Retorts

MELLEN Retorts are designed for use with any furnace brand. Our retort is capable of operating in a variety of atmospheres. Standard MELLEN retort assemblies are air-cooled but can be water-cooled upon request. Retorts come in a variety of sizes and shapes based upon customer requirements.

The MELLEN retort assembly contains the necessary heat shields, flange, and end seal assemblies to permit gas tight operation. Depending on the temperature and atmosphere requirements, the tubes for the retort may be made of multiple different materials including metal alloys such as stainless steel, or Inconel, ceramics such as alumina, mullite, or quartz, high temperature materials such as Hexoloy, and more.   

Standard feed-throughs are provided in the cover plates of the retort for gas in, gas out, and temperature measurement. The end seal assemblies, made of aluminum or stainless steel, can be equipped with NPT threaded holes, KF flanges, or other vacuum fittings based upon customer requirements. 

The differences between the MELLEN retort seal and the industry standard McDanel seal make all the difference for customers looking for an easy-to-use retort assembly. The secret is in our Double O-Ring seal.

Our Double O-Ring seal design provides several benefits over the industry standard flat seal design.  The unique design of our end seal assemblies with the Double O-Ring makes its easier than ever to replace the workcharge in a sealed tube. No longer does the user have to disassemble the entire end seal to get to their process.  Instead, the user removes a couple bolts, takes off the cover plate, does whatever work is required inside of the tube, then replaces the plate with those same bolts.  Compared to the industry standard method of fighting to attach the O-Ring seal, the MELLEN design takes the cake. 

The multilayer, Double O-Ring seal provides an additional benefit; it protects the tube.  The edge of the tube is usually the most fragile part of the tube, and a single tap on the edge can cause a chip, or even worse; the entire tube to crack. MELLEN sought to fix this issue by using a metal plate to secure the first O-Ring seal and simultaneously cover the inner edge of the tube. This way, accidental hits are taken by the strong metal plate, instead of the tube.

The Double O-Ring seal offers unprecedented leak protection from possible leaky seals and the retort assembly is more reliable thanks to the removable cover plate on the end seal. Without the worry of constantly removing and replacing the O-Ring seal, the user is able to get back to what really counts: their process.

In cases where a high level of vacuum, or hazardous gases, are used in the retort, MELLEN also supplies an additional level of O-Ring protection. This third layer allows the user to test the seal for leaks without pumping down the entire retort, saving time on testing, and allowing the user to use that time for production, rather than setup. The additional ring helps create the seal in the event the tube has defects. The extra O-Ring also helps the end seal withstand more pressure.

Tube

Each retort assembly comes with a tube that sits inside the furnace during use. This tube can be made of a variety of different ceramics, metals, and other alloys. Some standard ceramics are quartz (up to 1200ºC), alumina (1,750ºC), mullite (1,450ºC), or hexaloy (1,900ºC). Metals and metal alloys include stainless steel (900ºC), and inconel (up to 1,095ºC). Different materials are available upon request.

The tubes can be open both ends (OBE) or closed one end (COE) depending on your needs.

End Seals

Each retort assembly comes with an appropriate number of end seals. The end seals are made from lightweight aluminum, or stainless steel if your process would interact with the aluminum. All MELLEN retorts are designed with temperature in mind; our aluminum end seals are not limited by the furnace temperature when used in conjunction with the our heat shields and tubes.

For high thermal gradient applications, the end seals can be water-cooled.

The end seals come standard with a port for gas-in/gas-out, but additional ports and connections are available on request. For gas tight applications, MELLEN supplies NPT threaded fittings, KF flanges, or any other vacuum sealing fitting you may require.

Heat Shields

MELLEN Heat shields block the radiant energy inside a retort to prevent the end seals from overheating. They are also used to increase uniformity within the furnace by minimizing end losses. Heat Shields can be made in multiple shapes, sizes, and even from a variety of materials based on your temperature and atmosphere requirements. The heat shields can be made of a variety of metal alloys, such as stainless steel or Inconel, or even MELLEN’s custom ceramics!

The custom ceramics can be in high temperature applications, or where metal heat shields may interact with the work, or where the temperature is too high for standard metal alloys.
In addition to the standard solid heat shields, MELLEN also creates removable layer heat shields, that allow the user to swap the plates of the shield out. These removable layers can easily be replaced with ceramic or metal alloy layers. This can be an invaluable cost saving measure; contamination of the end layers no longer requires the entire heat shield to be replaced.

Still have questions? Contact MELLEN’s knowledgeable engineers to find out more!