MOV Heat Treatment Systems with Metal Resistance Heater

Charakteristics

MOV heat treatment furnaces are ideal for the treatment of sophisticated materials if high temperatures and an absolutely clean hydro-carbon free atmosphere are required.

Heat treatment sytem with metal resistance heater

Applications:

MOV systems are universally applicable if heat treatment with particularly high requirements in respect of cleanliness for exacting materials is involved, for example:

Degassing of electric or radiation tube components
Bright- and stress-free annealing of high-temperature alloys
Sintering of high-melting and heavy metals such as tungsten
Production of high-quality fluxless braze joinings of steels, steel-ceramics and many other materials.

Benefits for users:

MOV systems offer ideal conditions for an excellent quality of the treated products. The low leak rate and excellent thermal properties lead to a highly economic production.

System design

MOV-systems are cold-wall furnaces with water-cooled double wall vessel out of stainless steel. The material to be treated is heated by full metal resistance heater arranged around the working chamber. The heat is transferred by radiation. The heating insert is equipped with heating elements consisting of materials suiting the desired maximum temperature, such as molybdenum, tantalum or tungsten. Thermal insulation is provided by metal sheets or multi-layer foils or, for temperatures below 1.400 °C, also sandwich-constructions with inner and outer metal layers and an insulation graphite felt inbetween. For temperatures up to 1.700 °C metal wire heaters are fixed and supported by aluminium oxide insulators.

If higher temperatures are involved tungsten heaters in self supporting ceramicless design are used. The basic equipment of the furnace also includes a sight glass allowing optical temperature measurement. A three-phase high-current transformer is used for the power supply. The heating capacity is infinitely controlled by a thyristor controller.

The furnace vessel and, thus, the working chamber can be arranged vertically or horizontally. Vertical furnaces are equipped for charging from top or bottom optionally. All systems can be equipped with mechanical charging devices. The all-metal design of the MOV systems is particularly well suited for high vacuum operation. Due to its high vacuum conduction short pumping times and low ultimate vacuum pressures are ensured. The sandwich-type insulation for low temperature applications provides for a better energy exploitation. According to the process requirements, ultimate operating pressures in the heated and loaded furnace up to approx. 10E-6 mbar can be realised. Appropriate accessory equipment also allows operation under partial pressure or overpressure protective respectively process gas atmospheres.

A MOV heat treatment system mainly consists of: the furnace vessel, the vacuum pumping unit, the power supply and the control cabinet. These main system modules are combined in different versions according to the application requirements.