Wave Spring Semi-Cartridge Mechanical Seal for HDD Machine & Slurry Service

• Description 

The SSC690 is a single, semi‑cartridge, wave‑spring mechanical seal engineered specifically for abrasive slurries and dirty water duties in HDD rotary joints and swivels. Supplied as a factory‑assembled, pre‑set cartridge, it minimizes installation errors and ensures repeatable performance under vibration, pressure transients, and angular or radial misalignment. The compact wave‑spring arrangement reduces axial space requirements, making the seal well-suited to confined rotary joint envelopes and compact equipment layouts. Hydraulically balanced geometry, in combination with hard, slurry‑resistant face materials, provides controlled face loading, reduced heat generation, and extended seal life in highly erosive and contaminated fluid environments. 

 

In horizontal directional drilling (HDD) applications, the SSC690 mechanical seal is installed in the rotary joint or swivel that transfers drilling fluid while the drill string rotates, providing reliable sealing under fluctuating pressure, vibration, and shaft misalignment. The hydraulically balanced, heavy‑duty design, combined with slurry‑duty seal faces and robust spring loading, maintains stable face contact and maximizes service life in demanding trenchless construction operations such as road‑crossing cable ducts, pipe jacking, and other HDD installations where reliability and rapid seal replacement are critical. 

 

• Key Features 

• Factory assembled and pressure tested unit for reliability 

• Quick replacement capability is critical for HDD field operations 

• Bi-directional operation independent of shaft rotation direction 

• Non-clogging construction suitable for slurry and solids-laden fluids 

• Robust construction to withstand vibration, misalignment, and shock loads 

• Single semi-cartridge design for easy installation and reduced setting errors 

• Hydraulically balanced seal for improved stability under fluctuating pressure 

• Wave spring technology for compact axial length and consistent face loading 

 

• Typical Service Conditions 

Parameter	Value
Equipment	HDD rotary joints/swivels
Fluid	Drilling slurry, dirty water, low solids suspensions
Service Nature	Abrasive, erosive, intermittent solids
Operating Mode	Continuous with pressure fluctuations
Installation	Semi-cartridge, pre-set unit

 

 

• Technical Specifications 

Item	Min	Max	Typical / Notes
Shaft Size	20 mm (0.750”)	150 mm (6.000”)	Metric & inch sizes available
Pressure	—	40 bars	HDD slurry service
Temperature	-50°C (-58°F)	220°C (+428°F)	Depends on elastomer selection
Speed	—	2900 RPM	Typical rotary joint limit
Seal Type	—	—	Single, balanced, semi-cartridge
Spring Design	—	—	Wave spring (compact design)

 

 

• Materials of Construction 

Component	Standard Material	Optional Material	Comment
Seal Faces	Silicon Carbide	Tungsten Carbide	Abrasion-resistant pairing
Elastomers	FKM (Viton)	PTFE	Chemical & temperature compatibility
Metal Parts	SS 304 / SS 316	Hastelloy, Alloy 20, Titanium, Duplex SS	Based on corrosion severity
Springs	SS 316	Hastelloy, Alloy Steel	For corrosive slurry environments

 

 

• Applications 

• Construction and mining equipment 

• Pipe jacking and trenchless installations 

• Horizontal Directional Drilling (HDD) rigs 

• Rotary joints and swivels handling drilling fluids 

• Slurry pumps and abrasive media transfer systems 

• Crystallization processes and low solids suspensions 

 

 

• Operating Limits 

Parameter	Value
Pressure	Up to 40 bars (580 psi)
Temperature	-50°C to +220°C (-58 °F +428°F)
Speed	Up to 2900 RPM
Size Range	20 mm to 150 mm (0.750” to 6.000”)

 

 

• Engineering Notes & Selection Guidance 

• Ensure adequate flushing or dilution to prevent solids packing at seal faces. 

• Face selection should prioritize SiC vs SiC or SiC vs TC for maximum abrasion resistance. 

• For high solids or critical emission control, evaluation for dual seal (API 682 Arrangement 2/3) is advised. 

• Recommended for moderate-pressure slurry services where API Plan 11 or external flush (Plan 32) may be considered, depending on solids concentration.