Face-to-Face Double Cartridge Multi-Spring Mechanical Seal

Product Overview; 

The DC660 is a heavy‑duty face‑to‑face double cartridge multi‑spring mechanical seal engineered for centrifugal and API process pumps, mixers, agitators and other critical rotating equipment operating with hazardous, corrosive, volatile, abrasive and environmentally sensitive process fluids. In this face‑to‑face dual‑seal configuration, two balanced mechanical seals are arranged with their faces opposing each other and operated with a pressurised or unpressurised barrier/buffer fluid system, providing enhanced reliability, thermal stability and superior leakage containment under severe operating conditions. 

 

The face‑to‑face arrangement optimises pressure distribution across both seal sets, creating a stable sealing environment and effective leakage control on the process and atmospheric sides of the seal chamber. This configuration is particularly suited to applications involving hazardous or high‑pressure media, where process integrity, equipment protection and emission reduction are critical. 

 

The DC660 features a cartridge‑mounted construction with the seals pre‑assembled on a sleeve and gland plate, allowing the complete unit to be installed over the pump shaft or sleeve in a conventional stuffing box, regardless of pump make. Factory preset working length minimises installation errors and ensures precise axial positioning, while the cartridge design simplifies handling, enabling quick installation and easy removal that reduce maintenance time and the need for highly skilled labour. 

 

A multi‑spring distributed loading system provides uniform face loading and stable dynamic behaviour, maintaining reliable operation under fluctuating pressures, vibration, thermal distortion and shaft movement. Combined with hydraulically balanced face geometry and suitable barrier/buffer fluid systems, this delivers excellent heat dissipation, controlled leakage and extended seal life in continuous‑duty service. 

 

The DC660 is ideally suited for chemical processing, refinery and petrochemical plants, pulp and paper mills, pharmaceutical production, mining and steel facilities, slurry‑handling systems and wastewater treatment plants where dependable sealing performance, reduced emissions and high equipment uptime are mandatory. Its rugged, high‑integrity design offers an efficient, durable and safety‑focused sealing solution for the most demanding industrial process applications. 

 

Key Features; 

• High resistance to pressure transients, vibration and shaft deflection, maintaining stable sealing performance in demanding operating conditions. 

• Available in both metric and inch shaft sizes, ensuring compatibility with a wide range of pump specifications and international design standards. 

• Bi‑directional operation, independent of shaft rotation direction, allowing versatile use across different pump types and rotating‑equipment configurations. 

• Springs located outside or isolated from the process fluid path to resist clogging and corrosion, improving reliability in contaminated, viscous or particulate‑laden services. 

• Face‑to‑face double cartridge mechanical seal providing enhanced thermal control and reliable leakage containment for hazardous, toxic, crystallising and abrasive process media. 

• Cartridge construction – factory assembled and tested, supplied as a preset unit for quick installation and easy removal, minimising setting errors, downtime and the need for highly skilled labour. 

• Provision for flushing and quench connections, fully compatible with API 682 dual‑seal support systems including Plans 52, 53A, 53B and 54, to optimise cooling, lubrication and environmental containment. 

• Hydraulically balanced double‑seal design with rotating multi‑spring / wave‑spring loading ensures uniform face pressure distribution, reduced heat generation and extended seal life under varying pressures and temperatures. 

• Customisable metallurgy and elastomer combinations available to handle aggressive chemicals, hydrocarbons, slurries and other severe‑duty services while supporting reduced fugitive emissions and improved environmental compliance. 

 

Service Overview; 

Parameter	Value
Equipment	API process pumps, centrifugal pumps, mixers, agitators, compressors, rotary equipment
Fluid	Hydrocarbons, chemicals, solvents, slurry, acids, wastewater, viscous fluids
Service Nature	Corrosive, hazardous, abrasive, high-temperature, volatile fluids
Operating Mode	Continuous-duty industrial operation with barrier/buffer fluid support

 

Specifications; 

Item	Min	Max	Typical / Notes
Shaft Size	20 mm (0.750”)	300 mm (12.000”)	Larger sizes available on request
Pressure	Vacuum	40 bar (580 psi)	Depending on seal arrangement & materials
Temperature	-40°C (-40°F)	+220°C (+428°F)	Based on elastomer selection
Speed	—	3600 RPM	Higher speeds available for specific designs

 

Materials; 

Component	Standard Material	Optional Material	Comment
Seal Faces	Carbon vs Silicon Carbide	Silicon Carbide vs Tungsten Carbide	Selected based on fluid abrasiveness
Elastomers	FKM (Viton)	EPDM / FFKM / PTFE	Application-specific compatibility
Metal Parts	SS 316	Duplex SS / Hastelloy / Alloy 20 / Titanium	Corrosion-resistant construction
Springs	SS 316	Hastelloy C	Isolated multi-spring design

 

Applications; 

• Pulp and paper stock pumps 

• Power plant auxiliary systems 

• Food and beverage processing systems 

• API process pumps and refinery pumps 

• Sugar and distillery process applications 

• Steel and mining slurry handling systems 

• Water and wastewater treatment facilities 

• Chemical and fertilizer manufacturing plants 

• Pharmaceutical and hygienic process equipment 

• Petrochemical and hydrocarbon processing units 

• Agitators, mixers, and reactor circulation systems 

 

Operating Limits; 

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

 

Engineering Note; 

Operating parameters shown are typical industrial values for double cartridge multi-spring mechanical seals and should be verified against the actual application duty conditions, fluid characteristics, seal support plan, and equipment configuration before final selection.