High Temp. Furnaces
Different people think different things when and if they think about high temperature furnaces.
What's high temp to you may be low temp to somebody else.
Typically anything over 1100°C is considered high temperature. With the advent of the Molybdenum Disilicide element (sometimes referred to as Moly Disilicide, sometimes just as Moly D's,) in the late 1970's, high temperature furnaces were pushed past the 1500°C limiting factor of the Silicon Carbide element.
For most processes the 1500°C threshold will suffice. But like everything else in science, needs and processes have changed. A good example is Fuel Cell technology. Fuel Cells operate at high temperatures and therefore must be processed at high temperature, typically 1700°C and higher.
Most metal fabricators can get by with running in the 1100° to 1200°C range. What needs to be bent, dried, cleaned and annealed can all be done at those relatively low temperatures. Relative only to the higher temp furnaces.
We sell a number of small furnaces that measure a mere 4" wide x 5" deep x 4" high. A lot of the manufacturers I represent have chambers in that range and bigger, all the way up to 24" wide x 36"deep x 18" high. If you need a custom furnace, certainly they are available, and if you need a custom high temperature furnace, we represent a few manufacturers that can customize any furnace to your specifications. Give us a try.
Now back to my pizza analogy. I wouldn't recommend it, but if you're going to be so bold.....one to three minutes is all I recommend, and keep an eye on that sucker, frozen or not...you're going to burn it, and you're going to burn it quickly. Have fun, and let me know about your adventure.
Labels: furnaces, High Temp Furnaces
Mecahnical Convection Ovens
Now here's a series of ovens you can find a variety of uses for.
Mechanical Convection Ovens. sometimes known as Forced Air Ovens, sometimes simply referred to as a Lab Oven, typically can be found in sizes ranging from 1.4 cubic foot to 4.9 cubic foot, but certainly can be much bigger.....all the way to 18 cubic feet. Most are designed to be bench-top models, however the larger ones, by their shear size, necessitate a bench of their own or sit on a floor stand.
Mechanical Ovens have faster heat up times than a laboratory Convection ovens, closer temperature uniformity and a more efficient transfer of heat from the heating element.
It's pretty simple. A fan motor blows cold air across a heated element and into the chamber, either horizontally or vertically through the chamber, or a combination of both....horizontally and vertically.
It's more precise and more efficient than a Gravity Convection Oven because you are actually moving air within the chamber as opposed to the "natural" gravity oven which is also known as a passive system.
You'll pay more, but have better control over your temperature gradients, your heat up times, and with the advent of digital controllers, stability has been greatly increased, usually to +/-3% for uniformity and +/-0.5% for accuracy.
Most manufacturers stay in the 204°C to 300°C range. However Carbolite has a fine series of lab ovens, read mechanical convection here, that heat to the 400°C, 500°C and 600°C range. Leave it to the British to accomplish that.
I still would not recommend putting last nights leftover pizza in these ovens......you know what you've been processing in there,............would you want to digest any of those chemicals? I think not.
Next week we'll tackle the hot topic of laboratory furnaces..........from 1000°C to 1800°C. Stay tuned !!
Labels: Mecahnical Convection
Gravity Ovens
There are so many different types of ovens to choose from.
The smallest and least expensive, is the Gravity Convection oven.
Gravity Convection is most similar to what we all use in our homes. The heating coils are located at the bottom of the chamber, and through natural convection, (heat rises, no fan) heat the chamber to your desired temperature.
These ovens are used for drying parts in a general Laboratory, Life Science, or Industrial setting. I've had customers who dry soil, glassware, metal and moisture test in these ovens.
While not as precisely accurate as a Mechanical Convection Oven, and usually at lower temperatures, Gravity Ovens are a good workhorse to have in the lab when you don't have big batches to do, or you require a lower heat.
Since the introduction of the digital controller about 15 years ago, these Gravity Convection ovens are fairly accurate in maintaining a constant temperature... usually within a 5% range or less.
You can still purchase these ovens with analog controls, and with an independent thermometer can achieve good accurate results.
Gravity ovens come in many sizes.
They come in pretty handy when you can't afford for your powered samples to be blowing around in the chamber, as would be the case with a Mechanical Convection oven.
Although it would work, I wouldn't recommend heating your leftover pizza in these, but for your small batches, a Gravity Convection oven is a good way to go..... more on Mechanical Convection ovens next week.
Labels: Gravity Convection Ovens, ovens
