The theory is simple. Gas and air are delivered to a burner. They mix. They ignite. Thus, combustion occurs. But, in the drive for a gas burner that is more efficient and environmentally friendly, that three-step process evolves, additional devices are added and additional features tapped.

Burner suppliers, and the vendors that supply them, are working on ways to improve burner technology. According to Tim McCarthy, business unit director for internal combustion for Honeywell, efficiency and environmental impact are the critical issues driving the industry. Standards have become more stringent for a variety of appliances. OEMS and end users have gotten more discerning when specifying a product.

Fenwal 35-6x Series Gas Ignition Controls are third-party approved and perform the critical safety functions of burner ignition and flame monitoring.

As a result, designers now have a variety of options from which to choose. Systems can premix gas and air, or the content can be monitored and adjusted in situ. They can be microprocessor-based, or even have multiple microprocessors controlling their actions. They can heat up quickly, cool down fast, and burn at the highest BTU levels as well as the lowest.

These are just a few of the options available, and more and more products are coming onto the market. McCarthy points to two technologies that his company sells that help OEMs develop better burner systems. ControlLinks is an electronic linkage control that has the ability to position an air actuator and fuel actuator, down to a 0.1 degree of accuracy. It is a linkage-less burner system that removes mechanical linkages and mod-motors and replaces them with servomotors and microprocessors.

Proper integration of system components in the Fenwal Applications Lab assures optimal performance of the gas ignition system in a conveyor broiler under development for a well-known fast food restaurant chain.

A second product that McCarthy points to is a premix technology utilizing a Venturi valve system. The system incorporates a third-party fan to maintain the appropriate fuel-and-air ratio.

“Those are two technologies that are being deployed in very small systems to very large systems to get the most efficiency possible out a system,” says McCarthy. “That is the economic argument. The environmental impact argument is that you are getting more heat out of the fuel and you don’t need to run the equipment as long to get the same level of comfort. By doing that, you are not impacting the environment as much.”

Design for manufacturability (DFM) and reliable performance are key goals in this advanced pool heater.

The idea of running equipment only when necessary or under optimal conditions is an idea expounded upon by Jerry Hartin, vice president of marketing for Fenwal Controls, Kidde-Fenwal, Inc., Ashland, Mass. One of Fenwal’s customers builds commercial cooking equipment that is found in fast food restaurants around the world.

Hartin says that restaurant kitchens, the ovens and broilers are typically turned on full bore in the morning and left in that position until closing time -- a waste of expensive fuel and a strain on an appliance. But that is changing. “Some of the new technologies use a burner system that heats up in a matter of seconds,” he says. “You can turn off a broiler and then turn it back on when needed and it can be up to a safe temperature in 15 to 30 seconds, instead of 15 or 30 minutes.”

In-house laboratory tests of the Sabaf Series III burners have resulted in efficiency values amounting to 66 percent.

Fenwal recently announced that a number of its gas burner controls had achieved compliance with EN 298:2003, a European standard that covers automatic gas burner control systems for gas burners and gas burning appliances with or without fans. The standard, which replaces the 1993 version, when into effect in September 2006 and calls for extensive safety and fault assessment components to be factored into all automatic burner control systems.

One requirement of the revised standard is to implement an independent means of shutting off the gas valves. To become compliant, Fenwal added a second microprocessor control to the burner system that acts as a backup in case the first microprocessor fails, says Kevin Norby, Fenwal’s Product and Program Manager.

Solaronics’s group of infrared burners.

Burner suppliers that were compliant with the 1993 can continue to sell its current products, but, going forward, new products for use in the EU have to comply with the 2003 standard, says Norby. It is also important because Australia has decided to match their gas regulations to the European standard and that country is a hot market for Fenwal. These burners, series 35-60, 35-61 and 35-63, have received CE approval, CSA approval and Australian gas approval and essentially can be sold through many parts of the world.

Hartin adds that the burner control system, tentatively branded World Control, comes in three iterations. They are direct spark, direct spark with blower, and intermittent pilot. Another Fenwal product is the System 1, which features a standard digital temperature control that has been interfaced with a hot-surface ignition system.

Solaronics woven ceramic fabric gas burner.

These are just some of the products that burner manufacturers are now promoting. Italy-based Sabaf introduced the Series III burners that were designed to improve efficiency. .  In addition, the tests carried out at Sabaf laboratories also confirm a level of efficiency equal to 66 percent, an increase of more than 26 percent when compared with the requirements of the European legislations.

The burner works by entrainment of primary air from above the appliance top surface, and the radial Venturi. These features permit operation on both freestanding cookers and built-in hobs. It eliminates the problem of drawing in of combustion fumes from ovens situated beneath the cooktop, or by variations in aeration as a result of oven fans or open doors or drawers located beneath the cooktop.

ControlLinks is a linkage-less technology that replace mechanical linkages.

Solaronics, Rochester, Mich., sells the woven ceramic fabric (WCF) burner that can include both infra-red and blue-flame technology, rapid heat transfer and low pollutant emissions. Farshid Ahmady, vice president of research and development, says that the company’s WCF burners utilize a ceramic fabric having low conductivity and high-temperature resistance.

Another technology that can help improve efficiencies are those that allow for higher turndown rates. Typically, a system is turned on and runs until it reaches a set point, such as a furnace temperature setting. At the set point, the unit turns off until it falls below the set point and then turns the unit on again.

Honeywell offers premix burner systems.

“A lot of development efforts are based on modulating gas to work with high efficiency burners to achieve higher turndown rates,” says Mark Masen, senior engineer, research and development, for Maxitrol, Southfield, Mich.

The company’s Series 3 control, typically used in furnaces, eliminates the on-and-off cycling by modulating the amount of gas delivered to the burner. The percentage of turndown is set by the burner manufacturer and can be as low as 20 to 25 percent of the gas volume.

 “We work in a lot of different markets and the common thread is the need for higher efficiency,” says Masen. “Getting the higher turndown values can be a challenge depending on the particular burner design, but whatever the OEM might have in mind, we can make a control to do that.”

For more information, email:
Fenwal Controls: Teresa.Carroll@Kidde-Fenwal.com
Honeywell:  Pam.Enstad@Honeywell.com
Maxitrol: info@maxitrol.com
Sabaf.: info@sabaf.it
Solaronics:  fahmady@solaronicsusa.com