The PA200S is NAPCO's 2-inch stainless steel rotary gear pump. It is built for corrosive fluid transfer, food-grade service, and chemical applications where a ductile iron housing would fail. With a 69 GPM nominal flow rate, 100 PSI pressure rating, and full stainless steel wetted path, the PA200S is the most specified NAPCO pump for customers who need corrosion resistance in a compact, field-serviceable package.
This guide covers the PA200S specifications, performance data, application fit, gear options, model variants, and service requirements.
PA200S Quick Specifications
| Part Number | PA200S |
| Port Size | 2" NPT |
| Housing Material | Stainless Steel |
| Gear Material | Nitrile (standard) or Viton (optional) |
| Displacement | 11.5 cc/rev |
| Nominal Speed | 190 RPM |
| Max Flow Rate | 69 GPM @ 10 PSI |
| Flow @ 100 PSI | 60 GPM |
| Max Pressure | 100 PSI |
| Rotation | Bi-directional (CW/CCW) |
| Priming | Self-priming |
| Weight | 114 lbs |
| Repair Kit | PK200S |
All performance data is based on water at ambient conditions with a specific gravity of 1.0. Actual flow, pressure, and power requirements vary with viscosity, temperature, and suction conditions.
What Makes the PA200S a Stainless Steel Gear Pump
A stainless steel gear pump is defined by its wetted path: housing, shafts, and end covers are manufactured from stainless steel rather than cast iron or ductile iron. On the PA200S, the entire fluid-contact path is stainless steel. This matters because the housing is the first surface to corrode when a pump handles acids, caustics, salt water, or aggressive solvents.
The PA200S uses the same rotary gear pump working principle as NAPCO's ductile iron models. A drive gear and idler gear mesh inside a close-tolerance housing, trapping fluid between gear teeth and moving it from suction to discharge. The positive displacement design delivers a consistent volume per revolution regardless of viscosity changes or discharge pressure within the operating range.
For a side-by-side comparison of materials, see our Stainless Steel vs. Ductile Iron Pumps guide.
PA200S Performance and Flow Characteristics
The 2-inch frame size sits between small metering pumps and large 3-inch process pumps. At 190 RPM, the PA200S produces enough flow for tank transfer, reactor charging, and process circulation without the capital cost or footprint of a larger pump.
| RPM | PSI | GPM | HP |
|---|---|---|---|
| 190 | 10 | 69 | 0.65 |
| 190 | 30 | 65 | 1.8 |
| 190 | 50 | 64 | 3.2 |
| 190 | 70 | 62 | 4.0 |
| 190 | 100 | 60 | 5.7 |
Because output is proportional to speed, flow can be adjusted with a variable frequency drive, gear reducer, or pulley change. NAPCO pumps are not designed for throttling on the discharge side. Choking flow with a valve increases pressure, heat, and wear without reducing energy use.
For complete sizing guidance across the NAPCO product line, see How to Size a Rotary Gear Pump.
Where the PA200S Is Used
The PA200S is specified wherever the combination of corrosion resistance, moderate flow, and positive displacement accuracy is required.
| Application | Fluid Examples | Why PA200S Fits |
|---|---|---|
| Chemical transfer | Acids, caustics, solvents, oxidizers | Stainless housing resists corrosive attack; Viton option for aggressive chemicals |
| Emulsion explosives | Ammonium nitrate emulsion, bulk matrix | Proven mining pump; stainless shaft and housing handle corrosive oxidizers |
| Food & beverage | Syrups, concentrates, flavorings | Stainless construction suitable for food-grade transfer; self-priming for drums and totes |
| Petroleum & fuel | Diesel, fuel oil, lube oil | Nitrile gears standard for petroleum service; bi-directional for loading/unloading |
| Adhesives & sealants | Solvent-based adhesives, sealants | Positive displacement handles viscous, shear-sensitive materials |
| Paint & coatings | Paints, resins, coatings | Consistent flow for batching and circulation; Viton gears for solvent-rich fluids |
Chemical Processing
In chemical plants, the PA200S moves acids, bases, and solvents that would attack a ductile iron pump within months. The positive displacement action gives accurate batching and recirculation independent of viscosity. Viton gears are recommended for aromatic solvents, ketones, and elevated temperatures.
Read more: Rotary Gear Pumps for Chemical Processing
Emulsion Explosives and Mining
Ammonium nitrate emulsion is corrosive to carbon steel and cast iron. The PA200S is used worldwide as a mining pump for bulk emulsion transfer from manufacturing plants to mobile loading trucks and remote mine sites. The Orica-spec variant (PA200STA) adds a Speedi-Sleeve and additional assembly labor for customers who require that specification.
Read more: Gear Pumps for Explosives & Mining
Food & Beverage
Stainless steel construction makes the PA200S a practical choice for food-grade transfer of syrups, concentrates, and pastes. The self-priming design draws product directly from tanks and drums without external priming equipment.
Read more: Rotary Gear Pumps for Food & Beverage
Gear Elastomer Selection: Nitrile vs. Viton
The PA200S ships with Nitrile gears as standard. Viton gears are available for a material upgrade when chemical or temperature conditions demand it.
| Feature | Nitrile (NBR) | Viton (FKM) |
|---|---|---|
| Standard application | Petroleum products, water-based fluids, emulsion explosives | Aromatic solvents, aggressive chemicals, high temperatures |
| Temperature range | Standard industrial range | Higher temperature tolerance |
| Chemical resistance | Good for oils, fuels, mild chemicals | Excellent for solvents, acids, aromatics |
| Relative cost | Lower | Premium |
For applications with aromatic content above 10 percent or sustained elevated temperatures, specify Viton. The part number becomes PA200SV.
PA200S Model Variants and Upgrades
| Part Number | Description | When to Specify |
|---|---|---|
| PA200S | 2" Stainless Steel Rotary Gear Pump — Nitrile gears | Standard corrosive fluid transfer |
| PA200SV | 2" Stainless Steel Rotary Gear Pump — Viton gears | Aggressive chemicals, solvents, high temperature |
| PA200C | 2" Ductile Iron Rotary Gear Pump — Nitrile gears | Lower cost, non-corrosive or abrasive service |
| PA200C MOD | 2" Ductile Iron with Stainless Steel Shafts | Corrosion concern limited to shaft area |
| PA200SO1 | 2" Stainless Steel — Adhesive Application | Adhesive and sealant service |
| PA200STA | 2" Stainless Steel — Orica Spec | Speedi-Sleeve and extra labor for Orica specification |
If you are unsure whether stainless or ductile iron is the right housing, see Ductile Iron Gear Pumps for the alternative.
Installation and Operation Notes
The PA200S is self-priming when wetted, but it should not be run dry for extended periods. Key installation points:
- Use a full-size suction line. Undersized suction creates cavitation and flow loss.
- Avoid long vertical suction lifts. Gear pumps have limits on suction lift depending on fluid viscosity and vapor pressure.
- Do not side-load the shaft. Use a jackshaft or bearing arrangement if belt or gear driving.
- Mount on a rigid base. Pump and driver alignment affects bearing and seal life.
- Install a relief valve or pressure protection. Positive displacement pumps can over-pressurize a blocked discharge.
For troubleshooting flow, pressure, or noise issues, see the Gear Pump Troubleshooting Guide.
Service, Rebuild, and Parts
The PA200S is designed to be rebuilt in the field. The standard repair kit is PK200S, which includes the wear components required for a typical rebuild. Regular service extends pump life and avoids unplanned downtime.
| Service Item | Part Number | Notes |
|---|---|---|
| 2" Stainless Repair Kit | PK200S | Full rebuild kit for PA200S |
| High Pressure Seal | PM036 | 4 per pump, in bearing housing |
| Low Pressure Seal | PM037 | 4 per pump, in bearing housing |
| Centercase Gasket | PM007G01 / PM007G02 | Used to set gear clearance |
A step-by-step rebuild guide is scheduled for publication. Until then, the PK200S repair kit contains the components needed for a standard PA200S rebuild.
Frequently Asked Questions
What is the maximum pressure of the PA200S?
The PA200S is rated for 100 PSI maximum discharge pressure.
What is the maximum flow rate of the PA200S?
At 190 RPM and 10 PSI discharge pressure, the PA200S delivers 69 GPM with water. Flow decreases slightly as discharge pressure increases.
Is the PA200S self-priming?
Yes. The PA200S is self-priming when wetted. It will draw fluid from a source below the pump inlet without external priming assistance.
Can the PA200S run in both directions?
Yes. The PA200S is bi-directional and can be configured for clockwise or counter-clockwise rotation. Reverse rotation is useful for loading and unloading operations.
When should I choose Viton gears over Nitrile gears?
Specify Viton for aromatic solvents, aggressive chemicals, elevated temperatures, or any fluid known to attack Nitrile. The part number becomes PA200SV.
What is the difference between the PA200S and the PA200C?
The PA200S has a stainless steel housing and shaft for corrosion resistance. The PA200C has a ductile iron housing and is lower cost for non-corrosive applications.
What repair kit fits the PA200S?
Use the PK200S 2-inch stainless repair kit for standard rebuilds.
Ready to Specify a PA200S?
Request a quote for the PA200S or compare it to the 2" ductile iron version for your application.