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2012-01-17 19:30:32
Fire pump components

pump components and nomenclature
Show Answers:

  1. Positive Dispacement Pump definition
    Delivers a measured amount of water on each stroke or cycle of the pump.
  2. Positive Displacement Slippage
    No slippage. If discharge is stopped, pump will break.
  3. Types of Positive Displacemnt Pumps
    • 1. Piston
    • 2. Rotary Gear
    • 3. Rotary Vane
  4. Rotary Gear and Vane uses
    Driven by starter motor. Used as primer pump to exhaust air in a centrifugal pump.
  5. Centrifugal Pump advantage/disadvantage
    • 100% slippage (can run without discharge)
    • Can not exhaust air
  6. Centrifugal Pump Nomentclature
    • Volute- housing around impeller
    • Impeller- spinning part that creates flow
    • Eye- takes in water to center of impeller
    • Diffuser Vane -water thrown out of impeller here
    • Wear rings- take bulk of wear in spinning impeller
    • Freedom pump- Mechanical seal replaced packing gland for cooling the shaft
  7. Pump Rated Capacity PSI
    Rated at 150 psi net pump pressure. Above this output is diminished.
  8. Net Pump Pressure
    • Pump Pressure
    • minus
    • Intake pressure.
  9. Pump Capacity
    • 100% at 150 psi
    • 70% at 200 psi
    • 50% at 250 psi
  10. Cavitation
    • Occurs when impeller tries to thow more water than intake can provide.
    • Rapidly creates steam in pump and causes damage
    • Sounds like rocks in the pump
  11. Possible causes of cavitation
    • Diminished supply
    • Throttle too high
    • Clogged intake
  12. Priming System
    Positive Displacement pump lowers atmospheric pressure in the volute forcing water into the eye of the pump.
  13. Anti Siphon Hole
    • Top of priming system
    • Size of a broom straw .04"
    • Small intake to release suction on oil tank when priming is done
  14. Two Stage centrifugal pump
    • Has two impellers
    • independate (parallel or volume)
    • one feeds the other (series or pressure)
  15. Transfer valve
    • Used in two stage pump to change from parallel to series
    • Lower pressure to 50 psi before changing from volume to pressure, because pressure will double
  16. When to use parallel or volume
    When ever you pump more than 1/2 your rated capacity
  17. Intake relief or Dump Valve
    Takes excessive intak water pressure and dumps it on the ground.
  18. Tank to Pump
    Tank Discharge
    Opens tank water to gravity feed into the pump.
  19. Tank to pump notes
    • 500 gallons per minute
    • NFPA requires 80%
    • 3- 31/2 inch line
  20. Tank Fill valve
    • Fill the tank from the pump
    • 1" line
    • Helps to cool the pump
  21. Engine Cooler
    3/8 inch discharge line to cool the engine
  22. Relief Valve
    • Used on older engines to relieve excessive back pressure created by closing a discharge
    • Feeds water and pressure back to intake side of pump
  23. PSG (Pressure Sensor Governor)
    • Electronic control to maintain Master Gauge pressure when there are changes in the the hose lines
    • Used in stead of relief valve
    • Changes the fuel to the engine