The DSTI LT Series (Low Torque / Lightweight Through-Bore Series) Multi-Passage Rotary Unions, engineered and manufactured by Dynamic Sealing Technologies, Inc. (DSTI - USA), represent world-class dynamic fluid sealing technology tailored specifically for high-speed automated machinery, robotics, and clean semiconductor processing environments.

This specialized model portfolio—comprising LT-2121, LTM-2121, LT-2141, LT-2341, LT-2181, LT-2381, LT-21121, LT-23121, and the ultra-high density LT-21241—offers system builders extensive versatility, scaling seamlessly from 2, 4, 8, 12, up to an unprecedented 24 independent flow passages within a single, integrated rotary union housing:
1. Port Size Classification:
- 1/8" NPT / Rc 1/8" BSPT Group (LT-2121, LTM-2121, LT-2141, LT-2181, LT-21121, LT-21241): Features nominal 0.156" [3.96 mm] passage bore diameters, designed with an ultra-compact outer body diameter to minimize inertia and weight on robotic wrist joints and compact tooling heads.
- 3/8" NPT / Rc 3/8" BSPT Group (LT-2341, LT-2381, LT-23121): Features larger 0.375" [9.525 mm] passage bore diameters, significantly boosting pneumatic flow capacities for heavy-duty pneumatic actuators, air motors, and high-volume vacuum systems.

Key Engineering Features & Operational Advantages:
- All-Aluminum Lightweight Architecture: Precision-machined entirely from aircraft-grade aluminum alloy. Housings are protected with DSTI’s signature Blue Anodized finish for superior chemical and wear resilience, while rotating shafts are finished with Electroless Nickel (E-Nickel) plating, providing exceptional surface hardness, smooth sealing interfaces, and maximum resistance against abrasive friction.
- Proprietary Low-Torque Sealing Technology: Equipped with DSTI’s custom PTFE-based elastomeric dynamic seals, drastically reducing both breakaway torque and continuous operational drag. This prevents heat buildup, extends maintenance intervals to millions of continuous rotations, and permits the use of smaller, energy-efficient servo drives.
- Completely Isolated Media Passages: Every flow passage is physically isolated. This ensures that users can simultaneously route multiple pressure levels or entirely different media types (e.g., 90 PSI pilot air lines, -0.9 bar vacuum holding lines, and nitrogen purge lines) through a single unit without the slightest risk of cross-channel leakage.
- Central Through-Bore & Direct Slip Ring Integration: Standard models feature a central through-bore opening (0.375" to 0.440"), allowing passage of mechanical drive shafts, electrical wiring, or optical sensors. Furthermore, LT Series units are pre-engineered to mate directly with DSTI through-bore electrical slip rings, delivering a unified hybrid rotary transmission solution for fluid, electrical power, and high-speed data protocols (Ethernet, EtherCAT, Profinet).

Typical Industrial Applications:
- Multi-axis industrial robot End-of-Arm Tooling (EOAT) in automotive assembly, electronics, and aerospace manufacturing.
- High-speed automated Pick & Place equipment and semiconductor wafer handling chucks.
- Multi-station rotary indexing tables, rotary clamping pallets, and CNC fixtures.
- Rotary blow molding, bottle capping, automated labeling, and film winding machinery.

• Manufacturer: DSTI (Dynamic Sealing Technologies, Inc.)
• Origin / Country of Manufacture: USA
• Product Series: LT Series Lightweight Multi-Passage Rotary Unions (Low Torque)
• Model Breakdown & Configurations:
  - LT-2121: 2 Passages | 1/8"-27 NPT Connections | 0.375" [9.525 mm] Thru-Bore
  - LTM-2121: 2 Passages | Rc 1/8"-28 BSPT Metric Connections | 0.375" [9.525 mm] Thru-Bore
  - LT-2141: 4 Passages | 1/8"-27 NPT Connections | 0.375" [9.525 mm] Thru-Bore
  - LT-2341: 4 Passages | 3/8"-18 NPT Connections | 0.440" [11.176 mm] Thru-Bore
  - LT-2181: 8 Passages | 1/8"-27 NPT Connections | 0.375" [9.525 mm] Thru-Bore
  - LT-2381: 8 Passages | 3/8"-18 NPT Connections | 0.440" [11.176 mm] Thru-Bore
  - LT-21121: 12 Passages | 1/8"-27 NPT Connections | 0.375" [9.525 mm] Thru-Bore
  - LT-23121: 12 Passages | 3/8"-18 NPT Connections | 0.440" [11.176 mm] Thru-Bore
  - LT-21241: 24 Passages | 1/8"-27 NPT Connections | 0.375" [9.525 mm] Thru-Bore
• Maximum Operating Pressure: 600 PSI [40 BAR]
• Maximum Vacuum Rating: 30 in. Hg
• Maximum Rotational Speed: 500 RPM
• Operating Temperature Range: -18°C to 105°C [0°F to 220°F]
• Compatible Media: Clean Air, Industrial Vacuum, Inert Gases (Nitrogen, Argon) (Liquid media not recommended)
• Connection Types: Standard threaded side ports; optional shaft O-ring face seal glands for direct manifold flush mounting
• Housing Material: Aluminum with protective Blue Anodize finish
• Shaft Material: Aluminum with Electroless Nickel Plating
• Dynamic Sealing Technology: DSTI proprietary low-friction PTFE elastomeric seals
• Bearing System: Dual pre-lubricated high-precision ball bearings
• Mounting & Expansion: Integrated tapped mounting holes; fully compatible with DSTI electrical slip rings.