KNF Neuberger Vacuum Pump PJ21985-SR920

KNF Neuberger N 920 G Diaphragm Vacuum Pump – 21 L/min, 2 mbar, Speed-Controlled

The KNF Neuberger PJ21985-SR920 is a high-performance, oil-free diaphragm pump engineered for demanding laboratory applications such as rotary evaporation, centrifugal concentration, and distillation. Featuring a chemically resistant design with PPS pump heads, PTFE-coated diaphragms, and FFPM valves, this pump is optimized for the safe handling of aggressive solvent vapors and corrosive gases. With an ultimate vacuum of 2 mbar and a peak flow rate of 21 L/min, this pump provides the high suction capacity needed at low absolute pressures to ensure rapid and efficient solvent recovery.

Technical Performance and Design

• High Pumping Speed at Low Vacuum: Specifically engineered to maintain high suction performance throughout the entire vacuum range, significantly reducing process times for high-boiling-point solvents like DMF or DMSO.

• Integrated Speed Control: The built-in potentiometer allows for precise, stepless adjustment of the motor speed, providing the flexibility to tune the vacuum level for delicate or heat-sensitive samples.

• Chemically Resistant Flow Path: Constructed with high-durability PPS heads and PTFE-coated diaphragms, ensuring the pump remains protected against degradation from acidic, basic, or organic vapors.

• Whisper-Quiet Operation: Optimized for the benchtop environment, the pump operates with exceptionally low noise and vibration, contributing to a more ergonomic and focused laboratory setting.

Product Specifications

• Model Number: PJ21985-SR920

• Flow Rate (Max): 21 L/min (1.26 m³/h)

• Ultimate Vacuum (Max): 2 mbar abs. (approx. 1.5 Torr)

• Wetted Materials: PPS (Head), PTFE-coated (Diaphragm), FFPM (Valves)

• Gas Ballast: Integrated valve for clearing condensate from the pump heads

• Voltage: 100–240 V (Universal Power Supply)

• Weight: approx. 9.5 kg (21 lbs)

Key Benefits & Applications

• Rotary Evaporation: The 2 mbar ultimate vacuum and high flow rate make it the ideal companion for large-scale rotary evaporators, even when working with solvents that have high boiling points.

• Centrifugal Concentration: Provides the stable vacuum levels required for high-speed solvent removal in vacuum concentrators without the maintenance burden of oil-sealed pumps.

• Maintenance-Free Life: The dry-running diaphragm design eliminates the need for oil changes and disposal, while the brushless motor ensures a long service life and high reliability.

• Versatile Process Control: The integrated gas ballast allows the pump to handle high-moisture loads by preventing internal condensation, maintaining vacuum efficiency throughout long-running distillations.

Used, in great condition; with 30 day warranty. See video here.

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