EODD vs AODD Pumps: Energy, Air Use and Cost Compared

Short answer: an AODD pump is driven by compressed air; an EODD pump is driven by an electric motor. Both are double diaphragm pumps that self-prime, run dry and handle solids, but an EODD pump avoids the large energy losses of generating compressed air. In our paint-sludge recirculation project, replacing AODD pumps with EODD pumps cut energy use by more than 85%.

How an AODD pump works

Compressed air is switched between two air chambers. As one diaphragm is pushed, the other is pulled, drawing liquid in through one check valve and discharging it through another. The air is then exhausted to atmosphere. See how an AODD pump works.

How an EODD pump works

An electric motor and gearbox move the same pair of diaphragms mechanically. There is no air supply, no air exhaust and flow can be adjusted precisely with a variable-speed drive.

Side-by-side comparison

	AODD	EODD
Power source	Compressed air	Electric motor
Energy efficiency	Low – most energy is lost making compressed air	High – motor drives the diaphragms directly
Flow control	Air regulator; flow drifts with air pressure	Variable-speed drive; repeatable flow
Noise and exhaust	Exhaust noise, possible icing	No exhaust
Dry running and solids	Yes	Yes
Best fit	Plants with spare air capacity, intermittent duty, some hazardous areas	Continuous duty where energy cost and control matter

When should you switch from AODD to EODD?

• The pump runs many hours a day.
• Your compressor is near full load or you plan to add compressors.
• You need stable flow, for example in paint or chemical circulation.
• Air exhaust noise or icing is a problem.

Keep AODD where air is plentiful and the duty is short, or where the area classification makes an air-driven pump simpler.

Products

Cognito EODD pumps (1–4 inch) and Sandpiper AODD pumps.