How Does an AODD Pump Work?

What is an AODD Pump?

An Air Operated Double Diaphragm (AODD) pump is a type of positive displacement pump powered by compressed air. It uses two flexible diaphragms that move back and forth to draw and discharge fluids. These pumps are valued for their versatility, reliability, and ability to handle abrasive or viscous materials.

How Does an AODD Pump Work?

Operation summary (step-by-step):

1. Compressed air inlet enters an air valve and is directed to one diaphragm chamber.

2. Air pressure pushes the diaphragm outward, forcing liquid from that chamber out of the discharge port while the opposite chamber creates suction and draws liquid in through the inlet valve.

3. A mechanical/air valve shifts when the diaphragm reaches the end of stroke, redirecting compressed air to the other diaphragm and repeating the cycle.

4. Check valves (ball/seat or flap) control inlet/discharge flow; diaphragms and pilot valves determine stroke timing and balance.

Key operating notes: flow is pulsating (can be smoothed with pulsation dampeners), maximum discharge pressure is limited by available air inlet pressure, and pump flow is a function of displacement per stroke × cycles per minute (see performance curve section below).

Performance Curve

Key Features & Benefits

• Air-powered / explosion-safe (ATEX options) — safe for flammable environments.
• Runs dry safely (in many designs) — minimal damage risk during intermittent operation.
• Handles abrasive & viscous fluids — slurries, sludges, paints, adhesives, cement slurries.
• Self-priming & solids handling — able to pass solids depending on port size (check spec).
• Low maintenance / quick service — modular diaphragms and valves reduce downtime.
• Material versatility — metallic (stainless steel, aluminum) and non-metallic (PP, PVDF, ECTFE) construction for aggressive chemicals.

Applications of AODD Pumps

AODD pumps are used across multiple industries for transfer, circulation, and dosing tasks. They are ideal where reliability and material compatibility matter most.

• Mining: Slurry transfer, dewatering, and reagent dosing
• Chemical Handling corrosive and hazardous materials
• Food & Beverage: Sanitary fluid transfer with gentle pumping action
• Pharmaceutical: Clean, controlled transfer of liquids
• Water Treatment: Sludge transfer, filter press feeding

Limitations of AODD Pumps

Air consumption: less energy-efficient compared to electrically driven pumps at high continuous flows — operating cost depends on compressed air supply efficiency.

Pulsation: inherently pulsating flow (mitigated with dampeners).

Pressure limit: max discharge pressure limited by available compressed air (many units up to ~7–8 bar for typical industrial AODD designs; high-pressure models differ).

Noise: pneumatic operation can be noisy; mufflers or silencers recommended.

Not ideal for high head continuous pumping: best for transfer, dosing, slurries, not for very high heads over long continuous duty.

Why Choose Sando AODD Pumps?

Sando AODD pumps combine industrial-grade reliability with material flexibility — offering metallic and non-metallic options (PP, PVDF, ECTFE) for aggressive chemistries, ATEX and hygienic variants, low maintenance design, and competitive flow/pressure ranges suited for chemical, paint, adhesives and slurry handling. Sando’s modular design reduces downtime and simplifies spare-parts inventory — making them a strong choice for OEMs, chemical processors and dealers.

• High-quality diaphragms and valve materials
• Optimized air distribution system for reduced icing
• Energy-efficient air control design
• Custom configurations for industry-specific needs