How an Air Seal Can Help Solve Pulper Leakage

This SEPCO air seal eliminated the conventional packed seal and plays a major role in preventing pulper leakage.

According to a recent Efficient Plant magazine article, an upstate New York paper mill partnered with SEPCO while facing an ongoing problem with a leaking pulper that had significant shaft runout caused by uneven distribution when paper bales were dumped into it. Many mixers, agitators, and pulpers experience similar shaft leakage. Issues arise when the material weight in the bowls and any other movement cause packing movement, contamination, and premature failure.

“If mechanical seals are used in these applications, the same movement, the abrasive stock mixture, contamination, and shock damage the seal faces, again causing premature failure.”

One major concern with this sealing issue is that the pulper leakage was constant with an estimated yearly loss at $100,000. Additionally, the packing that sealed the pulper was ineffective; it trapped pulp, causing wear on the shaft and the need to be replaced every three months. All of the ongoing damage from the leakage eventually resulted in the need to replace the gearbox.

Clearly, the paper mill was in need of a long-term solution.

How Air Sealing Technology Solved This Pulper Leakage Issue

The team at the paper mill replaced all sealing technology in one fell swoop — first by sealing the pulp process with a a tight-tolerance, split-cylinder bushing made of bearing-grade PPS was installed to stabilize the shaft; then with a noncontact air seal in place of the packing follower.

Additionally, a true noncontact, compound labyrinth bearing isolator was used to replace the existing oil seal in the gearbox and to stem the contamination that caused the failure and ultimate replacement of the former gearbox.

According to the article, “The configuration formed an effective seal to protect the lubricant and the bearings.”

Read the full article on to learn more about this air sealing solution and how it saved the pulper at the paper mill.

About the Author
Anna Claire Howard is a contributing writer, editor, and content marketing specialist for Sealing Equipment Products Co. Inc. (SEPCO) and has been since Spring 2019. Before those two big life changes, she was the content marketing specialist for Fluke Accelix; assistant editor for Grand View Outdoors, publisher of Bowhunting World, Predator Xtreme, Whitetail Journal, Tactical Retailer, and Shooting Sports Retailer; managing editor for Media Solutions, Inc., publisher of Gear Solutions, Wind Systems, and Thermal Processing magazines; assistant editor for MSI; and the editorial intern for B.A.S.S., LLC, publisher of Bassmaster Magazine and In these B2B/B2C roles, Anna Claire developed an appreciation for the industrial sector, as well as the operators and technicians who make up the workforce. You can find her on LinkedIn at