Jun 21 2014

Features AWWA standard water meter, product structure, working principle, common problems and solutions

Measurement of water flow meter. Mostly is the cumulative flow measurement of water. Generally divided into volumetric meter and velocity meter two. The accuracy is higher than, but the high requirement of the water quality, water containing impurities easily blocked. Recording water water meter, installed in the pipe, when the user when discharging water, table rotation pointer or wheel pointed out that through the water.

AWWA Standard water meter

According to the soaking status

According to the counter is immersed in water to distinguish, divided into the wet water meter, water meter, water meter and dry liquid seal.

(1) the wet water meter: counter is immersed in the water meter, the meter glass bear hydraulic drive, sensor and counter gear linkage, use a period of time after the water quality will affect the clarity of the water meter reading.

(2): dry water meter counter is immersed in the water meter, phase separation chamber and counter sensor structure, water meter glass is not affected by the pressure sensor, transmission and counter with magnetic drive.

(3) the AWWA Standard water meter for meter reading meter: digital wheel or the counter liquid seal water all with certain concentration of glycerol, influence of counter seal the definition from the outside water, the rest of the same structure performance and wet water meter.

The term:

The minimum flow rate (Q1): showing the value of the maximum permissible error meets the minimum flow requirements of water meter.

The boundary flow (Q2): appeared in between, commonly used flow Q3 and minimum flow Q1 will flow range is divided into the two region specific maximum permissible error of “high” and “low” flow.

The commonly used flow (Q3): maximum flow rated working conditions. In this flow, water meter should work normally and meet the maximum permissible error.

Overload flow (Q4): water in a short time can meet the requirements of the maximum allowable error, maximum flow in rated working conditions can still maintain the metrological characteristics.

Pressure loss (Δ P): at a given flow rate, head loss caused by the existence of water pipeline

There are three types of water meter on the market.

1, the first type of  Volumetric Piston Plastic Remote Reading Gallon Water Meter with NSF Approval is composed of magnetic sensitive elements of magnetic materials used for drip proof mechanism, and the water inlet of the body, when the water in the drip flow outward outward form water, magnetic sensitive mechanism will intermittently to the water supply, the water meter, this way the starting flow meter is less than 0.5 L/H, but the structure of the water meter, the magnetic pole piston, so most afraid of water, iron rust and mud and sand and other impurities, the magnetic columns are most likely to be water impurities stuck and no longer has the drip proof function;

2, second types of drip Water Leakage table is a tubular or hole of the small flow of water into the impeller box of water meter, and alignment impeller form the core of the jet, will focus on promoting the impeller in a bit tiny flow water kinetic energy, so that the impeller rotation to achieve the purpose of small flow measurement, the methods the starting flow meters can be up to 2 L/H, but the structure of the micro flow meter in a concentrated on water jet, it will cause the meter to measure, because it will be the water pressure of tap water pipe network instability and the water table has great creep (i.e. in the user will tap all closed without the water, because the pressure of the pipe network instability caused a water meter idling phenomenon), the creeping up to 192 liters / day (a month even without water will air 5 ~ 6m³ tap water), leading to wrong delivery of water users, resulting in customer complaints and refusal to pay water charges phenomenon, another this kind of defect is very easily by the mud and sand blocking and clamping, over a period of time (usually three to five months) after the loss of the drip proof function;

3, the third type is the diaphragm integral drip Water Leakage table, it is in the case of ordinary water at the bottom of a cavity, the upper part of the structure is still the same with ordinary water, during which the sealing separated by a flexible diaphragm, the bottom cavity and the water outlet is communicated with the water outlet in the shell, has a special anti drip mechanism, when the tap water to drip the form of outward drip, drip proof system will still at the water outlet is closed, the water dripped out is at the bottom of the water in the water chamber, when the bottom cavity water (Volume 36 ml) was dripping is finished, anti leakage mechanism will be opened, thus replenishing discharge the water to the bottom cavity, the cavity after water is added, anti leakage mechanism under the action of the spring and the water outlet seal, and into the next cycle, anti leakage mechanism in open process supply water to the bottom cavity is more than a meter of the starting flow process, so the water meter can measure.