Rotary evaporators are indispensable in chemical laboratories when it comes to the gentle and targeted concentration of solutions and extracts or the recovery of solvents. Many solvents and distillation products are flammable, which is why explosion protection plays a major role in the safe operation of rotary evaporators. This also depends on the drive motors that set the distillation flask in rotation.

Servotecnica from Raunheim offers explosion-proof servomotors especially for these applications. The economical drive motors meet the highest quality standards and are also used in the explosion-proof Powervap systems from Genser Scientific Instruments in Rothenburg ob der Tauber. These are used wherever large quantities of product need to be processed quickly and gently at low cost with a minimum of manpower.

Conventional rotary evaporators for laboratory use are not leak-proof over a period of several thousand hours due to the rotating seal. In the 1980s, Genser therefore developed the pendulum system rotary evaporator, a device that is very leak-proof and reliable in the long term and is therefore also suitable for automated continuous operation and larger volumes. This also means that operating personnel can be saved and deployed more effectively. Decisive steps towards this were the development of a measuring method for the content of the rotary flask floating freely in the heating bath (inclinometer system) and a distillate removal device that empties under vacuum. Thanks to the high-performance sealing system and the surface-treated glass flanges, the system achieves the best possible tightness and excellent solvent recovery.

Automated and customized

The rotary flask is filled and emptied and the distillate vessel is emptied automatically. Temperature, vacuum and other process parameters are monitored so that foaming products, for example, can also be processed reliably. The entire distillation system is controlled by software that controls and monitors the sensors, valves and units of the distillation apparatus as well as providing an intuitive graphical user interface. By adapting the software, customer-specific problems can be solved, i.e. the rotary evaporator can be adapted to the specific application. For this purpose, the in-house developed Linux-based system is individualized via configuration files. As the system constantly saves all system parameters in CSV format during operation, evaluation for process optimization is possible using standard programs. The performance of the Powervap system is around five times higher than that of conventional rotary evaporators with the same rotary flask size. This means that, depending on the application, one Powervap system can replace up to five conventional rotary evaporators. The drive motor of the rotary flask is particularly important for continuous automatic operation. It must be reliable, durable, energy-saving and powerful. In many cases, it is also essential that the motor is explosion-proof. Features that the economical SVTM E series from Servotecnica fulfills.

Servomotors with explosion protection

As a specialist for special servomotors, Servotecnica's product portfolio also includes drives for potentially explosive environments in accordance with ATEX Directive 94/9/EC. The brushless servomotors of the SVTM E series are certified according to ATEX II 2G Ex d IIB T4 Gb, approved according to EN60079-0, EN60079-1 and tested according to EN 60034-18-41. As such, they may be operated in areas with potentially explosive dust and gas atmospheres. ATEX motors guarantee the required high level of safety when used in Ex zones 1 and 2. With their fire-resistant metal housing, they comply with temperature class T4 (maximum surface temperature 135 °C) and fire resistance class "D" (metallic fires). To increase application safety, a temperature sensor is fitted for each winding to prevent damage due to overheating and to increase the service life of the motor.

Fully encapsulated and fanless

The explosion-proof, brushless servomotors are characterized by a surface-cooled design of type IC 400. Their fully encapsulated motor does not require any additional ventilation. In order to achieve a longer service life, almost exclusively insulation materials of the insulation class up to 200 °C were used, all of which are UL-certified.

The special stator packing with winding in the slot and the use of neodymium magnets guarantee a high power density of the compact ATEX motors and result in a sinusoidal source voltage. Temperature sensors on each motor winding ensure increased safety. They protect against overheating and thus increase the service life of the motor. The ATEX motors have been tested in accordance with EN 60034-18-41 with regard to partial discharges between the coils.

Powerful, compact and safe

Servotecnica offers explosion-proof drives in two sizes. All ATEX motors are available with different encoder systems (resolver or absolute encoder) and brakes. Their flange dimension is 92 mm, the rated voltage 120/230 VAC and the rated speed 3000 ^min-1. The holding torque of the ATEX motors is 2.1 Nm, the holding current is 5.6 / 2.7 Arms and the peak torque is 4.3 Nm. Like all servomotors from Servotecnica, the explosion-proof servomotors in the SVTM E series are characterized by very high performance, great robustness and a particularly compact design. Thanks to the excellent properties of the brushless explosion-proof servomotors from Servotecnica, Genser Scientific Instruments customers can always rely on them to drive the reliable rotary evaporators.