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Short answer: A leaking ROTAN gear pump needs its installed shaft-seal design identified before a replacement is ordered. A packed gland, a single mechanical seal, a double seal and a magnetic-drive arrangement have different normal behavior and service parts. Isolate the pump, locate the exact leak path, record the full model and operating conditions, then compare the findings with the relevant DESMI ROTAN manual.
A drip near the drive end is not a complete diagnosis. Fluid may travel along a pipe or casing before it appears beneath the seal housing. Packing can require controlled leakage for lubrication, while uncontrolled loss from a mechanical-seal arrangement warrants investigation. A magnetic-drive pump has no conventional external drive-shaft seal, so a leak there points to another boundary or connection. Treat the actual configuration, not the ROTAN series name, as the starting point.
Identify the seal arrangement and leak location
Read the full pump nameplate and the order or service record. Record the ROTAN series, size and full configuration code, then verify the installed seal construction in its drawing or parts list. A heavy-duty HD pump, for example, can be supplied with different shaft-sealing arrangements. A photograph of the pump exterior cannot establish the faces, elastomers, flush connections or spare-parts set inside it.
Before opening a guard, follow lockout procedures for the motor and isolate the suction and discharge. Allow hot product to cool where required, relieve pressure and drain the casing to an approved container. If the liquid is hazardous or solidifies on cooling, use the site’s handling plan. Do not tighten a gland or dismantle a seal while the pump can start or remains pressurized.
Clean the exterior only after it is safe, then trace the first wet point. Check the piping joints, end cover, casing gasket, auxiliary seal lines and drain points. Fluid at a gasket or connection can run down toward the shaft and look like seal leakage. Photograph the leak before cleaning and note whether it occurs at rest, immediately after startup, only when warm or after pressure changes.
Swipe the table horizontally to view all columns.
| Observed pattern | Useful first checks | Possible service scope |
|---|---|---|
| Leak at a pipe or cover joint | Trace the first wet point and verify joint condition | Connection or gasket repair after inspection |
| Packed gland becomes hot or dry | Check permitted adjustment and required lubrication leakage | Packing, sleeve or gland review |
| Mechanical-seal area leaks during duty | Check fluid, temperature, pressure and any support line | Seal and mating-surface inspection |
| Leak repeats soon after seal replacement | Review installation, shaft condition and operating changes | Root-cause review before a second seal order |
Packed glands and mechanical seals need different decisions
A packed gland is not normally adjusted to be completely dry. The specific ROTAN manual describes the controlled leakage and adjustment needed for the installed packing design. If leakage is excessive, inspect the packing, gland, shaft or sleeve and operating pressure. If leakage is stopped by over-tightening, friction heat can damage the packing and shaft. Use the correct manual procedure and do not apply a generic leak-rate number from another pump or liquid.
A mechanical seal relies on correctly matched faces, secondary seals and operating conditions. Leakage may follow a damaged face, worn elastomer, unsuitable material, incorrect installation or loss of a required flush or barrier arrangement. Do not assume that a new seal will survive the same conditions that damaged the old one. Capture the actual product temperature and pressure, viscosity range, startup sequence and any recent process change. Inspect seal faces and the shaft area under the manufacturer’s service procedure rather than judging from the outside alone.
On a double-seal system, record the seal-support arrangement and its fluid, pressure and temperature before changing anything. A missing or wrongly operated support system can change the seal environment. Never substitute a single-seal parts list for a double-seal build. On a magnetic-drive ROTAN ED, the absence of a conventional external shaft seal changes the diagnostic route; see DFIN’s ROTAN ED versus mechanical-seal comparison when evaluating a different drive arrangement for a future duty.
Look for operating causes before ordering parts
Confirm that the pump is receiving liquid and that inlet and outlet valves are correctly set for the duty. ROTAN internal gear pumps depend on the pumped fluid and their configured support arrangements for proper operation. Running dry, prolonged blocked flow or an unexpected change in viscosity or temperature can harm bearings and seals. Check for a suction restriction, excessive lift, gas ingress or noisy operation, especially if the seal leak appeared with a fall in delivery.
If the pump also makes a rattling or crackling sound or loses output, review the inlet system rather than treating the leak as an isolated spare-part issue. DFIN’s ROTAN suction and cavitation guide explains how to separate an inlet problem from an internal wear assumption. Temperature at the seal housing, bearing area and liquid source should be measured under the site’s approved procedure; a hand touch is not a safe diagnostic method.
Compare the current duty with the commissioning record: liquid formulation, temperature at startup and steady state, viscosity, differential pressure, speed and runtime. Check alignment and pipe strain after maintenance if the leak began immediately after reinstallation. These observations do not prove one cause, but they tell the repair team whether a seal-only replacement is likely to repeat the failure.
Choose the repair scope from inspected evidence
After safe disassembly, inspect the seal or packing, mating surfaces, shaft or sleeve, bearings, gaskets and any seal-support lines. Keep removed components and note their orientation. A scored shaft can damage a new secondary seal. Worn bearings can allow movement that a fresh seal cannot correct. A hard or swollen elastomer may point to a compatibility problem. The exact repair scope follows the pump drawing, the inspection and the manufacturer’s manual.
The DFIN ROTAN range includes HD and other internal gear pump families. The HD product photograph accompanying this article is an actual catalog reference, not proof of the seal fitted to any customer’s pump. Confirm the complete model and seal code before selecting a packing set, mechanical seal, gasket or replacement pump. Do not infer stock, delivery or price from an image.
Send a complete seal enquiry
- Full ROTAN nameplate and configuration code, serial or order reference, and photographs.
- Seal drawing or current part references, if available, plus the removed components.
- Product name, concentration, temperature and viscosity across startup and normal duty.
- Flow, differential pressure, speed, suction condition and operating schedule.
- Leak location, rate and timing, including whether it changes with temperature.
- Flush, barrier, heating or cooling arrangements and their observed condition.
- Requested scope: seal parts, associated wear components or complete pump review.
Use the DFIN quotation form to send the record. Price depends on the actual seal design, materials, accessories, repair scope, quantity and delivery destination. Ask for a matched proposal rather than a generic ROTAN seal price. If the fluid or duty has changed, request a configuration review before repeating the previous order.
Verify the repair during controlled restart
Reassemble to the applicable manual and restore all guards and seal-support connections. Prime or fill the casing as directed for the configuration, open the required valves and start under the site’s approved procedure. Observe the first wet point, gland or mechanical-seal behavior, bearing and seal-area temperature, noise, flow and pressure. Compare with the pre-repair record. A packed gland and a mechanical seal must be judged by their respective instructions.
If leakage persists or temperature rises, stop and investigate. Repeated tightening or a second seal replacement without examining shaft condition and duty can make the problem worse. Record the installed parts and post-startup measurements for the next maintenance decision.
FAQ
Should a ROTAN packed gland be completely dry?
No universal dry target should be assumed. Packing normally needs the controlled leakage specified for its arrangement and operating conditions. Follow the exact ROTAN manual and site procedure.
Can I order a seal from the ROTAN HD series name alone?
No. The full configuration code and installed seal arrangement determine the parts. An HD photograph or series label cannot identify face materials, elastomers or support connections.
Why did the new mechanical seal leak again?
Possible causes include a damaged shaft or mating surface, installation damage, unsuitable materials, dry operation or an unchanged process problem. Inspect the removed parts and operating record before ordering another seal.
Does a ROTAN ED use the same shaft seal parts?
A magnetic-drive ED has a different containment arrangement from a conventional externally sealed shaft. Verify the actual pump design and its parts list before comparing or ordering components.