GRUNDFOS NK Horizontal Single-Stage End-Suction Pump (Split-Coupled)
1. Versatile Design
Wide Range of Applications: Suitable for five key areas: water supply, industrial pressure boosting, industrial liquid transfer, HVAC (heating, ventilation, and air conditioning), and irrigation. Specific applications include municipal waterworks, high-rise building pressure boosting, industrial cleaning systems, boiler feed, and district heating.
2. High Efficiency and Energy Saving
Optimized Hydraulic Performance: Features a hyperbolic closed impeller with a smooth surface to ensure efficient operation; impellers undergo both static and hydraulic balancing.
Energy Efficiency Ratings: Complies with the EU EuP Directive (EC No 547/2012); most pumps are classified by the Minimum Efficiency Index (MEI), with some models achieving the IE5 ultra-high efficiency rating (equipped with MGE permanent magnet motors).
3. Structural Features
Modular Design: Back-pull-out construction allows for maintenance without dismantling the pump casing or piping; a single person can perform maintenance with the aid of lifting equipment.
Double Volute Design (Selected Models): Extends the service life of seals and bearings, thereby reducing lifecycle costs.
Diverse Materials: Pump casings are available in cast iron (EN-GJL-250) or ductile iron (EN-GJS-500-7); impellers are available in stainless steel (1.4308/1.4408) or duplex stainless steel (1.4517) to suit various liquid media.
4. Flexible Configuration
Motor Options:
Standard Motors: IE3/IE4 efficiency; available in 2-pole, 4-pole, and 6-pole configurations.
Variable Frequency Motors (NKE Series): Integrated MGE permanent magnet motor (IE5) with a built-in frequency converter; supports constant pressure, proportional pressure, temperature, and flow control modes.
Flange Compatibility: Complies with EN 1092-2 standards; offers PN10/16/25 pressure ratings and supports DIN, ANSI, and JIS flange types.
5. Intelligent Control
Variable Frequency Function: Speed regulation via Grundfos CUE or a built-in variable frequency drive (VFD) adapts to dynamic operating conditions, achieving energy savings of up to 70%.
Communication Interfaces: Supports LON, PROFIBUS, Modbus, and BACnet protocols; enables integration with central management systems or monitoring via the Grundfos GO mobile app.
6. Reliability and Ease of Maintenance
Mechanical Seal: Complies with EN 12756 standards; offers material options such as EPDM and FKM, suitable for liquid temperatures ranging from -25°C to +140°C.
Bearing Design: Features lifetime-lubricated bearings or re-greasable heavy-duty bearings; selected models are equipped with insulated bearings for compatibility with VFD operation.
Testing and Certification: Static high-pressure testing up to 1.5× PN; performance testing complies with ISO 9906:2012 Grade 2B tolerances.
7. Customized Services
Special Requirements: Custom solutions available, including bare-shaft pumps, extended couplings, explosion-proof certification (ATEX), and corrosion-resistant materials.
8. Environmental Protection and Compliance
Low Noise: Optimized sound pressure levels; minimum 55 dB(A) for 2-pole motors.
RoHS Certification: Complies with Chinese environmental regulations.
Typical Model Examples
NK 32-180: Cast iron pump casing, 1.1 kW motor, center discharge; suitable for small-to-medium flow water supply systems.
NKE 65-225: Variable frequency pump with built-in sensors and intelligent control capabilities; suitable for HVAC circulation systems.




