WILDEN AODD Pump – High Viscosity, Paste and Sludge Transfer

Air-operated diaphragm pumps handle thick liquids better than most centrifugal pumps, because they are positive displacement pumps and have no close-fitting rotating parts. But viscosity still affects how a WILDEN pump performs, and sizing it well makes a big difference.

What changes with thick liquids

• Flow falls as viscosity rises, so the maximum flow on a data sheet is a water figure
• The pump needs time to fill each chamber; running it fast wastes air without moving more product
• Suction lift becomes harder, so a flooded suction helps

Sizing tips

• Choose a larger pump and run it slowly rather than a small pump at full speed
• Keep suction lines short and generously sized
• Use full-stroke rubber diaphragms where the chemistry allows; PTFE builds often run a reduced stroke

For reference, Wilden’s maximum flows on water range from 5 gpm (19 L/min) for the 1/4 inch P.025 to 277 gpm (1049 L/min) for the 4 inch XPS20. On a thick paste the real figure will be lower.

Send us the product, its viscosity or a description, and the flow you need. We will recommend a size based on that, not on the water rating.