Drying Oven Design

[warrenelec]

Hi,
I need to help design a drying oven for some parts. Unfortunately, I am not sure where to begin. We manufacture electric heaters , so as a cost saving measure are attempting to design an oven to dry heating elements and manufacture it in-house. I can calculate what is needed for heating requirements and a control device, but i'm unsure what to use for insulation. I also don't know about ventilation to remove moisture in the oven. The oven currently used is not really airtight, so the moisture isn't really a problem, however I don't know if this is the best idea for a new design. The basic plan of action is to use steel beams as a frame and have insulation enclosed in sheet metal and attached to the frame. The Oven runs at about 275-300 degrees F. Any help at all with this is greatly needed and appreciated.

Thanks
Warren

 

[tomwalz]

What follows is advice and philosophy worth exactly what you are paying for it (and you won’t be billed for it).

Equipment comes 5 ways. 1. Really common and inexpensive but well proven and reliable such as automobiles, knee mills, drill presses, etc. 2. Expensive and somewhat hard to find such but reliable such as limited equipment production equipment for industries. Diaper lines, packaging etc. 3. Expensive and semi custom such as manufacturing lines. Probably reliable eventually. 4. Truly custom for a unique use. Horribly expensive and may never work. 5. Equipment you build yourself. God knows how much or what you get.

We figure the trick is to use the least expensive, most reliable solution.

Many years ago I needed (wanted) a digital microscope. I couldn’t afford many thousands for an industrial model or a scientific model. About that time Intel and Mattel came out with a toy for $99. I still have a couple of them and I still use them occasionally although I have others that are superior. However I needed a scientific microscope for failure analysis and I used a toy which worked extremely well. (Photos all over our web site at

http://www.carbideprocessors.com)

How about something out of the food business?
I know Burger king uses electric elements in some of their broilers. Most are gas but not all.

Building something for the first time is a lot harder than it looks.
We build simple, straightforward filter systems to filter coolants. They look like you “could build them out of Granger.” Some guys do try to copy them. However we have seven years of research into them. There are two different filters which look and are described as being identical from two different sources. One last hours and the other lasts weeks. The one that lasts longer also cleans a lot better. It took us an intense four months of research and years of ongoing research to figure out which filters to use where.

I have a reputation for being an expert on brazing theory and applications. (Assume for the moment that is true. It makes for a funnier story.) Anyway I do not braze all day, every day as a lot of folks do. I was doing training and troubleshooting in a plant a couple years ago. I told the guys I was going to demonstrate a technique but that I knew the theory and that I wasn’t that skilled as a brazer. I was doing the demonstration and after a minute or two a voice in the back pipes up ‘Boy you really don’t do that very much, do you?” We all broke up laughing.

The point is that we prepare carbide, cermets and ceramics for brazing and do specialty brazing. What we do, we do very well. However the fact that we can braze beautifully here with our equipment does not mean I can braze well in the field with a torch. (It works but it is ugly.)

I would offer the thought that the fact you are an excellent manufacturer of heating elements does not mean you have much of an advantage as an oven manufacturer (as you admitted.)

Or, Plan B,

If you don’t care about time, cost or what you get go to a ceramic supply store that sells kilns, get a couple cases of fire bricks and some high temp wire and have a lot of fun.

Good Luck
Tom