Technical Resource
Chemical Resistant Gear Pump
Plant transfer of solvents, dilute acids, and other fluids that attack iron or swell nitrile gears. Tank to tank, tote into process, load-out.
This page is for plant transfer of solvents, dilute acids, and other fluids that attack iron or swell nitrile gears. Tank to tank, tote into process, load-out. NAPCO builds the 2-inch and 3-inch rotary gear pumps for that job. See chemical processing for the rest of the fluid list.
NAPCO does not make lined exotic-alloy pumps or fire pumps.
What chemical resistant means here
The housing metal has to survive the fluid. The gear elastomer has to survive the solvent.
A stainless housing with the wrong gears still fails. Viton gears in a rusting iron case still fail.
Gears mesh and carry a fixed volume each turn. Shaft speed sets flow. System backpressure sets the load, up to 100 PSI. Details: rotary gear pump working principle.
NAPCO pumps prime themselves. Reverse the motor and the same line unloads.
Housing: stainless
This duty is the stainless S models. Live product copy puts chemical transfer on PA300S and PA200S. Ductile iron is the housing when the fluid does not attack iron. That is not this page.
If you do not have pH or a full SDS, spec stainless. Comparison: stainless steel vs ductile iron pumps.
The chemical transfer guide is the longer system-design piece. This page is the resistant-spec pick.
Gears: nitrile or Viton
Nitrile gears are standard, rated to 240°F. They hold up on petroleum, mineral oils, water-based emulsions, dilute acids, weak alkalis, glycols, and many ester solvents at moderate concentration.
They swell and fail in benzene, toluene, xylene, and other aromatics. They are incompatible with chlorinated solvents (trichloroethylene, carbon tetrachloride). Concentrated nitric acid and hydrogen peroxide attack them.
Viton gears are the option for those aromatics, chlorinated solvents, strong acids, and oxidizers. Product pages call Viton the aggressive-chemical gear. Viton seals are already on every NAPCO pump. The gear is the part you change with the solvent.
Send ketone formulas (MEK, acetone, and similar) in before you order gears. Do not assume either elastomer is safe there.
Which model
PA300S
The PA300S is the 3-inch stainless pump. 158 GPM at 280 RPM and 10 PSI. 140 GPM at 100 PSI. 13.4 bhp at 100 PSI. Max 100 PSI, max 280 RPM, 173 lbs. 3-inch NPT.
Plant pump-over, tanker load and unload, high-volume solvent or chemical transfer.
PA200S
The PA200S is the 2-inch stainless pump. 69 GPM at 190 RPM and 10 PSI. 60 GPM at 100 PSI. 5.7 bhp at 100 PSI. Max 100 PSI, max 190 RPM, 114 lbs.
Tote and drum work, smaller batch lines.
Both sizes prime themselves and run either direction. C models are the non-corrosive spec. See PA300C if the fluid does not attack iron.
Rebuild
A factory kit is gears, seals, bearings, and gaskets. 2 to 5 hours on the 3-inch (PK300S). 2 to 4 hours on the 2-inch (PK200S). Hand tools. The product pages put kit cost at 30 to 50 percent of a new pump.
Performance tables on the product pages are water at rated speed. Thicker solvents and resins often need a lower RPM. Size from measured viscosity at pumping temperature, plus flow and pressure. Sizing: how to size a rotary gear pump.
Jobs this pump should not take
This is surface transfer, not a high-pressure injection skid and not a fire pump. NAPCO’s tested ceiling is 100 PSI.
If the gears swell or the housing rusts, change the elastomer or the metal. The pump type can stay if the job is still surface transfer.
FAQ
What is a chemical resistant gear pump?
A rotary gear pump specified so the housing and the gears survive the fluid. For NAPCO that is usually a stainless PA300S or PA200S, with nitrile or Viton gears picked from the SDS.
Iron or stainless? Nitrile or Viton?
Stainless for this duty. Iron only when the fluid does not attack iron, which is a different spec. Nitrile gears on petroleum and many water-based fluids, to 240°F. Viton on aromatics, chlorinated solvents, strong acids, and oxidizers. Send ketone formulas in.
Can it pump solvents?
Yes, on surface transfer, if the housing and gears match the solvent. Aromatics need Viton gears. Chlorinated solvents need Viton gears. Stainless if iron is a risk.
PA300S or PA200S?
PA300S up to 158 GPM. PA200S up to 69 GPM. Both 100 PSI. Stainless housing on both.
Specifying a chemical resistant gear pump
Send fluid type, SDS if you have it, viscosity at pumping temperature, flow, pressure, temperature, and whether the solvent is aromatic, chlorinated, or a ketone. We will confirm housing, gears, and size.