KNF N938.50KT.18 Diaphragm Vacuum Pump

Overview

The KNF N938.50KT.18 is a compact, oil-free diaphragm vacuum pump engineered for precision and reliability in demanding laboratory environments. Based on KNF’s proven dual-head diaphragm architecture, it operates via positive displacement using chemically resistant PTFE-coated polyphenylsulfone (PPS) diaphragms and perfluoroelastomer (FFPM) valves—enabling stable, pulse-free vacuum generation without lubricants or hydrocarbon contamination. Designed for continuous 24/7 operation, the pump delivers an ultimate vacuum of 15 mbar and a maximum flow rate of 30 L/min at atmospheric inlet pressure. Its robust thermal management system eliminates the need for duty-cycle limitations or automatic thermal shutdown, making it suitable for unattended operation during extended distillation, filtration, or solvent recovery protocols. Unlike water aspirators or oil-sealed rotary vane pumps, the N938.50KT.18 requires zero consumables—no water refills, no oil changes, and no scheduled maintenance beyond periodic inspection of gas-path components.

Key Features

• Dual-head configuration provides enhanced flow stability and redundancy for medium-scale applications such as rotary evaporation with 2–5 L flasks
• Integrated analog vacuum gauge (denoted by “.45” in model suffix) enables real-time monitoring and manual regulation of process vacuum levels
• Chemically inert wetted materials: PTFE-coated PPS diaphragms and FFPM valve assemblies resist degradation from common organic solvents (e.g., acetone, dichloromethane, ethanol), weak acids (e.g., dilute HCl, acetic acid), and alkaline vapors (e.g., ammonia, sodium hydroxide solutions)
• Low-noise operation (<52 dB(A) at 1 m) minimizes acoustic interference in shared lab spaces and adjacent analytical instrumentation rooms
• Compact footprint (402 × 212 × 110 mm) and lightweight design (6.8 kg) facilitate benchtop integration—even in space-constrained fume hoods or mobile lab carts
• CE-compliant electromagnetic compatibility (EMC) and safety certification per IEC 61000-6-3 and IEC 61000-6-4; fully compliant with EN 61000-3-2 harmonic current limits

Sample Compatibility & Compliance

The N938.50KT.18 is validated for use with non-explosive, non-particulate, and non-condensable vapor streams typical of academic, pharmaceutical, and industrial R&D laboratories. It is not rated for Class I, Division 1 hazardous locations or for pumping gases containing >10% condensable vapors without cold trap pre-treatment. All wetted materials meet USP Class VI biocompatibility requirements and comply with FDA 21 CFR 177.2470 (PTFE) and 177.2600 (FFPM) for incidental food contact. The pump supports GLP/GMP workflows through consistent performance traceability and optional documentation packages (e.g., Factory Acceptance Test reports, material certifications). While not intrinsically safe, its oil-free construction eliminates fire risk associated with hydrocarbon-lubricated systems—aligning with OSHA 1910.1200 hazard communication standards for solvent handling.

Software & Data Management

The N938.50KT.18 operates as a standalone analog device and does not feature digital connectivity or embedded firmware. However, its integrated vacuum gauge output (0–15 mbar range) is compatible with third-party analog-to-digital signal acquisition modules (e.g., National Instruments USB-6009, LabJack U3-HV) for time-stamped pressure logging in MATLAB, Python (PyDAQmx), or LabVIEW environments. For regulated environments requiring audit trails, users may pair the pump with external pressure transducers certified to ISO/IEC 17025 calibration standards and record data within validated LIMS or ELN platforms. KNF provides full technical documentation—including dimensional drawings, material declarations (RoHS/REACH), and electrical schematics—for integration into facility SOPs and equipment qualification (IQ/OQ/PQ) protocols.

Applications

• Rotary evaporation of heat-sensitive compounds under controlled vacuum (e.g., natural product isolation, polymer synthesis)
• Vacuum-assisted gravity filtration and Büchner funnel operations with corrosive filtrates
• Short-path and fractional distillation setups requiring stable sub-100 mbar conditions
• Desiccator evacuation and vacuum drying of hygroscopic or thermolabile samples
• Gas sampling and purging in headspace analysis or inert-atmosphere glovebox maintenance
• Supporting vacuum ovens, lyophilizers, and membrane degassers in QC/QA laboratories

FAQ

Can the N938.50KT.18 be used for solvent recovery with a rotary evaporator?

Yes—the dual-head design and 30 L/min flow rate support efficient solvent removal from 2–5 L round-bottom flasks under vacuum levels down to 15 mbar. Use with a condenser and cold trap is recommended when handling highly volatile or low-boiling solvents.
Is the pump compatible with aggressive acids like nitric or sulfuric acid vapors?

No—while resistant to weak acids (pH ≥3), prolonged exposure to concentrated oxidizing or strongly acidic vapors (e.g., >10% HNO₃, >5% H₂SO₄) will degrade FFPM valves and PTFE coatings. A chemical scrubber or secondary trapping stage is required.
Does this model meet FDA 21 CFR Part 11 requirements for electronic records?

As a purely analog device without digital control or data output, it does not fall under Part 11 scope. However, its mechanical consistency and documented material compliance support Part 11-aligned workflows when paired with validated external data acquisition systems.
What is the expected service life under continuous operation?

Based on KNF’s accelerated lifetime testing (per DIN EN 60068-2-64), the diaphragm assembly maintains >95% flow retention after 15,000 hours at rated load—equivalent to ~1.7 years of uninterrupted 24/7 use.
Can the vacuum setpoint be digitally controlled or automated?

Not natively—the integrated gauge is analog-only. For programmable pressure control, integrate a proportional vacuum regulator (e.g., KNF VRD series) upstream or use a PID-controlled solenoid valve with external feedback loop.