How to Select a Graco AODD Pump: Size, Flow and Materials
The correct order for selecting a Graco Husky air-operated double diaphragm pump is to establish fluid and material compatibility, define the real duty point, and then verify air supply, connections and approvals. Selecting only by port size or maximum flow can result in inadequate capacity, excessive air consumption, swollen elastomers or stuck check balls.
1. Collect six groups of duty data
- Fluid name, every component and concentration, temperature and pH.
- Viscosity, density, solids content, largest particle and abrasiveness.
- Normal, minimum and maximum required flow.
- Suction lift, discharge pressure, pipe size, length, fittings and valves.
- Available air pressure, air volume and compressed-air quality.
- Hazardous-area, sanitary, grounding and connection requirements.
2. Husky sizes and maximum free-flow capacity
| Product | Port | Maximum free flow | Typical role |
|---|---|---|---|
| Husky 205 | 1/4 in | 19 L/min | OEM and low-flow transfer |
| 3/8 in plastic pump | 3/8 in | 26.5 L/min | Portable, low-flow duties |
| 1/2 in plastic pump | 1/2 in | 57 L/min | Corrosive-fluid and equipment duties |
| Husky 716 | 3/4 in | 61 L/min | General transfer |
| Husky 1050 | 1 in | 189 L/min | Common industrial transfer |
| 1.5 in metal pump | 1.5 in | 378.5 L/min | Higher-flow industrial duty |
| 2 in plastic pump | 2 in | 568 L/min | High-flow corrosive service |
| 3 in metal pump | 3 in | 1,041 L/min | High flow and viscous transfer |
Maximum free flow is not the duty flow. Back pressure, suction conditions, viscosity and piping losses reduce capacity. Once a size is shortlisted, plot the actual flow and outlet pressure on its performance chart and check both operating air pressure and consumption.
3. Check every wetted material
Fluid sections may be polypropylene, PVDF, acetal, aluminium, stainless steel or Hastelloy, while diaphragms, balls and seats use a separate set of elastomers and polymers. A compatible casing does not make an incompatible diaphragm safe. Review the whole wetted assembly.
- PP and PVDF are often evaluated for corrosive chemicals, subject to temperature limits.
- For abrasive slurries, do not select solely for the broadest chemical resistance; wear performance matters.
- High-temperature, solvent and hazardous fluids require confirmation against the current material and approval data.
4. Viscosity, particles and suction
AODD pumps can handle viscous and solids-bearing media, but increasing viscosity raises suction loss and reduces actual flow. Keep the suction line short and generously sized, minimise fittings, prefer flooded suction, and apply the manufacturer's viscosity correction. Maximum solids passage is model-specific.
5. Do not undersize the air system
Air pressure determines whether the pump can overcome discharge pressure; air volume determines achievable cycling rate. Small air lines, clogged filters and insufficient compressor reserve can make a correctly sized pump underperform. Moisture control also reduces icing at the air valve and muffler.
Browse the diaphragm pump range. The selection method follows Graco's official AODD selection guidance; final configuration must be checked against the relevant model manual.