4. PARTS IN A MECHANICAL EQUIPMENT
Plain Bearings
Rolling-Element Bearings
Flexible Couplings for Power Transmission
Chains for Power Transmission
Cranes : Overhead and Gantry
Chain Hoists
Belt Drives
Mechanical Variable Speed Drives
Gear Drives and Speed Reducers
Reciprocating Air Compressors
Valves
Pumps: Centrifugal and Positive Displacement
4
5. Plain Bearings
Plain or sleeve bearings are designed to support shafts that
rotate, oscillate, or reciprocate.
One of the least expensive of mechanical parts, sleeve
bearings are highly engineered components
PREVENTIVE MAINTAINENCE:
Lubricant Supply
Cleanliness
Lubricant Type
Inspection and Reconditioning
5
6. Bearings – to be replaced not because they wear not but
do not perform intended function
Dirt
Fatigue
Excessive wear
Foreign material
Hot short phenomenon
Crankshaft and Crankcase distortion
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8. Foreign Particles on bearing
Skewed wear pattern caused by
bent connecting rod
Fatigue of bearing lining
Bearing with severe dirt
embedment
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9. WHY BEARINGS FAIL?
Heavier loading than original
Seals and mountings are too tight
Poor lubrication
Liquid or solid contaminants
Specific to industries
Pulp and paper industry
Poor lubrication and contamination
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11. 11
Thrust Bearings
Determining internal bearing clearance
for a spherical roller bearing
ISO and Anti Friction Bearing
Manufacturers Association –
Maintenance procedure
Roller Bearing – Series of 2,3 and 4 –
depending on the boundary plan.
Basic Rating Life
Service Life
Mounting of bearings
Mounted on shaft
Provision for thermal expansion
Located and held axially
Locking device – tight fit the shaft
Grease Lubrication is used.
12. FLEXIBLE COUPLINGS FOR POWER
TRANSMISSION
To connect two axially oriented shafts
Purpose: Transmit torque or rotary motion without slip
Functions: Minimize/Eliminate heat, electricity, sound.
Torsional dampening & Torsional tuning.
Flexible Couplings
Mechanical – Flexibility- components to slide/ move relative to
each other. Ex: Chain, Gear, Grid, Oldham flexible couplings
Material – Designed to flex. Metal, Rubber, Plastic or
Composite. Ex: Laminated disk, Spring, Elastomer
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14. 14
a
b
e
d
c
a. Roller chain coupling
b. Gear tooth coupling
c. Metallic grid coupling
d. Oldham coupling
e. Laminated disc-ring coupling
15. Failures occur due to
Improper/Poor Machining
Improper Product design
Diaphragm coupling
High speed, high horsepower applications
Elastomeric couplings
Placed in shear and in compression
15
Diaphragm coupling Elastomeric couplings
16. CHAINS FOR POWER TRANSMISSION
Roller Chains
Roller links
Pin links
Favorable service Factors for chain life:
Slow speeds, smooth steady load
Long centers, on adjustable center distance drives
Exceptionally good lubrication
Unfavorable
Small sprocket having fewer teeth
Impulse, load reversals, or shock loading
Three or more sprockets in the drive
Poor lubrication
Dirty or dusty conditions
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17. METHODS OF LUBRICATION
Type A: Manual or Drip
Lubrication
When manual lubrication is used,
oil is applied periodically with a
brush or spout can, preferably
once every 8 hours of operation.
When drip lubrication is used, oil
drops are directed between the
link plate edges by a drip
lubricator.
Precaution must be taken against
misdirection of the drops by wind
age.
Drops on the center of the chain
will not effectively lubricate the
joint areas.
The lubricant should be directed
at the inside of the pin and roller
side plate surfaces.
Type B: Bath or Disk Lubrication
With bath lubrication, the lower
strand of the chain runs through a
sump of oil in the drive housing
With disk lubrication, the chain
operates above oil level.
The disk picks up oil from the sump
and deposits it on the chain, usually
by means of a trough.
Type C: Oil-Stream Lubrication
The lubrication is usually supplied in
a continuous stream to each chain
drive.
Oil should be applied inside the chain
loop, evenly across the chain width,
and directed, preferably, at the slack
strand.
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18. CRANES: OVERHEAD AND GANTRY
Maintenance – to avoid premature
breakdowns or accidents
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19. CRANE
MAINTENANCE
Recommended spares
Brake solenoids, coils, disks
linings
Hoist-limit switches
Contactors
Contact kits
Timing relays
Push-button stations or parts
Crane wheels and guide rollers
Motor couplings and brushes
Current collectors or collector
shoes
Bearings
Load hooks, nuts, and thrust bearings
Hoisting ropes
Load brake parts 19
20. CHAIN HOISTS
Manually Lever Operated chain hoists – For
Pulling horizontally, vertically or at any angle.
Hand Chain manually operated chain hoists –
For overhead lifting application, Brake provided,
lower cost, lighter duty, spur geared hand chain
Powered Chain hoists – High speed applications,
Powered units
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21. 21
Light weight electric
chain hoist with push
button
Pulley/ratchet
level hoist
Spur geared
hoist
Screw geared
hoist
Differential
hoist
Twin-hook hoist
with link chain
22. 22
Hoist parts to be inspected and
serviced
Comparison of hand hoists.
23. BELT DRIVES
Gives dependable power transmission with minimum
maintenance.
V BELT can be
Heavy duty
Light duty
Wrapped/Molded notch
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Typical narrow cross-sectional
V-belt, banded construction.
Typical narrow cross-sectional V-
belt, molded notch construction
24. SYNCHRONOUS BELT
24
Toothed belts --- positive
engagement between belt
tooth and pulley or sprocket
groove
Trapezoid - most commonly
used
Curvilinear – increased
capacity over trapezoid,
higher horsepower
Modified curvilinear –
refinement in tooth shape,
depth
Sprocket – higher capacity
drive systems pulleys
25. MAINTENANCE
On critical drives, 1 to 2 weeks.
On normal drives, once per month.
A drive shutdown to thoroughly inspect belts, pulleys,
and other components should be performed every 3 to 6
months.
A visual and hearing inspection consists of the following
three items:
Look and listen for unusual noise and vibration while
observing the drive.
Inspect the guard for looseness and damage
Look for oil and grease dripping from the guard
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26. MECHANICAL VARIABLE-SPEED DRIVES
MAS – Mechanical Adjustable Speed - method of power
transmission for both accessory drives and main engine-
to-wheel drives
MAS Drive includes
sliding cone-face pulley with a wide V-belt
Types of friction drives
Adjustable While in Motion (Non-enclosed)
Static-Adjustment Types
Belt Transmissions
Packaged Belt Drives
Friction-Disk-Type Drives
Traction-Type Drives
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27. 27
Spring-loaded split pulley,
adjustable with drive-in operation
Fixed-center-distance compound-pulley
arrangement
Use of
compounded
variable-pitch
sheave to obtain
wide speed range
28. 28
Trouble Cause Correction Prevention
Short belt life Inherent slippage; contact
surface
speed varies across face of
belt
None
Slipping belt Overloaded; remember belts
are necessarily narrow to
approach
theoretically ideal line
contact
Reduce loading Do not overload
Slipping belt Belt has stretched Extend center
distance between
pulleys or use idler
roll
Slipping belt Pulley faces greasy Clean with solvent Keep clean
29. GEAR DRIVES AND SPEED REDUCERS
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Gear drives and speed
reducers
changes of speed, torque,
shaft direction, or
direction of rotation are
required between a prime
mover and the driven
machinery.
Basic types of gears
31. LUBRICATION
Lubricating oils –
high-grade,
high-quality,
well refined,
straight mineral petroleum oils, within the recommended viscosity ranges
They must not be corrosive to gears or ball or roller bearings.
They must be neutral in reaction.
They should have good de-foaming properties.
No grit or abrasives should be present.
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32. GOOD MAINTENANCE PRACTICE
During normal periods of operation, gear-drive units should
be given daily routine inspection, consisting of visual
inspection and observation for oil leaks or unusual noises.
If oil leaks are evident, the unit should be shut down, the
cause of the leakage corrected, and the oil level checked.
If any unusual noises occur, the unit should be shut down until
the cause of the noise has been determined and corrected.
Check all oil levels at least once a week. The operating
temperature of the gear-drive unit is the temperature of the oil
inside the case.
Under normal conditions, the maximum operating
temperature should not exceed 180°F. Generally, pressure-
lubricated units are equipped with a filter which should be
cleaned periodically.
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33. RECIPROCATING AIR COMPRESSORS
33
The suction inlet must be
tight,
free of dirt,
chips, and scale,
corrosion-resistant, and
of adequate size for the length
necessary to connect the air filter to
compressor suction
34. LUBRICATION
compressor well lubricated; check the oil level at least once
every 8 hour of operation
only oil and greases - low carbon-forming tendency and sulfur
content and contain an oxidation inhibitor
Non Lubricating Cylinders – avoids metal to metal contact
between piston and cylinder boxes
They have extended length piston rods
Equipped with baffle ring to prevent creepage of lubrication
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36. RECOMMENDED PIPING
valve be closed tightly by hand only, not use a wrench or
persuader
A valve that is cracked open is subject to the most severe
wire-drawing or throttling conditions possible,
decreasing valve life and increasing maintenance
Check valves should be installed as far as possible from
the pump discharge
Clean the inside of the pipe before installing or repairing
a valve
Remove rust, scale, welding beads, and dirt
Apply pipe dope or Teflon tape to male threads only
when making up a threaded joint.
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37. PUMPS: CENTRIFUGAL AND POSITIVE DISPLACEMENT
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A positive-displacement pump makes a fluid
move by trapping a fixed amount and forcing
(displacing) that trapped volume into the
discharge pipe
• Centrifugal pumps are used to induce flow
or raise a liquid from a low level to a high
level.
• A centrifugal pump converts rotational
energy, often from a motor, to energy in a
moving fluid
38. PERFORMANCE
Determined by,
Viscosity
Rotating Speed
Suction supply
Poor piping practices in hydraulic-system applications
are primary sources of positive-displacement pump
problems, particularly in parallel pump applications.
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39. SUMMARY
Different type of mechanical equipment
How they can be maintained to increase the performance
Safety issues
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