D MARK III · IMPELLER FITMENT
Durco Mark III Reverse-Vane Impeller Replacement and Fitment Guide
Review the reverse-vane impeller, rear cover relationship, material and installed pump configuration before ordering a replacement.
The impeller, rear cover, shaft and seal chamber should be reviewed as one installed relationship. A pump-family name alone is not enough to confirm fitment.
DURCO MARK III IMPELLER
Review the rotating and stationary parts together.
The brochure identifies a reverse-vane impeller and external impeller adjustment. Confirm the applicable Group, size, impeller reference, rear cover, shaft arrangement, material and operating duty.
DESIGN REFERENCE
Impeller specification context
Use these documented features as review prompts, not as a substitute for the installed drawing.
ENGINEERING COMPARISON
Reverse-Vane vs. Fully Open Impeller
Different geometries require separate casing, rear cover, shaft, seal-chamber and duty confirmation.
Main design
Fully open impeller for the applicable 3196 configuration.
Reverse-vane impeller identified in the D Mark III brochure.
Pump-out action
Back pump-out vanes help control seal-chamber pressure and axial thrust.
Reverse-vane design manages the rear-side clearance and seal environment.
Clearance adjustment
Confirm the applicable 3196 configuration and drawing.
Confirm the rear cover and applicable Mark III configuration.
Replacement check
Review impeller, casing, seal chamber, shaft and duty.
Review impeller, rear cover, shaft, Group, size, material and duty.
Do not treat the two impellers as directly interchangeable without pump-specific confirmation.
FITMENT CHECKER
Build the review summary
These fields prepare an RFQ summary. They do not approve fitment automatically.
Complete the known fields to prepare a structured review summary.
What Must Be Confirmed Before Ordering
- Group / ANSI designation and pump size
- Impeller reference or OEM number, diameter and trim
- Material, shaft and keyway arrangement
- Rear cover condition and seal-chamber configuration
- Speed, flow, head, fluid and operating temperature
- Required inspection documents and delivery date
What the 3196 Bulletin Adds to the Comparison
The bulletin presents the fully open impeller for corrosive, abrasive, solids-containing and stringy services, and states that back pump-out vanes reduce pressure at the shaft seal and reduce axial thrust. It also describes external adjustment as a way to restore the impeller relationship as wear occurs.
These are features of the 3196 design. They do not establish direct interchangeability with a Mark III impeller. The applicable drawing and configuration must be confirmed.
Rear Cover, Seal Chamber and Impeller Review
Inspect the rear cover or seal-chamber face, gasket surfaces, shaft or sleeve, keyway and adjustment hardware. Record erosion, corrosion, scoring and signs of contact. If the rear cover has changed from the original configuration, review the impeller and sealing arrangement as a matched scope.
- Identify the installed configuration. Confirm Group, ANSI designation, size, impeller reference and material.
- Record the rotating assembly. Check shaft, sleeve, keyway, diameter or trim and visible wear.
- Check the stationary parts. Review rear cover, seal chamber, gaskets and adjustment relationship.
- Document the duty. Provide speed, flow, head, fluid, temperature and solids information when available.
Reverse-Vane Impeller Questions
Is a Mark III reverse-vane impeller interchangeable with a 3196 fully open impeller?
No direct interchangeability should be assumed. The pumps use different geometries and require separate configuration confirmation.
Does every impeller use the same clearance?
No fixed clearance should be published for every Group and revision. Confirm the applicable drawing and rear-cover condition.