Unbalanced Multi-Spring Cartridge Mechanical Seal

Description; 

The SC625 is a robust single cartridge mechanical seal featuring an unbalanced design engineered for reliable sealing performance in general industrial and process applications. Designed as a pre-assembled cartridge unit, the seal minimizes installation errors, simplifies maintenance procedures, and delivers dependable sealing performance across a broad range of rotating equipment. Its compact architecture and rugged construction make it suitable for moderate-pressure applications involving clean fluids, light hydrocarbons, utility services, and non-critical chemical duties. 

 

Built for continuous industrial operation, the SC625 mechanical seal is suitable for centrifugal pumps, process pumps, mixers, agitators, industrial blowers, and auxiliary rotary equipment operating in chemical processing, food and beverage production, pharmaceutical plants, steel mills, mining facilities, pulp and paper mills, power stations, solvent recovery systems, and water treatment installations. The seal design combines operational simplicity, cost-effectiveness, and maintenance efficiency while maintaining reliable leakage control and equipment protection under demanding service environments. 

 

 

Key Features & Design Attributes; 

🔧 Construction & Installation 

• Interchangeable cartridge format — supports direct retrofit onto existing equipment, enabling like-for-like replacement without re-engineering the pump assembly. 

• Compact dimensional envelope — designed to fit within confined pump housing geometries without shaft or housing modification in standard Grundfos applications. 

• Single cartridge construction — factory assembled and tested to precise dimensional tolerances, eliminating the need for in-field setting and reducing installation error to a minimum. 

• Pre-assembled, factory-set unit — arrives ready for fitment, significantly reducing installation time and minimizing maintenance downtime across scheduled and unscheduled service intervals. 

 

⚙️ Mechanical & Sealing Design 

• Unbalanced seal design suitable for general-purpose industrial applications. 

• Robust spring-loaded rotary face assembly — maintains reliable face contact under dynamic operating conditions including vibration, shaft deflection, and minor misalignment. 

• Multiple and wave spring arrangement — delivers uniform axial load distribution across the full 360° sealing face, ensuring consistent face tracking and minimising the risk of localised wear or face distortion. 

• Internal seal arrangement — the sealing interface operates within the pumped fluid environment, providing inherent lubrication of the seal faces, improved pressure management, and protection against external contamination ingress. 

 

🔄 Operational Flexibility 

• Available in metric and inch shaft sizes — ensures global dimensional compatibility and supports both OEM and retrofit applications across international industrial standards. 

• Broad fluid and service compatibility — suitable for reliable operation across a comprehensive range of industrial process fluids, utility liquids, and chemically treated streams. 

• Bidirectional shaft rotation compatibility — fully independent of clockwise or counter-clockwise shaft rotation, supporting installation across a wide range of pump and drive configurations without design modification. 

• Optional flush and quench connections — seal housing can be supplied with or without auxiliary fluid connections, providing application-specific flexibility for services requiring face cooling, external lubrication, or secondary containment flushing. 

 

🛡️ Reliability & Lifecycle Performance 

• Continuous-duty rated — engineered and validated for sustained, uninterrupted operation in industrial rotating equipment applications. 

• Low maintenance requirement profile — the factory-set, pre-tested cartridge design reduces the frequency and complexity of planned maintenance interventions, supporting improved equipment availability. 

• Reduced shaft sleeve wear — the cartridge seal arrangement eliminates the dynamic contact associated with conventional compression packing, preserving shaft surface integrity and extending pump service life. 

• Refurbishment capability — the SC625 is designed to support component-level refurbishment, extending effective seal service life and delivering a lower total cost of ownership compared with single-use alternatives. 

 

🧪 Material & Configuration Options 

• Multiple metallurgy combinations — seal hardware is available in a range of metallic alloy options to match corrosion resistance requirements for specific service fluids and environments. 

• Multiple face material pairings — rotary and stationary face material combinations are selectable to optimise tribological performance, thermal resistance, and service life for the target application. 

• Multiple elastomer combinations — secondary sealing elements are available in a range of elastomeric compounds, selectable to suit fluid chemistry, temperature range, and regulatory compliance requirements. 

 

Service Overview; 

Parameter	Value
Equipment	Centrifugal pumps, process pumps, blowers, mixers, agitators, rotary equipment
Fluid	Chemical fluids, water, hydrocarbons, solvents, light slurry, utility fluids
Service Nature	General industrial process service
Operating Mode	Continuous duty
Installation	Cartridge-mounted mechanical seal

 

Specifications; 

Item	Min	Max	Typical / Notes
Shaft Size	20 mm (0.750”)	300 mm (12.000”)	Metric & imperial sizes available
Pressure	—	40 bar (580 psi)	Typical unbalanced cartridge limit
Temperature	-20°C (-4°F)	+220°C (+428°F)	Depends on elastomer selection
Speed	—	3600 RPM	Application dependent
Seal Type	—	—	Single cartridge, unbalanced
Spring Design	—	—	Multiple spring arrangement

 

Materials; 

Component	Standard Material	Optional Material	Comment
Seal Faces	Carbon / Silicon Carbide	Tungsten Carbide / Silicon Carbide	Service dependent face pairing
Elastomers	FKM (Viton)	EPDM / PTFE / FFKM	Based on chemical compatibility
Metal Parts	SS 304 / SS 316	Duplex SS / Hastelloy / Alloy 20	Corrosion resistance options
Springs	SS 316	Hastelloy	For corrosive or aggressive fluids

 

Applications; 

• Rotary utility equipment 

• Chemical process pumps 

• Pulp and paper stock pumps 

• Industrial blowers and mixers 

• Oil and gas auxiliary equipment 

• Pharmaceutical process systems 

• Chilling and refrigeration systems 

• Petrochemical and refinery pumps 

• Steel and mining process equipment 

• Solvent recovery and transfer systems 

• Water and wastewater treatment pumps 

• Food and beverage processing equipment 

 

 

Operating Limits; 

Parameter	Value
Pressure	Up to 40 bar (580 psi)
Temperature	-20°C to +220°C (-4°F to +428°F)
Speed	Up to 3600 RPM
Size Range	20 mm to 300 mm (0.750” to 12.000”)

 

Engineering Note: Certain operating parameters, metallurgy combinations, and performance limits have been inferred using standard industrial practices for single cartridge unbalanced mechanical seals. Final selection should be verified against actual process conditions, fluid properties, shaft dynamics, and equipment operating parameters prior to manufacture or installation.