Improvements in operational efficiency coupled with the ability to handle most chemicals make the air-operated double-diaphragm pump a perfect choice for chemical processors



Since its invention in 1955 as a mining pump, the air-operated double-diaphragm (AODD) pump has established a well-earned reputation as a technology that is ideally suited for utilitarian, auxiliary or basic liquid-handling and transfer applications. AODD pumps excel in these types of applications because they possess design characteristics that allow them to offer simple, sealless operation and enable them to self-prime, run dry, achieve suction lift up to 30 feet (9 meters or 14.7 psia), resist deadhead pumping conditions, operate while submerged and pass solids up to 3 inches (76 mm) in diameter. In fact, there are four key areas in which AODD pumps will outperform competitive technologies in terms of efficient, reliable and cost-effective operation. Chemical processors who are looking to optimize their operations would be wise to consider the advantages that AODD pumps can provide in these areas. Let’s take a closer look at all four:


1)      The Importance of Air

As their name states, the operation of AODD pumps relies on compressed air, which can be found in most chemical-processing plants around the world. Leveraging this ready availability of air can make the AODD pump a true plug-and-play device that requires no infrastructure upgrades to incorporate. Additionally, the use of air to power the pump is the key source of one of its most sought after capabilities, the ability to deadhead without damaging the pump, system or fluid. This makes AODDs very easy and flexible pumps to operate. Keeping air usage low is critical to maintaining a healthy environment and a healthy processing plant, and recent technological advances have taken significant steps toward realizing these goals. AODD pump developers kept working to conquer the air-loss quandary and eventually reached a new pinnacle of ADS operation in 2013 when the engineers at Wilden® Pump and Engineering Co., completed the development of the Pro-Flo® SHIFT ADS technology. This redesigned ADS features a revolutionary air control spool that reduces the amount of air that is allowed into the pump at the end of the stroke, which drastically reduces the amount of “wasted” energy that had traditionally been lost to the atmosphere.


2)       Low Maintenance Costs Through Proper Diaphragm Selection

Diaphragm pumps have a unique benefit when compared to many rotating-pump technologies in that they don’t require any seals. Elimination of the need for packing or expensive mechanical seals means that maintenance costs tend to be inexpensive and infrequent. Diaphragm material choice, shape and pump design all play a

role in enhancing the life of the diaphragm. Along with the advances in ADS design and operation, the improvements made in diaphragm construction and function over the years have been meaningful. Wilden has stepped forward in this area, as well, with the creation of the Chem-Fuse Integral Piston Diaphragm (IPD).


3)      Versatile and Compatible

AODD pumps can match the supposed advantages of competing pump technologies because of a number of operational advantages:


• They are appropriate for use with high-viscosity fluids and can handle fluids that range from water-like to medium and very viscous liquids

• They can run dry and strip discharge lines without getting damaged; if the pressures get to be too much, the pump will just stop running, but it won’t break

• They are simple devices and their control relies solely on solenoid operators, pump-cycle counters and surgedampener assemblies

• Their operating costs can be lower when all of the maintenance, accessories and controllers are included, and in many cases their total cost of ownership is lower over their entire operational lifespan when compared to competitive pump styles


4)      Pump Construction

AODD pumps are available in a wide range of materials of construction in order to meet a variety of chemicalhandling needs. Common chemical-pump materials include polypropylene, Kynar®, stainless steel, ductile iron and Hastelloy, with some companies, like Wilden, possessing the capability to offer special materials like super duplex when really unique materials are required to ensure uninterrupted production processes and the safety of plant personnel. If metal pumps are required, one overlooked material in the chemical-processing world is ductile iron, which works well in both acidic and basic PH application ranges of 4 to 10.


Conclusion Thanks to its simple yet innovative design, the AODD pump has proven to be able to consistently meet the demands of chemical processors while building a reputation as a go-to pumping technology where basic fluid-transfer capabilities are required. The AODD pump, which possesses a stable of notable operational characteristics, has become a first-choice technology for chemical manufacturers who are searching for a pump that meshes costconscious air consumption with reliable production rates.


Metrans Makina is the only authorized Widen® distributor and service provider in Turkey.


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