A dosing pump is a positive displacement pump designed to inject precise, measured volumes of liquid, typically a chemical, into a process stream, tank or pipeline. Dosing is essential wherever accuracy and repeatability matter: water treatment, chemical processing, food and beverage production, pharmaceutical manufacturing and pool maintenance all depend on reliable chemical dosing pumps.
At TF Pumps, we supply dosing pumps from ProMinent, one of the world’s leading dosing technology manufacturers. Whether you need a compact mechanical dosing pump for simple duties or a digitally controlled metering pump for complex multi-chemical systems, browse our ProMinent ranges below or call us on +44 1332 913500 for help selecting the right unit.
A dosing pump, sometimes called a metering pump or chemical injection pump, delivers a controlled volume of liquid per stroke or per unit of time. Unlike a transfer pump that moves bulk liquid from A to B, a dosing pump’s job is precision: it adds exactly the right amount of chemical at exactly the right rate, regardless of changes in system pressure or temperature.
Dosing pumps are positive displacement by design. Each stroke displaces a fixed, known volume, so the dose can be adjusted by changing the stroke length, stroke speed, or both. This gives operators fine control over dosing rates from fractions of a millilitre per hour up to hundreds of litres per hour, depending on the pump model.
Mechanical dosing pumps: also called mechanically actuated diaphragm pumps. A motor drives an eccentric or cam mechanism that pushes the diaphragm back and forth, creating suction and discharge strokes. Dose rate is adjusted by changing the stroke length (usually via a manual knob) and/or the stroke frequency. A mechanical dosing pump is robust, simple and well suited to steady-state duties where the dose rate doesn’t need to change frequently. They are the workhorse of chemical dosing in water treatment, cooling towers, boiler houses and pool systems.
Electronic (solenoid) dosing pumps: an electromagnetic solenoid drives the diaphragm. Dose rate is controlled electronically, allowing remote adjustment, proportional dosing linked to a signal (4–20 mA, pulse input from a flow meter or analyser), and integration with SCADA or BMS systems. Electronic dosing pumps suit applications where dose rates need to respond dynamically to changing conditions, pH correction, residual disinfection, proportional chemical feed.
Motor-driven diaphragm dosing pumps: for higher flow rates and pressures than solenoid pumps can handle. A geared motor drives the diaphragm via a mechanical linkage, with electronic stroke-length adjustment. Used in industrial water treatment, chemical processing and high-pressure injection duties.
Most dosing pumps are used to inject chemicals, which is why the term chemical dosing pump is used interchangeably with dosing pump across the industry. The chemicals involved range from relatively benign (sodium hypochlorite for pool disinfection) to highly aggressive (concentrated acids, alkalis, polymers and oxidisers in industrial water treatment).
Chemical compatibility is critical. The pump’s wetted parts, diaphragm, valve balls, valve seats, seals and pump head, must be chemically resistant to the dosed liquid. Common wetted-part materials include PP (polypropylene), PVDF, PVC, PTFE and stainless steel. ProMinent publishes detailed chemical resistance tables; we can advise on the right material combination for your application.
Selecting a dosing pump means matching the pump to three things: the dose rate required (litres per hour at the duty point), the discharge pressure the pump must work against (system back-pressure plus any static head), and the chemical being dosed (which determines wetted-part material selection).
Other considerations include whether the dose rate needs to be fixed or variable, whether the pump needs to accept an external control signal, whether ATEX rating is required for hazardous areas, and the available power supply. As experienced dosing pump suppliers we help clients specify correctly, call us on +44 1332 913500 with your application details and we’ll recommend the right ProMinent model.
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A dosing pump injects precise, measured volumes of liquid, usually a chemical, into a process stream, tank or pipeline. Common applications include water and wastewater treatment, swimming pool chemical dosing, cooling tower treatment, food and beverage processing, and pharmaceutical manufacturing. Any process that requires a controlled, repeatable dose of liquid is a candidate for a dosing pump.
A mechanical dosing pump uses a motor-driven cam or eccentric to move the diaphragm, with dose rate adjusted manually via a stroke-length knob. An electronic dosing pump uses a solenoid to drive the diaphragm, allowing remote adjustment, proportional dosing linked to a control signal (4–20 mA, pulse input), and integration with SCADA or BMS systems. Mechanical suits steady-state duties; electronic suits have variable or responsive dosing.
A chemical dosing pump is a dosing pump used specifically to inject chemicals into a process. The term is used interchangeably with “dosing pump” across the industry. The key consideration is chemical compatibility, the pump’s wetted parts (diaphragm, valves, seals, pump head) must resist the chemical being dosed. Common wetted-part materials include PP, PVDF, PVC, PTFE and stainless steel.
Sizing requires three inputs: the dose rate you need (litres per hour), the discharge pressure the pump must work against (system back-pressure plus static head), and the chemical being dosed (which determines material selection). The pump’s maximum capacity should exceed the required dose rate by at least 10–20% to avoid running permanently at full stroke. Send us your application details and we’ll specify the right model.
Modern diaphragm dosing pumps from manufacturers like ProMinent typically deliver accuracy of ±1–2% of the set dose rate under steady-state conditions. Accuracy depends on correct installation, proper priming, and appropriate valve and tubing sizing. Degassing valves should be fitted where the dosed chemical is prone to off-gassing.
With correct chemical compatibility and routine maintenance, a quality dosing pump typically lasts 10–15 years. The diaphragm is the main wear item and is usually replaced every one to three years, depending on the chemical and duty cycle. Valve balls and seats are also periodic replacement items. Stocking a small spares kit is good practice for critical dosing duties.
