We recently bought the blue robotics hull and the dome for our ROV. What is the lifetime of the O-rings that come with the flange of the hull ? We have already tested the ROV in a pond for 5 times. How frequent should we replace the O-rings before it loosens?
After 6 months of pretty rugged use of my ROV in an ocean environment, I am still using the same O-rings. Make sure they are clean, inspect for damage, and use plenty of silicone grease. In my opinion, unless damage occurs due to forceful closing of the endplates when dirt or debris is present, the O -rings will last forever. Also, protect them from UV damage.
According to one website: https://www.oringsusa.com/html/shelf_life.html
Shelf life of Nitrile (Buna-N) rubber o’rings is 15 years.
Generally, unless very old, o’rings fail only when cut, pinched, exposed to sunlight, ozone, dirt, solvents, or are otherwise damaged.
Shelf life and usage are different things. Just to give some historical usage data … I use Buna-N O-rings in my pressure tank that I run at 1000 psi. I will use the same O-rings for a long time. The o-ring life in the ROV’s like the one sold here and others that are not experiencing high pressure … they should last a LONG time.
The biggest thing you should do is to inspect your O-rings for nicks, cuts etc. As long as they stay clean and you keep them lubricated … they can last for a long long time.
Frankly I have had O-rings that have experienced hundreds of hours at 1000 psi with no issues. One of the things you should watch for is when you start seeing a black residue coming off on your finger if you rub against it … then replace them. That is carbon black starting to migrate and it can be a sign that the o-ring is starting to break down.