Air Operated Double Diaphragm pumps are one of the most versatile in industrial applications. From food and beverage production to mining, construction, pharmaceuticals, and chemistry, AODD pumps have proven reliability.

An AODD pump moves fluid by the alternate and repeated back-and-forth movement (strokes) of two flexible membranes or diaphragms mounted on a common shaft. It is essentially completely leak-free unless one of the diaphragms fails. Diaphragm failure is rare in AODD pumps as AODD diaphragms suffer less wear than those in mechanically driven diaphragm pumps.

5 Things When Selecting AODD Pumps

What liquid do you want to push using an AODD pump?

In order to prevent corrosion of the wetted parts and wear and tear on the pumping equipment, the type, composition, and nature of the fluid must be taken into account as the most crucial element.

The defining qualities include solid content, pH level, viscosity, density, specific gravity, and abrasion factor.

Different types of fluids include

  1. Flammable Fluids
  2. Corrosive Fluids
  3. Abrasive Fluids
  4. Toxic Fluids
  5. Shear Sensitive Fluids

E.g. Choosing an aluminium pump for abrasive fluids may be a costly mistake as aluminium only offers limited corrosion and abrasion resistance.

In this case, the right choice would be to go for polypropylene casting.

For use in chemistry settings, PVDF is preferred for its strong chemical resistance to acids and bases, whereas PTFE is also extremely chemically compatible but has poor abrasion resistance.

2. Flow Rate

The flow rate is related to the draining time of the machine. Flow rate is taken into account initially when determining pump size. For higher flow rates, use a bigger pump with larger port sizes, such as suction and discharge connections, and vice versa. Generally, the higher the flow rate, the shorter the draining time. When sizing an AODD pump for maximum efficiency and lifespan, it is usual to go up one port size if possible.
Vacuum type Maximum pressure (in mbars) Minimum pressure (in mbars) Molecules per cm³
Rough vacuum 1 10-3 1016 – 1013
High Vacuum 10-3 10-7 1013 – 109
Ultrahigh vacuum 10-7 10-12 109 – 104

3. Pressure conditions

Analyzing the need for correct pressure conditions inside the AODD chambers help select the appropriate size of the pump.

Suction Pressure is the pressure at the pump inlet. AODD pumps are self-priming, thus useful for flooded suction as well as suction lift conditions.

Since a higher pressure offers a better flow rate, one must also ensure it is controlled. Excessive pressure can hamper the lifting ability of the suction valves. This may lead to downtime.

Discharge Pressure, also known as delivery pressure, determines the height at which the fluid is pushed. It is calculated in addition to the frictional loss.

4. Flow Viscosity

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Viscosity is the resistance to the flow. AODD pumps are known for being gentle on the fluids they’re pumping, unlike some other types of pumps.

Their sealless design minimizes maintenance while preventing shearing or degrading the products they’re pumping.

It is critical to know the viscosity of the liquid. For liquids with more than 5000 cps, for example, 1.5″ is preferable. For convenience, air diaphragm pump manufacturers supply a viscosity correction factor for different viscosities based on pump size.

For high viscosity fluids, the flow rate must be lowered by applying a viscosity adjustment factor to the standard curves.

5. Temperature

Pump materials have temperature limitations. In addition to chemical compatibility and pump materials, temperature is also an essential factor in pump longevity.

To guarantee that the pump material is most suited for a certain application, we must know the operating temperature as well as the environmental circumstances.

Rubbers and thermoplastics have varying temperature ratings. Fluorocarbons, for example, can endure temperatures of up to 177 °C. Cold temperatures, such as those used in CBD synthesis, may benefit from Teflon.

The neoprene diaphragm, on the other hand, has a temperature limit of fewer than 100 degrees Celsius.

Conclusion

AODD Pumps excel in comparison to other mechanically operated pumps because of the robust design, low maintenance requirements and greater application versatility. With the benefit of low diaphragm wear, AODD pumps have a long operational lifespan, even in abusive environments.

 

An AODD pump may be run dry continuously since there are no internal seals or moving components that require lubrication or cooling. AODD pumps are self-priming, with some having a suction lift of up to 8m.

 

Because they are powered by compressed air rather than electricity, AODD pumps are acceptable for usage in hazardous applications such as

  • Mine dewatering, abrasive slurries transfer, reagent dosing, solvent transfer, and fuel transfer.
  • Ceramics slips, day tank transfer, mould filling, ceramic slurry circulation.
  • Chemicals – Loading and unloading tankers, totes and barrels, batching/dosing chemicals.
  • Oil & Gas – Settling pond transfer, oils and glycol transfer, sumps, filter press, bulk transfer.

 

Because they are strong, reliable, easy to maintain, and reasonably inexpensive, AODD pumps are ideal as a pumping workhorse for your application.

 

For decades, IDEX India has been the go-to air-operated double-diaphragm (AODD) pump manufacturer in India. We offer a variety of solutions to particular market application demands.

We take pleasure in assisting you with your basic AODD pumping requirements as well as working directly with you to solve your most difficult pumping challenges.

Trust our world-class technical experience and innovation to deliver industry-leading durability and performance.

We have the most adaptable product line to fulfil the demands of a wide range of market applications.