4 minute read
Don’t miss this safety net
Lagersmit Sealing Solutions.
Managing a ship requires to be on top of various tasks such as handling the content for shipping and supplies, registrations and visas, leading and managing staf, technical management and maintenance. The amount of responsibility is as vast as the ocean and the time at hand limited to a few droplets.
ALL PHOTOS COURTESY OF LAGERSMIT.
Unlike the engine, propeller, battery, bilge pump, electrical lines, oil and flter, other fuid levels and hull; seals for ship’s propulsion shafts, thrusters, gearboxes, tidal turbines, and pump shafts seem lesser at top of mind when considering the concerns of maintenance. However, in emergency cases seals can become worrisome – pinky toes are small but paralysing when broken. Naturally, preventing unforeseen circumstances or being prepared with a safety net when those occur can provide you with a peace of mind.
What safety net do I want and what’s in it for me? Lagersmit developed the infatable seal for emergency cases or in-situ maintenance. Being able to change seals while afoat saves you time and costs of not needing to get into the dry dock. Take for example the Supreme Hydrofuse (fg. 1). This seal is especially developed to prevent water leakage from your open water-lubricated stern tube system into your engine room. It is equipped with the infatable seal, so that the contents of the stern tube can
Can I beneft from an infatable seal for my oil lubricated stern tube applications? With EAL oils already being quite expensive, mineral oils are also increasing in price due to worldwide developments. Therefore, the infatable seal now also fnds its purpose in oil lubricated stern tube applications. Once in dry dock, the shipowner can decide to infate these seals and keep the oil inside the stern tube, whilst maintaining the aft and forward stern tube seals. It is unnecessary to change the lube oil in the stern tube when the lubricant is still in good condition. With the infatable seal from Lagersmit installed you ensure a real money saver.
How does an infatable seal work? The infatable seal assembly itself consists of two parts: an NBR seal profle and a plastic support ring which fts inside the cross section of the rubber seal (fg. 2). This support ring ensures air tightness at the interface surfaces. The infatable seal is ftted in a seal housing (ring) together with a closing (adaptor) ring (fg. 2). Having the infatable module enables insitu maintenance. Bonding divisible lip seals in situ is a cost-efective alternative of seal replacement without disassembling / removing the shaft or propeller. In this way an unnecessary dry dock can be prevented, and maintenance can be postponed safely. Under normal circumstances, during operation, the infatable seal will be in its defated state (fg. 2, left). The infatable seal makes no contact with the (rotating) shaft. In case of emergency or if maintenance is due while afoat the seal can be infated (fg. 2, right). For static sealing against an idle shaft the seal is infated using a pressurized medium provided by an external pump. After infation the pressurized seal will contact the opposing shaft surface, providing a radial acting static seal. The infatable seal is designed to handle a maximum pressure diference between inside and outside pressure of 10bar.
Is the infatable seal also suitable for applications with large radial bearing play? A great efort is made in the infatable seal design to make it suitable for applications
BOOTH NO. B2.EG-314
SMM 2022
Figure 1: Supreme Hydrofuse.
Figure 2: Infatable seal assembly.
that sufer from large bearing wear or applications that are coping with large shaft to bore misalignments. Radial eccentricity up to 2mm is allowed, making this infatable seal ideal for insitu maintenance for open water lubricated stern tube systems or respectively tidal turbines or any other application that needs to deal with large radial bearing play, giving you a reliable sealing solution for years to come.
Can I get the infatable seal as add-on? For the most common stern tube seal applications the infatable seal can be added to the existing Supreme Aft seal and Supreme Fwd seal. The interface dimensions of the infatable seal can be engineered to the required dimensions, making the seal suitable for retroftting the existing seal. The Lagersmit infatable seal can be supplied for shaft diameters of 70 up to 890mm.
Where do I get my safety net for a peace of mind? Lagersmit has been based in the Netherlands since 1856 and has one mission: to deliver Peace of Mind with the best sealing solutions for ships, pumps, and tidal turbines. Whether you choose to operate your vessel with airtype sealing systems or with water lubricated systems, Lagersmit is here to help you!
