These compact tabletop tube furnaces with integrated control systems can be used universally for many processes. Equipped with a standard working tube of C 530 ceramic and two fibre plugs, these furnaces have an unbeatable price/performance ratio.

• Tmax 1200 °C or 1300 °C
• Casing made of textured stainless steel sheets (non-rusting design)
• Outer tube diameter of 50 to 120 mm, heated length from 250 to 1000 mm
• Working tube of C 530 ceramic including two fibre plugs as standard equipment
• Type S thermocouple
• Silent solid-state power control relays

Additional Equipment

• Over-temperature limit controller with adjustable cutout temperature for thermal protection class 2 in accordance with EN 60519-2 as temperature limiter to protect the oven and load
• Cascade controller for temperature measurement in the working tube and behind the tube
• Working tubes designed for process requirements
• Three-zoned design with HiProSystem control (heated length from 750 mm, for 1300 °C models)

These compact tube furnaces are used when laboratory experiments must be performed horizontally, vertically, or at specific angles. The ability to configure the angle of tilt and the working height, and their compact design, also make these furnaces suitable for integration into existing process systems.

• Tmax 1100 °C, 1300 °C, or 1500 °C
• Compact design
• Vertical or horizontal operation freely adjustable
• Working height freely adjustable
• Working tube made of C 530 ceramic
• Type S thermocouple
• Operation also possible separate from stand if safety guidelines are observed
• Control system integrated in furnace base

The RS tube furnaces can be used for either horizontal or vertical operation. Using a variety of accessories, these professional tube furnaces can be optimally laid out for your process. By using different available gas supply packages, operations can be performed under a protective gas atmosphere, vacuum, or even with flammable gasses.

• Tmax 1100 °C or 1300 °C
• Casing made of sheets of textured stainless steel (non-rusting design)
• Tmax 1100 °C: Type K thermocouple
• Tmax 1300 °C: Type S thermocouple
• Frame for vertical operation, which can also be retrofitted as additional equipment
• Hinged design for simple insertion of the working tube
• Working tube made of ceramic C 530 for operation in air included in scope of delivery
• Switchgear and control unit separate from furnace in own wall or standing cabinet

The RS tube furnace line can be custom-fit to your needs with a variety of extras. Starting with various working tubes of different materials to protective gas or vacuum operation. For optimum temperature uniformity, all RS furnaces are also available as three-zone tube furnaces with modern PLC controls. The heat loss at the ends of the tube is compensated using this three-zoned control, and a longer uniform zone is the result.

Additional Equipment

• Cascade controller with temperature measurement in the working tube and in the oven chamber behind the tube
• Working tubes designed for process requirements
• Display of inner tube temperature with additional thermocouple
• Different gas supply packages (starting on page 24) for protective gas and vacuum operation
• Three-zone control for optimization of temperature uniformity
• Check valve at gas outlet avoids intrusion of false air
• Ceramic half pipe for heating elements and/or as support surface for the load
• Stand for vertical operation
• Base frame with integrated switchgear and controller

When the retention of the granular characteristics of the material is important, e.g. when drying or calcining, this rotary tube furnace is the optimum solution. The continuous rotary operation of the furnace tube and the option of operating it under protective gas lead to excellent results.

• Design like RS models
• Tmax 1100 °C
• Type K thermocouple
• Compact unit, designed as tabletop model
• Optionally supplied with quartz glass process reactor or quartz glass tube
• Easy working tube or process reactor removal through beltless drive and hinged casing
• Infinitely variable drive (approx. 1-20 rpm)
• Good flooding of load with process gas due to inlet on one side and outlet on other side of tube

Additional Equipment

• Gas-tight rotary feedthrough for connection to gas supply systems (suitable for operation in rough vacuum)
• Tilting device and/or feeder for powder transport through the tube
• Display of inner tube temperature with additional thermocouple
• Gas supply systems with gas cooler at the outlet
• Check valve at gas outlet avoids intrusion of false air
• Three-zone control
• Tube adaptor for alternative operation either with glass reactor or ceramic tube

These compact tube furnaces with SiC rod heating and integrated switchgear and controller can be used universally for many processes. With an easy to replace working tube as well as additional standard equipment options, these furnaces are flexible and can be used for a wide range of applications. The high-quality fiber insulation ensures fast heating and cooling times. The SiC heating rods installed parallel to the working tube ensure excellent temperature uniformity. The price-performance ratio for this temperature range is unbeatable.

• Tmax 1500 °C
• Textured stainless steel sheet casing (non-rusting)
• High-quality fiber insulation
• Active cooling of casing for low surface temperatures
• Type S thermocouple
• Solid-state-relays
• Prepared for assembly of working tubes with water-cooled flanges
• Ceramic tube, C 799 quality

Additional Equipment

• Over-temperature limit controller with adjustable cutout temperature for thermal protection class 2 in accordance with EN 60519-2 as temperature limiter to protect furnace and load
• Cascade controller with temperature measurement in the working tube and in the oven chamber behind the tube
• Fiber plugs
• Check valve at gas outlet avoids intrusion of false air
• Working tubes for operation with water-cooled flanges
• Display of inner tube temperature with additional thermocouple

The high-temperature tube furnaces are available in either horizontal (type RHTH) or vertical (type RHTV) designs. High-quality insulation materials made of vacuum-formed fibre plates enable energy-saving operation and a fast heating time due to low heat storage and heat conductivity. By using different gas supply systems, operations can be performed under a protective gas atmosphere, vacuum, or even with flammable gasses.

• Tmax 1600 °C, 1700 °C, or 1800 °C
• MoSi2 heating elements, mounted vertically for easy replacement
• Insulation with vacuum-formed ceramic fibre plates
• Rectangular outer casing with slots for convection cooling
• Models RHTV with hinges for wall mounting
• Casing made of sheets of textured stainless steel (non-rusting design)
• Ceramic working tube made of material C 799 incl. fibre plugs operation under air
• Type B thermocouple
• Power unit with low-voltage transformer and thyristor
• Switchgear and control unit separate from furnace in separate floor standing cabinet

Additional Equipment

• Over-temperature limit controller with adjustable cutout temperature for thermal protection class 2 in accordance with EN 60519-2 as temperature limiter to protect the oven and load
• Cascade controller with temperature measurement in the working tube and in the oven chamber behind the tube
• Working tubes designed for process requirements
• Display of inner tube temperature with additional thermocouple
• Gas-tight flanges for protective gas and vacuum operation
• Manual or automatic gas supply system
• Three- or five-zone control for optimization of temperature uniformity
• Check valve at gas outlet avoids intrusion of false air
• Stand for vertical operation

When equipped with various equipment packages, the tube furnace series RS, RHTC, RHTH, and RHTV can be adapted for operation with nonflammable or flammable gasses or for vacuum operation. The different equipment packages can be delivered together with the furnace, or later as needed.

This package represents a basic version sufficient for many applications, for operation with nonflammable protective gasses. The standard working tube made of ceramic C 530 delivered with the furnace can still be used.

• Standard working tube can be used
• 2 plugs of ceramic fibre with protective gas connections
• Gas supply system for nonflammable protective gas (Ar, N2, forming gas) with shutoff valve and flow meter with control valve (volume 50-500 l/hr), piped and ready to connect (gas intake pressure at 300 mbar to be provided by customer)

Additional Equipment

• Extension of gas supply system with a second or third nonflammable type of gas
• Bottle pressure regulator for use with bottled gas
• Automatically controlled gas supply with solenoid valves on the gas supply panel, which can be switched on and off through a controller with programmable extra functions (e.g. P 330)

For increased atmospheric purity requirements in the working tube, we recommend this gas supply system. The standard working tube is replaced by a dense working tube of ceramic C 610 or C 799 in a gas-tight design. Besides the longer working tube, the scope of delivery also includes gas-tight flanges and a corresponding bracket system in the furnace. The system can also be equipped for vacuum operation.

• Longer, gas-tight working tube of ceramic C 610 for furnaces to 1300 °C or of C 799 for temperatures above 1300 °C
• 2 vacuum-tight, water-cooled stainless steel flanges with fittings on the outlet side (cooling water supply with NW9 hose connector to be provided by the customer)
• Mounting system on furnace for the flanges
• Gas supply system for nonflammable protective gas (Ar, N2, forming gas) with shutoff valve and flow meter with control valve (volume 50-500 l/hr), gas outlet valve, piped and ready to connect (gas intake pressure at 300 mbar to be provided by customer)

Additional Equipment

• Extension of gas supply system with a second or third nonflammable type of gas
• Bottle pressure regulator for use with bottled gas
• Automatically controlled gas supply with solenoid valves on the gas supply panel, which can be switched on and off through a controller with programmable extra functions (e.g. P 330)
• Water-cooled end flange with quick connectors
• Cooling unit for closed loop water circuit
• Window for charge observation in combination with gastight flanges

Vacuum Operation

• Vacuum package for evacuation of the working tube, consisting of connector for the gas outlet, 1 ball valve, manometer, 1-stage manually operated rotary vane vacuum pump with corrugated stainless steel hose connected to the gas outlet, max. attainable end pressure in working tube about 10-2 mbar
• Alternative pumps for max. final pressure of up to 10-5 mbar on request

Adding gas supply system 3 to the tube furnace allows operation under a hydrogen atmosphere. During hydrogen operation, a safety pressure of approx. 30 mbar is ensured in the working tube. Surplus hydrogen is burnt off in an exhaust gas torch. The operator manually takes care of inerting the working chamber before process start, after process end, and in case of default.

• Safety system for operation with flammable gases including torch function and tube breakage monitoring (checking overpressure)
• Longer, gas-tight working tube
• 2 vacuum-tight, water-cooled stainless steel flanges (cooling water supply to be provided by customer via hose connector)
• Exhaust gas torch
• Pressure switch for monitoring the safety pressure
• Gas supply system for H2 and N2. Volume adjustment is carried out by hand (the customer provides an H2 supply at 1 bar, an N2 supply at 10 bar, an O2 supply at 6-8 bar and a propan supply at 300 mbar)

With extended safety logic and an integrated nitrogen purge container, the system can be used for fully-automatic, unattended operation. Equipped with a Safety-PLC control system, pre-purging, hydrogen inlet, operation, fault monitoring and purging at the end of the process are carried out automatically. In case of default, the tube is immediately purged with nitrogen and the system is automatically switched to a safe status.

Equipment in Addition to System 3

• Extended safety control system with emergency tube purging in case of default
• Emergency purge container
• Safety-PLC control system with touchpanel for data input

Additional Equipment for Systems 3 - 4

• Simplified safety package for operation when purging with hydrogen above 800 °C
  • Tube can be opened at working temperature above 800 C
  • Pilot flame at tube outlet
  • Purging with hydrogen below 800 C not possible, locked
  • Available for models RS
• Gas supply system extension for additional nonflammable gas types
• Bottle pressure reducer for use with bottled gas
• Cooling unit for closed loop water circuit
• Vacuum packages (with hydrogen operation, this package can only be used for pre-evacuation)
• PLC control system (as standard with gas supply system 4)
• Gas supply via program-dependent, controllable mass flow controllers (with PLC control system only

With respect to the final pressure different pumps are available (see also page 44):

• Single-step rotary piston pump for a max. final pressure of approx. 20 mbar.
• Two-step rotary piston pump for a max. final pressure of approx. 10-2 mbar.
• Pump system PT70 Dry (rotary vane pump with following turbomolecular pump for a max. final pressure of 10-5 mbar.

For protection of the vacuum pump only cold stage evacuation is allowed. The reduction of working tube strengthness limits the max. possible working temperature under vacuum

Furnace Chamber Control
with temperature measurement in furnace chamber outside the working tube.

• Advantages: Thermocouple protected against damage and aggressive load, very even control, attractive price
• Disadvantage: Process-dependent temperature difference between displayed temperature on the controller and inside the tube

Charge Control
with temperature measurement of load in the working tube.

• Advantages: Precise control inside of tube without temperature deviation
• Disadvantages: Slow control with danger of temperature overshoot, control parameters must eventually be adjusted to correspond to the process. At high application temperatures, the over-temperature limit controller can activate to protect the heating elements.

Cascade Control
with temperature measurement both in the furnace chamber outside the working tube as well as in the working tube.

• Advantages: Very precise and rapid control adjustment
• Disadvantage: Costs

Only the furnace chamber temperature is measured and controlled. Regulation is carried out slowly to avoid out-of-range values. Because the charge temperature is not measured during this process, the furnace chamber temperature deviates from the charge temperature by several degrees.

If the cascade is switched on, both the charge temperature and furnace chamber temperature are measured. By setting different parameters the heat-up and cooling processes can be individually adapted. This results in a more precise temperature control at the charge.

There are various working tubes available, depending on application and temperatures. The technical specifications of the different working tubes are presented in the following table: