Category type water meter
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.
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.
(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.irrigation water meter
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.
6. Press the temperature of the medium min
Into cold water and hot water.
Press medium temperature can be divided into cold water and hot water, the water temperature is 30 ℃ dividing lines
(1) cold water: the lower limit of the medium temperature is 0 ℃, the maximum temperature of 30 ℃ of water meter.
(2) hot water: the media minimum temperature is 30 ℃, the upper limit is 90 ℃ or 130 ℃ or 180 ℃ water meter.
It requires each country are slightly different, the upper limit of water table in some countries up to 50 degrees Celsius.
7. Press the pressure medium points
Divided into ordinary water meter and pressure meter.
The pressing force can be divided into general use and high pressure water meter water meter. In China, ordinary water are generally nominal pressure 1MPa. High pressure water meter is the maximum working pressure exceeds 1MPa types of water, underground water is mainly used for measuring the oil flow through the pipeline and other industrial water.
8. Classification meter
Press the counter is immersed in water to distinguish, it is divided into a wet meter, dry type water meter, water meter liquid seal.irrigation water meter
(1) Wet meter: meter counter is immersed in water, the watch glass to withstand water pressure sensor and the counter drive gear linkage, water quality after a period of time can affect the clarity of the water meter readings.
(2) dry water meter: meter counter is not immersed in water, the structure of the sensor and the counter chamber is isolated from pressure water meter glass table, sensors and counter drive ships with a magnet drive.
(3) liquid seal meter: digital meter for meter reading of the entire wheel or all counters with a certain concentration of the liquid seal meter and other preparation, clarity sealed from the external counter is not affected by the water quality of the remaining structural performance and wet the same meter.
9. Follow the instructions in the form of classification
Divided into analog, digital, analog and digital modular.
Speed-meter: installed in a closed conduit, made a motion components, the flow velocity directly by it to gain momentum speed meter.
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.
Overload flow (Q4): meter requirements in a short time can meet the requirements of the maximum permissible error, then under nominal operating conditions can still maintain metrological characteristics of maximum flow
Common flow (Q3): maximum flow rate under nominal operating conditions. In this flow, the meter should work and meet the requirements of the maximum permissible error.irrigation water meter
Transitional flow (Q2): Common flow occurs between Q3 and minimum flow Q1, is divided into a flow range has a specific maximum permissible error of the "high zone" and "low zone" traffic between two zones.
The minimum flow (Q1): comply with the requirements of the meter shows the maximum permissible error value of the minimum flow. Pressure loss (Δp): at a given flow rate, head loss caused by the presence of the meter in the pipeline.