What is a Top Hat furnace? And why would I want one?

What is a Top Hat furnace? And why would I want one?

Lab scale top hat furnace

Top Hat vs Bottom Load Furnaces

We all know that with the familiar “elevator” furnaces, aka “bottom loaders”, the load platform or kiln car is raised into the furnace body. In the “top hat” design, the opposite occurs. The furnace body is lowered over the platform or kiln car.

A frequently expressed concern is that because the furnace body is in motion, the insulation – and worse, the elements – will be subject to damage from vibration. Not so! This can be prevented with good design of the lift system.

Ok, but is there any reason to prefer the “top hat” over a bottom loader? There are several: application requirements, ergonomics, and maintenance considerations.

• Application requirements. If load stability is critical to your process, the top hat design eliminates any motion related disturbances. The manufacture of gradient glasses is a great example of such an application. The weight of the product load is also a consideration. The lift mechanism required to lift a fully stacked kiln car into a production size furnace could well be more expensive than one designed to raise and lower the furnace body. And speaking of that fully stacked kiln car, even with a smoothly operating electric or pneumatic lift mechanism, watching it leave the floor and make its way into the furnace can leave you quite literally holding your breath.
• Ergonomics. This consideration applies to lab scale furnaces. If you place your bottom load furnace on the floor, when the load platform is fully open the operator will be required to stoop over to place or remove the research sample or product. If the furnace is placed instead on a typical “waist high” table, the load platform is on the same level as the operator’s hands when she is placing or removing the workpiece. But that can present maintenance problems: see below.
• Maintenance. For lab scale bottom load furnaces placed on a table, depending upon the height of the table routine furnace maintenance such as element replacement could require standing on a ladder. This, as your safety officer will tell you, is hazardous. A batch size top hat furnace placed on a table is, when closed, readily accessible.

Production Scale Top Hat Furnace

Deltech manufactures both top hat and bottom load electric lab and production scale furnaces, and all are well designed. The choice is yours; we hope you find this information helpful in finding the furnace that will fit your need. Or contact us so that we can work with you on designing a unit with optimal features for your process.

For information on our bottom load models, click here. For information on our top hat models, click here. Both are available with operating temperatures up to 1800 degrees Celsius and featuring manual, electric, or pneumatic lifts and optional forced air and venting features.