Our 1800ºC Furnaces
These top loading furnaces are characterized by their flexibility and transparency to neutrons in applications for both neutron diffraction and spectroscopy. The outer furnace body is made of aluminium for use under high vacuum or inert gas atmosphere. All internal components in the neutron beam are made of thin niobium foils. On request all niobium components may be replaced by vanadium.
Heating is achieved by resistance heaters using low voltage and high current. A thermally decoupled heater and up to eight thermal shields guarantees small temperature gradients. Long term temperature stability is typically 0.1% of the actual temperature and gradients are in the order of 0.1 to 0.5% of the actual temperature.
The length of the heater element and an adjustable sample support allow for large samples, and variable heights. Thermocouples close to the sample allow independent temperature reading and control in two distinct temperature ranges from room temperature to 1100ºC and from room temperature to 1800ºC.
A typical vacuum of 10-9 mbar at 1000ºC can be obtained after one to two hours. Power is supplied by saturable self inductances. The temperature controller which has a standard computer interface is adapted for different types of thermocouples and has a self adjusting PID algorithm.
Physical Specifications
- Temperature: Room Temperature RANGE 1100ºC and 1800ºC
- Sample dimensions: Ø 4.5 cm, 10 cm high (max)
- Heater input: 0-15 volts, 0-400 Amps (max) 2000 VA
- High vacuum: Typically 10-5 to 10-6 mbar or inert gas atmosphere
- Neutron access: 360º in scattering plane and ±20º out of scattering plane.
- Ancillary equipment; temperature controller and indicator, rough and high vacuum gauges, control unit with alarms for cooling water, vacuum, upper and lower temperature limits.
High Temperature Neutron Scattering Furnace
The system is primarily designed to accept samples up to 40 mm in diameter. The samples are normally mounted in vacuum and can be increased in temperature up to 1800 °C for short durations of time. The recommended maximum operating temperature of this furnace is 1600 °C.
The system comprises three basic items with interconnecting pipes, leads etc. These items are:
- Furnace Body Assembly
- Turbo Pump Set
- Furnace Control System
- A number of optional extras are priced for, but these are not essential for initial operation. Some stock of these parts, however, is recommended to cope with service and replacements of the elements and shields, which inevitably deteriorate at very high temperatures.
Furnace Body Assembly
The furnace
body is made of aluminium alloy and designed for use under high vacuum.
The body is water-cooled. The top plate of the assembly is also made
of aluminium alloy and provides mountings for the turbo pump and its
vacuum gauges, the sample mount entry and the water-cooled high current
feed through. The body is designed to be mounted at the base.
Within the furnace body, there is a series of eight thermal mounted shields. The outer four shields are constructed from stainless steel with niobium window sections. The four inner shields are constructed entirely from niobium.
The heating element is manufactured from niobium and is mounted from the top plate via insulated copper bus bars connected to the water-cooled current feed through.
When inserted it forms the vacuum seal to allow the chamber to be evacuated. The centre stick is fitted with two W5 thermocouples which controls and monitors the lower sample mount temperature. Alternative thermocouples can be supplied if only lower temperatures are required.
Turbo Pump Set
This comprises a turbo pump capable of running in the inverted position, turbo controller,
backing pump and oil mist filter. The turbo controller will be housed
on the furnace control whilst the backing pump will be powered from
an external source. A stainless steel flexible vacuum hose is provided
to connect the turbo pump to the backing pump.
Temperature Regulation
Includes:
- Chassis
- Voltage and ampere meters for power control
- Primary and secondary vacuum measurements
- Temperature controller with standard interface and suited for a variety of thermocouples, but set for W5, 0-1800 °C
- Independent temperature indication for second thermocouple
- Security logic controlling vacuum cooling supply and upper and lower temperature limits
- Electrical connections and wiring
- Autotransformer to other connection to 208, 220 or 240 Volt AC supply