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HDF3 and HDF4 Metallic 3″ (80mm) and 4″ (100mm) AODD – Flap Valve Pumps

Sandpiper has your pumping solution for fluids containing up to 3″/4″ line-size solids!

The Sandpiper HDF3 and HDF4 heavy-duty flap valve pumps have a proven design that solves the most common challenges in sump applications, mine dewatering and any liquid application involving solids.

These air-operated double-diaphragm (AODD) pumps are recommended for abrasive slurries, suspended and non-suspended solids and up to 3″/4″ line-size solids. The heavy-duty flap valve pumps are configured with bottom discharge porting to provide superior suction lift and prevent settling solids from shortening pump life.HDF3 and HDF4 pumps are thick wall-constructed of sand-casted aluminum, cast iron and stainless steel with elastomer and TPE (thermoplastic elastomer) diaphragms and check valves.

HDF3 and HDF4 pump designs have recently been optimized for performance as part of the Sandpiper Evolution portfolio improvement. These efficient pumps experienced a 19% flow rate increase, with a new maximum flow rate of up to 310 gpm (1,173 lpm).




  1. Line-size solids handling
  2. Flap valve versus ball valve pumps
  3. Flap check valve pumps: A large flow area allows up to 3″/4″ line-size solids to pass directly through the pump. Additionally, bottom discharge porting allows settling solids to pass through the pump and not settle inside the pumping chamber, preventing damage and premature wear.
  4. Ball check valve pumps: Much less flow area for solids to pass through. Large solids get stuck in the suction manifold and small solids can settle in the outer chamber–both issues affect pump performance.
  5. Superior suction lift
  6. Flap valve versus ball valve pumps
  7. Suction lift advantage: SANDPIPER’s flap valve design provides superior suction lift capabilities up to 24 ft in water. Diaphragm placement and flap valve seating combine to create a unit capable of suction lifts 15% greater than ball valve pumps.
  8. Dry prime: These capabilities are from a dry prime, making the SANDPIPER flap valve pump an excellent solution for situations where limited choices are available for pump priming.
  1. Intake/Discharge Pipe Size: 3″/4″ 150# ANSI Flange
  2. Capacity: 0 to 988 litres/minute
  3. Air Valve: No-lube, no-stall design
  4. Solids Handling: Up to nearly 75mm
  5. Heads up to: 88m

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