The RD product line furnaces convince with their unbeatable price-performance ratio, very compact outer dimensions and their low weight. These all-rounders are equipped with a working tube which also serves as support for the heating wires. Thus, the working tube is part of the furnace heating which has the advantage that the furnaces achieve very high heat-up rates. The furnaces can be supplied for 1100 °C or 1300 °C. All models are designed for horizontal application. If the customer requires protective gas atmosphere, a separate working tube, e.g. made of quartz glass, must be inserted in the working tube.

• Tmax 1100 °C or 1300 °C
• Housing made of sheets of textured stainless steel
• Outer diameter of the tube: 15mm or 30mm, heated length: 150mm or 200mm
• Working tube made of C530 material including two fiber plugs as standard
• Thermocouple type K (1100 °C) or type S (1300 °C)
• Solid state relays provide for low-noise operation of the heating
• Heating wires wound directly around the working tube resulting in very fast heat-up rates

Additional equipment

• Over-temperature limit controller with adjustable shut-off temperature for thermal protection class 2 according to EN 60519-2 as over-temperature protection for furnace and load
• Additional working tube, inserted in the integrated tube, e.g. for protective gas operation
• Gas supply package for protective gas or vacuum operation
• Version as thermocouple test furnace

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
• Housing made of sheets of textured stainless steel
• 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
• Solid state relays provide for low­noise operation

Additional equipment

• Over-temperature limit controller with manual reset for thermal protection class 2 in accordance with EN 60519-2 as temperature limiter to protect the oven and load
• Charge control with temperature measurement in the working tube and in the oven chamber behind the tube
• Three-zoned design with HiProSystem control (heated length from 750 mm, for 1300 °C models)
• Process control and documentation with Controltherm MV software package

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

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
• Housing made of sheets of textured stainless steel
• High-quality fiber insulation
• Active cooling of housing for low surface temperatures
• Type S thermocouple
• Solid state relays provide for low-noise operation
• Prepared for assembly of working tubes with water-cooled flanges
• Ceramic tube, C 799 quality

Additional equipment

• Over-temperature limit controller with manual reset for thermal protection class 2 in accordance with EN 60519-2 as temperature limiter to protect furnace and load
• Charge control 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 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
• Housing made of sheets of textured stainless steel
• 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

• Charge control 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 44) 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
• Optical temperature measurement for the use as contiuously working furnace
• Stand for vertical operation
• Base frame with integrated switchgear and controller
• Laboratory table on castors or with fixed stand

If, for example, the focus lies on maintaining the individual grain characteristics of the material such as in drying or calcination, rotary tube furnaces of the RSR product line are the optimal solution. The permanently rotating working tube allows for the continuous movement of the charge.

These models can basically be designed for continuous processes and/or batch operation. Depending on process, charge and required maximum temperature, different working tubes made of silica glass, ceramics or metals are used.

Depending on the application, these models can be upgraded with additional accessories such as charging funnel, electric screw-conveyor for materials supply, or gas supply systems into a small production plant. Rotary tube furnaces can be operated at ambient air, under protective gas and even in vacuum. The necessary features can also be supplied as additional equipment.

Standard design of all models

• Housing made of textured stainless steel sheets
• Beltless drive and hinged furnace housing provide for very easy removal of working tube or reactor
• Adjustable drive of approx. 1-20 rpm

Additional equipment for all models

• Different tube diameters or heated lengths
• Manual or automatic gas supply systems
• Gas-tight rotary device for the connection to gas supply systems
• Check valve at gas outlet avoids intrusion of false air
• Three-zone control for the optimization of temperature uniformity
• Temperature display unit in the working tube with measurement by means of an additional thermocouple
• Charge control by means of an additional thermocouple in the working tube

Standard design for batch operation

• Tmax 1100 °C
• Thermocouple type K
• Furnace designed as tabletop model with quartz glass reactor open at both sides
• Reactor is removed from the furnace for discharging

Additional equipment for batch operation

• Different gas supply systems
• Vacuum design, up to 10-² mbar depending on the applied pump
• Reactor made of quartz glass, open at both sides, with burling for better conveyance of the charge in the tube
• Package for improved charging and discharging of the working tube in the following design:
  • Reactor made of quartz glass or stainless steel 1.4841, closed at one side, with integrated blade for a better mixing of the charge
  • Tilting mechanism to the left/to the right. For charging and heat treatment, the furnace is tilted towards the right side until the stop so that the load is charged into the furnace. For discharge, the furnace is tilted towards the other side to discharge the powder from the reactor.
  • Removal of reactor not necessary
  • Furnace mounted on the base
  • Base running on casters
• Base with manual spindle for tilting angle adjustment for charging, during heat treatment and for discharging the tube
• Digital display for the tilting angle of the furnace

Standard design for continuous processes

• Tmax 1100 °C
  • Thermocouple type K
  • Working tube made of quartz glass open at both sides
• Tmax 1300 °C
  • Thermocouple type S
  • Working tube made of C530 ceramics, open at both sides, not gas-tight
• Compact design with switchgear and controller, mounted in the base, including transport casters
• Furnace mounted on base, including manual spindle drive with crank for pre-adjustment of the tilting angle
• Base running on casters

Additional equipment for continuous processes

• Working tube made of quartz glass with burling for optimized transportation of the charge up to Tmax 1100 °C
• Gas-tight working tube made of C610 ceramics up to Tmax 1300 °C
• Different gas supply systems which cause process gas to flow around the charge due to inlet on the one and outlet on the other side of the tube (only in combination with an electrically driven screw-conveyor, see below) Charging funnel made of stainless steel with lockable powder outlet, as additional equipment also available as gas-tight funnel
• Electric vibration generator at the charging funnel for the optimization of material supply into the working tube
• Electrically driven screw-conveyor at the inlet of the working tube with 20mm pitch and adjustable speed between 0.28 and 6 revolutions per minute
  • Screw-conveyor with adjusted pitch for adjustment to the charge as requested
  • Different gear transmissions for other speeds on request
• Discharge blade at the outlet of the working tube
• Collecting bottle made of laboratory glass at the outlet of the working tube
• Digital display unit for the tilting angle of the furnace
• Electric linear drive for the adjustment of the tilting angle
• Alternating design for continuous processes or batch operation. The furnace can be tilted on the frame towards both sides. The customer can mount a working tube open at both sides for flow processes as well as a process reactor (Tmax 1100 °C) closed at one side for batch operation.
• PLC controls for temperature control and the control of connected aggregates such as gearshift and speed of the screw-conveyor, speed of the working tube, switching of the vibration generator, etc.

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 housing with slots for convection cooling
• Models RHTV with hinges for wall mounting
• Housing made of sheets of textured stainless steel
• 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
• Over-temperature limit controller with manual reset for thermal protection class 2 in accordance with EN 60519-2 as temperature limiter to protect the oven and load and with selectable maximum temperature gradient as tube protection
• Switchgear and control unit separate from furnace in separate floor standing cabinet

Additional equipment

• Charge control 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
• Laboratory table on castors or with fixed stand

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

Extension Package for Furnace Chamber Control

• with additional temperature measurement in the working tube and display of the measured temperature

Charge 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. As the charge temperature is not measured and controlled, it may vary a few degrees from the chamber temperature.

If the charge control 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.

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 system, 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 system, 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

• 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

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: