Coliter ® Double Flange Limit Retractor – DN65–DN3200, Axial Restrained Expansion Joint for Pipeline Safety & Alignment

VSSJA-2 Double Flange Limit Retractor – Full-Flanged Rigid-Limit Expansion Joint with Built-In Restraining Rods for Controlled Movement and Over-Extension Protection

The Coliter® VSSJA-2 Double Flange Limit Retractor is a high-performance, full-flanged expansion joint engineered to accommodate axial thermal movement while providing **mechanical restraint against pipeline separation** during pressure surges, water hammer, or seismic events. Unlike standard expansion joints, the VSSJA-2 features **integrated tie rods with limit nuts** that allow controlled linear extension/compression within a defined range (ΔL), then **rigidly lock** at maximum travel to transfer end thrust forces directly to the pipeline anchors—eliminating stress on pumps, valves, and supports. Both ends are equipped with ANSI/GB/DIN-compliant flanges for direct bolted connection to mating pipe flanges, simplifying installation and ensuring perfect alignment. The sealing system uses high-quality elastomers (NBR, NR, or FPM) for reliable leak-proof performance across diverse media. Constructed from ductile iron (QT400-15) or carbon steel (Q235A), with optional stainless steel fasteners (e.g., 1Cr18Ni9Ti), it offers excellent corrosion resistance and structural strength. Available in sizes from DN65 to DN3200, rated for PN10–PN16 (1.0–1.6 MPa), and compliant with GB/T 12465. Widely deployed in municipal water supply, HVAC networks, fire protection systems, power plants, and industrial pipelines, the VSSJA-2 ensures long-term operational safety, reduces maintenance costs, and provides critical protection in dynamic fluid systems.