VIP observation -DIP tubes

[OMyMyOHellYes]

Going through and doing a lot of VIPS in the past few weeks and noted something.

Last year I found the DIP tube rattling around in a friend's bottle when I did his VIP.

I'm doing a little different process of actually checking tightness of all the DIP tubes with the same allen key they were installed with and finding they all seem to take a little more turn to be completely snug.

Any reason those would back out slightly? Thermal expansion/cooling during fill cycles? Pressure changes during fills stretching in tube threads or valve body working things loose? Coriolis effect turning them? (If diving in the Southern hemisphere would they tighten themselves?) Tank gremlins?

 

[Johnoly]

.. DIP tubes with the same allen key

Several years ago after a shop VIP and having dove the tank a couple of times, I heard the dreaded "marble-in-a-can' sound. Upon bringing it back to my old shop for the tech to listen to it rolling on the carpet, I asked if he used an allen wrench to tighten it. Said, No it's finger tight just like valve on the bottle.

Like a car, it's a good idea to open the hood and check for problems a few times a year, cause tanks don't have check engine lights.

 

[flymolo]

any drawbacks to just leaving them out entirely? i stopped putting them in tanks

 

[GJC]

any drawbacks to just leaving them out entirely? i stopped putting them in tanks

The dip tube is there to prevent any small amounts of water or loose rust/aluminum oxide particles from exiting the tank while in the valve down position. Ideally, any particles coming out of the tank are blocked by the first stage filter, but if there is a lot it can clog the filter and reduce or stop gas flow. Any water goes through the filter into your regulator.

 

[GJC]

Going through and doing a lot of VIPS in the past few weeks and noted something.

Last year I found the DIP tube rattling around in a friend's bottle when I did his VIP.

I'm doing a little different process of actually checking tightness of all the DIP tubes with the same allen key they were installed with and finding they all seem to take a little more turn to be completely snug.

Any reason those would back out slightly? Thermal expansion/cooling during fill cycles? Pressure changes during fills stretching in tube threads or valve body working things loose? Coriolis effect turning them? (If diving in the Southern hemisphere would they tighten themselves?) Tank gremlins?

Pressure and thermal changes may contribute but I would suspect that vibration during transport buy car or boat would be the primary cause.