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Home >> Shaft Seals >> DMR Bearing Isolators >> SL Series Bearing Isolator

SL Series - Bearing Isolator

SL – Split, standard flanged isolator for time-saving retrofit installation, non-flooded applications 

Split, non-contacting bearing isolator enables time-saving, no tear-down installation on rotary shaft equipment. Constructed of proprietary PTFE materials, it is designed to retain lubrication and exclude contaminants in non-flooded applications. 


Technical Specifications

  • OPERATION TYPE: Non-Flooded
  • MAXIMUM SURFACE SPEED: Up to 3,000 fpm (15 m/s)
  • AXIAL MOVEMENT: 0.020 inch (0.51 mm)
  • ECCENTRICITY: 0.020 inch (0.51 mm)
  • OPERATING TEMPERATURE: -40° to 250 °F / -40° to 121 °C
  • SHAFT DIAMETER: 0.492 to 10.000 inch (12.5 to 254 mm)
  • BORE DIAMETER: 0.886 to 11.575 inch (22.5 to 294 mm)
  • O-RING MATERIAL: FKM is standard. Alternates available

Performance Advantages

Machine downtime due to bearing failure is costly, but getting up and running again without necessity of an exhaustive tear down lessens the pain. Due to its split configuration, the SL Profile design can reduce downtime hours to minutes when seal replacement is required. 

By keeping lubrication in and contaminants out, ProTech™ bearing isolators provide reliable, two-way sealing protection of rotating equipment for extended bearing life. Labyrinth sealing technology applied to high performance materials allows the ProTech™ bearing isolators to operate far beyond the shaft speed limits of standard radial lip seals and avoid shaft wear. Because it is a precision-machined seal, costs can be eliminated on tooling charges, allowing retrofit of most shaft and bore combinations. 

The non-contact design has virtually no torque consumption, will not wear or groove shafts, and allows for non-lubricated dry running. It also accommodates the greatest axial movement in the industry, reducing a major factor that causes labyrinth seal failure. 

We can custom engineer solutions to meet exacting specifications for either new or retrofit applications. When used to replace seals during planned or unplanned rebuilds, the SL Profile lowers shaft cost due to liberal surface finish specifications which require no wear sleeves or shaft refurbishment. 


The SL Profile is split for easy installation. Once re-connected on the shaft, an external O-ring on the outside diameter of the ProTech stator allows for easy seal installation, maintains a press fit in the seal housing, and provides a static seal against the bore for lubricant retention. The stator has a sophisticated series of grooves to retain oil splash. On the shaft, the rotor uses an external O-ring to maintain a static press fit once the two halves are joined. Since the rotor spins with the shaft, it will not wear, groove, or damage the shaft. 


The SL profile is our split, standard design for non-flooded applications where the seal must be flange mounted. It is ideal for repairs and field retrofits where electric motors, pumps, mixers, gear boxes, blowers and custom equipment cannot easily be uncoupled or disassembled. The flange seats against the housing and acts as an installation guide by ensuring the seal alignment is correct. The SL design seals and protects the bearing housings against heavy water spray and dry contaminants. It is excellent for retaining grease and oil splash, however the oil level must be below the inboard oil drainback (non-flooded). In vertical down mounting positions the SL Profile may require a locking collar. 

Total Eccentricity: 0.020” (.51 mm)
Shaft Speed: Up to 3,000 fpm (15 m/s). Contact factory for speed exceeding 3,000 fpm (15 m/s).
Maximum internal pressure: 0 psi (0 bar)
Axial Movement: 0.020” (0.51mm)
Shaft/Bore Tolerances: ±0.002” (±0.05mm). Special designs available.  

The SL Profile shaft mounting positions and respective compatible lubrication types are: 

  • Horizontal Mounting: Compatible for grease, oil and dry
  • Vertical Up Mounting: Compatible for grease, oil and dry (If contaminant level is heavy seeProTechLW design) 
  • Vertical Down: Compatible for grease, and dry. Not compatible for oil.


Stator & Rotor: ProTech uses proprietary PTFE compounds making it well suited for harsh environments, such as citric acids and strong caustics. This superior chemical resistance allows for the standardization of a single material within a plant, eliminating the cost associated with stocking duplicate sizes in expensive stainless steel or other exotic materials. 

Characteristics of the various PTFE materials offered: 

  • Temperature range: -40 to 250 F (-40 to 121 C)
  • Higher temperature applications can be handled with alternate materials.
  • Low wear, low coefficient of friction. Superior for dynamic applications.
  • FDA compliant
  • Anti-microbial
  • Sanitary standards for USDA food and dairy product contact

O-Rings: Come standard as FKM, but are also available in: 

  • NBR
  • FDA silicone
  • Fluorosilicone
  • EPDM
  • Aflas®

Size Range

The SL Profile in standard shaft diameters ranging from 0.492” to 10” (12.5 mm to 254 mm). Because this is a precision machined seal, we can manufacture virtually any configuration. 













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