Think about it. Common sense can go a long way when it comes to maintaining your company's combustion system.
In our effort to keep up with business, we tend to forget about the upkeep it takes to maintain equipment. Before your combustion system is in need of dire repairs, do the obvious: Care for and maintain it. Use the following 10 tips as your guide to common sense.
TIP 1: Not Enough Pressure? Check Your Blower Rotation
If the industrial combustion system is lacking the design air pressure, check to make sure the blower is in its proper rotation. You would be stunned at the number of new installations or retrofit systems that stumble during startup because of this simple wiring mistake.
An industrial combustion air blower is designed to spin toward the outlet in a laminar fashion. If the blower is rotating at a right angle to the outlet (the wrong way), better than a third of your capacity can be lost. It also can create problems for the motor.
TIP 2: Balance Your Pipework on Multiple-Burner Installations
With more and more furnaces using multiple burners with a common air source, pipework balance becomes more and more critical. In the past, burner designs and temperature balance within the chamber were not so critical. In today's world, tight temperature and burner control dictates that balance be considered all the way through the air and gas supply lines. With burner designs using air- and gas-staging to achieve lower emissions and higher performance, the correct design pressure for the burners is critical.
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, just getting the air and gas to the burner will not give you the performance you desire and expect.
TIP 3: Breathe In, Breathe Out (Ensure Adequate Makeup Air for Industrial Heating Equipment)
Just like the air and gas source at the inlet, exhaust systems should be balanced and provide for free flow of the flue products. It is particularly common for building pressure in Northern climes to affect combustion system performance during cool weather. Makeup air systems and building heating systems can pressurize or create a negative pressure during weather fluctuations, and burners can become unbalanced if the exhaust system cannot accommodate the change. Notice a change in furnace performance? Notice a change in the weather? They might be related.
TIP 4: Furnace Condition Can Affect Combustion Performance
This isn't really a combustion tip, but it's one that burner manufacturers see regularly. The oven or furnace begins to slow down or lose its temperature integrity. The first inclination is that the burners are out of whack. But, the truth is, over time, door seals and linings lose some effectiveness or get damaged in the wear and tear of everyday production. Remember that 1 ft2 of furnace opening can leak 40,000 BTU/hr at 1,700°F (927°C) -- just through radiation loss. Oven or furnace shell temperatures that are excessive indicate that you are heating the room and your operators, not the work. Check the oven shell and door seals regularly for signs of degradation.
TIP 5: Read a Good Book (aka, the Operations Manual)
Almost all of the burner manufacturers have extensive instructions for the combustion equipment they provide. Boring reading, yes, but it is full of valuable information that so often is overlooked when setting up a system. Safety issues alone should dictate that the manual is read by everyone operating the system.
Most manuals also contain troubleshooting guides that will help you identify problems before you contact your combustion service technician. Time is money, and you can save a lot of time on the front end of a project -- and during maintenance -- if you are well versed in the operating parameters.
TIP 6: Check Industrial Equipment Manufacturers' Websites for Equipment Spec Changes
It is a good practice to regularly check the web sites of your equipment manufacturers to see what changes may have occurred. Combustion controls, technologies and burner designs are changing to meet stringent EPA and safety concerns, not to mention performance upgrades. Updates and product bulletins usually are posted on web sites to get the information out quickly. Do not assume that just because you have a "Brand X" burner that "Brand X" knows you have it and will find you. Look at your equipment manufacturers' web sites regularly to stay well informed. It is a great spot to request literature, too.
TIP 7: Soot, Carbon and Other Debris on the Floor Isn't a Good Sign
Obviously, soot or carbon on the floor should be a call to action for any oven or furnace operator to get the combustion system tuned by a qualified combustion service technician. But, other signs of wear and tear can be early warning alerts as well. If you have radiant-tube furnaces or alloy-lined equipment, the presence of oxides or "alloy glitter" can be a sign that unusual oxidation is taking place. This can signify a "lean burn" situation in some cases.
Some oxidation is to be expected, but 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 be damaging the lining of the oven or furnace.
TIP 8: Walk Around Your Industrial Heating Equipment Once a Month
Obviously, a face-to-face inspection of the combustion equipment ensures regular communication between employees and supervisors. An even better reason to schedule a monthly tour of the combustion equipment and oven is so both the boss and the operator can see the systems in person together.
A work order for parts and such is a good thing, but nothing explains a need or a situation better than joint visual contact with the equipment. The old adage, "Two heads are better than one," is never more true than when looking at flame color, exhaust ductwork, etc. Sometimes, the people responsible on a day-to-day basis never notice the subtle changes. A simple question -- "Has that always been like that?" -- can lead to productive and maintenance-saving discussions.
TIP 9: The Future Is Moving. Move With It
"We've always done it this way" is a precursor to problems. The newer combustion technologies are just that: newer, more sophisticated and better performing. So, the days of throwing a burning oily rag into the oven or furnace to light it had better be gone from your plant. Not only must you keep up with the shifting technologies, you should embrace them. You would be surprised at how much your insurance man will be impressed with you too, perhaps in the form of lower premiums.
TIP 10: Get a Consistent Plan For Combustion System Service
Factory-authorized service providers will become more and more important in the future. These people have the blessing of the equipment manufacturer to perform service and tuneup activities. Many equipment manufacturers have service crews trained and at the disposal of the thermal processing industry. It can save you time -- and ultimately money in maintenance parts -- and eradicate downtime. A consistent plan also can be viewed as wise by insurance underwriters. Contact your equipment manufacturer/supplier for inquiries of how consistent service can help.
I've spent a little more time on the thinking side of combustion maintenance rather than completely dedicating the tips to the nuts and bolts of combustion maintenance. The simple truth is, combustion systems are getting more complex, and the thermal processing engineer is going to need to get help with keeping abreast. These are common-sense ideas that will help you and your company alleviate the concerns of how to keep your combustion systems in peak operating condition. As always, safety should be paramount in your mind.