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VENTILATION SYSTEM

VENTILATION SYSTEM. Why engine room need ventilation?. Engine must receive sufficient air for combustion Engine room should be cooled to acceptable temperature. Two modes in ventilation. At working engine – cooling and engine feeding At not working engine – moisture expelling.

garrett-sharpe
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VENTILATION SYSTEM

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  1. VENTILATION SYSTEM

  2. Why engine room need ventilation? • Engine must receive sufficient air for combustion • Engine room should be cooled to acceptable temperature

  3. Two modes in ventilation • At working engine – cooling and engine feeding • At not working engine – moisture expelling

  4. Engine room temperature Less than 45o – 50oC • Hot air getting engine cylinder decrease performance • Electrical system is sensitive to elevated temperature • Crew working in the engine room

  5. Requirements • Supply enough air • Effective routing • Sound insulation • Water from sea and rain should not enter • Closing air access in case of fire • Minimum resistance in air pipes

  6. Quantity Required (without combustion air) • Rough estimation – Change the air in the room every one or two minutes • 0.1 – 0.2 m3/min per installed horsepower

  7. Calculate required air for your engine Velocity of the air in personnel working area: • Do not exceed 1.5 m/s

  8. Combustion air Ducts • Quantity - 0.1m3 of air / min / kW 2.5 ft3 of air / min / bhp • Duct restriction – should not exceed 2.49 kPa (10 in of water) at engine full rated power • Velocity in duct should not exceed 610 m/min

  9. Effective routing

  10. Rules: • Fresh air should enter the ER as far from the sources of heat as practical • Fresh air should enter the ER as low as possible • Discharge air should leave ER at the highest point • Discharged air should leave ER above the heat source

  11. Using Fans • Improve air supply • Location – most effective in suction line • Type – axial and centrifugal– the motor should be outside the direct flow • Sizing – name plate rating is higher than as-installed

  12. Example

  13. Water Trap

  14. Through-hull Opening Design

  15. Air Discharge • Avoid recirculation • Higher and aft ward than intake

  16. Minimum Resistance • No more than three 90o elbows • More pipes – greater resistance • Longer pipes – greater resistance Resistance decreases efficiency

  17. Crankcase Fumes Disposal • Could be digested by engine • Could require ventilation piping

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