Featured on RFD-TV’s American Farmer

 

RPR Concaves™ were featured in a series of RFD-TV’s American Farmer programs beginning in 2013.​

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In four American Farmer programs, Don Estes discusses the development and operating rationale of the RPR Concave System. He begins with the principal problem the system was designed to address: when a conventional concave does not allow enough crop material to pass through during threshing, more material remains in the rotor path and is carried into the downstream separation section. As that section becomes overloaded, grain may be carried through the rotor and discharged from the rear of the combine instead of being recovered—a condition commonly referred to as rotor loss.

Don explains that the RPR system addresses this problem through two cooperating features: its restricted-flow, longitudinally notched round bars and its progressively open physical bar spacing.

The restricted-flow notch is designed to momentarily restrict crop movement at the bar, promoting more effective threshing and grain-on-grain action. At the same time, the bars are positioned progressively open, meaning the physical spacing between adjacent bars deliberately becomes wider around the concave from where the crop enters toward where it exits. This is different from rotor-to-concave clearance, cover plates, or a general statement that the concave has more open area.

In the 2014 American Farmer program, Don describes the historical RPR arrangement as progressing from approximately 7/8-inch spacing to approximately 1 1/8-inch spacing. He explains:

“Our bars are placed progressively open from where the crop comes in to where the crop leaves the concaves.”

As the crop is threshed, the progressively wider openings are intended to allow more separated crop material to pass downward through the concaves sooner. That earlier discharge places less material into the later rotor and separator regions, reducing the amount of work the downstream separation system must perform.

The same operating relationship is explained repeatedly across the programs:

• In the 2013 program, Don explains that removing more crop in the concave places more material onto the front augers and leaves less material to be separated at the rear.

• In the 2014 program, he identifies insufficient concave opening as a cause of separator overload and explains the progressively open spacing, its direction, approximate dimensions, and earlier-unloading purpose.

• In the 2016 program, he summarizes the principle by explaining that when crop is threshed quickly, it must also be removed quickly—and identifies that need as the reason for progressively open bars.

• In the 2017 program, he again states that progressively open bar placement was used as a way to remove crop sooner.

This explanation is also consistent with the historical patent record. U.S. Patent No. 8,454,416, issued June 4, 2013, describes spaces between adjacent concave bars becoming progressively wider for the stated purpose of helping remove crop material sooner and avoiding overload of the following separator section.

Together, the patent, agricultural publications, and American Farmer programs document a consistent operating principle: thresh the crop effectively, allow separated material to leave the rotor path earlier, and reduce the volume of material carried into the downstream separation section.

Don connects this earlier crop discharge and reduced downstream load with the RPR system’s stated objective of reducing rotor loss. The programs and historical customer accounts also discuss operating benefits such as improved threshing, cleaner grain samples, and increased harvesting capacity under appropriate conditions.

These descriptions explain the historical design rationale and reported operation of the RPR system. They are not guarantees of a particular result. Actual performance varies with crop type, moisture, yield, machine configuration, concave and rotor settings, throughput, maintenance, field conditions, and operator practices.

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Selected Program Passages

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American Farmer 2013 — Vimeo No. 102133522

• 04:14–05:08 — Insufficient concave opening, downstream separator load, and rotor loss

• 05:23–05:42 — More crop discharged onto the front augers and less material carried rearward

• 05:58–06:42 — Progressive physical bar placement and earlier crop removal

 

American Farmer 2014 — Vimeo No. 138202443

• 00:24–00:44 — Insufficient opening and separator overload

• 01:18–01:31 — Earlier downward movement of crop material

• 01:50–01:58 — Meaning of “progressively open”

• 02:42–03:36 — Direction, approximate spacing, earlier crop passage, and overload avoidance

• 11:24–11:38 — Earlier discharge and the stated rotor-loss rationale

 

American Farmer 2016 — Vimeo No. 176818053

• 02:50–03:31 — Crop threshed quickly must also be removed quickly

• 03:51–04:07 — Rotor-loss reduction identified as the system’s principal objective

 

American Farmer 2017 — Vimeo No. 250502489

• 00:50–01:19 — Earlier crop discharge and reduced separator load

• 02:08–02:24 — Bar placement, restricted-flow notch, and early separation

• 03:58–04:07 — Progressive bar placement used to remove crop sooner

Timestamps are provided for convenience. Visitors should watch the recordings for the complete statements and context.