Single Dry Mechanical Seal

Description; 

The SD900 Single Dry Mechanical Seal is a compact, externally mounted dry-running mechanical seal engineered for rotary equipment handling non-toxic, non-hazardous, and clean process media. Its single-seal arrangement provides dependable shaft sealing where liquid lubrication or continuous flush support is not preferred, making it suitable for agitators, mixers, reactors, and selected blower applications. 

 

Designed for chemical, petrochemical, pharmaceutical, and food & beverage environments, the SD900 uses precision-lapped seal faces, corrosion-resistant hardware, and compatible elastomeric secondary seals to support stable operation under moderate pressure, temperature variation, and intermittent process duty. The dry-running configuration helps reduce utility consumption, simplify installation, and minimize the risk of product dilution and contamination. 

 

Dry mechanical seals are especially suited to top-driven applications such as agitators, reactors, mixers, reaction vessels, and blowers, where the shaft is typically positioned at the top of the vessel. These seals operate without liquid lubrication, as the sealing faces are exposed only to process gases or vapours, eliminating the need for quenching or external supply systems. The externally mounted, rotating, multiple spring-loaded design on the atmospheric side provides reliable performance in gas-phase environments, while available non-cartridge, semi-cartridge, and cartridge configurations can be selected to match installation and maintenance requirements. 

 

By eliminating the need for auxiliary systems such as barrier fluid or cooling units, the SD900 significantly reduces maintenance complexity and the risk of contamination, making it a practical sealing solution for sensitive process applications across the chemical, pharmaceutical, and food industries. 

 

 

Technical Key features; 

• Precision seal face pairing for controlled leakage and stable dry-running performance. 

• Simplified installation and maintenance to minimize downtime and reduce service costs. 

• Balanced and unbalanced designs available to suit varying pressure and process conditions. 

• Single dry-running seal design for services where external liquid flushing is limited or undesirable. 

• Low-maintenance operation with simplified installation and reduced auxiliary piping requirements. 

• Top and side entry compatibility for broad installation flexibility across different equipment layouts. 

• Elastomer compatibility options to meet temperature, cleaning, and chemical resistance requirements. 

• Factory assembled and tested for consistent quality, reliable performance, and readiness for installation. 

• No cooling or lubrication required in the seal cavity, reducing system complexity and operating overhead. 

• Compact construction suitable for agitators, mixers, reactors, and other space-restricted rotary equipment. 

• Cost-effective with rapid delivery to provide a practical balance of performance, affordability, and lead time. 

• Application-specific customization available for shaft size, gland design, face materials, and mounting configuration. 

• Corrosion-resistant metallic hardware for chemical, pharmaceutical, petrochemical, and food-grade environments. 

• Single-seal configuration for dependable dry-running performance without the complexity of dual-seal arrangements. 

• Externally mounted design for easy inspection, operation, and maintenance without disassembling the process equipment. 

• Optional bearing assembly available with or without an integrated bearing to suit mechanical load and alignment requirements. 

• Flexible construction options available in non-cartridge, semi-cartridge, and cartridge formats to match installation preferences. 

• Directionally independent operation for reliable performance regardless of shaft rotation direction, improving installation flexibility. 

• Rotary multi-spring mechanism ensures uniform axial load on the sealing faces, supporting stable performance and extended seal life. 

 

 

Service Overview; 

Parameter	Value
Equipment	Agitator, mixer, reactor, blower, dry process rotary equipment
Fluid	Non-toxic media, clean process vapors, light chemical media, food-grade process fluids
Service Nature	Dry-running, non-toxic, non-hazardous, moderate-duty process sealing
Operating Mode	Batch or continuous operation, low-to-moderate pressure duty

 

 

Specifications; 

Item	Min	Max	Typical / Notes
Size	20 mm (0.750”)	300 mm (12.000”)	Custom sizes available on request
Pressure	Vacuum	6 bars (87 psi)	Suitable for moderate-pressure non-toxic service
Temperature	-20°C (-4°F)	+180°C (+356°F)	Depends on elastomer and face combination
Speed	—	3,000 rpm / 25 m/s (4,920 fpm)	Final limit depends on shaft diameter and equipment type

 

 

Materials; 

Component	Standard Material	Optional Material	Comment
Seal Faces	Carbon vs Silicon Carbide	Silicon Carbide vs Silicon Carbide / Tungsten Carbide	Selected based on dry-running duty and media compatibility
Elastomers	FKM / EPDM	PTFE / FEP-encapsulated FKM	Based on temperature, cleaning fluids, and chemical exposure
Metal Parts	SS 316	SS 304 / Hastelloy / Alloy 20	SS 316 preferred for chemical and hygienic service
Springs & Drive Parts	SS 316	Hastelloy C / Alloy Steel	Selected for corrosion severity and operating environment

 

 

Applications; 

• Pharmaceutical mixing and blending equipment. 

• Non-toxic vapor or light chemical media sealing applications. 

• Food and beverage process mixers, reactors, and batch vessels. 

• Chemical industry agitators and mixers handling non-toxic media. 

• Petrochemical reactors and process vessels with clean or light-duty service. 

• Blowers and low-pressure rotary equipment in clean process environments. 

• Dry-running rotary equipment where flush liquid contamination must be avoided. 

 

 

Operating Limits; 

Parameter	Value
Pressure	Vacuum to 6 bars (87 psi)
Temperature	-20°C to +180°C (-4°F to +356°F)
Speed	Up to 3,000 rpm / 25 m/s (4,920 fpm)
Size Range	20 mm to 300 mm (0.750” to 12.000”)

 

 

Engineering Note; 

Operating limits and material selections are inferred standard values for a single dry mechanical seal configuration. Final selection should be verified against actual media, shaft speed, vessel pressure, temperature, runout, and any hygienic or regulatory requirements.