I. Basic Parameters of DN200 Force Transfer Joint

II. Core Functions and Application Scenarios

• Functional Principle:
  Fix flanges to pipes via bolts, and use force transfer screws to transmit pipeline thrust to the entire system, preventing displacement, leakage or damage to the joint caused by medium pressure or thermal expansion/contraction.
• Typical Scenarios:
  • Inlet/outlet of water pumps, valve connections (to eliminate vibration stress);
  • Long-distance water/gas transmission pipelines (to balance axial thrust);
  • Water supply and drainage systems in high-rise buildings (to resist water pressure impact).

III. Correct Installation Steps (Preventing Leakage and Stress Damage)

• Check integrity of components: flanges, sealing rings, force transfer screws, nuts, limit bolts, etc.;
• Grind pipe end faces: remove burrs and welding slag to ensure flat flange sealing surfaces (roughness ≤12.5μm).

• Axial position: The natural length of the joint should be consistent with the pipeline spacing, and forced stretching or compression is prohibited (allowable deviation ±3mm);
• Flange parallelism: Use a feeler gauge to detect the spacing between two flanges, with a maximum deviation ≤1mm (DN200 standard).

• Bolt material: 8.8-grade galvanized bolts (corrosion-resistant), with length ensuring 2-3 threads exposed after nut tightening;
• Tightening sequence: Tighten diagonally and crosswise (as shown), gradually reaching the rated torque in 3 steps (reference value: M20 bolt torque 180-220N·m).

1. Adjustment of Limit Devices
   • After installation, loosen the limit bolt nuts, reserve a 10mm axial clearance, then lock the lock nuts;
   • If system pressure >1.6MPa, install additional limit supports (spacing ≤3 times pipe diameter).

IV. Key Selection Parameters and Precautions

• Medium Compatibility:
  • Water system: Select EPDM rubber sealing ring (temperature resistance -20℃~120℃);
  • Oil/acid-base media: Switch to NBR or fluororubber sealing rings (medium composition needs to be specified).
• Temperature Difference Compensation Calculation:
  Example: For a DN200 carbon steel pipeline with a temperature difference of 50℃, the thermal expansion amount ΔL=12×10⁻⁶×L×50 (L is pipeline length). If L=50m, ΔL=30mm, ensuring the force transfer joint is used in conjunction with a compensator.
• Adaptation to Special Working Conditions:
  • Buried installation: Flanges need anti-corrosion treatment (such as epoxy resin coating) with additional protective casings;
  • Vibrating environment: Install spring washers at screw connections and check bolt tightness quarterly.

V. Common Failures and Solutions

VI. Maintenance Specifications

1. Regular Inspection Cycles:
   • Within the first 3 months of operation: Check bolt torque monthly;
   • After normal operation: Inspect sealing ring aging condition semi-annually (replace if cracks >2mm).
2. Anti-corrosion Treatment:
   • For outdoor installation, paint flange surfaces with anti-rust paint every 1-2 years (iron red primer + aluminum powder topcoat);
   • For seawater environments: Switch to 316L stainless steel flanges and screws.

VII. Industry Standards and Selection References

• Execution standard: GB/T 12465-2017 Loose Sleeve Expansion Joints for Pipeline;
• Selection tool: Refer to the following table based on system pressure, medium temperature and installation method (overhead/buried):

  Working Condition Type	Recommended Model	Additional Configurations
  Municipal water supply/drainage	VSSJAF(C2F) force transfer joint	Anti-pull-off limit device
  Thermal pipeline network	VSSJA-2(B2F) double-flange force transfer joint	High-temperature silicone sealing ring (temperature resistance 180℃)