Project Background
A municipal water supply company operates a DN1200 main pipeline supplying about 300,000 tons of water daily. The original mechanical water meters suffered from wear and tear, leading to progressively larger measurement errors and a non-revenue water (NRW) ratio exceeding 15%. Frequent billing disputes with downstream industrial users and large communities resulted in revenue loss and administrative burden.
Customer Challenges
1. Mechanical meters had poor sensitivity at low flow rates, nearly missing small flows; 2. Large diameter (DN1200) and underground installation made replacement difficult without prolonged shutdown; 3. No remote data transmission, manual meter reading caused delays and errors; 4. User distrust of mechanical meter readings led to costly disputes.
Solution
SIENCUN recommended LDE series electromagnetic flowmeters. These meters feature all-stainless-steel electrodes and PTFE lining, corrosion and wear resistant, with no pressure loss. Accuracy is 0.5% of reading, turndown ratio 1:100, capable of measuring flow down to 0.1 m/s. Each meter includes a remote converter with 4-20mA, RS485, and GPRS for real-time monitoring. Hot-tap installation allowed sensor insertion without stopping water flow, requiring only brief pressure reduction.
Implementation
The project was executed in three phases, each installing 4 meters over about 3 weeks. First, hot-tap connections were made on the pipeline. Sensors were then hoisted and fixed, ensuring straight pipe runs of 5D upstream and 3D downstream. Finally, wiring and commissioning were completed with zero-point calibration and online validation. All data were integrated into the company's SCADA system via GPRS.
Results
After retrofit, measurement error decreased from ±5% to within ±0.3%. The NRW ratio dropped from 15.2% to 11.0%, saving approximately 1.2 million tons of water annually, equivalent to a financial benefit of about 2.4 million RMB (at local water tariff of 2 RMB/ton). Trade disputes were essentially eliminated due to the high credibility of electromagnetic meter readings. After one year of operation, only one electrode cleaning was required, demonstrating stable performance.