Crucial Factors in Purchasing an Industrial Kiln for Heat-Treating
Striking a balance between size, price, and accessibility is key when looking for a new industrial oven or furnace. Here are a few other crucial factors to take into consideration when looking for the perfect commercial kiln.
How Much Flexibility Do You Need?
Industrial furnaces are used by many different manufacturing sectors to make a wide range of products; the requirements of your product will dictate the heat-treating furnace you choose. There are two schools of thought on this issue: the first; purchase for the projects you know about, and the second; purchase for future flexibility. This decision needs to be established from the start. If you are only matching your new kiln to its current intended purpose, you don’t need to purchase an industrial kiln designed for firing ceramics to 2350º F if all you need is an annealing oven that can anneal your pieces at 950º F. But, if you want future flexibility for ongoing projects, a kiln that will allow you to go to higher temperatures, might be the better choice.
Do You Need a Continuous or Batch Furnace?
No matter what material you are heat treating, it is crucial to spend money on a unit that is designed to heat-treat your product efficiently. Do you need a commercial oven that processes your product continuously like a belt driven furnace or lehr that will run your items through a long firing chamber on a moving belt, or do you need one that will heat-treat large batches of items on a stationary shelf inside an enclosed firing chamber? A batch commercial furnace will most likely use more fuel than a continuous commercial furnace because the belt driven unit maintains a constant temperature, while the batch furnace must heat up from ambient temperature to processing temperature for each batch processed. Which type of industrial oven suits your needs the best?
What is the Best Shape for Your New Industrial Kiln?
The shape of your new commercial furnace is another important thing to consider. If your product is square or rectangular, would you be better off going with a square or rectangular commercial oven? Try to fit as many squares as you can into a circle, and you will see all the wasted space very quickly. If all of your parts that you need to heat-treat are five feet long, a 36” square kiln might not be the best choice! Think about how you are going to load your product into the new commercial kiln, and you will figure out which kilns to look at and which ones to disregard. The geometry of this issue also comes into play when considering the footprint of the unit and how much space you have available to commit to this piece of equipment. How creative do you need to be? Can the items be stacked, or will you need shelving in the kiln/oven? What internal configurations are necessary to make it the volume work?
How Hot Do You Need to Get?
The products you want to fire will determine the temperature range you need. For ceramics, you'll need a furnace that can achieve temperatures of between 1700ºF and 2350ºF. Check out this specialty article about choosing a ceramic kiln in Ceramics Monthly. For most glass work, you don’t need to go that high, so an industrial kiln that can hit 1700ºF will be plenty for you. If you are heat-treating metal, the type of metal will dictate what temperature you need to reach. For specialty industrial applications you may need to exceed 2500°F. Make sure you choose a unit that can accommodate the range of temperatures you’ll need to work within. Also, most controllers will accommodate C/F conversions with a simple switch of programming buttons.
Some products can need more than one firing at different temperatures, so that is another variable to consider. Keep in mind the top temperature that you will need as all industrial furnaces can be programmed to follow any firing profile and hold at any temperature you program within their firing range.
Draw down industrial furnaces are designed to heat-treat at lower temperatures, so if you are only heating your product to 500-800ºF, you don’t need to purchase a kiln that is designed to fire to 2300ºF, unless you want that future flexibility.
How Do You Plan to Load Your New Commercial Furnace?
Another very important consideration is how you are going to get your product into your new unit. Would a top loading kiln be best, or would a front-load with a carriage that rolls into the kiln be what you need? If you are working on large flat panels, maybe a kiln with a flatbed that rolls out and a clamshell lid is just what you need. There are lots of different configurations to choose from, so don’t let traditional design ideas get in the way of coming up with your best solution. Consider issues like weight, gravity, and heat escape when doors are being opened for hot loading when making these kinds of decisions. These overlooked issues can lead to poor choices if unconsidered.
What is Your Firing Cycle?
Your product will determine the firing cycle, and some items can need a longer firing cycles than others. The goal is to run the most efficient cycle possible while getting the best result and reducing waste all at the same time. Beyond a certain point, trying to shorten the cycle is counter-productive because your product will not achieve the desired result without the proper amount of heat work. Keeping your equipment in the best possible condition will assure you that you are getting the best result in the least amount of time. With this in mind, will the unit you purchase have the insulation to accommodate the short or long firing cycles and the range of temperatures you need?
Fire Brick Vs Fiber, Which Is Best?
Industrial kilns and furnaces can be constructed using fire brick, rigidized fiber, or a combination of the two materials. Each has its advantages. Kiln brick will retain heat longer and is great for kilns that need to maintain high temperatures for long periods of time. It is also a very durable material. Fiber heats and cools more quickly than brick and is great for kilns that need to cool quickly. It is also lighter than brick. For a more in depth look at the advantages of each building material, take a look at our comparison of these two materials: Fiber vs Brick in Industrial Kiln Applications
Will the Unit Need Internal or External Venting?
Another thing to think about is venting. Do you need the interior chamber of the unit vented due to any environmental issues, caustic or toxic fumes, chemistry issues, scale, etc.? Do you need the work environment vented to the outside for fumes burn off, etc.? Making sure that you have adequate air circulation and air exchange in the space where your unit is located is crucial to maintaining your equipment and extending the life of the electronics of the unit, not to mention the health and safety of the people in your space. It could also aid in cooling the industrial oven during the cooldown stage if heat isn’t allowed to build up in the environment. An internal vent will not speed up your firing cycles significantly by speeding up the cooling cycle, but it will help you exhaust harmful fumes out of the work environment and help you to maintain proper oxygen levels inside the unit to achieve your desired results. Maybe you need a firing environment that is oxygen free. Having the ability to introduce inert gases such as Argon into the firing chamber might be what you need. Replacing the oxygen in the firing chamber with an inert gas will greatly reduce scaling on your metal parts when heat treating, and many industrial ovens can be set up for this process. Internal vents like the Orton Vent Master are different than an external vent like Vent-A Fume.
What Is Your Production Volume?
How many items or units that you need to produce in a given amount of time will help you determine the size and capacity of your new industrial kiln. But what if you need to process several different items during the same period of time. Finding a balance between the items that will need the longest firing schedule and the other items that are more heat sensitive will help you to determine what can be processed together in a batch firing. Perhaps you need two smaller industrial furnaces instead of one larger one so that you can process two different batches at different temperature and firing schedules. Maybe you need a dual chamber unit so that you can do two firings at the same time or do a preheat or one load while you are tempering another load. There are so many possibilities.
How Much Space Do You Have for Your New Furnace (and Other Physical Considerations)?
How much space you have and what the footprint of the furnace that you are considering, including any clearances around the furnace, must be a good match. You also need to consider any local building codes that dictate furnace placement and spacing. What about building permits? Are you needing to install a new chimney or vent hood, or add on to your existing space?
What Is Your Power Supply and Where Is It Located?
Are you going to be powering your new commercial kiln with gas or electricity? If it is electricity, how much power do you have to spare coming into the building and where is the electric panel in relation to where the new kiln will be located? Is your power 240v, 208v, 480v, single phase or three phase? It is absolutely necessary to have your new commercial furnace built to the proper electrical supply, or it will not perform to specifications.
If you are using gas, is it propane or natural gas? Propane units will have smaller orifices in the burners and need pressure regulators to manage the pressure of the gas coming from the propane tank. Natural gas units will have larger orifices and do not need pressure regulators. All gas kilns must be vented properly as they produce much more external heat than electric kilns do. All gas industrial kilns will need a hood over the kiln to draw heat and exhaust fumes out of the environment if they are going to be in an indoor space.
Do You Have Any Special Requirements for Meeting Environmental Standards?
Regulations on fuel emissions, environmental concerns, and energy efficiency requirements apply to every industry. You will need to verify that your kiln ensures adherence to all applicable laws. We can help you determine what’s what in that department.
Are You Making the Decision Based on Your Current Needs or Possible Future Needs?
You might purchase a furnace today that is perfect for your current needs, but does it allow for expansion if your production needs to increase in the future? See question 1!
How Quickly Do You Need Your New Furnace?
Different manufacturers have different estimated build times, so you need to think about how long it will take to get your new furnace up and running when choosing between different models and manufacturers. Feel free to ask if you need insights into the production timeframes of different manufacturers.
Final Thoughts
Although selecting the ideal industrial furnace might be challenging, taking the time to thoroughly analyze all these factors will guarantee that you receive the most value out of the commercial kiln you select. At Heat Treat Now, we have years of experience in helping our customers select the equipment that is right for the job now and in the future.
As always, feel free to reach out to our experienced team with questions or comments. We're always here to help! Give our technical team a call at (210) 446-9979 or email us at customerservice@heattreatnow.com