Technical Resource
PA200S 2″ Stainless Steel Gear Pump: Spec Guide & Applications
A complete spec guide for the NAPCO PA200S, a 2-inch stainless steel rotary gear pump built for corrosive fluid transfer, chemical processing, emulsion explosives, and food-grade service.
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 stainless steel housing and shaft, the PA200S is built for customers who need corrosion resistance in a compact, field-serviceable package.
This guide covers the PA200S specifications, performance data, application fit, gear options, and service requirements.
PA200S Quick Specifications
| Part Number | PA200S |
| Port Size | 2″ NPT |
| Housing Material | Stainless Steel |
| Gear Material | Nitrile (standard) or Viton (optional) |
| Max 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
On the PA200S, the housing and shaft are stainless steel rather than ductile iron. 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 near-constant flow regardless of viscosity or pressure.
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 repeatable batching and recirculation, with near-constant flow regardless of viscosity or pressure. Viton gears are recommended for aromatic solvents and elevated temperatures.
Read more: Rotary Gear Pumps for Chemical Processing
Emulsion Explosives and Mining
Ammonium nitrate emulsion is corrosive to ductile 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.
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 | Rated to 240°F | Extends the range above 240°F |
| Chemical resistance | Good for oils, fuels, mild chemicals | Excellent for solvents, acids, aromatics |
| Relative cost | Lower | Premium |
For aromatic solvents, aggressive chemicals, or sustained elevated temperatures, specify Viton.
Installation and Operation Notes
The PA200S is self-priming when wetted. Never run it dry. 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 |
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.
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.