Precautions when measuring sewage with non full pipe flowmeter

Release time:


  Precautions when measuring sewage with non full pipe flowmeter

  Non full tube flowmeter is widely used in sewage, fluorine chemical industry, production water, tap water industry, medicine, steel and so on. Because of its principle, it can only measure conductive liquids. When ordering, you can't order according to the original pipe diameter. It's best to determine the instrument diameter according to your actual flow. Like other flowmeters, non full pipe flowmeters also have requirements for straight pipes before and after installation, but they have lower requirements than other types of flowmeters. Although the non full tube flowmeter has good reliability and will not be damaged in general, due to its principle, the electrode surface of the sensor has been in contact with the liquid for a long time, and the electrode surface is easy to be polluted. Therefore, in general, if the customer has the conditions to disassemble the non full tube flowmeter, it is recommended to disassemble and clean the electrode once a year to a year and a half to ensure the measurement accuracy of the whole flowmeter.

  How to install non full tube flowmeter? In fact, as long as the installation is in accordance with the requirements of the manual.

  (1) The installation location and position shall be determined as required, but the electrode shaft must be horizontal.

  (2) Non full tube flowmeter must be well grounded to reduce the introduction of interference signal. There are two requirements for grounding. One is that the grounding wire of the sensor and converter must be connected with the measured medium, and the other is to take the earth as the zero potential.

  (3) In order to avoid interfering with the signal, the signal line between the sensor and the converter must adopt a special shielding conductor and be threaded separately in the grounding steel pipe. The signal cable and power cable cannot be placed in the same steel pipe.

  (4) When the flowmeter is installed underground, an instrument well needs to be set.

  (5) The unstable medium flow has no effect on the measured value, so the installation of flow meter has no special requirements for the front and rear straight pipe sections. The maintenance workload of the non full tube flowmeter is very small, but after running for a period of time, the sewage often accumulates an adhesion layer on the inner wall of the sensor, which should be removed in time. Otherwise, when the conductivity of the adhesion layer is inconsistent with the fluid conductivity, the electrode circuit will be open or short circuited, and the instrument cannot work normally. Therefore, for the measurement of industrial sewage, it is best to ensure that the fluid flow rate is more than 3 ~ 4m / s when selecting the flowmeter, which can play the role of self cleaning the pipeline and preventing the deposition of adhesion layer to a certain extent. In terms of appearance, the non full tube flowmeter is no different from the ordinary electromagnetic flowmeter. It also has the advantages of no influence of fluid parameters, no movable parts, no flow blocking parts, minimal pressure loss, no measurement lag, linear output and wide range. The measuring channel of the non full tube flowmeter is a smooth straight tube without blocking, so it is especially suitable for measuring liquid-solid two-phase fluids containing solid particles, such as pulp, mud, sewage, etc. The installation of non full pipe electromagnetic flowmeter will not raise the water level upstream, so it will not bring head loss. The structure of the non full tube flowmeter is simple, there is no problem of shutdown maintenance, and the lining of the flow tube has good wear resistance and corrosion resistance. The liquid level in the pipeline that can be measured by the non full pipe flowmeter is 10% - 100% of the section. It can maintain good measurement accuracy under the conditions of non full pipe and full pipe flow, which is a breakthrough in the research and development of electromagnetic flowmeter. In the non full tube measurement, the liquid level in the measuring tube usually fluctuates. These fluctuations, especially when it is on the horizontal plane of the electrode, can lead to the fluctuation of the sensor output signal. The fuzzy logic and special filter circuit contained in the liquid level measurement system solve this problem well, which ensures that the flowmeter still has stable measurement value display in the case of unstable medium flow or change of flow distribution. It can be seen that with the continuous increase of environmental treatment, the application prospect of non full pipe flowmeter in sewage measurement is very broad.