Random Error Analysis Of Water Meter Measurement

Random Error Analysis of Water Meter Measurement

Reasons for random errors in water meter measurement:

(1) Errors caused by improper quality and selection of water meters

The quality of a water meter is directly related to its accuracy. Some unscrupulous vendors use inferior materials to manufacture watch core parts, and assemble a large number of counterfeit and inferior water meters, whose accuracy and lifespan are self-evident. There are serious issues with product quality, and if subjected to external collisions, vibrations, and changes in flow and pressure, it often causes serious misalignment or damage to the water meter. In addition, improper selection of water meter model and caliber cannot guarantee that the commonly used water volume of users meets the boundary flow and minimum flow requirements of the water meter, which can cause usage errors.

(2) Errors caused by human factors

During the process of water meter calibration, due to technical reasons and insufficient experience, the calibration regulations were not strictly followed. The air in the calibration device and water meter was not completely discharged, and the water in the measuring instrument was not completely discharged before measurement began. The water column was not in a stable state to read and take the reading value, resulting in reading error. Alternatively, the calibration personnel's eye resolution decreased, and the reading method was improper, resulting in reading error. In addition, It is also possible that reading errors may occur due to the lack of responsibility and carelessness of the calibration personnel.

(3) Errors caused by water meter installation and water quality

Some construction units under construction are not very familiar with the relevant regulations in the GB/T778.2-2007 water meter installation requirements. They are also unaware of the distortion of the water flow velocity profile and the impact of vortices on the water meter caused by improper installation. Prior to installation, pipelines were not pre washed, resulting in construction waste entering the water meter; The water supply pipeline in the city has been broken and repaired without flushing, which can also cause blockage due to debris such as meat, hemp, sand, and stones. Both can cause inaccurate and damaged water meters.

In addition, mixing air with the water meter during use can reduce the counterattack effect of the regulating plate on water, resulting in water indication error. According to the data, the DN15 water meter has a lateral tilt of 45 degrees at 1000L/h. The error increases by 1%. If the vertical tilt is 45 degrees, the maximum error will increase by 3%. At 180L/h, if the lateral inclination is 45 degrees, the error will increase by more than 5%; if the longitudinal inclination is 45 degrees, the error will increase by 20% or even more.