Important measurements in Pump Maintenance Part 1 Measurements for Bearings Shaft lift Check for Bearings Clearance measurement by Dial Gauge Shaft lift Check in rolling element bearing Clearance check in plain bearing Plain Bearing clearance check by Blue Matching Plain Bearing clearance check by Plastic gauge Plain Bearing clearance check by Led, Babbit Metal wire Measurements for Shaft Shaft deflection or whip measurements by dial gauge. Shaft end play measurements by Dial Gauge. Shaft eccentric(radial run out) measurements Shaft perpendicular (face run out) measurements

1. CG
Industrial
education
PUMP
MAINTENANCE
Made By : Pawan Kumrawat
Mechanical Engineer
PART 1-IMPORTANT
MEASUREMENTS

2. Important measurements in Pump Maintenance Part 1
Index
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Industrial
education
Measurements for Bearings
Shaft lift Check for Bearings Clearance measurement by Dial Gauge
Shaft lift Check in rolling element bearing
Clearance check in plain bearing
Plain Bearing clearance check by Blue Matching
Plain Bearing clearance check by Plastic gauge
Plain Bearing clearance check by Led, Babbit Metal wire
Measurements for Shaft
Shaft deflection or whip measurements by dial gauge.
Shaft end play measurements by Dial Gauge.
Shaft eccentric(radial run out) measurements
Shaft perpendicular (face run out) measurements

3. Bearings supports shafts and rotor may
have sustained some damage to check
this, lift check is performed
Procedure of checks
Positioning a dial indicator on the
top of the shaft as close as to get it
to the inboard bearing.
It is essential to anchor the indicator
to a stationary object with a
magnetic base or clamp.
lift the shaft upward enough to
detect if any motion occurs but not
with so much force as to
permanently deform the shaft.
Place the indicators on top of the shaft or
coupling hub and hold the dial indicators steady
Lift upward on each shaft and note the dial
indicator readings
Important measurements in Pump Maintenance Part 1
Shaft lift Check for Bearings Clearance by Dial Gauge
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4. Outer Race
Rolling Element
Inner Race
In rolling element bearing the amount of lift
on the shaft should be negligible (0 to may
be 1mil)
excess amount of shaft lift with a rolling
element bearing four possible reasons for
this is as follows
The inner race of the bearing is loose on
the shaft
There is too much clearance between the
rolling elements and the inner and outer
raceways of bearing
The outer race is loose in its housing.
A combination of two or more of the
items above.
For radial lift check. please lift the shaft on
which bearing is mounted
For axial lift check, move the shaft forward
or backward
Important measurements in Pump Maintenance Part 1
Shaft lift Check in rolling element bearing
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5. Upper Half
Lower Half
Lubricant
Shaft
Housing
Radial Clarence
the amount of lift on the shaft should be within acceptable radial bearing clearance
range. As per OEM
Plain Bearing Clarence depends on Thermal Expansion, Equipment and Speed
Plain Bearing Clearance checked by, Plastic gauge, Led or babbit metal wire, Blue match
Important measurements in Pump Maintenance Part 1
Clearance check in plain bearing
CG
Industrial
education

6. In babbit or led metal bearing surface of bearing may be uneven, so Clarence may be not
same at all location or may be shaft touch the bearing at some location, so first A thin
coat of Persian blue is applied both upper and lower half of bearing , the lower half of the
bearing is installed to its lower hemisphere and the shaft is lowered onto the bearing then
upper half is installed and both half tighten, then first upper half is taken out then
examined to determine how much of the bluing is transferred to the shaft to insure that
there is at least 80% shaft to bearing contact.
We can remove or scrape high positions. After that further we can check Clarence by
plastic gauge or led wire.
Important measurements in Pump Maintenance Part 1
Plain Bearing clearance check by Blue Matching
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7.  Plastic gauge is highly effective for measuring the clearance in large bearings Turbine housing bearings, Pump Bearings,
 Plastic gauge is used for measurement of Flatness and clearance in pipe-flanges and cylinder heads
 Plastic gauge provides a simple and effective method for the measurement of clearance (separation) between fitted or
hidden surfaces. It is particularly useful for measuring clearances in split bearings, or in situations where a feeler gauge
cannot be inserted.
 First the Bearing upper half is removed and both shaft and bearing are cleaned, then plastic gauge is kept on shaft then
upper half is again tighten and removed again, check the width of flatten plastic gauge , higher thickness low clearance,
less thickness high clearance
Important measurements in Pump Maintenance Part 1
Plain Bearing clearance check by Plastic gauge
CG
Industrial
education

8.  The shaft deflection is measured by
placing the dial indicator as close to
the stuffing box face as possible and
 lifting the shaft at the impeller end to
check the side-to-side movement.
Important measurements in Pump Maintenance Part 1
Shaft deflection or whip measurements by dial gauge.
CG
Industrial
education
Radial Bearing
Thrust Bearing

9.  Endplay is the axial or lateral (end-to-
end) movement of the shaft.
 A dial indicator is placed against the
shaft shoulder.
 The shaft is tapped on both ends with
a soft mallet and the results are read
on the dial indicator.
Important measurements in Pump Maintenance Part 1
Shaft end play measurements by Dial Gauge.
CG
Industrial
education
Radial Bearing
Thrust Bearing

10.  Shaft run-out is caused by the wobble of a bent
shaft.
 Run-out should be checked by taking readings on
minimum two points on the shaft. that exist
between shafts and coupling hubs, impellers or
other components.
 First, place the dial indicator on the shaft in the
area of the stuffing box face and turn the shaft.
 Then move the dial indicator to the coupling end of
the shaft and repeat the measurement.
 Excessive run-out will result in bearing damage,
which will cause vibration. The vibration will cause
a premature seal failure.
Important measurements in Pump Maintenance Part 1
Shaft eccentric(radial run out) measurements
CG
Industrial
education
Radial Bearing
Thrust Bearing

11. If the stuffing box face is not
perpendicular to the shaft, the seal
insert will not mate squarely with the
rotating seal.
This misalignment will cause the seal to
wobble as it spins, again resulting in
premature seal failure.
 This is measured by attaching the dial
indicator to the shaft with the stuffing
box bolted in place.
The instrument is then placed against
the face of the stuffing box and the
run-out is measured as the shaft is
turned.
Important measurements in Pump Maintenance Part 1
Shaft perpendicular (face run out) measurements
CG
Industrial
education
Radial Bearing
Thrust Bearing

12. This is Part – 1 of Important Measurements in Pump Maintenance in this part we
learn how to measure clearance in ball or roller bearing by Dial gauge or plastic
gauge or Blue in next PPT we will learn Measurement by Led Wire, Filler gauge and,
Depth gauge.