Stenner Peristaltic Metering Pumps: Chemical Feed Specification for Water Treatment

Stenner peristaltic metering pumps are positive-displacement chemical dosing units designed for precise, repeatable injection of liquid treatment chemicals into potable water, process water, and industrial fluid systems. The peristaltic operating principle — fluid is moved by compression of a flexible tube between rollers — eliminates contact between the chemical and pump internals, making these units the preferred specification for corrosive, oxidizing, or viscous chemical feeds.

Operating Principle & Design Advantages

In a peristaltic pump, a rotor with two or more rollers compresses a flexible tube against a circular housing. As the rotor turns, the compression point moves along the tube, drawing fluid in on one side and discharging it on the other. Key design advantages for water treatment applications:

·       No seals, valves, or diaphragms in the fluid path — eliminates the primary failure modes of diaphragm and piston metering pumps

·       Self-priming to 25+ ft of suction lift — suitable for chemical storage tanks positioned below the injection point

·       Bidirectional flow — pump can be reversed to purge the suction line

·       Chemical compatibility determined solely by tube material — Santoprene, Versilon (PTFE-lined), and other elastomers available for specific chemical families

Shop Stenner Peristaltic Metering Pumps at Water Services Inc

Available Models & Output Ranges

Water Services Inc carries the Stenner fixed-rate and adjustable-rate series, covering a broad range of dosing capacities and system pressures:

Fixed-rate models are specified where dosing demand is constant and system pressure is stable. Adjustable-rate models allow field calibration of output without replacing the pump head — preferred for systems where chemical demand varies with flow or seasonal water quality changes.

Industrial & Municipal Water Treatment Applications

Chlorination: Sodium hypochlorite (NaOCl) injection for disinfection of potable water systems, cooling towers, and process water. Stenner pumps are compatible with NaOCl concentrations up to 12.5%. Santoprene tubing is the standard specification for hypochlorite service.

pH Adjustment: Acid (sulfuric, hydrochloric, citric) or caustic (sodium hydroxide) feed for pH correction in industrial process water, boiler makeup, and reverse osmosis pretreatment. Versilon (PTFE-lined) tubing is required for concentrated acid service.

Scale & Corrosion Inhibitor Feed: Polyphosphate or phosphonate injection for scale control in distribution systems and heat exchangers. Adjustable-rate models allow output to track flow-proportional demand via external pulse input (on compatible models).

Bacteria Control: Biocide injection for Legionella control in cooling towers, and disinfectant feed for potable water systems where bacteria is the primary treatment challenge — a common requirement across Water Services Inc’s customer base in the USA, Africa, and the Middle East.

System Integration Notes

Stenner metering pumps are typically installed in-line on the suction side of a pressure tank or at the point of chemical injection on a distribution main. Key installation requirements:

·       Injection check valve (1/4” or 3/8” NPT) prevents backflow of system pressure into the chemical feed line — required on all pressure system installations

·       Suction/discharge tubing (UV-resistant black, 1/4” OD) rated for the specific chemical being dosed

·       Ferrule fittings for leak-free tube connections at the pump head and injection point

·       Roller clutch maintains consistent tube compression — inspect and replace per manufacturer’s PM schedule

The Econ Stennicator is a proportional injection unit designed for hose-end or low-pressure applications at a fixed 1:128 dilution ratio — suited for irrigation chemical injection and small-scale industrial applications.

Maintenance & Consumables

Pump tube replacement is the primary maintenance item. Tube life varies by chemical concentration, temperature, and duty cycle — typically 1,000–3,000 hours for hypochlorite service. Stenner replacement tube kits (No. 7 Pump Tube, PK2) and index pin springs are stocked at Water Services Inc.

View available Stenner pump models and accessories at Water Services Inc