Diaphragm-operated automatic control valves (ACVs) require reasonably clean water to function effectively and reliably. Having a strainer upstream of the actual ACV is important, as is having a smaller strainer located at the inlet of the pilot system on the ACV.
Donnacona, Quebec, Canada, is an industrial town just west of Quebec City. The town’s water treatment plant was built in 1969 and has since undergone three major retrofits: new high-pressure pumps and an electrical upgrade in 1995; a filter bottoms change in 2000; and a river water intake upgrade in 2005. The plant includes conventional treatment for coagulation, sedimentation (pulsator), filtration (sand filters) and disinfection (Cl2). The raw water pumping station is 1.5 km away from the plant and includes two single-speed pumps.
The city of Modesto, Calif., is situated 90 miles east of San Francisco and has approximately 200,000 residents relying on 55 million gal of water per day. In 2006, the city took on a project to upgrade three water storage tanks that hold approximately 750,000 gal each.
After years of using motor-operated valves to fill water storage tanks, the city recognized that there were just too many problems.