Presentation - Pump Troubleshooting & Maint Workbook (TM-01)

Tech Seminar
Pump Troubleshooting & Maintenance
Tech Seminar
Pump Troubleshooting & Maintenance
Session will
begin in
5 Minutes
Session will
begin in
4 Minutes
Tech Seminar
Pump Troubleshooting & Maintenance
Session will
begin in
3 Minutes
Session will
begin in
2 Minutes
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begin in
60 Seconds
Welcome
A Few Housekeeping Items
Course Workbook
Additional materials:
• Supplemental Material Packet
• At Your Service Bulletins
Pump Troubleshooting and
Maintenance Seminar
P H O TO O P P O R T U N I T Y – G R O U P P H OTO
Table of Contents
Introduction
4
Pump Basics
8
Pump Safety
28
Tool of the Trade
40
Pump Forensics (Troubleshooting)
44
Troubleshooting Checklist & Guide
52
Noisy Operation
67
Reference
86
Pump
Basics
Pump
Safety
Tools of
the Trade
Pump
Forensics
Checklist
& Guide
Noisy
Operation
Reference
Section
Text Ref: Pg. 3
Introduction
More pumps are manufactured than any other piece of
machinery with possibly the exception of electric motors
Several applications and uses including:
•
•
•
Transportation - Automobiles, ships, airplanes, or trains
•
Service Stations, Treatment plants, Oil Fields, Farming…
Appliances - Washing Machines, dishwashers, or air conditioners
Commercial Buildings – Boiler feed service, hot water service, water
service, & sanitation service
Text Ref: Pg. 4
Introduction (cont.)
If not moved by gravity, pumps are needed to move any liquid
Dating back to the time of the early Egyptians & Pharaohs – Pumps
were used to raise water from the Nile River for irrigation purposes
Archimedes
Screw
Shaduf
Text Ref: Pg. 4
Introduction (cont.)
What is a pump?
• A device that adds energy to a liquid in order to move it from
one point to another
There are several types and styles of pump designs
• Our focus will be on a variety of G-R’s more popular products
• Self-priming, priming-assisted, submersibles, & positive
displacement
Text Ref: Pg. 5
Introduction (cont.)
Basic hydraulic terms:
• Gallons per Minute (GPM)
• Static
• Dynamic
• Friction Head
• Atmospheric Pressure
• Performance Curve (Chart)
Pump
Basics
Pump
Safety
Tools of
the Trade
Pump
Forensics
Checklist
& Guide
Noisy
Operation
Reference
Section
Text Ref: Pg. 5
Pump Basics
Text Ref: Pg. 6
Pump Basics (cont.)
Text Ref: Pg. 7
Pump Basics (cont.)
Centrifugal Force ??
• Outward force placed on rapidly spinning (rotating) objects
• Fc=mv²/r
Examples of Centrifugal Force
• Sports car on a circular race course
• Spinning a bucket of water tied to a rope
• Tire on a wet roadway
Text Ref: Pg. 8
Pump Basics (cont.)
Centrifugal pumps operate on a
similar principle
• Impeller with vanes guide and
increase the velocity of the
liquid
• Casing (volute) controls the
path of the liquid as it leaves the
impeller
Text Ref: Pg. 8
Pump Basics (cont.)
Types of Pumps Discussed
• Standard (Straight) Centrifugal
• Self-Priming Centrifugal (Wet Primer)
• Priming-Assisted (Dry Prime)
• Submersible
• Positive Displacement
•
•
Diaphragm
Internal Rotary Gear
Text Ref: Pgs. 8-12
Pump Basics (cont.)
Standard Centrifugal Pumps
• Most common of centrifugal pumps
• Typically driven by electric motors or engines
• Used for a variety of water like liquids:
•
•
•
•
Water
Sewage
Petroleum
Petrochemical
Text Ref: Pg. 8
Pump Basics (cont.)
Self-Priming Centrifugal Pumps
•
•
•
•
•
Hyperlink
to Priming
Video
Capable of “self-priming” with dry (empty) suction line
Pump needs to have liquid in casing to prime
Some models capable of a 25 ft. (7.6 m) lift
Some designs capable of “re-priming” (half casing)
Many applications
•
•
•
•
Water like liquids
Excellent trash (solids) handling
Industrial, Municipal, Construction
Agriculture and Petrochemical
Text Ref: Pg. 9
Pump Basics (cont.)
Priming-Assisted Pumps
•
•
•
•
•
•
Hyperlink
to Priming
Video
Designed to handle large volumes of air
Dry-prime capable (empty pump casing)
Requires an external priming device (venturi,
diaphragm, or vacuum pump)
Large seal oil chamber for extended dry run capability
Suitable for long suction lines, snoring or slurping
applications
Many applications:
•
•
•
•
Water like liquids
Excellent trash (solids) handling
Industrial, Municipal, Construction
Mining & Agriculture
Text Ref: Pg. 10
Pump Basics (cont.)
Submersible Pumps
•
•
•
•
•
Operates on same principle as all centrifugal pumps
Designed with integral watertight motor assembly
Entire assembly typically submerged in liquid
Depending on environment may require explosionproof design (UL, FM, CSA, or MSHA)
Many applications:
•
•
•
•
Water like liquids
Excellent trash (solids) handling
Industrial, Municipal, Construction
And Agriculture
Text Ref: Pgs. 10-11
Pump Basics (cont.)
Diaphragm Pumps
• Positive displacement style of pump
• Operates in combination of a reciprocating
•
•
•
diaphragm and two valves on either side of
diaphragm pot chamber
Work well on viscous or liquids containing large
solid content
Flow is typically not linear (subject to surging)
Many applications:
•
•
•
Excellent trash (solids) handling
Industrial, Municipal
Construction & Agriculture
Text Ref: Pgs. 11-12
Pump Basics (cont.)
Internal Rotary Gear Pumps
Hyperlink to
Operation
Video
•
•
Positive displacement style of pump
•
•
•
•
Work well on thick viscous liquids to 2,000,000 SSU
Operates in combination of a rotor with internal cut
teeth and a nested idler with external cut teeth
Flow remains constant with change in pressure
Relatively high pressure capability - 300 psi
Many applications
•
Industrial, Municipal, & Petrochemical
Text Ref: Pg. 12
Pump Basics (cont.)
• Typical Pump installations?
Text Ref: Pg. 13
Pump Basics (cont.)
How does liquid get in the pump?
•
Atmospheric
Pressure
@ sea level
Atmospheric Pressure –
•
•
Pushes liquid into the pump
Keeps liquid in a liquid state
14.7 psi
33.96 Ft of Water
29.9 In. Hg.
10.3 Meters or
1 Bar
Text Ref: Pg. 13
Pump Basics (cont.)
How much will a pump produce?
• Centrifugal Pump Elements
•
Pump Design – Size of pump, impeller
design & quantity
•
•
•
Speed (RPM) of impeller
Impeller size (diameter)
System pressure (Total dynamic head –
TDH)
Text Ref: Pg. 14
Pump Basics (cont.)
How much will a pump produce?
• Positive Displacement (Gear) Elements
•
•
•
Rotor & idler design
Speed (RPM) of rotor
Size of rotor and tooth profile depth along with
idler height
Text Ref: Pg. 14
Pump Basics (cont.)
Reading Pump Performance Curves and Charts
• Manufacturer’s chart plotting the performance characteristics
• Use to select and troubleshoot pump performance
• Use in conjunction with speed, pressure and electrical data
• Often contain additional useful information
• Every pump model has its own exclusive curve
Text Ref: Pg. 15
Pump Basics (cont.)
Text Ref: Pgs. 16-17
Pump Basics (cont.)
Text Ref: Pgs. 18-19
Pump Basics (cont.)
Text Ref: Pgs. 19-20
Pump Basics (cont.)
Text Ref: Pg. 21
Pump Basics (cont.)
Text Ref: Pgs. 22-23
Pump Basics (cont.)
Text Ref: Pgs. 23-24
Pump Basics (cont.)
Text Ref: Pgs. 24-25
Pump Basics (cont.)
Pump
Basics
Pump
Safety
Tools of
the Trade
Pump
Forensics
Checklist
& Guide
Noisy
Operation
Reference
Section
Text Ref: Pgs. 26-27
Pump Safety
Text Ref: Pg. 28
Pump Safety (cont.)
This material is meant to be a “Quick-Reference” guide only!
Use it with an Installation, Operation and Maintenance Manual
•
Typically developed to alert personnel of situations that could damage
equipment and/or could be dangerous to personnel
Follow all established safety guidelines and protocols
It is the responsibility of the owner, operator and maintenance
personnel to assure that only safe procedures are followed!
Text Ref: Pg. 29
Pump Safety (cont.)
Hyperlink to
Pump Safety
Video
Potential Pump Hazards
• High Voltage
• Automatic Equipment
• High Pressure
• Physical Heights
• Rotating Equipment
•
•
Confined Space Entry
Open Sumps
•
•
•
Hazardous Gases
Cool, Damp Environment
•
Pump
Basics
Pump
Safety
Tools of
the Trade
Drowning and Diseases
Insects, spiders, bees, snakes, rats, alligators…
Pump
Forensics
Checklist
& Guide
Noisy
Operation
Reference
Section
Text Ref: Pg. 29
Pump Safety (cont.)
Potential Pump Hazards
• High Voltage
• Automatic Equipment
• High Pressure
• Physical Heights
• Rotating Equipment
•
•
Confined Space Entry
Open Sumps
•
•
•
Drowning and Diseases
Hazardous Gases
Cool, Damp Environment
•
Insects, spiders, bees, snakes, rats, alligators…
Text Ref: Pg. 29
Pump Safety (cont.)
General Pump Safety
•
•
•
•
•
•
•
Do NOT operate pumps without all guards and shields in place
Pump ONLY liquids for which pump was designed
Do NOT pump flammable or corrosive liquids unless pump and
driver is design for such
NEVER operate pumps in explosive or volatile atmospheres unless
designed for environment
CAUTIOUSLY approach any pump that has been in operation
Do NOT operate a pump against a closed suction or discharge
Unless designed, NEVER operate centrifugal pumps with no liquid in
the pump casing
Text Ref: Pg. 30
Pump Safety (cont.)
General Pump Safety (cont.)
•
•
•
•
•
•
DISCONNECT driver and/or lock-out and tag control panel
before maintenance
Overheated pumps can cause severe burns and injury
•
Approach a hot pump cautiously
ALWAYS allow pump to cool to room temperature
Isolate suction and discharge lines
•
Lock-out and tag all isolation valves
SLOWLY and CAUTIOUSLY vent pump at drain
Do NOT work underground or in limited egressed areas without
following confined space guidelines
Text Ref: Pg. 31
Pump Safety (cont.)
Electric Motor Driven Pumps
•
•
•
•
•
ONLY have qualified personnel install, wire
and operate electric driven pumps
Make sure all electrical connections are in
accordance with all local and National
Electrical Code requirements
ALWAYS properly ground electric-driven units
Check an assure proper rotation on threephase electrical power installations
DISCONNECT driver and lock-out and tag
control panel before maintenance
Text Ref: Pg. 32
Pump Safety (cont.)
Engine-Driven Pumps
• Assure ONLY qualified personnel operate
•
•
•
•
engine-driven pumps
Do NOT operate combustible engines
without proper ventilation
DISCONNECT spark plugs and/or battery
from starter before working on pump
NEVER refuel a hot or running engine
Follow the engine manufacturer’s OM
manual instructions
Text Ref: Pg. 33
Pump Safety (cont.)
Electric-Driven Submersible Pumps
•
•
•
•
•
•
ONLY have qualified personnel install, wire and
operate submersible pumps
Make sure all electrical connections are in
accordance with local and National Electrical
Code requirements
Always operate with properly sized and
protected control panel
NEVER attempt to lift pump by its power cord
or discharge hose (portable pumps)
Check an assure proper rotation on three-phase
electrical power installations
DISCONNECT or lock-out and tag control panel
before any maintenance
Text Ref: Pg. 34
Pump Safety (cont.)
General Electrical Safety
• Severity of electrical shock depends on:
•
•
•
•
•
Amount of current
Person’s resistance
How well-grounded the service tech is
Path the current takes through a body
Length of time a body is exposed to current
Text Ref: Pg. 35
Pump Safety (cont.)
General Electrical Safety (Cont.)
• Possible effects of low-voltage contact
(110V):
•
•
•
1 mA – No sensation
2-8 mA – Slight sensation, not harmful except
possibly to pacemaker wearers
15-20 mA – In the “can’t let go” range; likely to
cause painful shock, muscle control loss &
ventricular fibrillation should current flow
across the heart
Text Ref: Pg. 35
Pump Safety (cont.)
General Electrical Safety (Cont.)
• Possible effects of high current exposure:
•
•
•
Severe burns
Loss of limb
Muscular contractions to the point where
the heart is stopped (Requires CPR and/or
defibrillation shock to revive victim)
Text Ref: Pg. 35
Pump Safety (cont.)
General Electrical Safety (Cont.)
• Before maintenance of any electrical device:
•
•
•
•
Read all warning tags
Shut-off main power
Follow proper lockout and tag protocol
Adhere to all caution and warning labels
•
If you do NOT have a good basic knowledge
of electricity LEAVE IT ALONE!
• Good rule in Electrical Safety:
Text Ref: Pg. 36
Pump Safety (cont.)
General Confined Space Guidelines
• Before entering make sure protocol is
•
followed
Confined spaces include - tanks,
vessels, silos, vaults, pipelines, sewers,
tunnels, or pits
Text Ref: Pg. 37
Pump Safety (cont.)
General Confined Space Guidelines (cont.)
• In addition, any open top space 4 ft. or deeper
with at least one of the following:
•
•
•
•
•
•
•
Limited means of egress
Not designed for continuous occupancy
Less than 19.5% O2
Flammable, combustible, or explosive
atmosphere
Toxic atmosphere
Substances that could potentially trap,
suffocate, or harm – (Water, gas, sand, gravel,
ore, grain, coal, biologicals, radiation or
corrosives)
Poor ventilation
Text Ref: Pg. 37
Pump Safety (cont.)
Commonly Found Hazardous Gases
• Methane – CH4
• Ammonia – NH3
• Hydrogen Sulfide – H2S
• Carbon Dioxide – CO2
• Carbon Monoxide – CO
• Chlorine Gas – Cl2
Pump
Basics
Pump
Safety
Tools of
the Trade
Pump
Forensics
Checklist
& Guide
Noisy
Operation
Reference
Section
Text Ref: Pg. 38
Tools of The Trade
Text Ref: Pg. 39
Tools of the Trade (cont.)
Essential Tools for the Job
• Equipment data
• Record-keeping program
• Education on product(s)
• Physical tools
•
•
•
•
•
Gauges
Amp Probe
Tachometer
Voltmeter
Temperature probe
• Unique or special tools
Text Ref: Pg. 40
Tools of the Trade (cont.)
What Gauges Can Tell You?
•
•
•
•
•
Where system is allowing the pump
to perform
If pressure is too high or low
If there is an obstruction in suction
Evidence of vortexing or entrained air
When pump is not running:
•
•
•
Static pressure
Suction leak
Discharge check valve problem
Text Ref: Pg. 40
Tools of the Trade (cont.)
• Connect gauges close to
•
•
pump inlets and outlets
Account for gauge correction
Adding the values of the two
gauges will provide system
performance
Text Ref: Pg. 42
Tools of the Trade (cont.)
• Use quality gauges
• Consider using hose
connections to raise
or lower gauge height
Text Ref: Pg. 42
Tools of the Trade (cont.)
• To assure accurate gauge
•
•
readings consider a bleed valve
Vacuum gauges should be
absent of any liquid
Pressure gauges should be
absent of air
Text Ref: Pg. 43
Tools of the Trade (cont.)
•
•
•
Pump
Basics
Pump
Safety
Tools of
the Trade
Pump
Forensics
Checklist
& Guide
Gauge corrections may
require addition or
subtraction of value
Zero gauges (vent) to
assure accuracy
If permanently mounted,
use isolation valves
Noisy
Operation
Reference
Section
Text Ref: Pg. 43
Pump Forensics
(Troubleshooting)
Text Ref: Pg. 44
Pump Forensics (cont.)
My Pump Isn’t pumping… Why?
• First reaction – It’s the pump fault!
• Reality is – 85-90% of the time it’s
•
a system problem
Pump is simply responding to
changes in the system
Text Ref: Pg. 45
Pump Forensics (cont.)
Troubleshooting Topics Discussed
• Low Performance
•
Reduction in flow, pressure or no flow
•
Loss of prime, slow to prime, failure to prime
•
Mechanical Causes
• Priming challenges
• Air Bound
• Noisy Operation
• Shaft Failures
• Corrosion and Abrasion Damage
Text Ref: Pg. 45
Pump Forensics (cont.)
Low Performance – Cause #1
• Excessive Clearances
•
•
•
•
•
•
Over equipment lifespan performance lowers
as internal components wear
Critical components include; wear rings, wear
plates, impellers, & pump casing cutwater area
Real cause is excessive clearances
Solution - Replace worn components
Some models have adjustable clearances
Field analysis and shut-off test will assist in
performance validation
Text Ref: Pg. 46
Pump Forensics (cont.)
Low Performance – Cause #2
• Reverse rotation
•
•
•
Typical result is lower flows and pressures
In addition, increased amperage due to increased horsepower
Cause in new installations, typically due to improper wiring
•
Cause in existing installation ,occur from a variety of reasons:
•
• Modification of wiring will correct the problem
• Modification of electrical panel, motor, or incoming power grid
transformer change out
Note – Running PD pumps in reverse will reverse the flow
• Suction becomes discharge and discharge becomes suction
Text Ref: Pg. 46
Pump Forensics (cont.)
Low Performance – Cause #3
• Change in Speed (RPM)
•
•
•
•
Typical cause - Incorrect speed selection
Slower speed – Lower flow and less pressure
Incorrect replacement motor – 3450, 1750, or
850 RPM
Noted – Increase of RPM typically results in
higher flow rate and pressure
Text Ref: Pg. 46
Pump Forensics (cont.)
Low Performance
• Additional Common Causes
•
•
•
Incorrect replacement impeller
Debris lodged in impeller
Partially blocked or clogged piping
Text Ref: Pg. 47
Pump Forensics (cont.)
Priming Challenges – Cause #1
• Excessive Clearances
•
•
Worn components reduce ability
to create a vacuum
• Replace or adjust clearances
Note – Priming-Assisted pump
priming issues can stem from
worn auxiliary priming system
components
Text Ref: Pg. 47
Pump Forensics (cont.)
Priming Challenges – Cause #2
• Air Relief System Issues
•
•
•
Air Bleed Line
Air relief line missing
Incorrect air release valve
Poor ARV plumbing design
Text Ref: Pg. 47
Pump Forensics (cont.)
Priming Challenges – Cause #3
• Leak on vacuum side
•
•
•
•
Often difficult to locate
Thoroughly review all suction
piping, hose, joints, & pipe plugs
Could be mechanical seal
Use gauge and monitor vacuum
reading when pump is not
running
Text Ref: Pg. 48
Pump Forensics (cont.)
Priming Challenges – Cause #4
• Obstruction in Plumbing or Pump
•
•
•
Slow to prime or failure to prime
as a result of an obstruction
Typical cause- Debris in impeller or
a partially block suction line or
suction strainer
Solution remove, clean and restart
Text Ref: Pg. 48
Pump Forensics (cont.)
Air Bound (Failure to go Dynamic) – Cause #1
• Too much air in impeller/casing area
•
•
•
Problem can occur with standard centrifugal,
submersible and certain self-priming pumps
At start up on new installations typically this is
a result of air left in suction lines
Manually fill pump and bleed off air
Text Ref: Pg. 48
Pump Forensics (cont.)
Air Bound (Failure to go Dynamic) – Cause #2
• Failure to overcome static discharge pressure (head)
•
•
Air Bleed Line
•
Missing air bleed (vent) line
Often Self-Priming pumps require an air release line
when there is more static head on a system check
valve to push the air out discharge
Automatic air release valves (ARV) are recommended
to operate more efficiently and/or to reduce potential
nuisance clogging
Text Ref: Pg. 48
Pump Forensics (cont.)
Air Bound – Cause #3
• Failure on existing installation
•
•
Result of air entering pump inlet
Typical causes include:
•
•
Solutions include raising liquid level and/or redirecting inflows
Noted – Applications where slurping and snoring cannot be
designed out, a priming-assisted (dry prime) pump may be a
better solution
• Insufficient submergence – (vortexing, slurping, snoring)
• Force entrapped air – inverts cascading over pump inlets
Text Ref: Pg. 48
Pump Forensics (cont.)
Noisy Operation (Mechanical Noise)
• Noise can be hydraulic or mechanical
•
Will cover Hydraulic Noise in a separate section
•
•
•
•
Submersible - Remove pump from liquid and run briefly dry
Centrifugal, self-primer or PD pump - drain pump and run briefly dry
If noise goes away it’s hydraulic challenges
If noise remains…
• How can you tell the difference?
Text Ref: Pg. 49
Pump Forensics (cont.)
Noisy Operation (Mechanical Noise) – Cause #1
• Debris in the pump causing hydraulic imbalance
Text Ref: Pg. 49
Pump Forensics (cont.)
Noisy Operation (Mechanical Noise) – Cause #2
• Badly worn or damaged bearings
Text Ref: Pg. 49
Pump Forensics (cont.)
Noisy Operation (Mechanical Noise) – Cause #3
• Impeller rubbing due to improper clearances
•
•
•
•
•
•
Debris lodged between
Wear ring(s)
Wear plate(s)
Seal plate
Suction head
Diffuser
Text Ref: Pg. 49
Pump Forensics (cont.)
Noisy Operation (Mechanical Noise) – Cause #4
•
Impeller out of balance
•
•
Damaged (Vane broken)
Severe wear
Text Ref: Pg. 49
Pump Forensics (cont.)
Noisy Operation (Mechanical Noise) – Cause #5
• Drive Alignment
•
•
•
Misalignment or worn
Coupling
Belt(s) & Sheaves
Text Ref: Pg. 49
Pump Forensics (cont.)
Noisy Operation (Mechanical Noise) – Cause #6
• Driver Issues
•
Motor bearing problems
• If possible uncouple motor from pump and run briefly
• Follow motor manufacture’s procedures
Text Ref: Pg. 49
Pump Forensics (cont.)
Shaft Failures
• Shaft breakage occurs
typically in one of two
modes
•
•
Radial (fatigue) breaks
Torsional (twisting) breaks
Text Ref: Pg. 50
Pump Forensics (cont.)
Shaft Failures (cont.)
• Radial (fatigue) breaks
•
•
Impeller end failure due to hydraulic
imbalance (air) or TDH too high
Drive end failure due to improper
drive arrangement including extreme
side load such as belts over tightened
Text Ref: Pg. 50
Pump Forensics (cont.)
Shaft Failures (cont.)
• Torsional (twisting) breaks
•
•
•
Failure cause is typically due to
something being injected into the
pump causing it to lock-up
Extreme start torque due to reverse
rotation with sudden call to start
Typically a result of discharge check
valve failure or absent of valve
causing flow to pass back through
pump when not running
Text Ref: Pg. 50
Pump Forensics (cont.)
Chemical and Abrasion Damage
• Abrasive Damage
•
•
Pumps are often exposed to fluids that have small suspended
solids such as sand or grit traveling a high velocities
Typical failure mode will be a smoothing, rounding or grooving
of areas of the pump in direct contact to the flow
Solution is an alternate material more suitable
•
Wear will also transmit to casings, shafts, wear rings, etc.
•
• Austempered Ductile Iron
• High-Chrome
• Polymer based (urethanes)
• Specialized coating (ceramics or epoxy)
Text Ref: Pgs. 50-51
Pump Forensics (cont.)
Chemical and Abrasion Damage (cont.)
• Corrosion or Chemical Attack
•
•
•
•
Pump
Basics
Pump
Safety
Tools of
the Trade
Stems from material compatibility
Under dynamic operation, chemical attack
can soften surface of material - gives
appearance of divots/ melon balling
In extreme cases, chemical attack erodes
or dissolves the material (all surfaces get
thinner and any holes grow in size)
Solution - Select a more suitable material
more compatible with liquid
Pump
Forensics
Checklist
& Guide
Noisy
Operation
Reference
Section
Text Ref: Pg. 51
Troubleshooting
Checklists & Guides
Text Ref: Pg. 52
Checklists & Guides (cont.)
Suggested checklists and troubleshooting guides
• Assist in keeping pump at peak performance
•
Decreases operation cost and/or boosting profits
• Reduce fuel consumption
• Reduce unnecessary replacement parts use
• Minimize down time
Text Ref: Pg. 53
Checklists & Guides (cont.)
Refer to text for further
details
• Use of Checklist
• Preventative Maintenance
•
Schedules
Maintaining these records
will assist when problems
arise
Text Ref: Pgs. 53-58
Checklists & Guides (cont.)
Troubleshooting guides
are useful tools when
you are unfamiliar with
equipment
Pump
Basics
Pump
Safety
Tools of
the Trade
Pump
Forensics
Checklist
& Guide
Noisy
Operation
Reference
Section
Text Ref: Pgs. 60-66
Noisy Operation
(Hydraulic Noise)
Text Ref: Pg. 67
Noisy Operation (cont.)
My pump is noisy… Why?
• Mechanical noise challenges were
•
•
discussed earlier
Nonetheless, hydraulic noise is
another challenge that causes a
variety of pump issues
Addressing these will not only
improve the site operating
conditions, but will improve the life
of the equipment
Text Ref: Pg. 68
Noisy Operation (cont.)
Items to discuss in this section
include:
• Vortexing
• Air entrainment
• Cavitation
• Improper inlet spacing
• Surging or water hammer
• Excessive velocity
Text Ref: Pg. 68
Noisy Operation (cont.)
#1 Cause - Vortexing
• One of the more common problems of
•
•
•
•
hydraulic noise challenges
Makes a growling noise within pump
Can produce a visible whirlpool at surface
Created due to insufficient surface tension
Caused due to insufficient submergence
Text Ref: Pg. 68
Noisy Operation (cont.)
Vortexing (cont.)
• In extreme cases, a vortex tail will extend
•
to pump inlet, allowing a direct path for air
to enter pump inlet
Will cause noise, vibration and potentially
can cause several failure modes:
•
Bearings, shaft fatigue, seals, weldments…
• Solution is to increase level in sump and/or
add an increaser to pump inlet
•
Larger cross-sectional area - reduces the
inlet velocity, eliminating vortex formation
Text Ref: Pg. 69
Noisy Operation (cont.)
Vortexing (cont.)
• Minimum submergence
recommendations to resist
formation of vortexes
Text Ref: Pg. 69
Noisy Operation (cont.)
#2 Cause - Air Entrainment
• Standard centrifugal, self-priming or
•
submersibles are not designed to operate
continuously on mixtures of liquid and gases (air)
Continued operations in these conditions lead to:
•
•
•
Shortened life
Unsatisfactory performance
Serious mechanical trouble
Text Ref: Pg. 70
Noisy Operation (cont.)
Air Entrainment (cont.)
• 2% free air can result in a 10%
•
reduction in capacity
Additional challenges may include:
•
•
•
Destructive vibration
Loss in prime
Accelerated corrosion
• Solution is to install a baffle or extend
the invert below the surface of liquid
Text Ref: Pg. 70
Noisy Operation (cont.)
#3 Cause - Cavitation
• All types of pumps can
suffer from effects of
cavitation
•
•
•
•
•
Standard Centrifugal
Self-Primer
Priming-Assisted
Submersible
Rotary Gear
Text Ref: Pg. 71
Noisy Operation (cont.)
#3 Cause – Cavitation (cont.)
• What causes cavitation?
•
•
The rapid formation and collapse of
vapor pockets in a flowing liquid in
regions of very low pressure
When these collapse, pitting or other
damage is caused on metal surfaces in
contact
Text Ref: Pg. 71
Noisy Operation (cont.)
#3 Cause – Cavitation (cont.)
• When does cavitation occur?
•
•
•
•
When negative pressure exceeds the
vapor pressure of a liquid
These vapor bubbles collapse when
sufficient localized pressure is found
The concentrated force of implosion
can exceed 100,000 psi
Metal in close proximity will flake or
chip away by this exerted force
Text Ref: Pg. 71
Noisy Operation (cont.)
#3 Cause – Cavitation (cont.)
• What causes cavitation?
•
Suction (Eye) Cavitation
•
Discharge (Tip) Cavitation
• Occur in eye of an impeller
• Caused by too high of a vacuum
• Occurs at external tips of an
impeller as it crossed the cutwater
• Caused by too high of discharge
pressure
Text Ref: Pg. 72
Noisy Operation (cont.)
#3 Cause – Cavitation (cont.)
• Damage caused by discharge cavitation
•
•
•
•
Breaks shafts
Shortens bearing life
Destroys impellers and volute casings
Ruins mechanical seals
Text Ref: Pg. 73
Noisy Operation (cont.)
#3 Cause – Cavitation (cont.)
• Damage caused by suction cavitation
•
•
•
•
Shortens bearing life
Destroys impellers
Destroys wear plates
Ruins mechanical seals
Text Ref: Pg. 74
Noisy Operation (cont.)
Text Ref: Pg. 76
Noisy Operation (cont.)
#4 Cause – Pump and Suction Spacing
• In multiple pump installations spacing
and invert locations should be reviewed
to prevent starvation
Text Ref: Pg. 77
Noisy Operation (cont.)
#5 Cause – Net Positive Suction Head (NPSH)
• Measure of liquid pressure at the pump end of a suction system
•
•
NPSHa – Difference between atmospheric pressure and (atmospheric
pressure at site, TDSL, vapor pressure, and a safety factor)
NPSHr – Atmospheric pressure required to move liquid through
suction side of a pump
• When finished for any pump to operate satisfactory the value
must be a positive number.
Text Ref: Pg. 77
Noisy Operation (cont.)
#5 Cause – NPSH (cont.)
• NPSH Calculation (five deductions)
•
•
•
•
•
•
Starting with standard atmospheric
pressure
Altitude elevation at job site
Vapor pressure of liquid pumped
Total Dynamic Suction Lift (TDSL)
Safety Factor (2 ft. water/3 ft. fuel)
NPSHr @ flow rate
Text Ref: Pg. 80
Noisy Operation (cont.)
#5 Cause – NPSH (cont.)
• NPSH value must be a positive number
• If negative, NPSH needs to be
•
increased
To increase NPSH - Reduce the TDSL
•
•
•
Lower pump elevation
Raise liquid level
Increase suction line diameter
Text Ref: Pg. 82
Noisy Operation (cont.)
Review example in text
Pump
Basics
Pump
Safety
Tools of
the Trade
Pump
Forensics
Checklist
& Guide
Noisy
Operation
Reference
Section
Text Ref: Pgs. 83-85
Reference
Text Ref: Pg. 86
Reference (cont.)
Variety of useful materials
•
•
•
•
Terminology
Charts and Tables
Formulas
Affinity Laws
Text Ref: Pgs. 87-108
Reference (cont.)
Variety of useful materials
• Motor Maintenance
• Electrical Insulation
Resistance
• V-Belt Maintenance
• Coupling Alignment
Text Ref: Pgs. 87-108
Questions
and
Comments
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