontally and symmetrically due to the space limitation of the installation site, the sensor can be installed vertically or obliquely under the condition of ensuring that there are no bubbles in the upper part of the pipe.

　　Problems easily neglected in the selection of ultrasonic flowmeter

　　1、 Ultrasonic flowmeter can measure various media such as water, gas and oil, and its application field is very broad. The hand-held ultrasonic flowmeter probe is directly installed on the outer wall of the pipeline, which is not affected by the medium. The installation is simple and fast. There is no need to cut off the process pipeline, stop the process, and have no pressure loss. It is very suitable for measuring corrosive medium and ultrapure medium. Its pressure loss is almost zero, and its convenience and economy of measuring flow are the best.

　　2、 In dangerous occasions, explosion-proof ultrasonic flowmeter shall be selected.

　　3、 The pipeline ultrasonic flowmeter uses the method of ultrasonic transmission time to measure the flow rate without moving parts. The ultrasonic wave is transmitted in the direction of water flow in the measuring pipe and then returned. The flow velocity is calculated by the time difference between the two ultrasonic waves. The ultrasonic flowmeter is insensitive to medium, temperature, conductivity and pollutants.