Progressive Cavity Pump Speed for Abrasive Fluids
Abrasion severity directly affects the recommended operating speed of a progressive cavity pump. Lower rotor/stator sliding speed can reduce wear, but maintaining the required flow may require selection of a larger pumping element.
Why Abrasive Service Requires Lower Pump Speed
In progressive cavity pumps, rotor-to-stator motion creates sliding contact. In abrasive service, wear is closely related to operating speed. Reducing speed decreases the rate of sliding wear; when the required capacity cannot be achieved at the reduced speed, the engineering solution is often to move to a larger pumping element rather than operate a smaller element too fast.
Abrasion Classification Used for Selection
| Abrasion Class | Representative Fluids |
|---|---|
| None | Water, polymer, oil |
| Light | Sewage, milk or lime |
| Medium | Sludge, clay or gypsum slurries, chocolate |
| Heavy | Emery dust, lapping compounds, drilling mud, grout |
2000 Series Suggested Maximum Pump Speeds for Abrasive Fluids
The following historical application-selection values show how maximum recommended RPM and corresponding capacity are progressively derated as abrasion increases. They are engineering selection guidance, not universal operating limits. Final pump selection must also account for viscosity, pressure, solids, particle size, materials and actual duty.
| Element | None | Light | Medium | Heavy | ||||
|---|---|---|---|---|---|---|---|---|
| RPM | GPM | RPM | GPM | RPM | GPM | RPM | GPM | |
| 008 | 880 | 70 | 704 | 56 | 528 | 42 | 352 | 28 |
| 012 | 815 | 97 | 652 | 77.6 | 489 | 58.2 | 326 | 38.8 |
| 018E | 600 | 118 | 450 | 89 | 300 | 59 | 150 | 30 |
| 022 | 724 | 159 | 580 | 127 | 434 | 95 | 289 | 63 |
| 033E | 550 | 192 | 420 | 146 | 275 | 96 | 140 | 49 |
| 036 | 656 | 226 | 525 | 181 | 394 | 135 | 262 | 90 |
| 050 | 600 | 300 | 480 | 240 | 360 | 180 | 240 | 120 |
| 054E | 460 | 266 | 340 | 201 | 230 | 133 | 120 | 71 |
| 065 | 573 | 367 | 458 | 293 | 343 | 220 | 229 | 147 |
| 075E | 450 | 370 | 340 | 279 | 225 | 185 | 120 | 99 |
| 090 | 520 | 468 | 416 | 374 | 312 | 280 | 208 | 187 |
| 098E | 400 | 438 | 300 | 329 | 200 | 219 | 100 | 110 |
| 115 | 497 | 607 | 398 | 486 | 298 | 364 | 199 | 243 |
| 175 | 450 | 748 | 360 | 599 | 270 | 449 | 180 | 299 |
| 335 | 302 | 995 | 242 | 796 | 181 | 597 | 121 | 398 |
| 345 | 330 | 1140 | 264 | 910 | 198 | 680 | 132 | 455 |
| 620 | 200 | 1860 | 161 | 1494 | 119 | 1116 | 80 | 744 |
| 800 | 300 | 2400 | 240 | 1920 | 180 | 1440 | 120 | 960 |
How to Use the Abrasion Table
First classify the pumped fluid by abrasion severity. Then locate the candidate element and compare the maximum recommended speed and resulting capacity for that abrasion class. If the candidate element cannot deliver the required flow at the reduced speed, evaluate the next larger element rather than exceeding the abrasion-based speed guidance.
Example: Medium-Abrasion Raw Sewage
For the worked raw-sewage application in the engineering training material, the service was classified as medium abrasion. The initially selected 008 element was shown at up to 528 RPM and approximately 42 GPM under the medium-abrasion column, so it could satisfy the required 40 GPM duty before the remaining pressure, speed and horsepower checks were completed.
Abrasion is only one part of the selection. High viscosity can impose a lower speed than abrasion, and abrasive service can also reduce recommended differential pressure per stage. The most restrictive applicable condition should control the selection.
Abrasion, Pressure and Stator Life
Abrasive particles can increase wear on both rotor and stator surfaces. Higher speed increases sliding distance per unit time, while higher differential pressure can increase slip and loading across the pumping element. For this reason, severe abrasive applications may require both lower RPM and additional stages to keep pressure per stage within the recommended range.
See the ACCA Stator Elastomer Compatibility & Ratings Guide →
Need Help Selecting a Pump for Abrasive Service?
Send ACCA the required flow, differential pressure, fluid description, solids concentration and size, viscosity, temperature and duty cycle. We can review the appropriate element size, operating speed, stages and materials for the application.
Moyno® is a registered trademark of its respective owner. ACCA Pumps is not affiliated with or endorsed by Moyno. Historical manufacturer model references and engineering data are used to identify compatibility and explain application-selection principles. Final selection should be verified for the specific operating conditions.