AODD Pumps Spun Out: Is It Time for A Pump Revolution in the Chemical Industry?

Author / Editor: Edison Brito and Rob Jack* / Dominik Stephan

For decades, centrifugal pumps were the standard choice for the process industry. Now, advancements in overall efficiency and the ability to handle a wide array of unique chemicals combine to make the air-operated double-diaphragm pump a first choice for chemical processors.

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Air-Operated Double-Diaphragm Pumps with a Wilden Pro-Flo Shift air distribution system have matured into a real alternative for centrigual pumps in the chemical Industry.
Air-Operated Double-Diaphragm Pumps with a Wilden Pro-Flo Shift air distribution system have matured into a real alternative for centrigual pumps in the chemical Industry.
(Bild: Wilden; © Erich Muecke/

The circumstances that prompted Jim Wilden to develop the air-operated double-diaphragm (AODD) pumping principle six decades ago have taken on almost mythic status: a ruptured water pipe, a flooded workshop and an exclamation from a coworker that “Slim” (Wilden’s nickname) could “make a million dollars” if he could invent a solution.

In the ensuing years, those words proved to be prophetic as the technology that was “conceived out of necessity” has become a go-to choice for operators in rough-and-tumble industries, as the AODD design allows the pump to obtain dry self-prime, run dry, maintain suction lift up to 30 feet (9 m or 14.7 psia), withstand deadhead conditions, operate while completely submerged and pass solids up to 3 inches (76 mm) in diameter.

Furthermore, these characteristics allow AODD pumps to be extremely effective in delicate liquid-handling applications, including those in the pharmaceutical and food-and-beverage industries.

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Applying the Correct Pump Technology

Thanks to a series of technological advancements, the unit is considered a true “process” pump and has gained acceptance as such in diverse industries, as the following examples illustrate:

  • When one of the largest independent chemical distributors in the US moved into a new facility, it needed a pump technology that could perform well in a number of operating environments. The solution was to outfit the site with bolted AODD pumps, which possess the capability to handle a plethora of chemicals. “We wanted better product containment and the AODD pump has given us great performance with no worries,” said the distributor’s facilities maintenance manager.
  • An Indonesian leader in solvents for paints and coatings was looking to improve operational efficiency at its production plants, as the time to load and unload holding tanks was becoming prohibitive. After a series of onsite tests, the plant’s operators learned that advanced AODD pumps could not only reduce the transfer times through higher flow rates, but could do so with less compressed air.
  • A Spanish company that produces printing inks had problems with gear pumps, as constant breakdowns led to increased downtime and maintenance costs. The solution was found in replacing the ill-performing pumps with AODD technology featuring an advanced air engine that requires less air while delivering the same flow rates. “Compressed air as an energy source is relatively expensive, so if we can do the same work with half the energy it is very important,” said the company’s president.

Despite the fact that AODD pumps have proven their effectiveness in utilitarian applications, there has always been one annoying glitch: at the end of every pump stroke, a small, but significant, amount of air was wasted. Because of that, pump manufacturers — led, of course, by Jim Wilden — were searching for ways to decrease or eliminate the air loss at the end of the stroke. This has led to a series of advancements in Air Distribution System (ADS) technology that enabled the pump to optimize air usage (and cost) while still maintaining its standard-setting operational characteristics.