Rotary Seal Literature
Ordering Information

Seal Styles & Sizes
Kalsi Seal Events 

Introduction to the Submerged Dredge Pump Application

Submerged dredge pumps are used to excavate sediment from harbors, channels, and other waterways to maintain appropriate water depth. Such pumps are a critical sealing application because of the high cost and downtime associated with replacing the large diameter impeller shaft bearings when they become flooded with abrasive-laden salt water. Since the pumps are filled with lubricant, environmental concerns also exist when seal failure causes the pump lubricant to be dumped into the waterway. Pump operating conditions include significant shaft surface speed (800 ft/minute typical), dirty water conditions (sand & gravel), shaft impact loads from encounters with various sizes of submerged objects, and environmental pressure due to the submerged depth of the pump.

Introduction to Kalsi Seals

Kalsi Seals were originally developed for the harsh oilfield downhole drilling environment. They have now been used successfully in submerged dredge pumps and gearboxes for several years, and have proven to be superior to conventional face seals. The conventional seals have a long history of being prone to problems such galling, seizure, infant mortality, and catastrophic failure. It isn’t unheard of for such face seals to leak significantly while still on the deck, before being used.

Although other types of Kalsi Seals may be even more appropriate, the Silicone-Filled Kalsi Seal (shown above) is the Kalsi Seal that is in most widespread use in submerged dredge pumps. The Filled Kalsi Seal  incorporates a soft silicone energizer that reduces contact pressure at the dynamic sealing interface. The lubricant-side of the dynamic lip (see below) incorporates a wavy edge that hydrodynamically lubricates the dynamic interface. This combination of features minimizes running torque and seal-generated heat.

Application Support

General seal implementation guidelines are provided in the Kalsi Seals Handbook, which is available online at http://www.kalsi.com/Rotary_Seal_Literature.htm. Experienced personnel are also available to provide technical support.  If you would like Kalsi Engineering to review your rotary seal application, please download an application questionnaire in PDF or Word format, and return it to us by  e-mail or fax (281-240-0255). Alternately, you can forward your seal questions by e-mail, or call us directly at 281-240-6500.