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Bearings and lubrications

  1. Bearings and Lubrication Prepared By Muhammad Nadeem
  2. Agenda  Bearing Basic  Bearing Definition  Main Types of Bearing  Anti friction Bearing types, Advantage & Disadvantage  Identify Bearings by Bearing Number-Calculation and Nomenclature  Plain Bearing and its Materials  Plain Bearing types  Lubrication System
  3. Bearing Basics  Bearings permit smooth low-friction rotary or linear movement between two surfaces. Bearings enhance the functionality of machinery and help to save energy. Bearings do their work silently, in tough environments, hidden in machinery where we can't see them. Nevertheless, bearings are crucial for the stable operation of machinery and for ensuring its top performance.  Bearings are evaluated on the basis of;  How much load they can carry,  At what speeds they can carry this load,  And how long they will serve under the specified conditions.  And how Reduced friction .  Ability to withstand impact or harsh environments,
  4. Bearing  Definition  Bearing Refers to any kind of support, which is in direct contact with a moving machine part.  Bearings are designed to minimize friction, wear and power loses. Every kind of machine uses bearings of some kind.  Main Types of Bearings  Anti-friction Bearings  Plain Bearings
  5. Anti-friction Bearings Antifriction bearings provide rolling contact rather then sliding contact therefore the total effective contact area is much less in antifriction bearings as compared to plain bearings. Starting friction of antifriction bearings is therefore considerably less than in plain or sleeve bearings. Types of Anti friction Bearing 1 Ball Bearing 2 Roller Bearing 3 Needle Bearing
  6. Anti- Friction Bearings  Ball Bearing Types  Deep Groove Ball Bearing.  Single Row Angular Contact Ball Bearing.  Double Row Angular Contact Ball Bearing.  Ball Thrust Bearing.
  7. Ball Bearing Parts & Construction  Outer race  Retainer or cage  Inner race  Rolling elements
  8. Anti- friction Bearings  Roller Bearing Types and parts.  Cylindrical Roller Bearing  Spherical Roller Bearing.  Tapered Roller Bearing  Needle Roller Bearing  Roller Thrust Bearing Outer race (cup) Rollers
  9. Advantage & Disadvantage of Anti-Friction Bearing Advantage  Less power demand because of low starting friction  Less maintenance and lubrication is required.  Both radial and axial loads can be carried by certain types.  Higher speed operation  Ability to perform under adverse condition. Disadvantage  More noisy at very high speeds.  Low resistance to shock loading.  More initial cost.  Design of bearing housing is complicated.
  10. How to Identify Bearings by Bearing Number-Calculation and Nomenclature
  11. How to Identify Bearings by Bearing Number-Calculation and Nomenclature
  12. How to Identify Bearings by Bearing Number – Calculation and Nomenclature
  13. Plain Bearing  Plain bearings have sliding contact between the shaft and the bearing surfaces.  The simplest type of bearing is made by supporting the shaft directly in a hole in the supporting component as shown in Fig 2, The supporting component is often the casing of the machine.
  14. Plain Bearings Materials  Bronze  Babbitt metal (Tin Alloy)  Cast iron/steel  Aluminum alloys
  15. Plain Bearing Types  Journal Bearing  Thrust Bearing  Guide Bearing
  16. Journal Bearing  The Journal Bearing includes a Babbitt, sleeve and shell bearing. The journal bearings only for the radial load that is perpendicular to the shaft, usually because of the downward load or weight of the shaft
  17. Thrust Bearing. Purpose of Thrust Bearings • Absorb axial thrust forces generated by Process differential pressures on Shaft or Rotor, discharge to suction • Axially position rotor with respect to stationary parts
  18. Thrust Bearing Construction
  19. Advantages of Plain Bearings  Lower costs  Longer fatigue-free service life of their elements.  Lighter weight.  Less noisy.  They require less radial space, since they are built with thin walls.  Their installation is simpler.  Using self-lubricating bearings, lubrication procedures are not required.  They allow for higher rotational speeds.  Greater shock resistance.
  20. Disadvantages of Plain Bearing  Higher friction during transient processes (especially during startup).  They require more axial space.  The use of friction resistant materials in their manufacturing is indispensable.  Greater wear when compared to rolling bearings, since there is a direct friction between the bush and the shaft
  21. Journal Bearing Damages. Plain bearings have been used for many years in all types of rotating machinery and the vast majority gives excellent service over long periods of time. When, however, they suffer damage the cause may be vague Typical Damage Types 1. Scoring Due To Foreign Matter Or ’Dirt’ 2. Fatigue Cracking Of Bearing Surface 3. Pivot Fatigue Or Fretting 4. Corrosion 5. Lacquering Due To Oil Breakdown Or Contamination 6. "Black Scab" Or "Wire Wool" Damage
  22. Journal Bearing Damages contd…. 1. Scoring Due to Foreign Matter or ’Dirt’ Fig. 1 Material: White metal Severity: Moderate Description: Bearing scored and pitted with dirt Fig. 2 Material: White metal Severity: Severe Description: “Holes” caused by dirt particles
  23. Journal Bearing Damages contd…. 1. Scoring Due to Foreign Matter or ’Dirt’ Fig. 3 Material: Tin-based white metal Severity: Severe Description: Concentric scoring of thrust due to dirt entering bearing at high speed Fig. 4 Material: Tin-based white metal Severity: Moderate Description: Scoring by dirt entering at start-up Fig. 5 Material: Tin-based white metal Severity: Moderate Description: Surface of pad in Fig. 4 at higher magnification showing irregular tracks caused by rolling of shot-blast spherical steel particles
  24. Journal Bearing Damages Recommended Action: Bearings in condition shown in Figs 2 & 3 should be scrapped or relined, and replacement bearings fitted after cleaning journal, oil ways and filters. Bearings in condition shown in Fig 1, 4, and 5, should be refitted, after cleaning bearings and journal surfaces, provided clearance increase due to wear can be tolerated. In all cases, consideration should be given to improving the level of full- flow filtration or installing a by-pass centrifugal filter.
  25. Bearing Lubrication.  Bearings cannot be discussed without considering lubrication. Lubricant film separates the shaft journal from bearing and thus reduces friction and prevents the shaft and the bearing from overheating.  When the shaft begins to rotate, a wedge of oil is forced under the journal, lifts it away from the bearings and thus Full-film lubrication is achieved.  Both Oil and grease can be used as a lubricant. However grease is used where the shaft rotates at a very slow rpm.
  26. Lubrication Systems. 1. Manual Lubrication Manual lubrication requires the use of a portable pump, which is not part of the machine, and an oil cup or grease fitting. Tubing or drilled passages carry the lubricant from the fittings to the friction points. Lubricant is applied by connecting the pump outlet to the fitting and injecting a specified amount of lubricant.
  27. Centralized / forced Lubrication Systems Centralized lubricating systems lubricate all the friction points from a single pump source. The pump can be manual, mechanical, or motor operated. Positive pressure controls the flow rate and also provides a means of indicating correct operation or malfunction.
  28. Self-lubrication In this process, the material is inherently self-lubricating or the mechanism does the work of delivering lubricant to critical points. Examples of the latter are oil splash systems, oil slingers, and oil baths.
  29. WHAT IS MIST LUBRICATION Oil-Mist is centralized lubrication system that continuously atomizes oil into small particles and then conveys and delivers the correct amount of the pressurized lubricant to the surfaces requiring lubrication. Oil mist can be used to continuously lubricate several different classes of operating or stand-by equipment in widely dispersed physical locations within the same facility using only one type of lubricant. •Oil mist is considered a “best practice” by many companies in the process industries. Many mist systems are retrofits on existing oil lubricated applications pumps and motors. Oil mist was developed in Europe in the early 1900’s to replace grease and circulating oil systems on high speed spindle bearings.
  31. ADVANTAGES OF MIST SYSTEMS  •Bearing failures reduced 50-90%  •Positive pressure prevents ingression of contamination  •Lower friction, no oil churning, reduced bearing temperatures (typically 10°F and often 20°F)  •Very slight cooling by air  •Application without contamination in dirty environment  •Automated system ensures the right amount of lubricant all the time  •Rust and corrosion protection of non-running pumps (maintains an oil fog environment)  •Elimination of thermal cycling in idle equipment  •Reduce energy consumption (bearings operate in a thin film of oil instead of a pool of oil, typically 3 percent)
  32. ADVANTAGES OF MIST SYSTEMS  •Better lubricant properties, because the oil on the bearings is always new (not so with closed loop systems)  •No oil changes, less maintenance  •Reduction in cooling water usage, elimination of cooling water in bearing housing  •Increases safety -- eliminates hand labor next to moving machines  •Reduced lubricant consumption (up to 40 percent compared to sump lubrication)  •Low maintenance (no moving parts, lubes difficult areas, no need to check individual housings)
  33. THANKS Thank you so much for your patience & kind attention !!!