Centrifugal Blowers for Foundries and Non-Ferrous Metals

Foundries and non-ferrous metal plants use centrifugal blowers for combustion air on melting and holding furnaces, mold and core drying, cooling of castings and equipment, and ventilation of hot, fume-laden buildings. The largest fans in a foundry’s melt shop, part of its pollution-control system, are specialist heavy-duty machines. Everything else, the combustion air, the drying, the cooling, and much of the general ventilation, is centrifugal blower territory, and that is where this page focuses.

Where Blowers Fit

Duty	Typical pressure	Notes
Furnace combustion air	High	Melting, holding, and heat-treatment furnaces
Mold and core drying	High	Sand-mold and core-making ovens
Casting and equipment cooling	Medium to high	Cooling parts and process equipment
Sand-handling area ventilation	Low to medium	General ventilation, dust dilution
Shaker table and grinding dust collection	High	Clean-side, moderate scale
Building ventilation	Low to medium	Heat removal from the melt shop
Melt shop pollution-control fans	Very large flow	Often outside our range

Combustion Air for Melting and Holding Furnaces

Furnace combustion air needs stable, pulsation-free flow across the firing range, which is a natural fit for backward-curved centrifugal blowers.

Worked example. A furnace has a fuel input of 4 MW, about 3.44 million kcal/h. With 15% excess air, the required air is about 4,668 Nm³/h, or roughly 5,010 m³/h at 20 °C, about 1.39 m³/s. If the burner and ductwork need 400 mm WC (3,923 Pa), air power is about 5.5 kW, and at 65% efficiency the blower needs about 8.4 kW at the shaft. See combustion air.

Mold and Core Drying

Sand molds and cores are often dried or cured in ovens before use, which is an industrial drying duty, sized from the moisture to remove and the operating temperature. Fibre and dust carried off the sand can foul blades, so filtration and cleaning access matter. See industrial drying and process air.

Cooling Castings and Equipment

Hot castings leaving a mold or a heat-treatment furnace need cooling air, sized from the heat to remove and the allowed air temperature rise, the same method used for steel parts. See cooling air.

Where 800 HP Ends: Melt Shop Pollution Control

The largest fans in a foundry are usually part of the melt shop’s pollution-control system, handling very high airflow from furnace exhaust hoods. These are specialist, high-energy machines, and finding the highest-efficiency fan for them is a significant part of a foundry’s energy bill. They are outside our 800 HP range. Send us the combustion air, drying, and cooling duties instead.

Silica Dust: A Warning, Not a Blower Duty

Sand handling, core making, and shake-out release respirable crystalline silica, a serious health hazard controlled by properly designed local exhaust ventilation and high-efficiency filtration, not by general ventilation blowers. A ventilation blower dilutes air and removes heat; it does not substitute for source capture. See dust collection system design for the difference between capture and dilution.

Non-Ferrous and High-Temperature Recirculation

Non-ferrous smelting and casting, including aluminium and copper, uses combustion air, cooling, and in some processes hot-gas recirculation fans. Where a blower handles hot gas directly, rather than ambient combustion air, our high-temperature range applies: furnaces up to 800 °C, kilns up to 650 °C, and ovens up to 500 °C. See furnaces, kilns and ovens.

Grinding and Deburring Dust

Grinding, deburring, and shaker-table operations generate dust that is typically captured by local exhaust and a filter, with the blower on the clean side. This is ordinary dust collection duty within our range. See dust collection and filtration.

Heat and Dust Protection

Foundry blowers near furnaces see heat, radiant load, and metallic dust. Check motor and bearing temperature limits, keep the motor out of radiant heat where practical, and plan cleaning access, since dust deposits unbalance wheels. See maintaining industrial blowers.

Standardising Blower Models Across a Foundry

A foundry with several furnaces, drying ovens, and cooling duties benefits from standardising on a small number of blower models rather than specifying each one individually. That reduces the spare-parts inventory, since bearings, belts, and seals interchange, and it lets maintenance staff become familiar with one family of machines rather than many. Before specifying a new furnace or oven, check whether an existing blower model on site already covers the duty.

Where Our Range Fits

NextAir Systems manufactures centrifugal blowers up to 800 HP (about 597 kW) and up to 500 mm WC (about 4.9 kPa) static pressure, with backward-curved and forward-curved wheels and high-temperature designs for furnaces up to 800 °C. That covers combustion air, mold and core drying, cooling, and general dust collection and ventilation in foundries and non-ferrous plants. Melt shop pollution-control fans at very large scale are outside our range.

What to Specify

1. Duty: combustion air, drying, cooling, or dust collection.
2. Airflow and resistance, at clean and worst-case conditions.
3. Furnace fuel input, or heat load for cooling duties.
4. Gas or air temperature.
5. Dust type and whether silica or other hazardous dust is present.
6. Control approach and noise limits.

Vibration From Casting and Shake-Out

Foundries generate mechanical vibration from shake-out, knock-out, and other impact processes, which can transmit through the floor into nearby blowers and their supports. Where a blower sits close to such equipment, use flexible mounts and check that its own running speed does not coincide with the vibration frequencies the process generates, since a coincidence can amplify wear on bearings and fixings well beyond what the blower’s own unbalance would cause.

Get a Blower Selection for Your Foundry

Send your duty, whether combustion air, drying, or cooling, and we’ll size the blower. Contact us for a free quote.

Frequently Asked Questions