hi pump faq
Hydraulic Institute explains characteristics of this common pump type.

What is an AODD pump?

The air-operated double-diaphragm (AODD) pump is a class of positive displacement pump that is driven by compressed gas. The gas motor actuates opposing diaphragms that are connected to a common connecting rod. There are check valves that control the flow from inlet manifold into the liquid chambers and then out to the discharge manifold. The liquid chambers fill and evacuate respective to the motion of the diaphragm. Image 2 provides a sectional view of the AODD pump and highlights the component nomenclature.

IMAGE 2: AODD pump configuration, from ANSI/HI 10.1-10.5
IMAGE 2: AODD pump configuration, from ANSI/HI 10.1-10.5

Some benefits of AODD pumps include: solids passage, self-priming, low liquid shearing, efficient over wide viscosity range, no mechanical seal or packing, flow and pressure adjusted by air inlet pressure and no electric motor.

Some limitations of AODD pumps are: limited by available air pressure, inherent pressure pulsation, air consumption may be less efficient than motor driven system and stingy materials may be an issue.

For more information on AODD pumps refer to ANSI/HI 10.1-10.5 Air-Operated Pumps for Nomenclature, Definitions, Application, and Operation at pumps.org.   

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