How to choose flow meters in water industry

1. The process pipeline has a large diameter, which requires the flow meter to have as little pressure loss as possible. Generally, the method of local pipe reduction is not used to increase the flow rate;

2. For newly designed and installed pipelines, an appropriate flow rate is generally selected. Because the flow rate of the fluid is too low, the diameter of the flow meter is large, and the corresponding instrument investment increases. If the flow rate of the fluid is too high, it will cause a large loss of power pressure and increase the operating cost, which is not economical, but when selecting the model, a flow margin should be left for future expansion;

3. Due to the low flow rate of the fluid, the dirt in the fluid, sludge and scale will appear after a long period of operation, which is very easy to deposit on the inner wall of the pipeline and the electrode. The cleaning of the contact part between the instrument and the fluid should be considered in the engineering design; if it cannot be cleaned and an electromagnetic flow meter is selected, a scraper electrode can be used;

4. The measurement range of the instrument is required to be large. The flow rate of some water at night and during the day, in winter and summer is very different, up to several times. Therefore, the flow meter for these waters requires a particularly large range;

5. The protection level of the instrument is required to be high. Most large-diameter pipelines are laid underground to save investment and space. In the north, it is also necessary for antifreeze. Therefore, split flow sensors are mostly installed in instrument wells. Rainwater, well wall leakage and pipeline leakage often cause the water level in the well to rise and submerge the flow sensor. Therefore, this situation should be estimated during the design, and a submersible flow sensor, such as an IP68 protection level, should be selected. At the same time, the instrument well should be waterproofed.

6. Since the verification of large-diameter flow meters is often difficult to disassemble, transport and install, and the process does not allow interruption of flow and shutdown, it is hoped that the meter can be dry-calibrated online.