1. Press measuring principle points Divided into the speed-meter and volumetric water meter. (1) Speed-meter: installed in a closed conduit, made a motion components, the flow velocity directly by it to gain momentum speed meter.Woltman water meter A typical speed-type water meter rotor type water meter, Lo Wing-meter. Rotor type water meter and there were a single stream and multi-jet water meter water meter. Lo Wing-meter (2) volumetric water meter: Installation in the pipeline, meter by some to be successively filled with fluid and a discharge capacity of a known volume of the fluid chamber and with the drive mechanism consisting of, or simply quantitative emission-meter. Volumetric water meter commonly used piston structure. 2. Measurement Rating Press version of the standard, can be divided into Class A table, Table B grade, C grade table, D scales. Level of measurement reflects the work flow meter range, especially under low flow measurement performance. In accordance with the order from low to high, generally divided into Class A table, Table B grade, C grade table, D scales, which measured performance reached the national standards set forth in metering grades A, B, C, D of the corresponding requirements. After the release of the new standard, the measurement method of classification become quite complex, mainly based on the parameters of the flow rate value and span ratio is determined. Simply put, the greater the range, the higher the level metering. 3. Press the nominal diameter points Divided into pre-paid Water Meters, small caliber water. According to nominal diameter is usually divided into small-caliber prepaid Water Meters and water meters. Nominal diameter 50mm and below the water meter is usually known as the small diameter water meter, nominal diameter 50mm water meter referred to above pre-paid water meters. These two meter meter meter sometimes referred to civil and industrial water table, and that the task was to be open from the case of connection difference meter, nominal 50mm and below the water meter with threaded connection, 50mm and above flange connection. But some special type of meter is also 40mm flange connection. 4. By Use Meter is divided into civil and industrial water table. 5. Press the mounting direction points Speed can be divided into water-meter and water meter installed Longjing vertical meter installation. Usually divided by the mounting direction Longjing water meter installation and meter vertical installation (also known as vertical list), which refers to the installation of flow parallel or perpendicular to the horizontal plane of the meter, the meter dial with "H" represents water Longjing fitted with a "V" for vertical installation. Volumetric water meter can be installed in any position does not affect accuracy.