Friction Testing of Faces in Bearing Isolators and Oil Mist Lubrication

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Friction Testing of Faces in Bearing Isolators
andOil Mist Lubrication

• By
• Hrishikesh Gadre

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Outline

• Part I Testing of seal faces.
• About Isomag Bearing Isolators.
• Problem definition.
• Experimental Apparatus.
• Part II About Oil Mist Lubrication.
• Introduction
• Generation, Transportation and Reclassification
• Typical Oil-mist system
• Dry sump Vs Wet sump oil mist system
• Lubricants

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Bearing Isolators

• Isolate the bearings from outside environment.
• Prevents oil from leaking.
• Combine the advantages of labyrinth and
  contacting seal faces.
• Magnetic force as a closure means.
• Runs dry as well as lubricated.

Photo courtesy Isomag Corporation
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Flat face seal basics
Photo courtesy Isomag Corporation
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Magnum C bearing Isolator
Photo courtesy Isomag Corporation
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Magnum S bearing Isolator
Photo courtesy Isomag Corporation
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Problem Statement

• ExxonMobil uses these isolators.
• Usage hasnt been for long enough to determine
  life of the isolator.
• Aim is to conduct various tests to calculate the
  wear life and/or to suggest a better solution.
• Effect of introduction of Oil Mist.
• Also, performance of another material pair.

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Experimental Apparatus
LRI-1a Tribometer
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Test samples
Rotor
Stator
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Experimental Apparatus
Rotor
Stator
Temperature probe
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Experimental Apparatus
Modifications for introducing Oil Mist
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Testing outline

• Parameters that can be changed
• Pressure 5, 7, or 12 psi.
• Speed 1800 or 3600 rpm.
• Material pair 17-4PH Composite or SS 416
  Carbon.
• Lubrication Dry or mist lubricated.
• Total of 24 tests.

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Results

• COF decreases as load increases.
• It increases with increase in speed.
• Presence of oil helps reducing the friction.
• Temperature is also comparatively lower.

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Part II Oil Mist Lubrication
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Introduction

• Need for this kind of lubrication.
• Centralized lubrication system.
• Where it is successfully used?
• Hydrocarbon processing industry, refineries
• Process pumps, electric motors

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Generation of mist

• Vortex type or Venturi type.
• Air with high speed and low pressure at exit.
• Low pressure pulls oil.
• High speed air breaks the oil.
• Optimum size of particles.
• Line condensate
• Stray mist

Photo courtesy Bloch Shamin
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Transportation

• Can be conveyed over long distances.
• 97 of the mist reaches the application point.
• Optimum velocity of flow.
• Gravitational settling
• Turbulent settling

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Main header
Application point
Photo courtesy Bloch Shamin
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Reclassification

• Type of fitting depends upon the application
• Low speed Condensing type
• High speed Mist or Spray type

Photo courtesy Bloch Shamin
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Typical Oil-Mist system
Photo courtesy Bloch Shamin
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Dry sump Vs Wet sump
Dry sump
Wet sump
Photo courtesy Bloch Shamin
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Lubricants

• Virtually any oil can be used.
• Some specific properties needed.
• Good aerosol characteristics
• Thermal and oxidation stability
• Special additives designed.
• To reduce stray mist
• Anti-wear, anti-foaming etc

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Case study
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Acknowledgement

• Dr. Michael Khonsari.
• Center for Rotating Machinery.
• David Hertel.
• Michael Ciolino.
• Everybody in this group who helped me.