First, the meaning of each symbol in the naming of water meters
The first L of the water meter represents the flow meter, the second represents the water meter rotor type water meter, the third position s represents the rotary type horizontal spiral wing type, the third position L represents the horizontal spiral wing type vertical spiral wing type, the third position R represents the vertical spiral wing type, the third position F represents the compound quantity, the third position D represents the quantitative hot water;
The fourth limit of the water meter represents the hot water vertical, the fourth L of the water meter represents the vertical positive countercurrent, the fourth imitation of the water meter represents the positive countercurrent, the fourth G of the water meter represents the dry liquid seal, the fourth place of the water meter? Stands for liquid seal, collapsible water meter fourth C stands for detachable.
G is not quite complicated! Yes, we do! This is the “it” that accompanies our lives but we never really know!
Second, why do you see bubbles on the surface of the water meter
The water meter is divided into wet type and dry type according to the form of the counter, the tap water can enter the counter is wet type, the counter is sealed is dry type, the air released by the accumulation of water on the surface of the wet type water meter forms bubbles, and the bubbles on the surface do not affect the metering of the water meter.
Third, whether the water meter can be installed diagonally
The water meter should be installed in accordance with its marked installation mode (king – horizontal or V-vertical) and the direction of water flow. The mechanical water meter has rotating metering elements inside, and the center of gravity of all rotating elements rotates most smoothly on the rotating axis, so the metering accuracy cannot be guaranteed when the water meter is installed diagonally.
Fourth, the requirements of water meter upstream and downstream pipelines
The upstream water meter must install a straight pipe segment with a diameter (D) of 10D and the same length as the water meter. The downstream water meter must install a straight pipe segment with a diameter (D) of 5. In order to avoid excessive pressure on the water meter, the axis of the upstream and downstream pipes and pipe fittings of the water meter should be ensured to coincide.
Fifth, Provisions on the service period of water meters
For the nominal caliber is less than or equal to 50mm, and the common flow rate does not exceed 16m/, the water meter used for trade settlement is only used for the first mandatory verification, the time limit is used, the expiration of the rotation, and the water meter under the rotation is scrapped.
The service life of a water meter with a nominal diameter of 25mm and below is generally not more than 6 years: the service life of a water meter with a nominal diameter greater than 25mm to 50mm is generally not more than 4 years.
Sixth, What affects the accuracy of water meters?
There are currently 3 scenarios:
One is surface rust, or sediment blocking the pipe,
Second, the parts are aging, deformed or damaged by water pressure impact,
Third, the digital display is unclear, leading to misreading and misreading.
Seven, the various flow of the water meter
Initial flow QS: refers to the flow rate at which the minimum gear pointer of the water meter begins to rotate
Minimum flow Qmin: indicates the minimum of the rated flow range of the water meter. Depending on the accuracy level of the water meter is different, such as the grade water meter: 3% of the nominal flow Qn :B grade water meter: 2% of the nominal flow Qn.
Boundary flow Qt: The boundary point of the accuracy value of the water meter between the nominal flow Qm and the minimum flow Qmin, the following part is the low area. The precision level of the water meter is different, such as A grade water meter: 10% of the nominal flow rate Qn; Class B water meter: 8% of the nominal flow of Qq.
Nominal flow Qn: Maximum flow under rated operating conditions. The nominal flow rate of DN15 is 1.5m³/h; the nominal flow rate of D20 is 2.5m³/h; Dn25 has a nominal flow rate of 3.5m³/h. The “N2.5” on some water meters refers to “the nominal flow Qn of the water meter is 2.5m³/h”, which can be known that the caliber of the water meter is Dn20. (Nominal traffic is also called common traffic).
Overload flow Qmax: the maximum flow rate that the water meter can withstand in the accuracy range, generally Qmax=2Qn. People’s Republic of China national standard GB/T 778.1-3-2007 and metrological verification regulations.