Water meters are just devices for measuring and paying for water resources, and water meters are a must-have appliance for thousands of households. They are also the basis for energy saving, consumption reduction and economic expenditure. However, the understanding of water meters by laymen is only a kind of instrument, and the understanding of water meters is very little. Let us learn about common knowledge of water meters.
中国水表交易网络说,meaning of each symbol in the name of the water meter. Code Name Description The first digit L of the water meter represents the flow meter, the second digit represents the water meter rotor-type water meter, the third digit S represents the rotor-type horizontal screw-wing water meter, and the third digit L represents Horizontal screw-wing vertical screw-wing water meter The third digit R represents the vertical screw-wing double-type water meter (combined) water meter third digit F represents the compound quantitative water meter third digit D represents the quantitative hot water meter fourth digit R represents the hot water The fourth digit of the water meter L represents the vertical positive and negative current water meter fourth digit N represents the forward and reverse current fourth digit G represents the dry liquid seal water meter fourth digit Y represents the liquid seal detachable water meter fourth digit C represents the detachable type Q: Why do I see bubbles on the surface of the water meter?
Answer: The water meter is divided into wet and dry types according to the form of the counter. The tap water can enter the counter is the wet type, and the counter seal is the dry type. The accumulated air on the surface of the wet water meter forms bubbles, and the bubbles on the surface do not affect the water meter. Measurement.
Q: Can the water meter be installed at an angle?
Answer: The water meter should be installed according to its marked installation mode (H-horizontal or V-vertical) and the direction of water flow. The mechanical water meter has rotating measuring elements inside, and the center of gravity of all rotating elements rotates most smoothly on the rotating shaft, so The measurement accuracy cannot be guaranteed when the water meter is installed obliquely.
Q: Are there any requirements for upstream and downstream pipelines?
Answer: The upstream of the water meter requires the installation of a straight pipe section with a diameter of 10D and the same length as the water meter, and the downstream of the water meter requires the installation of a straight pipe section with a diameter of 5D and the same length as the water meter. In order to avoid excessive stress on the water meter, it should be ensured that the axes of the upstream and downstream pipes and fittings of the water meter coincide.
Q: Are there any regulations on the use period of water meters?
Answer: For the nominal caliber less than or equal to 50mm, and the commonly used flow rate does not exceed 16m / h, the water meter used for trade settlement is only for the first mandatory verification, used within a limited period, and expired rotation. Rotated water meters fulfill the scrapping procedures.
The service life of a water meter with a nominal diameter of 25mm or less generally does not exceed 6 years; the service life of a water meter with a nominal diameter of more than 25mm to 50mm generally does not exceed 4 years; Q: What affects the accuracy of the water meter?
Answer: There are currently three situations: one is the rust of the watch body, or the foreign body is blocked by the sediment; the second is the aging of the components, which is deformed or damaged by the impact of water pressure; the third is the unclear digital display, which leads to misreading and misreading. "
Introduction to various flows of water meters. Starting flow rate QS: The flow rate at which the minimum gear pointer of the water meter starts to rotate; Minimum flow Qmin: The minimum value of the rated flow range of the water meter. Depending on the accuracy level of the water meter, such as a class A water meter: 3% of the nominal flow rate Qn; a class B water meter: 2% of the nominal flow rate Qn. 3. Cut-off flow Qt: The cut-off point of the accuracy value of the water meter between the nominal flow Qn and the minimum flow Qmin, the following part is the low zone. Depending on the accuracy level of the water meter, such as a class A water meter: 10% of the nominal flow rate Qn; a class B water meter: 8% of the nominal flow rate Qn.
Nominal flow rate Qn: The maximum flow rate under rated operating conditions. Regulations: DN15 nominal flow rate is 1.5 m3 / h; DN20 nominal flow rate is 2.5 m3 / h; DN25 nominal flow rate is 3.5 m3 / h. The "N2.5" marked on some water meters refers to "the nominal flow rate Qn of this water meter is 2.5 m3 / h", so that the caliber of the water meter is DN20. (Some people with a nominal flow are also called common flow). Overload flow Qmax: The maximum flow that the water meter can withstand within the accuracy class, generally Qmax = 2Qn. B) The National Standard GB / T 778.1-3—2007 of the People's Republic of China and the metrological verification regulations.