Description
The DD910 is a double dry running mechanical seal engineered for hygienic and sterile rotating equipment where leakage control, contamination prevention, and cleanability are critical. Its dual-face arrangement operates with a clean, dry barrier gas such as nitrogen or sterile air, helping prevent atmospheric contamination from entering the vessel while minimizing product-side leakage during critical batch operations.
Designed for fermenters, bioreactors, aseptic mixers, API manufacturing reactors, and food-grade process vessels, the DD910 supports CIP/SIP operating philosophies, sterile containment, and low-maintenance operation. The seal is suitable for top-entry and side-entry agitators handling culture media, sterile process fluids, vapours, and sensitive pharmaceutical or biotechnology products where cleanliness, reliability, and batch integrity are essential.
All product-contact surfaces are finished to a high polish to reduce surface roughness, minimize microbial retention, and improve cleanability. A baffle arrangement in the gland helps prevent dislodged carbon particles from entering the media, supporting product purity. The gland and housing are equipped with dedicated ports for steam sterilization and CIP/SIP processes, and may be configured for steam jacket or cold-water circulation where thermal control is required.
The inboard seal is a self-closing reverse-balance design that remains sealed even under pressure fluctuations. The seal system is also designed to prevent ingress of external air into the vessel, even if the inboard seal is compromised, while a nitrogen buffer/barrier gas between the seal faces helps maintain an aseptic environment and stable pressure balance.
Technical Key Features
- Double dry-running seal design for sterile, gas-buffered operation without the risk of liquid barrier contamination.
- Barrier gas pressurization using nitrogen or sterile compressed air, typically set about 2 bar (29 psi) above vessel pressure.
- Reverse-balanced inboard seal with self-closing action to maintain sealing under reverse pressure conditions.
- Low-friction dry-running face combination designed for stable operation under low-speed agitator conditions.
- Mirror-finished wetted surfaces minimize bacterial retention and support hygienic compliance.
- Baffle protection traps potential loose carbon particles and helps prevent media contamination.
- Steam and CIP/SIP ports in the gland allow integration with sterilization and clean-in-place systems.
- Steam-jacketed housing enables heating of the seal chamber to prevent condensation and support sterilization.
- Optional cold-water circulation ports to dissipate heat during operation.
- Hygienic construction with SS 316L wetted hardware and cleanable geometry.
- Compact cartridge-style assembly for reduced installation error and repeatable maintenance.
- Application-specific elastomer selection for steam, cleaning chemicals, and process media.
Service Overview
| Parameter | Value |
|---|---|
| Equipment | Fermenters, bioreactors, hygienic mixers, API reactors, sterile process vessels |
| Fluid | Culture media, sterile process liquids, vapours, food-grade fluids, pharmaceutical intermediates |
| Service Nature | Hygienic, sterile, aseptic, dry-running, gas-buffered sealing duty |
| Operating Mode | Batch or continuous low-speed mixing with CIP/SIP cleaning and sterile barrier gas support |
Specifications
| Item | Min | Max | Typical / Notes |
|---|---|---|---|
| Size | 25 mm / 1.000” | 300 mm / 12.000” | Selected to agitator shaft diameter |
| Pressure | Full vacuum | 10 bar (145 psi) | Depends on configuration; barrier gas set above vessel pressure |
| Temperature | -20°C (-4°F) | +180°C (+356°F) | With steam jacket; without jacket, limit set by elastomer selection |
| Speed | — | 140 rpm | Low-speed agitator duty; sliding velocity approx. 2.2 m/s (7.2 ft/s) at 300 mm |
Materials
| Component | Standard Material | Optional Material | Comment |
|---|---|---|---|
| Seal Faces | Carbon (food grade) vs Silicon Carbide | Silicon Carbide vs Silicon Carbide, Tungsten Carbide | Face pairing selected for dry-running and hygienic duty |
| Elastomers | FKM (FDA grade) / EPDM | PTFE, Kalrez (FFKM) | Selected for CIP/SIP, steam and chemical compatibility |
| Hardware | SS 316 / SS 316L | Hastelloy B & C, Alloy 20 | SS 316L preferred for pharmaceutical and food-grade wetted parts |
Applications
- Pharmaceutical fermenters and sterile production vessels.
- Biotechnology bioreactors and cell-culture processing systems.
- API manufacturing reactors and intermediate process vessels.
- Aseptic mixing systems for sterile liquids and suspensions.
- Food-grade mixing vessels and hygienic batch reactors.
- Top-entry and side-entry agitator drives in cleanroom process areas.
- CIP/SIP-compatible hygienic equipment requiring dry gas-buffered sealing.
Operating Limits
| Parameter | Value |
|---|---|
| Pressure | Full vacuum to 10 bar (145 psi), depending on configuration |
| Temperature | -20°C to +180°C (-4°F to +356°F), with steam jacket |
| Speed | Up to 140 rpm |
| Size Range | 25 mm to 300 mm / 1.000” to 12.000” (inch series) |
