AODD Pumps for Filtration Systems: Benefits and Selection Guide

Choosing an AODD pump for a filtration system starts with understanding both the liquid and the filter. The pump must deliver the required flow while overcoming resistance through the pipework, filter media and downstream equipment. As the filter collects particles, that resistance changes.

The OVELL equipment shown here combines a plastic air operated double diaphragm pump with a stainless-steel filtration vessel. This arrangement illustrates how fluid transfer and filtration can be brought together in a compact package. The exact pump materials, filter media and operating conditions should be selected for each application.

How an AODD Pump Works with a Filtration System

An air operated double diaphragm pump uses compressed air to move two diaphragms alternately. Check valves direct the liquid through the pump and towards the filter. The filter then retains particles according to the selected media and filtration rating.

A practical filtration package may include the pump, filter housing, connecting pipework, isolation valves and an air regulator. Pressure measurement before and after the filter helps operators understand filter loading and decide when servicing is needed.

Why Consider an AODD Pump for Filtration?

Adjustable Operation

Air pressure and available air flow influence pump operation. Operators can adjust the air supply to suit the transfer duty, provided the pump and every downstream component remain within their rated limits. This adjustment does not guarantee constant liquid flow: viscosity, suction conditions and filter resistance also affect the operating point.

Flexible Material Options

OVELL offers diaphragm pump configurations using materials such as PP, PVDF, stainless steel and aluminium alloy. Selection must consider the liquid composition, concentration and temperature, together with the compatibility of diaphragms, valve components and seals.

A corrosion-resistant pump alone does not make the complete package compatible. The filter housing, filter media, hoses and fittings also contact the liquid and require the same review.

Convenient Package Layout

Mounting the pump and filter close together can simplify connections and provide convenient access for inspection. Fixed skid and mobile arrangements can be considered according to the installation. Leave sufficient clearance to open the filter housing and remove the filter media.

What Happens When the Filter Becomes Blocked?

A clean filter and a loaded filter present different operating conditions. As retained particles increase resistance, the flow delivered by an AODD pump may decrease. A slowing pump can therefore indicate rising back pressure, although restricted suction, inadequate air supply or pump wear can produce similar symptoms.

For a conventional 1:1 AODD pump, discharge pressure approaches the available air pressure at stall, with actual behaviour depending on the model and operating conditions. A pressure-boosting pump behaves differently. Always use the selected model's performance curve and pressure limits.

Do not respond to falling flow simply by increasing air pressure. Check the filter differential pressure and service the filter at the limit specified by its supplier. The maximum rated pump flow and maximum discharge pressure are different operating points; they should not be treated as simultaneously available performance.

Five Questions to Answer Before Selecting the Pump

1. What is the liquid? Specify its chemical composition, concentration, temperature and viscosity, including changes during the process.
2. What flow is required through the filter? Use the required operating flow, rather than the pump's unrestricted maximum flow.
3. What pressure must the pump overcome? Include pipe losses, elevation, downstream pressure and the filter resistance throughout its service cycle.
4. What particles are present? Identify particle size, loading and abrasiveness. Pump solids-handling capability and filter micron rating describe different requirements.
5. What compressed-air supply is available? Check pressure and air capacity at the pump during operation, including losses through hoses, regulators and valves.

Installation and Operating Checks

• Keep the suction line adequately sized and avoid unnecessary restrictions.
• Check the pressure and temperature ratings of the filter housing, pipework, hoses and fittings.
• Provide accessible isolation and a safe method of releasing trapped pressure before maintenance.
• Use clean, suitably conditioned compressed air in accordance with the pump manual.
• Assess whether a compatible pulsation dampener is needed for the filter and process. An AODD pump produces pulsating flow.
• Review grounding, ventilation and equipment suitability where flammable liquids or hazardous areas are involved. A pneumatic drive alone does not establish explosion protection.

Before opening a filter housing, isolate the equipment and release trapped pressure using the approved site procedure. A stopped pump does not mean that the vessel or pipework is depressurised.

Matching the Package to the Application

Filtration requirements differ between water treatment, chemical processing, paints and other industrial liquids. The equipment shown here is an example of a pump-and-filter arrangement, rather than evidence of a particular customer's liquid, throughput or filtration result.

For a specific coating application, see our 2-inch AODD pump and bag-filter package for paint transfer. For available pump sizes and configurations, explore the OVELL standard pump range.

Discuss Your Filtration Duty with OVELL

Send OVELL your liquid details, required flow, operating temperature, filtration rating, expected pressure loss and available air supply. Include the filter housing pressure limit and any installation requirements so the pump and filter can be reviewed as one system.

Contact OVELL for AODD pump selection and filtration-package enquiries.