Progressive Cavity Pump Stator Elastomer Guide
Compatibility and performance screening for the elastomer families ACCA supplies in progressive cavity pump stators.
Stator material selection affects swelling, heat generation, abrasion resistance, chemical attack, starting torque and service life. This guide is intended as an engineering screening tool—not a substitute for reviewing the actual fluid, concentration, temperature and cleaning chemistry.
How to Read the Ratings
The ratings below are broad polymer-family screening values. Actual stator performance depends on the specific ACCA compound, rotor/stator interference, fluid concentration, temperature, exposure time, solids, speed and cleaning agents.
Performance Rating Legend
Excellent = commonly strong fit for that service category. Good = generally suitable with normal application review. Conditional = strongly dependent on exact chemistry, concentration or temperature. Poor = generally not a preferred choice for that service.
ACCA Stator Elastomer Performance Rating Table
| ACCA Material / Family | Typical Hardness / Legacy Code | Abrasion | Oils & Petroleum | Water / Wastewater | Acids | Alkalis | Solvents | Heat Capability* | Typical Use |
|---|---|---|---|---|---|---|---|---|---|
| NBR / Nitrile | 70A · Q Nitrile 100 | Excellent | Excellent | Good | Good | Good | Conditional | Medium | General industrial, sludge, oils, wastewater |
| NBR / Nitrile 103 | 50A · C | Good | Excellent | Good | Good | Good | Conditional | Medium | Softer-interference applications requiring NBR chemistry |
| NBR / Nitrile 110 | 70A · E | Excellent | Excellent | Good | Good | Good | Conditional | Medium | General industrial NBR service |
| NBR / Nitrile 100M | 70A · M | Excellent | Excellent | Good | Good | Good | Conditional | Medium | General industrial NBR service |
| White NBR | 70A · Z Nitrile 150 | Excellent | Excellent | Good | Good | Good | Conditional | Medium | Applications requiring a white nitrile compound; compliance must be verified separately |
| HNBR | Current ACCA option; compound-specific | Excellent | Excellent | Good | Good | Good | Conditional | High | Abrasion, oilfield, elevated-temperature and demanding industrial service |
| EPDM | 70A · B EPDM 300 | Good | Poor | Excellent | Excellent | Excellent | Good | High | Water, wastewater, many acids/alkalis, cleaning solutions |
| FKM / Fluoroelastomer | 75A · F Fluoroelastomer 500 | Good | Excellent | Conditional | Excellent | Conditional | Good | Very High | Hydrocarbons, aggressive chemicals and elevated temperature |
| Natural Rubber | 55A · R Natural Rubber 200 | Excellent | Poor | Excellent | Good | Good | Poor | Low | Highly abrasive aqueous slurries where oil resistance is not required |
| Urethane / PU | 70A · U | Excellent | Excellent | Conditional | Conditional | Conditional | Conditional | Medium | Severe mechanical wear and abrasion; chemistry must be reviewed closely |
| CSM / Hypalon-type | 70A · K Hypalon 800 | Good | Good | Good | Excellent | Good | Conditional | High | Oxidizing environments, weathering and selected chemical services |
| Polysulfide / Thiokol-type | 70A · P | Fair | Excellent | Good | Good | Good | Good | Medium | Fuel, oil and solvent-resistant legacy applications |
| Special Application Compound | X | Application-specific | Application-specific | Application-specific | Application-specific | Application-specific | Application-specific | Application-specific | Custom compound selected after application review |
*Heat Capability is a relative screening category, not a published maximum stator operating temperature. Pump geometry, interference, speed and process fluid can lower allowable service temperature.
Legacy ACCA / Compatible Stator Material Codes
ACCA L-Frame documentation identifies the following elastomer suffixes for compatible stator part numbers. The same code system is useful when decoding existing stators and replacement requirements.
| Code | Material | Durometer |
|---|---|---|
| B | EPDM 300 | 70 |
| C | Nitrile 103 | 50 |
| E | Nitrile 110 | 70 |
| F | Fluoroelastomer 500 | 75 |
| K | Hypalon 800 / CSM-type legacy designation | 70 |
| M | Nitrile 100M | 70 |
| P | Thiokol / polysulfide-type legacy designation | 70 |
| Q | Nitrile 100 | 70 |
| R | Natural Rubber 200 | 55 |
| U | Urethane | 70 |
| X | Special to application | — |
| Z | White Nitrile 150 | 70 |
ACCA Stator Chemical Compatibility Matrix
This matrix is a screening guide for elastomer families. It is not an approval for a specific stator compound or a guarantee of service life. Ratings can change materially with concentration, temperature, contaminants, cleaning chemicals, exposure time and rotor/stator heat generation.
Chemical Matrix Legend
A = preferred screening candidate. B = generally suitable. C = conditional; verify concentration, temperature and compound. D = generally avoid. R = application/compound review required because generic family data are not sufficient.
Water, Wastewater & Food/Process Fluids
| Fluid / Service | NBR | HNBR | EPDM | FKM | Natural Rubber | Urethane | CSM / Hypalon-type | Polysulfide |
|---|---|---|---|---|---|---|---|---|
| Fresh water | A | A | A | B | A | B | A | B |
| Municipal sewage / wastewater | A | A | A | A | A | C | A | B |
| Seawater / sodium-chloride brine | A | A | A | A | B | C | A | B |
| Wine / must / whiskey | A | A | A | A | B | R | B | R |
| Ethyl alcohol / ethanol | B | B | A | A | B | C | B | R |
| Vegetable oils | A | A | C | A | D | A | B | A |
| Polymer solutions used in wastewater | A | A | A | B | B | C | B | R |
| Lime slurry / calcium hydroxide slurry | B | B | A | C | B | C | B | R |
Petroleum, Fuels & Oilfield Fluids
| Fluid / Service | NBR | HNBR | EPDM | FKM | Natural Rubber | Urethane | CSM / Hypalon-type | Polysulfide |
|---|---|---|---|---|---|---|---|---|
| Mineral oil / lubricating oil | A | A | D | A | D | A | B | A |
| Hydraulic oil, petroleum base | A | A | D | A | D | A | B | A |
| Diesel / fuel oil | A | A | D | A | D | B | B | A |
| Gasoline | B | A | D | A | D | C | C | A |
| Crude oil | A | A | D | A | D | B | B | A |
| Produced water with hydrocarbon contamination | A | A | C | A | C | B | B | A |
| Drilling mud — water based | A | A | A | B | A | B | B | R |
| Drilling mud — oil based | A | A | D | A | D | B | B | A |
Common Water-Treatment & Process Chemicals
| Chemical / Service | NBR | HNBR | EPDM | FKM | Natural Rubber | Urethane | CSM / Hypalon-type | Polysulfide |
|---|---|---|---|---|---|---|---|---|
| Sodium hydroxide / caustic soda | B | B | A | C | B | C | B | R |
| Sodium hypochlorite / bleach solution | B | B | A | A | C | D | A | R |
| Sulfuric acid — dilute/moderate concentration | C | C | A | A | C | D | A | R |
| Hydrochloric acid — dilute/moderate concentration | C | C | A | A | C | D | A | R |
| Ferric chloride solution | C | C | A | A | C | D | A | R |
| Alum / aluminum sulfate solution | B | B | A | A | B | C | A | R |
| Sodium carbonate / soda ash | A | A | A | A | B | C | A | R |
| Hydrogen peroxide | C | C | A | A | C | D | A | R |
Important: “Sulfuric acid,” “hydrochloric acid,” “bleach,” “caustic,” and similar names do not define one operating condition. Hot or concentrated solutions can change a rating by one or more grades. Mixed fluids can behave differently from each component by itself. For critical service, ACCA should review the actual SDS/process composition and operating temperature before final stator selection.
Temperature: Use Compound-Specific Limits
Generic polymer charts are useful for comparison, but a progressive cavity stator is not an O-ring. The elastomer is continuously flexed and compressed by the rotor, creating internal heat. ACCA therefore recommends using the specific stator compound and pump-family limit when available.
For example, the 500 Series service documentation lists NBR at 10–160°F, EPDM at 10–210°F and FPM/FKM at 10–240°F for those pump models. Those values should not be automatically applied to other ACCA stator families.
Quick Material Selection Guidance
Oils & Hydrocarbons
Start with NBR, HNBR or FKM. EPDM and natural rubber are generally poor choices for petroleum exposure.
Water & Wastewater
EPDM, NBR and natural rubber are common screening candidates depending on oil contamination, chemicals, solids and temperature.
Abrasive Slurry
Natural rubber, HNBR, NBR and urethane can be strong candidates, but speed and rotor finish are equally important.
Acids / Alkalis
EPDM and FKM often provide strong chemical resistance in different chemical families. Exact concentration and temperature must be checked.
Elevated Temperature
FKM and HNBR generally provide higher heat capability than standard NBR or natural rubber, subject to pump-specific limits.
Unknown Chemistry
Do not select by generic elastomer name alone. Provide fluid composition, concentration, temperature and cleaning chemistry for review.
Why Stator Compatibility Can Fail
Elastomer failure may appear as swelling, softening, hardening, cracking, chunking, blistering or loss of interference. Chemical incompatibility is only one cause. Dry running, excessive speed, high differential pressure, abrasive solids, poor suction filling and an incorrect rotor/stator fit can produce similar symptoms.
Engineering Reference Basis
The family-level compatibility screening in this guide is cross-checked against established elastomer references including the Parker O-Ring Handbook and Trelleborg Chemical Compatibility Guide. These references describe generic elastomer behavior; ACCA stator selection still requires pump-specific and compound-specific review.
Related ACCA Resources
Progressive Cavity Pump Parts
Rotors, stators, joints, shafts, seals and repair components.
Moyno® Compatible Stators
ACCA stators engineered for supported Moyno® progressive cavity pump models.
PC Pump Troubleshooting
Diagnose capacity loss, suction problems, noise, seizure and uneven flow.
Need an Elastomer Recommendation?
Send ACCA the fluid name, concentration, operating temperature, solids, cleaning agents, current stator material and previous failure mode. We can narrow the appropriate stator compound for the application.