Multi Spring Semi-Cartridge Mechanical Seal for HDD Machine

• Description: 

The SSC695 is a single, hydraulically balanced, semi-cartridge mechanical seal specifically engineered for abrasive slurry, dirty water, and horizontal directional drilling (HDD) applications. It is particularly suited for rotary joints and swivels in HDD rigs, where sealing integrity must be maintained under fluctuating pressure, vibration, and shaft misalignment. 

 

This non-clogging slurry seal is supplied as a factory-assembled, pre-set unit consisting of a seal head, sleeve, and gland, eliminating on-site setting measurements and minimizing alignment and installation errors. The semi-cartridge design ensures consistent installation quality and simplifies maintenance, supporting quick seal replacement to reduce downtime in demanding trenchless operations. 

 

In typical HDD service, the SSC695 is mounted in the rotary joint or swivel that transmits drilling fluid while the drill string rotates, providing reliable sealing performance in road-crossing cable ducts, pipe-jacking, and other trenchless installations where operational reliability is critical. The hydraulically balanced, rugged construction—combined with slurry-duty face materials—maintains stable face loading, reduces heat generation, and delivers extended seal life in erosive, particle-laden environments. 

 

A multi-spring configuration distributes load uniformly across the seal faces, enhancing face stability and resistance to distortion at higher speeds. This arrangement helps prevent spring clogging and improves performance in services involving low solids, crystallizing media, and suspended particles, ensuring dependable operation across a wide range of contaminated fluid conditions. 

 

• Key Features: 

• Available in metric and inch sizes. 

• Single, balanced mechanical seal design. 

• Independent of the direction of rotation. 

• Factory tested for reliability before dispatch. 

• Non-clogging design suitable for slurry service. 

• Multi-spring arrangement for stable face loading. 

• Suitable for rotary joints/swivels in HDD machines. 

• Quick installation and easy removal (reduced downtime). 

• Semi-cartridge construction (pre-set, factory assembled). 

• Designed for cost-effective maintenance and long service life. 

 

• Service Overview: 

Parameter	Value
Seal Type	Single, Semi-Cartridge, Multi-Spring
Typical Service	HDD drilling fluid, slurry, dirty water
Equipment	Rotary joints, swivels, HDD rigs
Fluid Characteristics	Abrasive, low solids, crystallising media
Operating Mode	Continuous/intermittent duty
Installation	Pre-assembled, no field setting required

 

 

• Technical Specifications 

Item	Min	Max	Typical / Notes
Shaft Size	20 mm	150 mm	Standard range
Pressure	—	40 bars	HDD / slurry service
Temperature	-50°C	+220°C	Depends on the elastomer
Speed	—	2900 RPM	Typical HDD rotation range
Balance Type	—	—	Hydraulically balanced
Seal Arrangement	—	—	API Arrangement 1 equivalent

 

 

• Materials of Construction 

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

 

• Applications 

• Chemical processing industries 

• General industrial slurry services 

• Crystallization processes (low solids) 

• Construction and trenchless technology 

• Steel plants and slurry handling systems 

• Rotary joints/swivels handling drilling fluids 

• Horizontal Directional Drilling (HDD) machines 

 

• 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
Shaft Size	20 mm to 150 mm (0.750” to 6.000”)

 

 

• Engineering Notes & Selection Rationale 

• Multi-spring configuration avoids clogging compared to single large spring designs in slurry service. 

• Ensure adequate flushing (API Plan 32 equivalent) if the solids tendency increases beyond recommended limits. 

• Hard vs hard face combination (SiC/TC) is recommended to withstand abrasive drilling fluids and extend seal life. 

• Semi-cartridge design minimizes installation errors, which is critical in field HDD operations where alignment control is limited. 

• For higher solids (>5–7%) or severe abrasion, a dual seal (API Arrangement 2/3) with flush/barrier fluid should be evaluated.