Durco Mark 3 (Flowserve) · ANSI/ASME B73.1 · IOM 71569102 and brochure
Durco Mark 3 shaft dimensions by group
The 3 Durco Mark 3 power ends, Group 1, Group 2 and Group 3, with the journals, bearings and seat fit Flowserve publishes for each, and the Group 2 dimensions its brochure adds. The Mark 3 is its own geometry, not a 3196 interchange.
The Mark 3 is Flowserve’s reverse-vane ANSI B73.1 process pump. Its shaft is grouped by power end, Group 1, Group 2 and Group 3, and is not interchangeable with the Goulds 3196: the standard fixes the pump envelope, and the two makers chose different bearings and spans.
Journal seat diameters and fits come from the IOM’s journal-seat figures and its bearing table; both journals on each group are cut to the k5 bearing-seat fit for the rotating inner ring. The brochure’s deflection comparison publishes the Group 2 overhang and sleeve seat, shown in the second table.
Flowserve does not publish the Groups 1 and 3 seal/sleeve seat, coupling diameter and key, bearing span and overhang; the Group 2 coupling diameter and key and bearing span; nor the impeller and between-bearing diameters or the impeller thread for any group. The part pages show configurable values for those, estimated by ANSI analogy; confirm against your shaft; they are not listed here. The nose thread on each catalog part is representative.
Bearings, journals and seat fit by group
| Frame (part page) | Inboard radial bearing (bore) | Inboard journal Ø (in) | Outboard thrust bearing (bore) | Outboard journal Ø (in) | Bearing-seat fit |
|---|---|---|---|---|---|
| Durco Mark 3 Group 1 | 6207 (35 mm) | 1.3783 | 5306 (30 mm) | 1.1813 | k5 (+.0005 / +.0001) |
| Durco Mark 3 Group 2 | 6310 (50 mm) | 1.9688 | 5310 (50 mm) | 1.9688 | k5 (+.0006 / +.0001) |
| Durco Mark 3 Group 3 | 6314 (70 mm) | 2.7562 | 5314 (70 mm) | 2.7562 | k5 (+.0006 / +.0001) |
Journal diameters in inches at the finished size. The fit is the ISO 286 class with its deviations from nominal; the bore in millimetres is the bearing bore the journal is sized to. Outboard bearings are double-row.
Dimensions Flowserve publishes beyond the journals
| Published dimension | Inches |
|---|---|
| Group 2 seal/sleeve seat Ø | 1.500 |
| Group 2 overhang | 7.688 |
From the Mark 3 brochure. Overhang is impeller end to the inboard bearing centre. Groups and fields not listed are not published; the part pages show configurable values for them.
Part of ANSI pump shaft frame groups. Other pages in the series: Goulds 3196 · 3196 interchange.
Reading the group off the bearings
6207/5306 on 35 mm journals is Group 1; 6310/5310 on 50 mm journals is Group 2; 6314/5314 on 70 mm journals is Group 3. A 6207 inboard bearing also appears on a Goulds 3196 frame, so confirm the outboard number and the pump model before ordering.
Goulds, 3196, 3796, 3996, Durco, Mark 3, Summit, Griswold, PumpWorks, and all other pump model, frame, and brand names shown are trademarks or trade names of their respective owners. Great Lakes Shafts is an independent manufacturer and is not affiliated with, sponsored by, or endorsed by any of them. These are aftermarket replacement shafts machined to fit the referenced pumps, dimensioned to the pump makers’ published data; the names are used only to identify the equipment our parts fit.
Frequently Asked Questions
These references are for specifying a part; every value here is one the configurator applies when you build one. Numbers are representative of the standard; check them against your part and its mating components before ordering. See all guides on the guides page.