The compact retort furnaces of the VHT product line are available as electrically heated chamber furnaces with graphite, molybdenum, tungsten or MoSi₂ heating. A wide variety of heating designs as well as a complete range of accessories provide for optimal retort furnace configurations even for sophisticated applications.

The vacuum-tight retort allows heat treatment processes either in protective and reaction gas atmospheres or in a vacuum, subject to the individual furnace specs to 10^-5 mbar. The basic furnace is suited for operation with non-flammable protective or reactive gases or under vacuum. The H₂ version provides for operation under hydrogen or other flammable gases. Key of the specification up is a certified safety package providing for a safe operation at all times and triggers an appropriate emergency program in case of failure.

Alternative Heating Specifications

In general the following variants are available with respect to the process requirements:

VHT ../..-GR with Graphite Insulation and Heating

• Suitable for processes under protective and reaction gases or under vacuum
• Tmax 1800  °C, 2200  °C or 2400 °C (VHT 40/.. - VHT 100/..)
• Max. vacuum up to 10^-4 mbar depending on pump type used
• Graphite felt insulation

VHT ../..-MO or VHT ../..-W with Molybdenum or Tungsten Heating

• Suitable for high-purity processes under protective and reaction gases or under high vacuum
• Tmax 1200  °C, 1600  °C or 1800  °C (see table)
• Max. vacuum up to 10^-5 mbar depending on pump type used
• Insulation made of molybdenum rsp. tungsten radiation sheets

VHT ../..-KE with Fiber Insulation and Heating through Molybdenum Disilicide Heating Elements

• Suitable for processes under protective and reaction gases, in air or under vacuum
• Tmax 1800  °C
• Max. vacuum up to 10^-2 mbar (up to 1300  °C) depending on pump type
• Insulation made of high purity aluminum oxide fiber
• Exclusive use of insulation materials without categorization according to EC Regulation No. 1272/2008 (CLP)

Basic version

• Standard furnace sizes 8 - 500 liters
• Water-cooled retort made of stainless steel
• Frame made of stable steel profiles, easy to service due to easily removable stainless steel panels
• Housing of the VHT 8 model on castors for easy repositioning of furnace
• Cooling water manifold with manual tap, automatic flow monitoring, open-loop cooling water system
• Adjustable cooling water circuits with flowmeter and temperature indicator and overtemperature protection
• Switchgear and controller integrated in furnace housing
• Process control with controller P570
• Over-temperature limiter with adjustable cutout temperature as temperature limiter to protect the furnace and load
• Manual operation of the process gas and vacuum functions
• Manual gas supply for one process gas (N₂, Ar or non-flammable forming gas) with adjustable flow
• Bypass with manual valve for rapid filling or flooding of furnace chamber
• Manual gas outlet with overflow valve (20 mbar relative) for over-pressure operation
• Single-stage rotary vane pump with ball valve for pre-evacuating and heat treatment in a rough vacuum to 5 mbar
• Pressure gauge for visual pressure monitoring
• Defined application within the constraints of the operating instructions