KNF N938 Series Brushless DC Diaphragm Vacuum Pump

Overview

The KNF N938 Series is a compact, oil-free diaphragm vacuum pump engineered for precision and reliability in demanding laboratory and analytical environments. Based on positive displacement via elastomeric diaphragm oscillation, the N938 operates without lubricating oil—eliminating risk of sample or process contamination, hydrocarbon backstreaming, or maintenance-related downtime. Its brushless DC motor enables smooth, low-vibration operation with precise speed control, supporting stable vacuum generation across variable load conditions. Designed to meet stringent requirements in gas-sensitive applications—including analytical instrumentation, emissions monitoring, and medical vacuum systems—the N938 delivers consistent performance at an ultimate vacuum of 160 mbar (abs.) and a maximum flow rate of 35 L/min under standard conditions (20 °C, 1013 mbar). The pump’s aluminum housing ensures thermal stability and mechanical robustness, while its lightweight construction (2.1 kg) facilitates integration into space-constrained platforms such as benchtop analyzers, portable emission testers, and OEM instrument modules.

Key Features

• Oil-free operation with EPDM diaphragms and FPM valves—ensuring chemical resistance to common solvents, acids, and humid gases
• Brushless DC motor providing high efficiency (82 W nominal power), extended service life, and programmable speed control via analog or digital interface
• Low-noise design (<52 dB(A) at 1 m), optimized for shared laboratory environments and noise-sensitive applications
• Dry-run capability—no damage occurs during transient vacuum loss or zero-flow conditions
• Compact footprint (145 × 110 × 170 mm) and modular mounting options for seamless integration into OEM equipment and automated test systems
• Thermally stable aluminum pump head with integrated heat dissipation—supporting continuous operation at ambient temperatures up to 40 °C

Sample Compatibility & Compliance

The N938 is suitable for handling clean, dry, non-condensable gases and low-concentration vapor streams. It is not intended for pumping explosive, corrosive beyond EPDM/FPM compatibility limits, or particulate-laden media without upstream filtration. All materials in wetted contact comply with EU Regulation (EC) No. 1935/2004 for materials intended to come into contact with foodstuffs. While the pump itself carries CE marking per the Machinery Directive 2006/42/EC and EMC Directive 2014/30/EU, system-level compliance with ISO 8573-1 (compressed air purity), ASTM D3924 (laboratory vacuum standards), or IEC 61000-6-3 (EMC for industrial environments) depends on full system configuration and installation practices. For regulated environments (e.g., clinical diagnostics or GLP-compliant QA labs), optional firmware-enabled audit trail logging and password-protected parameter access may be implemented via external controller integration.

Software & Data Management

The N938 does not include embedded software or onboard data storage. However, its analog (0–10 V) and digital (RS-485 Modbus RTU or optional CAN bus) interfaces support real-time integration into supervisory control systems (SCADA), LIMS, or custom LabVIEW/Python-based acquisition platforms. Speed, current draw, and runtime can be monitored and logged externally; motor temperature and diaphragm cycle count are accessible via diagnostic registers in Modbus-compatible configurations. When deployed in FDA-regulated workflows, the pump may be validated as a Class I ancillary device—its operational parameters documented within instrument qualification protocols (IQ/OQ/PQ) and aligned with 21 CFR Part 11 requirements through traceable electronic records generated by the host control system.

Applications

• Gas supply and evacuation for GC, HPLC degassers, and mass spectrometer inlet systems
• Vacuum generation in portable emissions analyzers (e.g., NO_x, CO, THC measurement units)
• Sample aspiration and filtration in environmental monitoring stations and water quality analyzers
• Pressure/vacuum actuation in microfluidic platforms and diagnostic cartridge readers
• Secondary vacuum source in fuel cell test benches and hydrogen purity verification setups
• Medical device integration—including wound therapy systems, dental suction units, and lab automation fluid handlers

FAQ

Can the N938 pump condensable vapors?
It is not recommended for sustained pumping of condensable vapors without cold traps or coalescing filters, as accumulation may impair diaphragm flexibility and valve sealing.
Is the N938 suitable for use in explosion-hazardous areas?
No—standard N938 models lack ATEX or IECEx certification. Intrinsically safe variants require factory customization and separate certification documentation.
What is the expected service life under continuous operation?
Rated for ≥20,000 hours of operation when operated within specified ambient and duty-cycle limits; no scheduled maintenance is required, though periodic visual inspection of inlet filters is advised.
Does KNF provide application-specific validation support?
Yes—KNF’s global engineering team offers technical consultation, compatibility testing reports, and OEM documentation packages aligned with ISO 13485, IATF 16949, or ISO 9001 frameworks upon request.
Can the pump be mounted in any orientation?
Yes—fully orientation-independent operation is supported, including inverted or horizontal mounting, provided adequate ventilation and unrestricted exhaust path are maintained.