The Ductile Iron Transmission Joint (also called a force transfer coupling or thrust transmission joint) is a short, flanged connecting component installed between a pump discharge flange and a pipeline flange. Its primary function is to transmit axial forces (thrust loads) from the pipeline to the pump casing or to a downstream thrust block, preventing these forces from damaging the pump or causing flange separation. The joint consists of a ductile iron body with integral flanges on both ends. Unlike a standard pipe spool, the transmission joint allows a small amount of axial movement (typically ±5mm to ±20mm depending on size) to accommodate installation tolerances and minor thermal expansion. The body is manufactured from ductile iron QT450-10 with a fusion-bonded epoxy coating (250 microns minimum) for corrosion resistance. The joint is installed using standard flange bolts and gaskets.
Why Choose Us / Advantage
Force Transmission Calculated: We provide thrust force calculations upon request — ensures proper sizing.
100% Hydrostatic Tested: Each joint tested at 1.5x rated pressure before shipment.
Custom Drilling: Flanges can be drilled to ANSI, EN, BS, or JIS standards.
Stainless Steel Bolts Option: SS304 or SS316 bolts available for corrosive environments.
Quick Lead Time: Standard sizes (DN80-DN600) in 15-20 days.
Technical Data
★ Body Material Ductile Iron QT450-10 (GJS-400)
★ Coating Fusion Bonded Epoxy (250μm min)
★ Pressure Rating PN10 / PN16 / Class 125 / Class 150
★ Size Range DN50 – DN1200 (2″ – 48″)
★ Axial Movement ±5mm to ±20mm (size dependent)
★ Connection Flanged both ends (ANSI / EN / BS / JIS)
★ Gasket Included EPDM rubber (replaceable)
Applications
● Pump suction and discharge connections (protects pump from pipeline thrust)
● Pipeline connections at bend points (transmits thrust to support structure)
● Valve replacement spools (allows minor length adjustment during replacement)
● Treated water transmission mains
● Industrial cooling water pump piping
