•  Hardening in vacuum or inert gas

•  Bright anneal in vacuum or inert gas

•  Homogenizing, Solubilitation

•  Brazing

•  Sintering

•  Degasing

VMS 20-100

(Click image to zoom)


It is a vacuum furnace series of medium dimension for laboratory and industrial applications.

The hot zone has a cylindrical shape and top loading VLT U.H.V. furnaces are completely metallic and at the state of the art in the U.H.V. technology.

The use of metals as Tungsten, Molybdenum, OFHC Cupper, AISI 304L and the use of Turbo and dry pumps, allows to perform high vacuum processes in an oil-free atmosphere .

The high efficient metallic hot zone allows very fast heating and cooling cycles. With a very low power consumption. The cooling time can be greatly reduced with the input of inert gas.

The furnaces can operate in automatic or manual, and the operator interface is very simple.

Process data can be transmitted to a remote PC.

VLT can supply different furnace configurations , responding to specific client needs.

This U.H.V. Furnace series is supplied for working temperature of 1200°C, 1500°C and 1800°C, the useful volume can be from 20lt to 100lt, with a maximum diameter of 420mm. The overall dimension of the furnace is related to the Hot Zone dimension. On request VLT can supply bigger furnaces and with horizontal loading.

Furnaces lay-out is made of three modules:

  • Stainless steel vacuum chamber double wall.

  • Power supply cabinet and control system PC.

  • Service module


  • Working : Automatic and,or manual

  • Working temperature : 1200°C, 1500°C, 1800°C.

  • Temp.uniformity : +/- 5°C

  • Useful volumes : From 20lt to 100lt

  • Power : 380V 3F+N+G. from 10 to 45 Kw(depending of useful volume and temp.)

  • Thermocouples:

    • N° 2 Pt-PtRd 10% for 1200°C and 1500°C.

    • N° 2 W-WRe5% for 1800°C.

  • Ultimate Vacuum : See table 1.

  • Cooling : water 20°C, 40lt/min.

  • Compressed air : 6/8 bar

  • Max dim. : See fig.1.

  • Max weight : 800 Kg.

  • Fast cooling : By inert gas flow.


1) AISI 304L vacuum chamber cooled wall

  • Main cylindrical body max diam.900mm, max height 1000mm, on it there are vacuum flanges for vacuum pump, vacuum instruments, thermocouples, vacuum valves, inert gas valve, power feedthroughs etc.
  • AISI 304 L cover double wall water cooled, hydraulic open and 120° rotation. On request a viewport can be mounted for optical measurement.
  • AISI 304L bottom double wall water cooled.

2)  Hot zone 1200°C

•  It includes the Molybdenum resistor, 7 thermal shields (5Mo+2AISI) for cylinder, top and bottom. The hot zone is easy to remove for maintenance operations.

2a) Hot zone 1500°C

•  It includes the Molybdenum resistor, 9 thermal shields (8 Mo+1 AISI) for cylinder, top and bottom. The hot zone is easy to remove for maintenance operations.

2b) Hot zone 1800°C

•  It includes the Tungsten resistor 9 thermal shields (2 Wo+6Mo+1 AISI) for cylinder, top and bottom. The hot zone is easy to remove for maintenance operations.

3) Power supply cabinet and control system / PC

The cabinet includes:

  • Electrical power supply system; power triphase transformer (400/12Vac), triphase thyristors Unit Eurotherm Mod TC3001, chart record Eurotherm Mod. 4103M/6CH six channel for Vacuum and temperatures, automatic triphase circuit breaker, protection fuses, voltage-current instruments, door interlocks.

  • Control system/ PC; programmer temperature-vacuum controller Eurotherm Mod. 2704 serial port to PC. The software is upper graded at the state of the art. The control system allow to operate in automatic or manual, and can be settled to a prefixed safety vacuum value, so if this value is reached the program will stay in hold condition until the vacuum value start to decrease.

4) Service module

The service module is a complete unit in a wheeled metallic closed cabinet, it is connected to the Vacuum Chamber by the high vacuum Electropneumatic Valve.

The module includes:

  • Vacuum pump systems as the table 1

  • Vacuum control and monitoring instrumentation for the automatic cycle

  • Service fluids flow rate and pressure instrumentation and control

  • Hydraulic system to open the Vacuum Chamber

  • Water cooled trap or chiller for vacuum pump system with diffusion pump

The vacuum system use Varian or equivalent pumps, in figure 2 a typical scheme of Vacuum Furnace with diffusion pump is showed.

5) Safety and interlock

A wide range of safeties are included:

  • Low cooling water flow rate

  • Over-temperature of water cooling

  • Thermocouple failure

  • Vacuum loss

  • Door interlocks

  • Furnace over temperature


Fig. 1

Fig. 2

Fig. 3