7/30/2023 0 Comments Bearing isolator vs labyrinth sealMagnetic-face (mag-face) seals are mechanical seals that use magnetic force to keep the contacting faces together instead of the springs and bellows that traditional mechanical seals use. Any application with limited work space.Conveyor belt idlers, where the replacement cost of a new idler is 25 percent of the cost of a set of bearing isolators.Engineered applications, which can have large shafts where a bearing isolator is not economically practical.Light-duty pumps and motors like those used in the food processing industry (in most situations, a set of bearing isolators do not make economic sense for these applications).Low-speed, flooded shafts, such as gearboxes.This type is applied in much smaller numbers. The other type of contact seal is the magnetic face seal. The most widely used contact seals for industrial equipment are elastomeric lip seals. Typically, the lubrication comes from the lubricant migrating to the contacting surface elements. All contact seals must be lubricated, or they will run hot and fail prematurely, usually damaging the components they directly con- tact. Contact sealsĬontact seals are friction devices with a finite life. With the air comes contamination in the form of moisture and dust, which migrates into the bearing housing if protection is not used. The result is air being drawn in from the outside environment as the housing approaches equilibrium. Let’s examine the technologies currently available to help end users determine which technology best meets their application requirements.īecause cool air is denser than warm air, the bearing housing quickly will consume what air is inside and begin to create a vacuum. Other manufacturers have developed their own bearing isolators with varying degrees of success. The original design evolved over the years but remains a basic, two-piece compound labyrinth seal that sets the industry standard for bearing housing protection. Pumps and motors, the most prevalent industrial rotating equipment in the world, benefitted most from the upgrade. When compared to traditional sealing methods, the bearing isolator represented a paradigm shift in bearing housing protection and equipment reliability. The rotating equipment on which they were installed had short mean times between failure relative to the bearing’s rated life. Some customers learned to adjust their maintenance practices accordingly, but it was a hard fight because these designs did not adequately protect the bearing lubrication from environmental contaminants. Before then, lip seals and traditional labyrinth seals were the only real options available for machine designers and end users. In the 1980s, Inpro/Seal pioneered and marketed the first compound labyrinth seals, bearing isolators. It was the start of an ongoing journey to supply permanent bearing protection to industrial rotating equipment.Shaft seals have been around since Archimedes invented the first pump, but only in the 20th Century was shaft sealing given adequate attention. The first Bearing Isolator was installed in 1975 at the Grain Processing Corporation plant in Muscatine, Iowa, to address a critical issue. It would perform much better than any other labyrinth seals made by pump manufacturers because it would hold off any contamination without contact.” “We finally found a combination of rotor and stator that would keep oil in, but also ward off contamination up to and including a fire hose. “It took about six months to design something that would work in severe hose-down conditions,” said Orlowski. As he experimented with labyrinth seals, Orlowski started with the challenging application of pumps in the corn processing industry, which were cleaned daily – with a fire hose. Orlowski then turned his attention to solving this issue on process pumps, where rubber lip seals were standard. Orlowski and his team retrofitted the API refinery pumps with standard API labyrinth seals, made with a rotor and a stator. It went through there and into the bearing housing, causing bearing failure and a catastrophic wreck.” One of the single spring mechanical seals started to spray water and of course the water was coming out of the seal and going right through and under the lip seal, which was worn. The building structure began to suffer and several windows had fallen from the 110-story building onto the street below.Īccording to Orlowski, “They were refinery pumps with rubber lip seals, which is a rarity. One of the chilled water pumps had failed, though, resulting in a cooling system failure. Orlowski was working in the pump distribution and repair business when he was called out to repair and retrofit 16 HVAC pumps at Chicago’s Sears Tower.Įven though it was February in Chicago, the south side of the building was supposed to be cooled because of the intense daytime sun load. Falling Windows: The Origin of the Bearing Isolator
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