YanShan Shunlinfeng Pipeline Manufacturing Co., Ltd.
Product Description
Standard
Product introduction
High-Pressure Threaded Pipe Couplings (Screwed Unions) – Technical Specification
1. Product Definition
A high-pressure threaded pipe coupling (screwed union) is a mechanical pipe connector designed to join two pipes in a straight run using precision-cut threads for systems operating at 1,000–10,000 psi. These fittings provide a separable joint while maintaining pressure integrity in critical applications where welding is impractical.
2. Design Features
✔ Heavy-Duty Threads: Rolled or machined threads with 30% deeper engagement than standard couplings for high-pressure resistance.
✔ Metal-to-Metal Seal: Tapered threads (NPT/BSPT) create a mechanical seal under tension.
✔ Hex Nut Design: Allows wrench tightening without damaging the pipe.
✔ Anti-Blowout Shoulder: Reinforced collar prevents thread stripping under extreme pressure.
✔ Optional Sealing Methods:
- PTFE tape (for NPT threads up to 3,000 psi)
- Liquid thread sealant (Loctite 545 for >5,000 psi)
- Metal sealing rings (for BSPP parallel threads)
3. Performance Advantages
- Quick Installation: No welding required—suitable for field repairs.
- Reusability: Can be disassembled and reassembled multiple times.
- Vibration Resistance: Thread-locking compounds prevent loosening in dynamic systems.
- Space Efficiency: More compact than flanged connections.
4. Installation Guidelines
1. Thread Preparation:
- Clean threads with a wire brush.
- Apply 2–3 wraps of PTFE tape (for NPT) or high-pressure sealant (e.g., Henkel 577).
2. Hand-Tightening:
- Engage threads fully by hand (minimum 3.5 turns for NPT).
3. Final Torque:
- Use a strap wrench to avoid thread damage.
- Tighten 1.5 turns past hand-tight (per ASME B31.3).
4. Pressure Testing:
- Hydro-test at 1.5× working pressure before full operation.
5. Industry Applications
- Oil & Gas: Wellhead control lines, hydraulic fracturing manifolds.
- Power Plants: Steam instrumentation lines.
- Chemical Processing: High-pressure reagent dosing systems.
- Aerospace: Fuel and hydraulic test rigs.
6. Quality & Compliance
- Material Certs: ASTM A105/A182 with 3.1 mill test reports.
- Thread Inspection: 100% GO/NO-GO gauge verification.
- Pressure Testing: Each unit hydro-tested per ASME B16.11.
- NACE MR0175: Compliant for sour (H₂S) environments.
7. Limitations
✗ Not for Cyclic Loading: Threads may fatigue under constant vibration.
✗ Limited to Small Pipes: Generally not used above 2" NPS for high-pressure.
✗ Sealant Dependency: Requires proper sealing to prevent leaks.
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Company Address:Yanshan County,Cangzhou City,Hebei Province,China
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