The RP-SF Single Flange and RP-DF Double Flange Jaw Flexible Couplings serve heavy-machinery flange connections. The SF variant allows elastomer replacement without moving the drive or driven equipment; the DF radial-flange design enables installation and removal purely in the radial direction. Maximum torque 19,650 N·m; maximum bore Φ200 mm.
The RP-SF and RP-DF series provide the jaw flexible coupling technology of the RP platform in a configuration purpose-built for flanged connections found in heavy industrial machinery. Both designs use a bolt-circle flange on one or both sides of the coupling body to mount directly to flywheel flanges, pump flanges, or gearbox output flanges — a connection geometry common in large pumps, compressors, mixers, and marine auxiliary drives where standard shaft-to-shaft couplings are not practical.
The RP-SF single-flange variant is particularly notable for its maintenance advantage: because the radial flange can be released and the coupling body slid off in the axial direction, the elastomeric spider can be inspected and renewed without any movement of the driving or driven equipment. This is a significant benefit in installations where the machinery is large, heavy, or pipework-constrained — situations where moving an electric motor or a pump body even a few centimetres involves substantial preparatory work. The RP-SF requires the drive to be isolated but not moved to carry out an elastomer replacement.
The RP-DF double-flange variant takes this concept further: both flanges are radial, so the entire coupling can be assembled and disassembled purely in the radial direction. This is invaluable in confined installations — for example, between a close-coupled pump and motor where axial access is blocked by a wall or by piping — where the drive and driven equipment cannot be separated axially at all.
| Model | Torque (N·m) | Speed (rpm) | Bore d (mm) | D (mm) | D1 (mm) | D2 (mm) | E (mm) | S (mm) | L_SF (mm) | L_DF (mm) |
|---|---|---|---|---|---|---|---|---|---|---|
| RP24SF/DF | 35 | 14000 | 8–24 | 55 | 36 | 40 | 18 | 2 | 94 | 86 |
| RP28SF/DF | 95 | 11800 | 8–28 | 65 | 42 | 48 | 20 | 2.5 | 110 | 100 |
| RP38SF/DF | 190 | 9500 | 10–38 | 80 | 52 | 66 | 24 | 3 | 134 | 124 |
| RP42SF/DF | 265 | 8000 | 10–42 | 95 | 62 | 75 | 26 | 3 | 150 | 138 |
| RP48SF/DF | 310 | 7100 | 10–48 | 105 | 70 | 85 | 28 | 3.5 | 164 | 152 |
| RP55SF/DF | 410 | 6300 | 15–55 | 120 | 80 | 98 | 30 | 4 | 192 | 176 |
| RP65SF/DF | 625 | 5600 | 15–65 | 135 | 94 | 115 | 35 | 4.5 | 217 | 201 |
| RP75SF/DF | 1280 | 4750 | 20–75 | 160 | 108 | 135 | 40 | 5 | 248 | 229 |
| RP90SF/DF | 2400 | 3750 | 30–90 | 200 | 142 | 160 | 45 | 5.5 | 285 | 265 |
| RP100SF/DF | 3300 | 3350 | 30–115 | 225 | 158 | 180 | 50 | 6 | 320 | 295 |
| RP110SF/DF | 4800 | 3000 | 40–125 | 255 | 178 | 200 | 55 | 6.5 | 347 | 321 |
| RP125SF/DF | 6650 | 2650 | 40–145 | 290 | 206 | 230 | 60 | 7 | 400 | 370 |
| RP140SF/DF | 8600 | 2360 | 40–160 | 320 | 235 | 256 | 65 | 7.5 | 443 | 409 |
| RP160SF/DF | 12800 | 2000 | 60–180 | 370 | 270 | 290 | 75 | 9 | 501 | 463 |
| RP180SF/DF | 19650 | 1800 | 85–200 | 420 | 315 | 325 | 85 | 10.5 | 555 | 515 |
| Feature | RP-SF | RP-DF |
|---|---|---|
| Flange configuration | Single radial flange | Double radial flanges |
| Elastomer replacement method | Axial, without moving machinery | Radial, no axial access needed |
| Axial installation space needed | Moderate | Minimal |
| Drive must be isolated? | Yes | Yes |
| Drive must be moved? | No | No |
| Overall length (example RP90) | 285 mm | 265 mm |
For complementary shaft-to-shaft solutions, browse the jaw coupling range or explore the full coupling catalogue.
🇳🇱 Netherlands — Large Pump Station
A water management authority in Zuid-Holland installed RP-SF couplings on twelve vertical turbine pump sets. The ability to replace elastomeric spiders without disconnecting the pipework or moving the motors reduced scheduled maintenance from a two-day to a four-hour operation per pump.
★★★★★
"The SF design was the deciding factor in selecting these couplings for our pump stations." — Chief Mechanical Engineer
🇬🇧 United Kingdom — Industrial Compressor OEM
A screw compressor manufacturer in Yorkshire standardised on RP-DF for their 75 kW to 250 kW range. The radial assembly principle allowed their customers to replace elastomers in cramped compressor rooms where axial access to the coupling was completely unavailable.
★★★★★
"Our service engineers report the RP-DF as one of the easiest couplings to service in the field." — Service Manager
🇪🇸 Spain — Marine Auxiliary Systems
A shipyard near Valencia specified RP-SF and RP-DF couplings for bilge pump and ballast pump drives across a series of offshore supply vessels. The flange-mount design matched the existing flywheel flanges directly, eliminating the need for custom adapter plates.
★★★★☆
"Bolt-circle dimensions were delivered exactly to our drawings — no rework required." — Outfitting Supervisor
The RP-SF uses a single radial flange on one side; after releasing the flange bolts the coupling body slides axially to allow elastomer access. The RP-DF uses radial flanges on both sides, enabling the complete coupling and its elastomeric spider to be assembled and removed entirely in the radial direction — no axial clearance between the machines is required at all. Use RP-SF when some axial access is available; use RP-DF when the machines are constrained axially.
Yes — this is the core maintenance advantage of the RP-SF. With the drive isolated, the flange bolts are removed, the coupling body is slid axially a short distance, and the spider is withdrawn and replaced. The motor and the driven machine remain on their baseplate without any mechanical repositioning. This significantly reduces both the downtime and the labour involved in routine elastomer maintenance compared with couplings that require machine movement.
Both variants share the same outer diameter D and flange bolt-circle geometry for a given size, so the mating flange on the machine does not need to change. However, the overall axial length differs between SF and DF — the DF is slightly shorter. Before substituting one type for the other, always compare the L_SF and L_DF dimensions in the specification table to verify the available space is adequate.
Yes. Non-standard bolt-circle diameters, numbers of bolts, flange thicknesses, and flange outer diameters can be manufactured to customer-specific drawings. This makes the RP-SF/DF suitable for retrofit projects where existing machinery flanges do not match standard bolt-circle dimensions. Please provide a flange drawing and dimensional data when requesting a quotation.
The series spans from the RP24SF/DF at 35 N·m up to the RP180SF/DF at 19,650 N·m, at maximum allowable speeds from 14,000 rpm (smallest size) down to 1,800 rpm (largest size). This range covers the majority of industrial pump, compressor, blower, and marine auxiliary drive applications.
RP welcomes enquiries from OEM manufacturers, engineering contractors, and distributors for the RP-SF/DF range. Custom flange dimensions, bore specifications, and technical drawing support are available. Contact us to discuss your project.
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