If you’re new to process heating, or you’re working on a new type of product or application, it can seem like an overwhelming task to wade through the myriad of industrial drying oven designs to determine which one is best. The truth is, there is no one “best” dryer design for all applications.
Choosing the right heating oven is a matter of carefully considering the characteristics of your product and the requirements of your process. There may also be space issues to consider. Once you have a good understanding of these factors, you need to provide the following information to the potential oven suppliers for them to review your application and make a recommendation for the dryer.
What is your process and what is the finished product you are making?
A brief description will be extremely helpful for the oven supplier as they might have worked on the same or similar process in the past.
What are the physical characteristics of the material to be coated?
- What’s the width and weight or thickness of the substrate?
- What is the maximum temperature the web can stand?
- What is the line speed you need to run?
- How the web is supported though the dryer? Is it a roll supported, flotation type oven or moved on a conveyor?
- What kind of tension can the web tolerate?
- Are there any product quality issues?
What are its heating or drying requirements?
- What are you trying to accomplish? Preheating? Removing moisture? Curing?
- If drying a coating, what is the percentage of solids in the coating?
- How much moisture needs to be removed? What level of residual solvent is acceptable?
- Is it water or solvent-based?
- Is the web saturated with coating, or is the coating applied on one side only?
- If drying a coating, is the material coated on only one side or both sides?
- Is there curing involved with the coating? If yes, what is the cure temperature?
- How uniform must the drying be?
- Will high velocity air from a nozzle disturb the coating?
What are the needs of your production process?
- What processes need to take place before and after drying?
- Do you need a clean room environment for the dryer? If yes, what level?
- Is there a need to remove dust or VOCs?
- What are the needs for cleaning, maintenance and ease of operation?
Are there space or location restrictions to be taken into consideration?
- How much space is available for the dryer?
- What fuel sources are available and which are most economical?
- What electric voltage do you have available in the plant?
- What is the air quality, temperature and humidity conditions where the dryer will be located?
- Are there zoning or environmental regulations to consider?
Using your answers to narrow your process heating options
Once you have supplied the information above to the dryer manufacturer, they will be able to assess your requirements to a great extent. However, you may need to conduct testing to determine the answers to some of these questions, especially about the drying and process requirements. Once you do, you will be able to eliminate some types of process heating ovens that obviously won’t work for you and focus your search on the types that seem most promising.
For example, if you’re tight on space a conventional hot air dryer may take up too much room on your floor. You may want to consider an infrared (IR) dryer or a hybrid IR-air dryer if the product can’t tolerate much intense heat. On the other hand, if you’re drying a heavy solvent-based coating you may need to go with hot air since the high heat of an IR may cause skinning and blistering of the coating.
Here’s another example. Let’s say you’re drying a coating on a web. If the material is coated on both sides, you’ll want to consider a flotation design that moves the web on a bed of air so that both sides can be dried at once, without contacting any rolls. An alternate maybe to move the web up vertically in a tower dryer.
Trust the experts to guide you
There are many types of dryers using different heating technologies, heat transfer methods, and material handling designs. Even if you’re not a process heating expert, you need not be overwhelmed by all the options available to you. Once you’ve gathered as much information as you can, take advantage of the expertise of process heating vendors who make all different kinds of equipment for many industries. Better yet, spend a couple of days doing testing in a well-equipped pilot lab, where the experts can help guide you to the right dryer design and also help you perfect your process.
Stay tuned: In the coming weeks, we’ll be explaining more about the various types of dryers and the best applications for each.
Selecting the right heating equipment manufacturer might seem just as overwhelming as choosing the correct hot air ovens for your business, especially if you’re considering using an unfamiliar vendor. How can you be sure they will deliver on their promises? To learn how to thoroughly vet equipment vendors and make the best choice for your needs, get a copy of our free guide: CHANGE WITH CONFIDENCE: Mitigating the Risk of Choosing a New Equipment Vendor.