Pump Questions

Question 1

How would you go about replacing the bearing on a pump?

Answer 1

• Day before job
• Check manual for procedure (Print and laminate copy)
• Consult electrical drawings to ensure correct source isolation.
• Check for spare parts

• Complete a Risk Assessment, Permit to work & a toolbox talk with staff involved
• Get permission to carry out the job ensuring my actions won’t compromise the safety/operation of the vessel
• Isolations both Electrically and Mechanically
ELECTRICALLY:
• Identify device & turn it off
• Isolate it by opening the breaker
• Secure isolation with safety lock (lock out, tag out)
• Then prove dead via multimeter
MECHANICALLY:
• Identify device
• Close all inlet and outlet valves on device
• Note all valves that are closed
• Lock valves closed
• Consider blanking valves depending on system
• Release pressure in system. Best done through any drain valves.

• Complete and Release PTW
• Carry out work following manufacturer’s instructions.
• Remove Mechanical & Electrical isolations
• Cancel PTW
• Test Device via multimeter
• Restore to operation as required

Question 2

What is cavitation

Answer 2

It occurs when the pressure of a liquid drops below its Vapor pressure, causing Vapor bubbles to form in the fluid. These bubbles then implode as pressure increases which can lead to damage

Question 3

How to prime a centrifugal pump

Answer 3

• I would ensure the pump is off and isolated (lock out, tag out)
• I would open the air vent valve and priming plug at the highest point of the casing
• Then pour liquid (seawater for example) into the priming port until the casing is completely filled and fluid overflows from the vent
• Close the vent valve and priming plug
• Start the pump with the discharge valve closed (this prevents water hammering, motor overload and voltage dips & sudden acceleration casing stress on couplings)
• Then slowly open the discharge valve