Cupellation oven N 4/13 CUP

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Overview
Cupellation is a metallurgical process used to separate precious metals (for example gold and silver) from base-metal alloys. The process generates corrosive vapors that attack insulation and heating elements. The N ../13 CUP cupellation furnace series and the pit-type S 73/HS are engineered specifically to meet these demanding process conditions, combining a ceramic muffle with a tailored fresh‑air and exhaust system.

Design and function
The furnace chamber is formed by a ceramic muffle that protects heating elements and insulation from aggressive vapors. A dedicated fresh-air intake and exhaust arrangement channels exhaust gases through a ceramic exhaust tube into an integrated extraction hood located on the furnace roof and above the door; this hood provides the interface for on-site extraction systems. The design allows straightforward maintenance: wear parts such as the ceramic muffle and heating elements are easily replaceable. Models differ in chamber height and heating configuration to match cupellation and crucible-melting requirements.

Standard Equipment of Cupellation Furnace N 4/13 CUP

• Compact tabletop design
• Double-shell housing in textured stainless steel with additional fan cooling to keep external surface temperature low
• Exclusive use of insulation materials without classification according to EC Regulation No. 1272/2008 (CLP)
• Ceramic muffle protecting heating elements and insulation
• Chamber heated from three sides (floor and sides) with heating elements on support tubes
• Extraction system with integrated exhaust hood on furnace roof and above the door for connection to customer exhaust system
• Manual lift door
• Defined application within the constraints of the operating instructions
• NTLog Basic for Nabertherm controller: process data recording on USB flash drive

Standard Equipment of Cupellation Furnaces N 10/13 CUP and N 30/13 CUP

• Ceramic muffle protecting heating elements and insulation
• Double-shell housing in textured stainless steel with additional fan cooling
• Exclusive use of insulation materials without classification (CLP)
• Chamber heated from four sides with heating elements on support tubes
• Heating elements designed as a unit for easy replacement
• Ventilated furnace chamber for additional protection of heating elements
• Precise temperature control with control thermocouple placed directly in the muffle
• Closing brick for the muffle with handle (N 10/13 CUP)
• Electro-mechanical lift door (N 30/13 CUP)
• Bench/shelf in front of the muffle
• Special fresh-air and exhaust system for the ceramic muffle; exhaust gases guided via a ceramic tube at the rear of the muffle; adjustable air exchange
• Extraction system with integrated exhaust hood on furnace roof and above the door
• Over-temperature limiter with adjustable cut-out temperature for protection of furnace and load
• Defined application within the constraints of the operating instructions
• NTLog Basic for Nabertherm controller: process data recording on USB flash drive

Standard Equipment of Pit-Type Furnace S 73/HS

• Compact pit-type furnace for crucible melting
• Double-shell housing in textured stainless steel with additional fan cooling
• Exclusive use of insulation materials without classification (CLP)
• Split lid, manually swivelled open
• Heating from four sides
• Heating elements and floor protected against abrasion and aggressive substances with silicon carbide tiles
• Ventilated furnace chamber as additional protection for heating elements
• Exhaust air box with insulated tube to the rear; provisions for connection to customer extraction system
• Defined application within the constraints of the operating instructions
• NTLog Basic for Nabertherm controller: process data recording on USB flash drive

Additional equipment
For N 4/13 CUP

• Over-temperature limiter with adjustable cut-out temperature for furnace and load protection

For N 10/13 CUP and N 30/13 CUP

• Electro-mechanical lift door for N 10/13 CUP (option)
• Swivelling inspection window as heat protection
• Timer to program switching on/off times (preset temperature)
• Base mounted on castors

For S 73/HS

• Manual rolling lid
• Pneumatic rolling lid (option)
• Over-temperature limiter with adjustable cut-out temperature
• Timer to program switching on/off times (preset temperature)

Technical specifications (excerpt)
Model | Tmax (°C) | Inner w (mm) | Inner d (mm) | Inner h (mm) | Volume (l) | Outer W (mm) | Outer D (mm) | Outer H (mm) | Load kW | Connection | Weight (kg)
N 4/13 CUP | 1280 | 185 | 250 | 80 | 3.7 | 600 | 770 | 750 | 3 | 1-phase | 100
N 10/13 CUP | 1300 | 250 | 540 | 95 | 8.0 | 900 | 1200 | 1850 | 15 | 3-phase | 380
N 30/13 CUP | 1300 | 250 | 500 | 200 | 25.0 | 1000 | 1200 | 2250 | 15 | 3-phase | 430
S 73/HS | 1300 | 530 | 380 | 360 | 73.0 | 1050 | 1530 | 900 | 26 | 3-phase | 890

Key features / technical summary

• Maximum temperature up to 1300 °C (N 10/13 CUP, N 30/13 CUP, S 73/HS); N 4/13 CUP rated to 1280 °C
• Ceramic muffle protects heating elements and insulation against corrosive cupellation vapors
• Heating arrangement: 3-sided (N 4/13) or 4-sided (N 10/13, N 30/13, S 73/HS)
• Ventilated furnace chamber options for protection of heating elements
• Extraction: dedicated fresh-air and exhaust-air system with integrated exhaust hood and ceramic exhaust tube for the muffle (adjustable air exchange)
• Over-temperature limiter available as protective device
• Replaceable heating elements (designed as unit for easy replacement)
• Optional electro-mechanical or manual lift/rolling doors and closing bricks (model dependent)
• NTLog Basic data logger for Nabertherm controller (process data recording on USB flash drive)
• Insulation: only non-CLP-classified insulation materials used
• Protective lining options (silicon carbide tiles) for S 73/HS against abrasion and aggressive substances