Swelling number furnace (SNF)

• Maximum temperature : 900°C
• Heating element : Yttria stabilised iron chrome aluminium alloy resistance wire wound around an SiO2 tube.
• Temperature sensor : NiCr/NiAl thermocouple Type K.
• Crucible information:
•    Capacity : 17ml
•    External height : 26mm
•    External diameter at top : 41mm
•    Internal diameter at base : 11mm
• Crucible holder : Supplied with wire type crucible holder
• Door switch : The nature of the test requires the heating element to remain on when the furnace lid is open, so no door switch is fitted. As a safety measure, a 30mA residual current circuit breaker is built into the furnace.
• Controls : The furnace is offered with a choice of different PID digital temperature controllers.

• Over temperature protection : Available as an optional extra. Using an independent thermocouple, a Eurotherm controller operates a contactor to shut down the furnace until manually reset.
• Power control : Encapsulated solid-state relay with zero voltage switching control and over voltage spike protection.
• Diagnostics : The control circuit includes mains on indication, instrumentation on/off switch and a ‘heater on’ light, in parallel with the heating elements, and showing the output of the solid-state relay. The temperature controller gives several helpful status signals and in the event of thermocouple failure, will shut down the furnace.
• Power rating : 800W
• Supply required : 220 – 240V, 50-60Hz, single phase and neutral supply, with protective earth (ground connection). The supply must be capable of supplying a current of 4 amps. Other voltages are available on request.
• External dimensions : 330mm (h) x 410 (w) x 300 (d)
• Net weight : 26kg
• Optional extras : Crucibles with lids, additional crucible holder and separate temperature indicator.
• Spare parts kit : Spare parts are available separately or in a kit comprising: thermocouple, sheath, heating element, solid-state relay and door (lid) insulation piece.
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