Pumps Flashcards
How would you service a pump?
- Refer to manufactures guidelines
- Create a permit to work
- Isolate the pump
- Lockout and tag out
- Ensure the system is still operational if possible or inform all crew that this service is out of action till further notice
- Disconnect electrically
- Drain the pump
- Remove the pump
- Disassemble
- Inspect
- Replace serviceable parts and any damaged parts
- Rebuild
- Reinstall insuring alignment
- Test
- Recommission the system
- Close permit
- Inform all crew system is back operational.
What damage would you be looking for in a centrifugal pump?
- Corrosion and erosion on the impeller
- Corrosion on the casing
- Cracks on the casing
- Pitting on the shaft
- Wear on the bearings
- Damage to the seal
How would you check the motor?
- Visual inspection
- Inspect electrical wiring for overheating, good earth
- Perform a insulation resistance test (Low resistance is a breakdown or water ingress)
- Bearing condition
- Temperature and Vibration
What are you looking for in an internal mechanical inspection?
- Mech pump failing points,
- Erosion from wear and cavitation,
- Impeller,
- Volute casing and wear ring,
- Check clearances against manufacturer specifications,
- Shaft and mech seal.
What could be causing low flow if the mechanical side is okay?
The pump is down a phase, known as single phasing
Your centrifugal sea water pump is losing pressure?
- Dirty strainers
- Marine growth in the pipework
- Damaged or worn impeller
- Wear rings
Why do we use positive displacement pumps for oil and fuel?
- Precise and consistent flow rate, making them ideal for metering
- Can handle high viscosity fluids
- Self priming
- Can operate at high pressures
- Compact
List all types of pumps
Two main classes of Positive Displacement
- Reciprocating
- Rotary
Positive Displacement pumps are;
- Lobe pump
- Gear pump
- Piston pump
- Diaphragm pump
- Screw pump
- Vane pump
Reciprocating Pumps are;
- Plunger pump
- Diaphragm pump
Rotary pumps are;
- Gear pumps
- Lobe pumps
- Vane pumps
- Screw pumps
Difference between PD and centrifugal pumps?
PD have relief valve as they can’t be run against a closed valve, centrifugal pumps have a priming pump.
