Latest from Melt/Pour

Jonathan Weiss | Dreamstime
Aleksandr Matveev | Dreamstime
Molten Metal Equipment Innovations
The burners on the left and right have been adjusted to near-stoichiometric levels. The flame on the right is short and cold, meaning that the energy requirements will increase.

Optimal Air-to-Fuel Ratio for Optimal Results

Feb. 12, 2018
Near-stoichiometric burner adjustment saves energy, cuts metal oxidation

In furnace combustion operations, achieving an optimal air-to-fuel ratio is every operator’s goal. Excess air in the fuel mix is the the frequent cause of rising fuel consumption in foundry and diecasting melting furnaces. “If you don’t keep an eye on air-fuel ratios, you are literally burning money,” according burner expert Rudolf Hillen of StrikoWestofen, which is introducing an economical approach to near-stoichiometric burner adjustment.

A measuring section is installed in front
of the fan during burner adjustment,
serving to set the optimal air ratio for
melting, upstream of the combustion
air ventilator.


At a combustion-air ratio (λ) of 1, the oxygen in air reacts completely with the fuel gas. While gas flow is easy to measure via a meter, measuring the amount of air requires more complex equipment and may cause a steady loss of pressure in the combustion-air system.

“This is why we are now offering our customers a solution for which we only have to measure air-flow once, during the commissioning of the furnace,” Hillen explained. “To do this, we install a measuring section in front of the combustion-air fan. The pressure drop at the standardized metering orifice is an exact measure of the air flow.”

With the help of specially defined software, the air vent of the burner can then be positioned precisely to produce an optimal combustion-air ratio λ of near 1.

As such, the minimized excess air in the combustion process also reduces oxidation during the melting process. Suitably adjusted burners ensure a high flame temperature and optimal heat transfer to the charge metal, saving energy and costs.

“We are talking about approximately seven kilowatt hours less energy per metric ton of metal,” meaning annual savings estimatable at around $3,000. “In other words, at a melting rate of two metric tons per hour, the additional one-time investment pays for itself within two years,” Hillen added.

Starting this year, near-stoichiometric burner adjustment will be included with the standard versions of StrikoMelter PurEfficiency and BigStruc melting systems, and it is available as an option for all other StrikoMelters systems.