Grundfos S-Series submersible sewage pumps (models 72/74/78) are heavy-duty sewage pumps designed specifically for municipal and industrial applications.

I. Structural Design and Materials

Wear-resistant materials

The pump body is made of cast iron or stainless steel. Key components such as the volute and impeller can be made of stainless steel (e.g., 1.4408 stainless steel), suitable for corrosive liquids.

The impeller features a self-cleaning channel design with long vanes to minimize clogging risks, capable of passing solid particles up to 90–145 mm in size.

Modular design

Offers multiple installation types: submersible (automatic coupling), dry vertical/horizontal, and shaft installation, adaptable to different scenario requirements.

Sealing System

Dual mechanical shaft seals (silicon carbide/silicon carbide + silicon carbide/carbon combination), the oil chamber isolates the pumping liquid from the motor, supporting bidirectional operation.

IP68 protection rating; the motor is fully enclosed and waterproof, with a standard moisture sensor to monitor for liquid ingress.

II. Intelligent Functions and Maintenance Optimization

SmartTrim Impeller Clearance Adjustment

The factory clearance can be restored via an external adjusting screw, eliminating the need to disassemble the pump and maintaining efficient operation.

SmartSeal self-coupling seal

The DN250 and above outlet flanges come standard with a sealing system that optimizes the seal between the pump and the base, reducing the risk of leakage.

Sensor Monitoring

Built-in Pt100 temperature sensor (bearings, windings), oil moisture sensor (WIO), and humidity switch for real-time monitoring of equipment status.

Optional vibration sensors (PVS3) are available to provide early warnings of mechanical faults.

III. Motor and Performance

High-efficiency motor

Power range 90-520kW, number of poles 2-12 (depending on model), insulation class F (155℃), strict temperature rise monitoring.

Explosion-proof versions comply with ATEX/IECEx standards, suitable for explosive atmospheres (Gas Group IIB, Temperature Class T3/T4).

Wide performance coverage

Head range: Extra low (Type E) to ultra-high (Type F), with flow rates suitable for various scenarios such as municipal sewage and industrial wastewater. Supports variable frequency operation (requires CUE or third-party VFD) to optimize energy consumption and flow control.

IV. Safety and Reliability

Multiple Protections

Automatic power-off protection for thermal switches (per phase) and humidity sensors (junction box/stator housing).

Explosion-proof models certified with flameproof enclosure (Ex db) and increased safety (Ex eb) protection.

Testing and Certification

Tested to ISO 9906:2012 Level 3B before shipment; 1B/1U higher acceptance levels are available as options.

Static high-pressure testing (1.5 × nominal pressure); witness testing or third-party certification available as options.

V. Application Scenarios

Municipal: Sewage treatment plants, pumping stations, and underground parking lot drainage.

Industrial applications: car wash areas, food processing wastewater, and corrosive chemical liquids.

Buildings: apartment buildings, hotels, garage rainwater drainage.

VI. Selection Support

Stainless steel versions (impeller/volute), special coatings (epoxy resin/Belzona), and custom cable lengths (10-50m) are available.

Compatible controllers (e.g., Grundfos DC dedicated controllers, LC231 level controllers) available for automated management.