How Does an Air-Operated Double Diaphragm Pump Work?

An air-operated double diaphragm pump operates using compressed air supplied to an air distribution system. The air system directs pressure behind one diaphragm, causing the diaphragm to move and discharge fluid from one liquid chamber. Because the two diaphragms are mechanically connected, the opposite diaphragm moves at the same time and creates a suction stroke that draws fluid into the other chamber.

When the air distribution system changes direction, the pumping action reverses. The diaphragm that was previously completing the suction stroke begins the discharge stroke, while the opposite side begins drawing in more fluid. Ball or flap check valves help control the direction of fluid entering and leaving the pump.

Actual AODD pump performance depends on the selected pump model, available air supply, discharge conditions, piping system and the physical properties of the fluid being transferred. For this reason, pump selection should be based on the complete operating requirements rather than connection size alone.

What Fluids Can AODD Pumps Handle?

AODD pumps are used across a broad range of industrial fluid-handling duties. Depending on the pump configuration and materials selected, they can be applied to clean process liquids, chemical solutions, viscous fluids, abrasive products, slurries and liquids containing suspended solids.

The ability to handle a particular fluid depends on more than the pump technology itself. Wetted pump components must be compatible with the process fluid. These components can include the pump body, diaphragms, valve balls or flap valves, valve seats, seals and other parts that come into contact with the liquid.

Fluid concentration, temperature, viscosity, solids content and operating conditions should therefore be considered before the final pump materials are selected.

Metallic and Non-Metallic AODD Pump Construction

AODD pumps are available in different construction materials depending on the manufacturer, pump model and application. Metallic options across AODD pump ranges can include materials such as aluminium, cast iron and stainless steel. Non-metallic pump ranges can include materials such as polypropylene and PVDF.

The correct construction should be selected according to chemical compatibility, mechanical requirements, temperature and the operating environment. A metallic pump is not automatically the correct choice for every industrial application, and a non-metallic pump is not automatically suitable for every corrosive liquid. The actual fluid and process conditions must always be considered.

Diaphragm and check-valve materials are also important because they are directly exposed to the pumped fluid. The appropriate elastomer or PTFE configuration should therefore be selected according to the relevant chemical compatibility and operating requirements.

How to Choose the Right AODD Pump

Choosing an AODD pump involves more than identifying the required port size. The expected flow rate and discharge pressure should first be established, followed by the suction conditions and characteristics of the liquid being handled.

Fluid viscosity and solids size can affect pumping performance and may influence whether a ball-valve or flap-valve configuration is more appropriate. Chemical compatibility and operating temperature also affect the selection of the wetted pump body, diaphragms, valve components and seals.

Installation conditions should also be reviewed, including available compressed air, suction and discharge piping, required pump location and actual process duty. Specialist configurations may be available for applications involving hygienic processing, containment requirements, large solids or higher discharge pressures.

Common Industrial Applications for AODD Pumps

The versatility of air-operated double diaphragm technology allows AODD pumps to be used across many industrial processes. Typical applications include chemical transfer, wastewater treatment, sludge and slurry handling, food and beverage processing, pharmaceutical processing, paints and coatings, mining, marine operations and general manufacturing.

Different applications require different pump configurations. General fluid transfer may use a standard-duty AODD pump, while applications involving larger solids may require a flap-valve design. Hygienic processes may require pumps designed with appropriate sanitary materials and connections, while specialist high-pressure or containment applications require pumps designed specifically for those duties.

Sandpiper, Versa-Matic and Blagdon AODD Pumps

ABS Engineering provides AODD pump solutions from Sandpiper, Versa-Matic and Blagdon. Each brand offers different pump sizes, materials and configurations for a variety of industrial fluid-handling requirements.

Use the product finder on this page to explore available pumps by brand, construction and pump size. Individual product pages provide further information on pump features, specifications and available documentation. When the correct pump configuration is uncertain, the process fluid and operating conditions should be reviewed before final selection.