Failure Mode of Quick Disonnect

[PQ2]

I have a 4000 psi quick-disconnect that ejected the plug. It may have been subjected to higher pressures than 4000 psi. Does anyone know if quick-disconnects will first rupture or will it fail to hold the mating fitting when subjected to excessive pressure?

 

[alexit]

I am not working in your high pressure but experience with our fittings is to leak/split/burst before allowing the mated fitting to release.

 

[Eltron]

How often is this disconnect used? Is it possible that it just wasn't mated properly the last time the connection was made? Many times these fittings will make a seal at low pressures even if they are not correctly mated, but as soon as they see higher pressures they will fail.

 

[burkett1]

Eltron is correct. QD fittings will hold a surprising amount of pressure when, for instance, the locking sleeve is not completely engaged. I don't know which coupling design you use, but I've run QD couplings all the way up to 10,000 psi in water jetting applications and have never had one separate that was properly mated to begin with (burst pressure was 40kpsi for these couplings). That does not mean separation can’t happen, but the majority of failures I observed were hose bursts and coupling seal leakage. Remember that QD couplings have moving parts that wear and must be maintained / inspected from time to time, especially if they are used frequently. I suspect the burst pressure of your coupling is in the 12,000-16,000 psi range if its max working pressure is 4000 psi. Check with the manufacturer to verify this or seek advice from someone like Aeroquip. You may also want to look at installing some type of pressure relief device to protect the system and its operators if you don’t already have one.