KNF N920G High-Performance Chemically Resistant Diaphragm Vacuum Pump

Overview

The KNF N920G is a high-performance, oil-free diaphragm vacuum pump engineered for demanding laboratory environments where chemical compatibility, long-term reliability, and precise vacuum control are critical. Based on KNF’s proven 9-series diaphragm technology, the N920G operates on a brushless DC frequency-controlled motor—enabling continuous, stepless speed regulation via front-panel rotary control. This architecture delivers exceptional responsiveness across the full vacuum range (2–1000 mbar), with stable ultimate vacuum performance of ≤2 mbar (≤5 mbar when gas ballast valve is engaged). Unlike traditional AC-driven pumps, the N920G’s intelligent motor control minimizes thermal drift, reduces mechanical wear, and ensures consistent flow and vacuum stability during extended operation—particularly essential in applications such as solvent-sensitive rotary evaporation or multi-step vacuum drying protocols.

Key Features

• Chemically resistant wetted parts: PTFE-coated diaphragms, NBR elastomer valves, and stainless steel housing components ensure robust performance with aggressive solvents including acetone, chloroform, methanol, and acidic vapors.
• Brushless DC motor with integrated frequency converter: Enables real-time speed modulation (0–100% RPM) to match process requirements—reducing energy consumption, noise (<52 dB(A)), and vibration transmission to sensitive instrumentation.
• Integrated gas ballast valve: Allows controlled admission of ambient air to prevent condensation of volatile solvents in the pump head—extending service life and maintaining vacuum integrity during wet-gas applications.
• Compact, stackable footprint (324 × 226 × 158 mm) and low mass (8.6 kg): Optimized for benchtop integration, fume hood placement, or mobile cart mounting without compromising structural rigidity.
• No oil, no mist, no maintenance intervals: Eliminates risk of hydrocarbon contamination in vacuum lines and downstream analytical systems—fully compliant with ISO 8573-1 Class 0 air purity requirements for instrument-grade vacuum.

Sample Compatibility & Compliance

The N920G is validated for use with corrosive, condensable, and mildly reactive vapors commonly encountered in organic synthesis, pharmaceutical QC, and polymer characterization workflows. Its material set meets ASTM D471 resistance criteria for NBR and complies with EU Regulation (EC) No 1907/2006 (REACH) for restricted substances. As a CE-marked device under the Machinery Directive 2006/42/EC and Electromagnetic Compatibility Directive 2014/30/EU, it supports GLP-compliant documentation practices—including traceable calibration logs and operational parameter records. While not intrinsically rated for ATEX Zone 1, it may be deployed in non-hazardous laboratory zones per IEC 61000-6-3 emission standards.

Software & Data Management

The N920G operates as a standalone analog-controlled unit; no proprietary software or USB/RS-232 interface is included by default. However, its 0–10 V analog input enables seamless integration into centralized lab automation systems (e.g., LabVIEW, DeltaV, or Siemens Desigo CC) for remote speed setpoint control and status monitoring (running/stopped/fault). Optional KNF Digital Interface Module (sold separately) adds Modbus RTU support, enabling audit-trail-capable logging of runtime hours, thermal events, and motor load history—facilitating preventive maintenance scheduling in GMP-regulated environments governed by FDA 21 CFR Part 11 requirements.

Applications

• Rotary evaporation of heat-labile compounds under controlled vacuum gradients
• Reduced-pressure distillation of multicomponent solvent mixtures
• Gel drying and lyophilization pre-vacuum stages
• Gas scavenging and inert atmosphere purging in Schlenk-line setups
• Backing pump for turbomolecular and cryogenic high-vacuum systems
• Replacement of water aspirators and oil-sealed rotary vane pumps in eco-conscious labs seeking zero wastewater discharge and VOC containment

FAQ

What vacuum level can the N920G achieve with common organic solvents?
Under dry conditions, the pump reaches ≤2 mbar absolute pressure. With condensable vapors present (e.g., ethyl acetate at 20 °C), activation of the gas ballast valve maintains ≤5 mbar while preventing liquid accumulation in the diaphragm chamber.
Is the N920G suitable for continuous 24/7 operation?
Yes—the brushless DC motor, thermally optimized housing, and self-lubricating PTFE composites enable rated duty cycle of 100% at ambient temperatures up to 40 °C, provided adequate ventilation is maintained.
Can it be used as a forepump for a turbomolecular pump?
Absolutely. Its 21 L/min free-air displacement and ≤2 mbar base pressure meet ISO 21360-1 requirements for backing pumps serving TMUs with pumping speeds up to 300 L/s.
Does KNF provide calibration certificates traceable to national standards?
Upon request, KNF issues factory-verified performance reports (including vacuum vs. time curves and flow rate verification at 50/100 mbar) traceable to DKD-accredited metrology labs in accordance with ISO/IEC 17025.
How often does the diaphragm require replacement?
Under typical lab usage (8 h/day, moderate solvent load), KNF specifies a service interval of ≥12,000 operating hours—approximately 5 years—based on accelerated life testing per DIN EN 60068-2-6.