Author: Daniel G. Teleoaca – Marine Chief Engineer

The main engine of a ship is the main propulsion element, propelling the vessel across vast stretches of water. But just like any powerful engine, it generates a lot of heat. That’s where auxiliary blowers come in, playing a critical role in keeping the engine running smoothly and efficiently.

What are the auxiliary blowers and their operation?

Auxiliary blowers are essentially electrically-driven fans specifically designed for ship engines, typically two-stroke diesels.

Unlike four-stroke engines, two-stroke engines rely on scavenging, a process where fresh air is pushed through the cylinders to expel exhaust gases and prepare for the next combustion cycle. At low engine speeds, the exhaust gas-driven turbocharger isn’t powerful enough to provide sufficient airflow for efficient scavenging. Here’s where the auxiliary blowers step up.

The vital functions of auxiliary blowers are:

• Ensuring Smooth Starts: Before starting the main engine, auxiliary blowers are activated. They pump fresh air into the cylinders, purging any residual gases and ensuring a clean and efficient combustion process from the very beginning.
• Boosting Scavenging at Low Load: As mentioned earlier, auxiliary blowers provide the extra airflow needed for effective scavenging at low engine loads, typically around 30-40%. This maintains optimal engine performance and reduces emissions.
• Improved Engine Cooling: The flow of fresh air generated by auxiliary blowers also aids in cooling the engine internally. This helps prevent overheating and potential damage to critical engine components.
• Uniform Cylinder Conditions: The flow of fresh air helps to create a more uniform temperature and pressure distribution across all cylinders. This even distribution is crucial for smooth and synchronized combustion across the engine.

Auxiliary Blowers Maintenance

Auxiliary blowers are vital for a ship’s main engine, ensuring smooth starts, efficient operation, and overall engine health. But just like any other hardworking piece of machinery, they require regular maintenance to keep them functioning optimally.

Here’s a breakdown of key maintenance practices for auxiliary blowers:

Routine Inspections:

• Visual Checks: Regularly inspect the blowers for any signs of damage, wear, or leaks. This includes checking the impeller for cracks or excessive wear, ensuring proper balance, and looking for any loose bolts or fasteners.
• Air Filters: Auxiliary blowers rely on air filters to prevent dust and debris from entering the engine. Regularly inspect and clean or replace the filters as per the manufacturer’s recommendations. Clogged filters can restrict airflow, reducing blower performance.
• Bearings: Pay close attention to the bearings, which are crucial for smooth blower operation. Listen for any abnormal noises that might indicate bearing wear. Schedule periodic lubrication or replacement of bearings based on manufacturer’s guidelines and operating hours.
• Air flaps: Check the air flaps for integrity, cracks and deformation. Clean the seat of any dust and debris that can affect its sealing.
• Electrical motor: Check electrical motor for any abnormalities like: abnormal vibrations, noise and overheating. Check motor current as it can indicate bearings problem.

Cleaning:

• Internal Cleaning: Over time, dust and debris can accumulate inside the blower housing and impeller. This can lead to unbalanced operation and reduced airflow. Following the manufacturer’s instructions, disassemble the blower periodically for thorough internal cleaning.
• Air Intake and Exhaust Paths: Ensure the air intake and exhaust paths of the blowers are clear of any obstructions. Built-up dirt or debris can significantly hinder airflow and blower performance.

Performance Testing:

• Airflow Testing: Regularly test the blowers’ air output to ensure they are delivering the required air pressure and volume. Consult the manufacturer’s specifications for the recommended airflow parameters for your specific blowers. Reduced airflow indicates potential issues with the blower itself or clogged filters.
• Vibration Monitoring: Monitor the blowers for excessive vibration during operation. Abnormal vibration could be a sign of unbalanced components, loose parts, or bearing wear.

Additional Tips:

• Maintain Records: Keep detailed records of all maintenance activities performed on the auxiliary blowers, including the date, type of maintenance, and any parts replaced. This helps track maintenance trends and identify potential problems early on.
• Consult Manuals: Always refer to the manufacturer’s operation and maintenance manuals for specific instructions on maintaining your auxiliary blowers. These manuals will provide detailed information on lubrication schedules, troubleshooting procedures, and recommended replacement parts.
• Training: Ensure crew members responsible for blower maintenance are properly trained on the specific procedures and safety precautions involved.

Auxiliary blowers troubleshooting

A malfunctioning auxiliary blower can lead to a variety of problems for a ship’s main engine, potentially impacting performance, increasing emissions, and even causing safety hazards. Here are some examples of auxiliary blower malfunctions and their consequences:

• Reduced Airflow:
  • Cause: This could be due to clogged air filters, worn-out impellers, or leaking ducts.
  • Consequence: The engine won’t receive the necessary amount of fresh air for proper scavenging and combustion. This can lead to incomplete combustion, resulting in increased smoke emissions, reduced engine power, and higher fuel consumption.
• Bearing Failure:
  • Cause: Worn-out bearings due to lack of lubrication, excessive vibration, or contamination.
  • Consequence: Bearing failure can cause the blower to seize or vibrate excessively. This can lead to damage to the blower itself, surrounding components, and potentially disrupt the engine’s starting process.
• Electrical Issues:

• • Cause: Malfunctioning motor, faulty wiring, or blown fuses.
  • Consequence: Electrical problems can prevent the blower from starting at all. This could lead to difficulties starting the main engine, especially when relying on auxiliary blowers for low-speed scavenging.
• Unbalanced Impeller:
  • Cause: Dirt build-up, foreign object damage, or manufacturing defect.
  • Consequence: An unbalanced impeller can cause the blower to vibrate excessively, leading to bearing wear, potential damage to the blower housing, and reduced blower performance.

These are just a few examples, and the specific consequences of a malfunction will depend on the severity of the problem and the operating conditions of the engine. Early detection and rectification of auxiliary blower malfunctions are crucial to prevent further damage, ensure smooth engine operation, and maintain optimal engine performance.

In conclusion, auxiliary blowers may seem like a small cog in the grand machinery of a ship, but their role is undeniable. They ensure smooth engine starts, efficient operation at low loads, and contribute to overall engine health. By understanding their function and importance, you gain a deeper appreciation for the intricate systems that keep these modern seafaring giants moving.

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•  LECKYJAKE – YouTube
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