The mROY series of metering pumps from Milton Roy is the little pump that can. Featuring a design life of 20 years, the low-maintenance pumps are available in PVC, PVDF, 316 stainless steel and alloy 20 with flow rates from 0.017 to 170 gph.

“While improvements have been made over the years with various materials, advanced casting technologies, coating systems and control interfaces, the pump has at its core the dependable design that the industry relies on,” says Jim Carling, global product line manager for Milton Roy.

Applications include the injection of coagulants, flocculants, filter aids, pH control chemicals, chemicals for taste and odor control, dechlorination and disinfectants such as sodium hypochlorite in the municipal water treatment process.

Weighing about 65 pounds, the pump is 8 inches wide, 12 inches deep and 18 inches high (including motor).

Key features include a hydraulically balanced diaphragm with a 96,000-hour design and turndown ratios up to 100-to-1 for a full range of adjustments based on plant treatment requirements.

“Most diaphragm pumps used in water treatment, or even peristaltic pumps, are pressurized on one side, or in the case of a tube, on the inside,” he says.

“On the outside or backside of the diaphragm it’s atmospheric. So the diaphragm or tube is containing all of the pressure. With the hydraulically balanced diaphragm you have the process fluid on one side and hydraulic fluid on the other. So the diaphragm is balanced between two pressurized fluids. It’s under very low stress. You’re not stretching anything. You’re not compressing anything. All you’re doing is flexing a piece of Teflon.”

Other features include powder-coated housing for corrosion resistance, plus/minus 1 percent accuracy regardless of pipeline pressure fluctuations, separate or combined capacity adjustment for maximum turndown and fine-tuned control from SCADA systems or other process signals.

Depending how the pump is used, Carling recommends annual maintenance of the wetted parts, primarily the check valves and diaphragm.

“Many people can go years without maintenance, it really depends on the service,” he says. “Is it operating 24/7? Are there a lot of particulates in the pump that are being pumped where it might cause wear? Annual maintenance is always recommended as a preventive, but the diaphragm will last about 10 years.”

Pump options include motors and variable-speed drives based on system requirements and installation condition, electronic capacity adjustment for remote control and advanced technology diaphragm leak detection system.

“It’s really a unique item in the world of industrial products,” Carling says of the pump. “Its fundamental design has been around for many years, and yet, the mROY continues to evolve and is still an innovative technology.” 215/441-0800; www.miltonroy.com.