pump troubleshooting
TRANSCRIPT
PUMP TROUBLESHOOTING
Brian GongolDJ Gongol & Associates, Inc.
November 4, 2015
Nebraska AWWA Fall ConferenceKearney, Nebraska
Quick survey
Are you here for water, wastewater, or both?
Sir Arthur Conan Doyle (as Sherlock Holmes)
"Once you eliminate the impossible,whatever remains, no matter how improbable,
must be the truth."
Handout
Pump troubleshooting flowchart
All pump problems are either mechanical...
...or hydraulic
Secondarily, they are either internal...
...or external to the pump
How to tell a mechanical problem
Take away the water
How to tell a hydraulic problem
Take measurements
Mechanical problems - internal to the pump
Bearings
Seals
Packing
Tightness of fit
Suction flap valves
Debris
Internal rubbing
Friction
Mechanical problems - external to the pump
Motors
Controls
Alignment
Balance
Transmission
Belts
Sheaves
Couplings
Valves (throttling)
Valves (isolation)
Valves (air-release)
Piping
Rotation
Jay-Z had 99 problems
We've come up with about 50...and this is halftime
Hydraulic problems - internal to the pump
Recirculation
Clearances
Wearplate wear
Wear ring wear
Volute wear
Impeller wear
In at least three flavors...
Chemical attack
Abrasion
Cavitation*
Cavitation damage happens inside the pump...but it's almost always caused outside the pump
Hydraulic problems - external to the pump
Suction side or discharge side
The two flavors of external hydraulic issues
Hydraulic problems - external - suction
NPSH
NPSHa (net) = Atmospheric pressure- vapor pressure- safety factor- total dynamic suction lift- NPSHr for the pump
Atmospheric pressure
Heat/vapor pressure
Air entrainment
Air in high spot
Turbulence
Vortexing
Minimum submergence
Plugged suction
Debris
Never underestimate what a storm can do...and deposit in your wetwells
Horizontal runs
Valves
Leaks
Not water getting out,but air getting in
Changes to fluid properties
For instance...
Gases in solution
Surfactants
Viscosity
Specific gravity
Froth/foam/bubbles
Hydraulic problems - external - discharge
Handout
Engineering data booklet
Valves
Leaks/breaks
Sediment
Debris
Changes to effective pipe diameter
Caused by...
Air
Ice
Corrosion
Scaling
Buildup
Tools to assist in your investigation
Impeller condition: Excess wear
Impeller condition: Suction cavitation
Impeller condition: Discharge cavitation
Shaft breakage
Seal failure
Strange or unwelcome noises
Strange or unwelcome noises
Suction cavitation
Discharge cavitation
Surges
The scream
Use all of your available senses (minus taste)
Record performance
Keep pump curves handy
Gauge readings make a huge difference
Gauge readings make a huge difference
Look in the direction of change
Was the change gradual or abrupt?
Some are dead giveaways,others just point in the right direction
Gauge case studies
Gauge case studies
The prime that took forever
Gauge case studies
Gauge case studies
The prime that took forever The hole in the suction line
Gauge case studies
Gauge case studies
The prime that took forever The hole in the suction line The plugged suction
Gauge case studies
Gauge case studies
The prime that took forever The hole in the suction line The plugged suction
The forcemain failure
Gauge case studies
Gauge case studies
The prime that took forever The hole in the suction line The plugged suction
The forcemain failure The sedimentation
inclination
Gauge case studies
Gauge case studies
The prime that took forever The hole in the suction line The plugged suction
The forcemain failure The sedimentation
inclination The bubble, bubble, toil,
and trouble
Gauge case studies
Gauge case studies
The prime that took forever The hole in the suction line The plugged suction
The forcemain failure The sedimentation
inclination The bubble, bubble, toil,
and trouble The surge-and-slam
Gauge case studies
Always divide and conquer
Questions?
Thank you for coming!
Thank you for your attention!
Contact us anytime with questions
Brian Gongol DJ Gongol & Associates 515-223-4144 [email protected]
References:
Photo: Mechanic tightening nut (public domain) http://loc.gov/pictures/resource/fsac.1a35263/
All other photos are original work by and copyright reserved to Brian Gongol