■What liquids cannot be measured with electromagnetic methods?! Electromagnetic methods can only measure conductive liquids due to their principle. They cannot measure non-conductive substances such as gases, oils, or ultra-pure water. The extent to which liquids with low conductivity can be measured varies depending on the detection method and model. ■What happens if the pipe is not full? Electromagnetic methods are designed for fully filled pipelines, and if the detector is not full or if there are air bubbles, it can cause unstable readings. If there are bends or valves upstream, a straight pipe section of at least 5 to 10 times the pipe's diameter (D) is required. It is important to choose a position where the pipe is always full during installation. ■Differences in pressure loss Pressure loss does not occur with electromagnetic and ultrasonic methods, but it can be significant with differential pressure methods like orifices. However, in the case of time-difference ultrasonic methods, measurements may not be possible if there are air bubbles or debris in the ultrasonic path. ■Is there a method that measures by mass? The Coriolis method measures mass rather than volume. It determines mass flow rate from the twisting that occurs in the pipe and can simultaneously measure density. On the downside, it is expensive and has a significant pressure loss.

■How to Measure in Drainage Channels? In channels that do not reach full capacity, methods such as triangular weirs or partial flumes can be established to determine flow rates from the water level upstream. This is because if the shape and dimensions of the weir or flume are fixed, a consistent relationship between water level and flow rate is established. ■Measuring Drainage Volume under Total Quantity Regulation In facilities where total quantity regulation applies, the pollution load of discharged water is measured and recorded. The Enforcement Regulations of the Water Pollution Control Act stipulate that the volume of discharged water, along with the pollution status, should be measured to determine the daily pollution load. ■Are Drainage Flow Meters Subject to Calibration?! The Enforcement Order of the Measurement Act designates drainage flow meters, drainage totalizers, and water meters with a diameter of 350mm or less as specific measuring instruments. When using specific measuring instruments for transactions or certifications, it is necessary to use those that have calibration certification marks. ■Be Cautious of Pulsation in Chemical Injection! Reciprocating positive displacement pumps generate pulsation, which can lead to inaccurate measurements with certain flow meters. There are flow meters designed to accommodate pulsation for chemical injection. Our company offers consultations on chemical injection equipment and water quality measurement devices. Please feel free to reach out to us.