KNF N938.1.2 Brushless DC Diaphragm Vacuum Pump

Overview

The KNF N938.1.2 is a compact, brushless DC-driven diaphragm vacuum pump engineered for precision gas handling in analytical, medical, and industrial laboratory environments. Operating on positive displacement principles, it utilizes an elastomeric diaphragm actuated by an eccentric cam to alternately expand and compress the pumping chamber—enabling oil-free, contamination-free transfer of gases and vapors. Unlike rotary vane or piston pumps, the N938.1.2 eliminates lubricant carryover, making it suitable for applications where sample integrity, chemical compatibility, and regulatory compliance are critical. Its ultimate vacuum capability of 140 mbar (abs.) and maximum continuous flow rate of 53 L/min support robust performance across moderate vacuum ranges—ideal for interfacing with gas analyzers, emission monitoring systems, fuel cell test benches, and vacuum-assisted sampling manifolds.

Key Features

• Brushless DC motor: Delivers precise speed control, extended service life (>20,000 hours MTBF), and stable torque output across variable load conditions—enabling consistent flow regulation without mechanical wear.
• Fully oil-free operation: No internal lubricants contact the gas stream; ensures zero hydrocarbon contamination and eliminates maintenance associated with oil changes or filter replacements.
• Chemical-resistant wetted materials: Standard configuration includes EPDM diaphragms and FPM (Viton®) valves, providing broad compatibility with acidic, polar, and mildly aggressive gases—including CO₂, NOₓ, SO₂, humid air, and trace organic vapors.
• Low-noise design: Acoustic emission rated at ≤52 dB(A) at 1 m distance—optimized for integration into noise-sensitive instrumentation enclosures and shared laboratory spaces.
• Compact aluminum housing: Precision-machined pump head with integrated thermal management enables stable operation up to 40 °C ambient temperature while maintaining dimensional stability under cyclic duty.
• Dry-run capable: Designed for continuous operation without inlet gas—critical for intermittent vacuum applications such as auto-sampling valves or leak-check sequences.

Sample Compatibility & Compliance

The N938.1.2 meets fundamental requirements for use in regulated environments where material compatibility and operational traceability are essential. Its construction adheres to ISO 8573-1 Class 0 (oil-free air) standards for compressed gas purity. While not intrinsically rated for hazardous areas, optional configurations with reinforced motor insulation (IEC 60034-1) and enhanced sealing meet IP54 ingress protection for dust and water resistance. The pump supports GLP-compliant workflows when integrated with validated instrument control systems—its digital speed interface allows synchronization with data acquisition platforms that enforce audit trails per FDA 21 CFR Part 11 requirements.

Software & Data Management

The N938.1.2 features analog (0–10 VDC) and digital (RS-485 Modbus RTU) control interfaces, enabling seamless integration into SCADA, LabVIEW, or custom PLC-based monitoring architectures. Speed can be dynamically adjusted from 0–100% of nominal RPM, allowing real-time adaptation to changing process demands—such as modulating vacuum level during TGA-MS coupling or ramping flow during breath analysis calibration. Optional KNF SmartControl firmware provides built-in diagnostics including motor current monitoring, thermal event logging, and runtime hour counters—exportable via serial protocol for preventive maintenance scheduling and ISO/IEC 17025 documentation.

Applications

• Gas chromatography (GC) carrier gas supply and auxiliary vacuum for detector housings
• In-line vacuum sampling for continuous emissions monitoring systems (CEMS) compliant with EN 15267 and EPA Method 3A
• Fuel cell test stations requiring clean, pulsation-dampened suction for anode/cathode exhaust recirculation
• Medical devices including portable suction units, dental evacuation systems, and respiratory therapy equipment
• Environmental chambers and accelerated aging test rigs requiring stable low-vacuum hold-down or purge cycles
• OEM integration into automated liquid handling platforms where space-constrained, silent vacuum generation is mandatory

FAQ

Is the N938.1.2 certified for medical device integration?

Yes—when configured with biocompatible wetted materials and documented in a manufacturer’s Design History File (DHF), it complies with ISO 13485 quality system requirements for Class IIa/IIb medical equipment subassemblies.
Can this pump handle condensable vapors?

It tolerates limited moisture content (<60% RH) and non-aggressive condensables; however, prolonged exposure to liquid ingress or high-humidity saturated streams requires optional condensate traps or coalescing filters.
What is the expected lifetime under continuous operation?

With proper thermal management and clean inlet gas, the brushless motor and EPDM/FPM components achieve >20,000 hours MTBF—validated per ISO 16000-18 accelerated life testing protocols.
Does KNF offer application-specific customization?

Yes—custom porting, voltage variants (12–48 VDC), EMI-filtered electronics, and ATEX-compatible versions (N938.1.2-ATEX) are available under OEM engineering collaboration agreements.
How does the pump perform at elevated ambient temperatures?

Rated for continuous operation up to 40 °C ambient; derating applies above this threshold—see KNF Technical Bulletin TB-012 for thermal performance curves and forced-air cooling recommendations.