What is the Danfoss Hansen UQD couplings?
A liquid-cooled rack is only as reliable as the fittings a technician handles every day, which is why couplings deserve a record of their own. Danfoss builds these to the Open Compute Project Universal Quick Disconnect specification, so a server and a manifold from different suppliers should mate. Four sizes are offered. Bodies are 303 and 304 stainless steel with a peroxide-cured EPDM seal, giving broad fluid compatibility. The face is flat and both halves shut off, so disconnecting a running server does not spill coolant onto hardware. Danfoss states an operating range of 5 to 65 degrees Celsius and a typical working pressure of 6.9 bar, rising to 20 bar in the smaller sizes. It also claims flow at least 25 percent above the Open Compute Project ratings, which matters because pressure lost in fittings is pump energy spent for nothing. Every coupling is helium leak tested rather than sample tested, and sleeves are colour coded red and blue to make a reversed connection visible. Danfoss does not publish the pressure drop at a stated flow for each size, the expected number of connect cycles, or the seal replacement interval. Ask for all three, since a coupling that meets a flow rating but degrades after a few hundred cycles is a maintenance problem rather than a specification problem.