A GFC Kilns Co. sanitaryware shuttle kiln.
I had the opportunity to become quite familiar with the GFC Kilns Co. of Melbourne, Australia, at ceramitec last October, and I was impressed by the company’s innovative solutions and sound business ethics. GFC recently decided to offer its products to the U.S. market, giving ceramic manufacturers several new options in firing technology.
During subsequent meetings with the company, I was able to conduct an interview with several people that have been key to the success of this Australian company, including Terry Wight, chairman; Andrew Currie, managing director; Harold Wight, sales director; Don Walker, technical director; and Thien Nguyen, electrical engineer and software designer. These men gave me an insight into the background of the company and how some of its technologies are helping to improve the ceramic manufacturing process.
Ruark: What is the background and history of GFC? Harold Wight:
The company was started in 1969. When we took over management in 1978, we initially fabricated kilns for a variety of other kiln and furnace design companies. As time went on, we learned about the business and began offering suggestions for improvement to our customers. After being told several times that our ideas were “impossible” or “we already tried that,” we decided to design our own products and pursue the technological innovations that we believed in. We had to build a test kiln and prove to customers our suggestions were true. Today, we market our products in 25 countries; our clients are our partners, and we always listen to their suggestions.
Ruark: GFC designs and fabricates kilns in Melbourne as well as China, both periodic and continuous. I have noticed that all of the designs employ pulse systems. Why have you adopted this firing technique? Walker:
We embraced the pulse firing technique back in 1986, and the refinements that we have made in the past 15 years have proven our original belief that pulse firing is the best way to produce temperature accuracy within a kiln. As you know, high velocity burners produce strong internal recirculation, but only when the burner operates at high output. Our system allows the burner to operate under variable length pulses, depending on heat demand, and our minimum input is so low that it does not add appreciable input. This results in the maximum number of pulses for a given firing situation, and the result is the best uniformity achievable.
Schematic showing the downdraft in a section of a typical GFC shuttle kiln.
Ruark: Other companies offer pulse firing. What makes the GFC system special? Harold Wight:
We’ve been working on our system for many years, and we have to admit that although our early pulse systems were better than standard firing systems employing excess air, etc., we were not happy with the reliability of some hardware components. When we started down this path, practically no one had experience with pulse firing. We had to design our own high cycle valves and our own burners. Like a high-performance jet airplane, our system achieves its capability in concert with proprietary software.
Terry Wight: We believed in the pulse firing advantages of enhanced temperature uniformity, reduced NOx emissions and reduced fuel consumption from the very start of our efforts. From our initial installations, we gathered a large amount of data that helped us develop the system we have today. Our pulsing designs are not just about pulse firing. For example, in our periodic kilns, the pulse design consists of many factors. First, every single burner is individually controlled as a separate zone, each with its own thermocouple. After all, variations in load, kiln geometry and burner positions mean that each burner must cope with different heating requirements. Only by controlling them separately can we obtain the remarkable results that we have achieved. In addition, we allow for communication among the burners in a single firing area. The output level of one burner can act on the output level of another as necessary to minimize or eliminate temperature spreads. Our exhaust ports are strategically located in the sidewalls of the kiln to provide a perfect balance of exhaust geometry that complements the burner firing location.
Ruark: Software seems to play a major part in your design. Tell us about it. Nguyen:
We developed our software control system out of necessity, using a PLC for switching and logic, along with a PC interface. Today we use a Windows front end, but our early efforts were DOS-based. We control the sequence of pulsing very carefully because it has a profound effect on uniformity. We can develop localized areas of higher and lower pressure in portions of the kiln, and these pressure differences create convection across the setting of products. As Terry said, our burners communicate with each other, but in addition, the software can artificially create small burner pulses at times of slow heating and cooling to enhance uniformity.
Currie:As the only non-engineer here, I would like to add something that is important about our software: It was developed in direct discussions with dozens of customers. It is so user friendly that non-technical people find it easy to use. And data is displayed in a variety of ways—graphically, in spreadsheet form and in combinations of both. You can see exactly what the kiln is doing without the need to scroll through a variety of screens.
In addition, all of our kilns come with a modem, and part of our service is to monitor the kiln from our location in Melbourne. In this way, we can make suggestions for improvement, diagnose problems and upload software updates at a very low cost for our customers. At the same time, our customers routinely monitor their kilns from home to maintain constant observation of their process.
Harold Wight: We have worked diligently on this system, and it has undergone continuous improvement. We have taken our customers’ suggestions to heart, and their best ideas over several years have been incorporated. For example, in the event of a thermocouple failure, the control for a particular zone automatically defaults to the nearest thermocouple so that there is no loss of control. All points are alarmed at multiple levels. For periodic kilns, in the event of a power failure, the software automatically restarts at the appropriate temperature by selecting the zone with the lowest temperature (in heating) or the highest temperature (in cooling) as the setpoint. In this way, the operator doesn’t have to contend with reprogramming anything, and the loss of ware from excessive heating and cooling power on restart is eliminated.
Ruark: You mentioned power failures. GFC has an unusual system in place in the event of power failures. Nguyen:
Yes, that’s correct. When the power is totally interrupted, all of our kilns can maintain burner operations for a minimum period of two minutes, with no lapse of safety devices. The design of this system is proprietary and depends on our software and mechanical design to achieve this capability.
Ruark: What about your proprietary kiln lining design? Walker:
We use our own system consisting of a lightweight cordierite hot face, backed with varying grades of ceramic fiber. Not only is this the best way to retain the fiber, but also we notice enhanced glaze quality because there are no tiny fibers flying around in the kiln. In addition, there are no free fibers of cristobalite that might cause environmental difficulties. In higher temperature kilns, we use a similar system but with different hot face materials. Our lining life is more than 10 years with minimal maintenance, and the interiors of our kilns are exceptionally clean.
Ruark: Anything else? Terry Wight:
Our customers are our reason for being in business, and we never forget it. The dozens of refinements to our kilns, made through years of experience, have helped GFC build the most accurate and trouble-free kilns in the world. Listening to what the customer says is the best way to ensure that your business will prosper, and it is our guiding philosophy. Our partnerships with customers extend over many countries, and their ideas—and problems—have helped us to serve them better and better with each passing year.
For More Information
For more information about GFC Kilns International Pty. Ltd., contact the company at 227 Princes Hwy., Dandenong, Melbourne, Victoria 3175, Australia; (613) 9792-5211; fax (613) 9792-5605; email@example.com
; or visit http://www.gfckilns.com.au
SIDEBAR: Reaping Rewards from Kiln Investments When Giessdorf Plumbing Incorporation began operations in Guang Dong, China in 1998, the company purchased three GFC shuttle kilns to meet its required production levels. The company was impressed with the quality of GFC’s kiln design. “The protection of overlapping refractory tiles on the hot face of the kiln wall and roof keeps the fiber dirt from falling down on our products,” said Sean Wang, vice-manager of the company’s ceramic department. “Additionally, the IMPS (Integrated Multizone Pulsing System) control system and the kiln’s downdraft design ensure that the atmosphere and temperature inside the kiln remain even throughout the firing cycle.”
Giessdorf has been pleased with the results. “We have achieved better quality products, faster firing cycles and increased productivity with the new kilns compared to other sanitaryware plants,” said Wang. “We are getting more than 80% good wares for both first firing and refiring, but this accounts for some glazing, casting and loading defects. If we could eliminate those, our recovery rate would probably be greater than 95%," said Wang.
Marcotta Tiles Pty. Ltd. also invested in a new GFC kiln to fire split tiles in its Marybourough, Australia, plant. The company believed GFC offered the best value and was impressed with GFC’s Melbourne testing facilities. It was also pleased with the simple operation of the new kiln. “The operator’s manual is very well set out and easy to follow,” said Ken Lawrence, plant manager. “Basic computer skills were all that was required to operate the kiln competently, and GFC supplied on-site training.”
Lawrence uses a phone link from home to check up on his firings, and should the need arise, GFC can also access the computer system by modem to provide assistance. “This capability is very reassuring to the kiln operators,” Lawrence said.
The new kiln has enabled Marcotta Tiles to increase production of its split tiles. “The temperature uniformity throughout the kiln is quite good. We have achieved faster cycles due to the better control provided during firing and cooling,” Lawrence said.