O-ring maintenance is as important as any other piece of equipment. Depending on what the O-Rings are sealing, which in most cases in the diving industry is the regulator, scuba cylinder, the tubes that connect your regulator to the oxygen tank, lights and underwater cameras.
All of the equipment mentioned before is expensive. But in most of the cases, the underwater camera is the most expensive piece of equipment you have underwater. That means that you want to keep the O-Ring maintenance done regularly. That will avoid the extra costs that come from replacing that specific part of the equipment.
What are the O-Rings?
The O-Ring is a doughnut-shaped object or a torus, most of the time made from an elastomer. They can also be made out of PTFE (Polytetrafluoroethylene) and other plastic materials, and in metals, both hollow and solid. The primary use for these O-Rings is sealing.
An O-Ring seal is a means for closing off a passageway, preventing an unwanted escape or loss of fluid. In the case of diving, the O-Rings ensure no water will enter the camera’s underwater housing. They also prevent water from entering in any of the stages found on the breathing apparatus.
The seal consists of an O-Ring installed in a slot and is exactly that; a circular run in which the elastomeric material has a section that is virtually circle. The slot is the cavity (usually within metal) into which the O-Ring is placed. The combination of these two elements comprises an O-Ring seal.
O-Rings failure analysis
The O-Rings made of an elastomeric material, are unlike other materials. The reason behind this is that in order for an O-Ring to function properly, it has to deform. Once an O-Ring is installed into the slot and compressed, there will be zero clearance. It’s this aspect that seals the flow of fluids and gases.
As the pressure increases, so does the forces acting on the surfaces. This results in a tighter seal and deforming the O-Ring. The sealing procedure works well for a lot of fluid-powered or air-powered systems. In order for it to work well, it requires careful design, selection, and installation procedures.
There are many ways the O-Rings can fail, and we will go over the most common ones for an underwater camera housing.
The appearance of this failure is when the surface of the O-Rings appears to have been twisted or to have rolled in its slot or against a reciprocating rod. It stays in position when freed. The sources for these types of damages can be uneven surfaces, no suitable lubrication or misfit components. This can easily be avoided with proper handling of the removal and insertion of the O-Rings and proper greasing.
The installation damage may appear as scratches or peeling on the surface of the O-Ring. Thin can both occur in the static and dynamic O-Rings. Usually, the sources of these failures are the use of sharp-edged tools, sharp corners on the O-Rings slot, improper lubrication or when the O-Ring was twisted or trapped between metal surfaces. This can easily be avoided by using the right amount of lubrication and by removing the O-Ring with a blunt and not sharp object.
Sometimes if you do not use the right greasing solution for the specifics of the materials the O-Rings were made, issues can appear. When the O-Rings fail for these reasons, the appearance of the ring will be obvious dimension changes. These changes will reduce the physical properties which cause an improper fit. Heat and friction accelerate seal failure. This can be avoided by always making sure to use THE RIGHT AMOUNT OF GREASE (extra is not better) and use the right lubricants.
No apparent reason for failure
Sometimes it is not so obvious the reason why the O-Ring failed. Usually, the cases of these failures come from combined tolerances of all components are not correct, there is not enough squeeze. It can also be that the parts are not fitting properly or the components are not shaped perfectly. Also, an improper shape of the O-Ring slot or too much residue left can be the reason. Always make sure if you change any component (or even O-Rings) that it fits properly and it is made for that specific product.
Excessive grease under the O-Rings
Another issue that we came across was that some people grease the O-Rings only on the outside. By doing that multiple times without removing them to clean them and to clean the slot where they fit in, there is a high risk to push the grease under the rings. When that happens, there are high chances of the O-Rings to be pushed out of their grooves and when it tightened up, there is a high probability that the O-Ring will get damaged or moved, which will result in the flooding of the camera. To avoid this, make sure that from time to time you remove the O-Rings and clean them and the grooves for any foreign materials or excess grease.
O-Ring maintenance for the Paralenz Dive Camera+
There are 4 O-Rings present in the Paralenz Dive Camera: 3 located at the end cap and one located around the lens. The O-Ring maintenance should be done on the three ones located at the end cap. You should do that before each dive, to make sure your camera will not flood.
When you check the O-Rings before the dives, you should make sure that the O-Rings are moist. If they are dry, they will not shine and that means that they need greasing. Make sure that the O-Rings are not in contact with any foreign elements (dust, hair, organic materials, etc.). If all of the above applies, there is no need to remove the O-Rings from the slots. Just gently lubricate them with a minimum quantity of silicone grease.
If one or more of the above does not apply, you should remove the O-Rings for a better inspection. To do that, you should use a soft O-Ring maintenance pick to remove them and inspect them closely. After the removal, make sure to clean the O-Rings. To do that, gently run the O-Ring through your fingertips to check of any cuts and tears. By doing that, you will also remove any foreign material that might have been stuck on it. If any visible damage is present on the O-Ring, it needs to be replaced!
When lubricating the O-Rings, less is more! Put just a bit of lube on your fingers and run the O-Ring through them while gently massaging the lube into the O-Ring. If there is an excess of lubricant, use a microfiber cloth and gently wipe off the excess. In the case of Paralenz Dive Camera, it is recommended to use diving dedicated grease. Do not use any spray lubricant or petroleum based grease!
Replacing the O-Rings
When installing back the O-Rings, clean the grooves using a microfiber cloth. That will ensure there is no grease or foreign materials that can damage the O-Rings or the sealing will not be tight. Make sure that you do not stretch the O-Rings. When adding them back to the groove, do it gently and one by one.
And remember: always clean the camera in fresh water after use and before opening the end cap. This will ensure the longevity of the camera and it will avoid some of the issues that might appear when wanting to check up the O-Rings.
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