My team and I have been having some troubles regarding our BlueRov2 lately. We have not been successful in passing a pressure test for the past two weeks, we have tried different pumps, tested pumps, etc. But are losing about 5 inHg with every 15-minute test we perform (15-10 inHg over 15 minutes).
We have looked at o rings and made sure penetrators and screws are tight, not loose but still have this unsuccessful pressure test.
We read up on how switching the pump to pressure and putting soapy water around the enclosure could help us locate the leak. So, we attempted and think we have found the culprit. (photo below, video of bubbles being made will not upload but were appearing, popping, growing)
We find it odd that air is escaping in this place and are wondering what next steps we should take to resolve the issue and get our ROV back in the water doing research dives.
Looking for the help of anyone who knows what the best way to tackle this leak would be. We are thinking of opening it up and possibly replacing the face seal o ring. We are unsure if we will have to remove on penetrators to take apart the piece. (we are still fairly new to the ROV world) Hoping someone with some more experience or who has had this issue occur could give us some guidance.
Looks like you have a leak between your end cap and flange, so I’d start by pulling out the six screws that hold the end cap (the piece all the penetrators are attached to) to the flange and having a look at the O-ring that provides the seal between the two. Maybe the O-ring got nicked during assembly or there’s a hair in there or maybe the faces of the flange or end plate got damaged. Hopefully it’s just some debris in there. The penetrators shouldn’t be involved at all, but if you need to replace the O-ring you’ll probably have to disconnect all the wiring and pull that whole end cap assembly out from the enclosure and flange.
Thank you for your suggestion! When we opened it up there was quite a bit of debris between the two plates. We successfully cleared the debris out and when inspecting the o ring there was no visible damage.
after cleaning out the debris and putting it back together we attempted a pressure test again yet still had the pressure drop from 15 inHg to around 9 inHg after a 15-minute test. We are stumped. Do you think this is a leak coming through a penetrator as well?
When inspecting our watertight enclosure we did notice a little nick near the camera on the opposite side but it doesn’t look substantial… could this also be where the air is leaking out from?
Tracking down leaks can be frustrating! From what you’ve described it sounds like you are putting positive pressure into your enclosure or “inflating” it. In general the BR enclosures are designed to resist negative pressure, which is better simulated by pulling a vacuum in the enclosure. In other words, under water the pressure of the water helps to squeeze the parts together as opposed to positive internal pressure pushing things apart. So my first suggestion would be to get a cheap vacuum pump and use it to pull a vacuum on your enclosure after coating it with soapy water. You should see little bubbles appear inside the enclosure wherever your leak is. You’re at an advantage here with your transparent cylinder, making things easier to see as they happen. If that doesn’t work, you might try something I did once when I was desperate: removing the electronics tray, packing the enclosure full of crumpled-up paper towels, reassembling the enclosure and submerging the whole kit and caboodle in the deepest water you can find for awhile. Bring it back up and check the paper towels to see at least roughly where the leak is coming from. But I think the soapy water+vacuum test ought to reveal your problem.
We found the leak and the ROV passes the pressure test again! thank you for all your help!