1. Not Enough Pressure? Check Your Blower Rotation. If the combustion system is lacking the design air pressure, check to make sure the blower is in its proper rotation so that it spins toward the outlet in a laminar fashion. If it's rotating at a right angle to the outlet, you'll lose better than a third of your capacity, says Jim Roberts, director of strategic accounts at Eclipse Combustion Inc., Rockford, Ill.
2. Balance Your Pipework on Multiple-Burner Installations. With multiple burners, pipework balance is critical for lower emissions and higher performance. Tight temperature and burner control dictate that balance be considered all the way through the air and gas supply lines.
3. Breathe In, Breathe Out. Just like the air and gas source at the inlet, exhaust systems should be balanced and provide for free flow of flue products. It's common for building pressure to affect combustion system performance during cold weather because make-up air systems and building heating systems can pressurize or create a negative pressure during weather fluctuations, and burners can become unbalanced.
4. Oven Condition Can Affect Combustion Performance. When the oven begins to slow down or lose temperature integrity, it may not be the burner's fault. Over time, door seals and linings lose some effectiveness or get damaged, so check out their condition and replace if needed.
5. Read a Good Book. Actually read your burner manufacturer's operating manual! Boring, yes, but safety issues alone should dictate that all operators read the manual.
6. Surf the Net to Keep Abreast of Changes. Regularly check your equipment manufacturers' web sites for equipment upgrades that incorporate new technologies as well as meet EPA and NFPA changing requirements.
7. Stuff on the Floor Isn't Good. Soot or carbon on the floor is a call for a combustion system tune-up. If you have radiant-tube or alloy-lined equipment, the presence of oxides or "alloy glitter" can be a sign of oxidation.
8. The Future Is Moving. Move with It. "We've always done it this way" is a precursor to problems. Newer combustion technologies are more sophisticated and better performing. The days of throwing a burning oily rag into the oven to light it had better be gone from your plant.
More Nuts and Bolts Thoughts
- Wear and tear of everyday production may leave your oven's gaskets, handles and linings in need of attention. Just a small crack in your oven's seal can leak enough heat to boost your costs as you attempt to maintain product quality. Excessive oven shell temperatures indicate you are heating the room and your operators, not the work. Check the oven shell and door seals regularly for signs of degradation.
- When your blower is not in proper rotation, it may be because of a wiring glitch. You would be stunned at the number of new installations and retrofit systems that stumble during startup because of this simple wiring mistake. When the blower spins the wrong way, not only is capacity lost, buy the motor may be affected.
- Several combustion reference books and mechanical engineering manuals have simple guidelines that will provide you with correct air and pipe sizing and flow capacities. In retrofits and upgrades, simply getting the air and gas to the burner will not give you the performance you expect.
- While some oxidation is expected in a combustion system, excessive amounts around the flue or on the floor can signal trouble. In direct-fired equipment, fibers or refractory dust can signal flame impingement that could damage the oven lining.