28 GPM -- 3/4" Port Size


Click link to download printable PDF for:

NDP-20 Specs, Curves, Drawings (540K)

Bill of Materials

Maintenance Manual (1.14MB)


Port Dimensions

Intake & Discharge Connection

Polypropylene (PPG): 3/4" Female NPT
or 3/4" ANSI Flange B16.5 #150

Aluminum (ADC-12): 3/4" Female NPT

Stainless Steel (316): 3/4" Female NPT

Air Inlet

1/4" Female NPT (includes ball valve)

Air Exhaust

3/4" Female NPT (includes silencer)

Maximum Liquid Temperature*

Diaphragm Material / Temperature

Neoprene: 180°F (82°C)

Buna N: 180°F (82°C)

EPDM: 212°F (100°C)

Hytrel® (TPE) 248°F (120°C)

Santoprene® (TPO) 225°F (107°C)

Viton® fluoroelastomer 248°F (120°C)

Teflon® (PTFE) 212°F (100°C)

*Polypropylene pumps have a maximum liquid temperature of 180°F (82°C) regardless of diaphragm material.

Air Supply Pressure (All Models)

20 to 100 PSI (1.4 to 7 kgf/cm²)

Discharge Volume Per Cycle

Rubber diaphragm: 0.14 gallons (490 cc)

PTFE diaphragm: 0.10 gallons (290 cc)

Maximum Cycles Per Minute

Rubber diaphragm: 195

PTFE diaphragm: 195

Maximum Size Solid

1/16" (2.0 mm)

Maximum Dry Suction Lift

Rubber-fitted pump capability: 18-feet

Air Motor

Standard: Aluminum

Optional: Epoxy-coated, Teflon-coated, or Electroless Nickel Plate

Notes: Hytrel®-fitted pumps include Buna N check balls & wetted o-rings. Santoprene®-fitted pumps include EPDM check balls & wetted o-rings.

NDP-20 Metal NPT
NDP-20 Poly Flange
NDP-20 Poly NPT
NDP-20 Metal NPT
NDP-20 Poly Flange
NDP-20 Poly NPT
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Nordel®, Teflon®, & Hytrel® are registered trademarks of DuPont Dow Elastomers. Viton® is a registered trademark of DuPont Performance Elastomers. Santoprene® is a registered trademark of Monsanto Co. Swagelok® & VCR® are trademarks of the Swagelok Companies. Flaretek® is a registered trademark of Entegris®. Kynar® is a registered trademark of ATOFINA®. Ryton® is a registered trademark of Chevron Phillips Chemical Company. AutoCAD® is a registered trademark of Autodesk, Inc. Due to Yamada’s continued commitment to product improvement, specifications may change without notice.