The process
Container and float glass furnaces burn fuel with combustion air through regenerators or recuperators and exhaust a hot gas with batch carry-over and condensing sulphates. Combustion air blowers at steady pressure, dilution air ahead of the filter, cooling air on the furnace steel, and high pressure blowers for forming and annealing.
The gas at the fan
Regenerator exhaust is very hot and carries batch dust with sulphates that condense as the gas cools. Dilution or cooling precedes the filter, and the fan material resists the condensing species.
Selection for this duty
| Blade form | Radial tipped, or backward inclined where the fan sits after the collector |
| Material of construction | Stainless steel on all wetted parts, grade to suit the gas analysis |
| Drive and bearings | Direct coupled, shaft cooling disc, bearings in a pedestal outside the gas stream, allowance for thermal growth |
| Density at the fan | At about 400°C the gas density is close to 0.52 kg/m³, 44% of standard air. Pressure developed and power drawn fall in the same ratio, so the selection is made at this density and the motor is checked at cold start. |
Feeds a burner with air at the pressure the burner register needs. Sized for the burner turndown range, and often fitted with an inlet silencer. Client-stated blade types for the Combustion Air Blower in general: Backward curved and radial tipped.
Industries
Other fans in glass melting furnaces
Combustion Air Blower in other processes
Information needed to select or quote
- Duty point. Volume flow and static pressure at the fan inlet, with the gas density and temperature or the conditions to derive it.
- Operating conditions. Site altitude, normal operating temperature and continuous or intermittent duty.
- Gas stream. Dust loading and particle size, corrosive species, moisture, upset temperature and any tendency of the material to deposit on the impeller.
- Mechanical. Rotation viewed from the drive end, discharge orientation and motor power.