Six Maintenance Tips to Extend Rotary Joint Service Life
A rotary joint works under combined pressure, temperature and speed, connecting fixed piping to rotating equipment. The same DN-series joint can run reliably for years when maintained properly, or start leaking within months without care. Since 2006, DEWEL has supplied joints covering DN6-DN350, up to 138 MPa and up to 30,000 RPM; the following six tips summarize the maintenance questions we see most often in the field.
1. Inspect seal faces and seals regularly
The seal face is where most leaks begin. Stop the machine at planned intervals and check the seal rings for scoring, grooves or uneven wear. Seals are consumable parts: when leakage rises noticeably, replace them promptly instead of waiting for visible media loss, which can also damage nearby bearings and piping.
2. Watch bearing lubrication and temperature
High-speed duty is sensitive to bearing condition - coolant-through joints for machining centers reach up to 30,000 RPM. Listen for unusual noise, monitor bearing temperature, and relubricate on schedule. Once pitting starts, higher running resistance accelerates seal face wear, so bearing care is just as important as seal care.
3. Track leaks early
A slight weep does not mean immediate failure, but record how fast it develops. If leakage multiplies within a short period, the seal face or secondary seals have likely reached the end of their life. For high-pressure duty handled by a high pressure rotary joint, always release system pressure before disassembly - never open a pressurized joint.
4. Manage heat-up and cool-down in thermal oil service
Heat transfer oil duty typically runs at 180-320 C. When the line sits static during shutdown, oil can coke near the seal faces and score them at the next start-up. Circulate cool oil to bring temperatures down before stopping, and heat up gradually on restart so the seal material is never shocked between temperature extremes.
5. Keep media and piping clean
Solid particles are a leading cause of premature seal wear. Replace filters on cooling water and hydraulic circuits on schedule, and flush new piping before installation so weld slag and metal chips never reach the joint. For duties that need several circuits, the double circuit rotary joint or a multi station rotary joint reduces the number of pipe interfaces - and therefore the number of potential leak points and daily inspection items.
6. Keep a maintenance log
Record the installation date, media, temperature, pressure, speed and every inspection result for each joint. Over time the log reveals the seal life pattern under your own duty conditions and gives the manufacturer accurate field data. DEWEL supports custom designs and adjusts seal material combinations to match media and temperature, with production under ISO 9001 quality management. See the rotary joint overview or the pipeline rotary joint page for large-bore products, and request 2D/3D drawings during the ordering stage to confirm installation dimensions.
