Progressive Cavity Pump Pressure per Stage – Elastomer & Abrasion Guide
Progressive cavity pump stage selection depends on differential pressure, stator elastomer, element size, rotor/stator geometry and abrasion severity.
This guide presents the pressure-per-stage selection limits used for industrial and sanitary progressive cavity pump configurations and shows how they determine the required number of stages.
How to Determine the Number of Stages
Determine the approximate number of rotor stages by dividing the maximum differential pressure by the maximum recommended pressure per stage for the applicable elastomer, element size and abrasion condition. If the result is fractional, round up to the next higher available number of stages.
Stage Selection Formula
Required stages = Maximum differential pressure ÷ Maximum recommended pressure per stage
Always round a fractional result upward to an available standard stage configuration.
Suggested Maximum Pressure per Stage — 1:2 Ratio
Industrial Pump
| Elastomer Code | Pump Element Size | No Abrasion | Light | Medium | Heavy |
|---|---|---|---|---|---|
| Q, B, F | 1 | 58 PSID | 43.5 PSID | 29 PSID | 14.5 PSID |
| Q, B, F | 2 thru 8D and A thru K | 87 PSID | 65.25 PSID | 43.5 PSID | 21.75 PSID |
| R | 1 | 38.7 PSID | 29 PSID | 19.3 PSID | 9.7 PSID |
| R | 2 and above, A thru K | 58 PSID | 43.5 PSID | 29 PSID | 14.5 PSID |
Sanitary Pump
| Elastomer Code | Pump Element Size | No Abrasion | Light | Medium | Heavy |
|---|---|---|---|---|---|
| E, B, V | 3 thru 66 | 75 PSID | 56.25 PSID | 37.5 PSID | 18.75 PSID |
| R | 3 thru 66 | 58 PSID | 43.5 PSID | 29 PSID | 14.5 PSID |
Suggested Maximum Pressure per Stage — 2:3 Ratio
| Elastomer Code | Pump Element Size | No Abrasion | Light | Medium | Heavy |
|---|---|---|---|---|---|
| Q, B, F | 2E thru 800E and AE thru KE | 100 PSID | 75 PSID | 50 PSID | 25 PSID |
Worked Example: 125 PSI Raw Sewage
Consider a raw-sewage application with 125 PSI differential pressure, medium abrasion, and an 008 element. For the applicable industrial elastomer group and element category, the maximum recommended pressure per stage is 43.5 PSID.
125 PSI ÷ 43.5 PSID per stage = 2.87 stages
A 2.87-stage pump is not a standard configuration, so the selection must move to the next available stage count: 4 stages. The example therefore becomes a 4-stage 008 element configuration.
Why Abrasion Changes Stage Count
For the same elastomer and element group, the recommended pressure per stage falls as abrasion severity increases. A duty that can use fewer stages with a non-abrasive fluid may require additional stages when the pumped material is abrasive.
Pressure per Stage Is Not the Complete Pump Pressure Rating
After determining the pumping-element stage requirement, the selected drive end and internal materials must also be checked against their allowable pressure limits. The drive/element combination can impose a separate maximum operating-pressure constraint.
Stage count should therefore be treated as one part of the complete selection process: fluid characteristics → element size → abrasion/viscosity speed → stages → actual RPM → drive-end selection → horsepower.
Related Engineering References
Progressive Cavity Pump Speed for Abrasive Fluids – 2000 Series →
Progressive Cavity Pump Speed for Viscous Fluids – 2000 Series →
Need Help Determining the Correct Number of Stages?
Send ACCA the fluid, differential pressure, flow, viscosity, abrasion severity, solids information, temperature and existing pump configuration. We can review element size, stage count, operating speed, materials and drive-end requirements.
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