Foundry Air Management

Paucity of fresh air as compared to exhaust air causes problems with the ventilation of work zones in foundries. This is worsened often by excessive dust and a high Carbon Monoxide content. Traditionally foundries combat this problem by large sized vents and exhausts.

Excessive air exhaust due to too much exhaust air outflow and faulty system of air supply causes a negative pressure. Other wastages include heat surplus lost by exhausts and water, which is sewered off after cooling the air just once.

Leaving doors and windows open harm a good ventilation system. A foundry found solution to dust and heat and ventilation in the following way: Incoming air is pre heated in winter. The ventilation system for incoming air regulated fan’s capacity in inlet section by monitoring air pressure of incoming air. Each zone had separate exhausts, along with speed regulators. The system was then converted to Central Monitoring System to obtain balance between incoming and outgoing air. This process not only improved plant ventilation but also halved the costs for the same.

Another plant solved their ventilation problem by establishing ventilation zones for the entire plant. Only areas where processes were being held were fully ventilated, and the rest were left as such.

• Keeping doors and loading bays closed for proper functioning of ventilation system.
• Using ventilation and heating ONLY when required.
• Shut down exhausts and ventilation system when not in use.
• Assign task of turning off fans, closing vents etc, weekly, to a specific person.
• Assign task of switching on the exhaust system, weekly, to a specific person.
• Use only as many exhausts as essentially required in winters.
• Seal points of wastage of air supply.
• Regular upkeep of air filters.
• Examine present system to check if more exhaust fans are being used than necessary.
• Reduce maintenance.
• Lower energy costs
• Reduce emission
• Reduce noise
• Regular upkeep of dust collection system
• Monitor CO levels to check effectiveness of ventilation system.
• Tune motors and trucks and other vehicles and machinery to reduce excessive CO emission.
• Study the system to recapture heat from clean areas.
• Start foundry ventilation only when heat of foundry processes has warmed inside areas.
• Make small openings in large doors to allow passage of trucks without opening the full door. Use curtains to ward off continuous stream of cold air.

• Install hoods over hot/ dusty areas to prevent escape heat or dust.
• Use of exhausts only during dust generation periods.
• Recapture heat accumulated in foundry rafters and use in winters.
• Use exhausts with speed control.
• Supply outside air in plant instead of air heated by plant when possible.
• Use curtains to stop inflow of air at openings.
• Install double doors to stop inflow of air at openings.

• Replace generally ventilation with better suited exhausts located over required places.
• Use rotary heat exchange for supplying fresh air of uniform temperature. The air from exhausts heats the fresh air in the exchanger.