Assembling tank valves.

[wunat]

Is there any special procedure in regards to assembling valves onto the tank? Do we just screw it in?

Thanks a ton!!!

 

[mike_s]

You mean installing valves on a tank? (Assembling implies putting a vale that is taken apart and needs put back together).

To install a valve on the tank, simply screw it in hand tight and then use a rubber hammer and give it a few light taps... Don't overtighten it. It might seem you want to get it tighter, but under pressure of 500+ psi, it'll be plenty tight.

While you've got the valve off, it's always a good time to do a visual inspection of the inside of the tank and the threads also. Visually inspecting the o-ring on the valve neck is a good thing also.

 

[oxyhacker]

Tanks tend to use the neck O-ring as a crush seal rather than the way god intended O-rings to be used. As a result, they take a permanent set in service, so a used one will have an almost triangular cross section, and the general rule is not to reuse them. If one must (and we all do it occasionally) they should be inspected carefully and replaced in the same alignment (same side facing out) as they were originally so as not to torture them anymore than necessary.

Visually inspecting the o-ring on the valve neck is a good thing also.

 

[H2Andy]

yeah... basically screw it in by hand until it is tight...

i then give it a further "twist" to be sure, but don't use any tools

you don't really need to, like mike_s said

 

[pescador775]

I place the tank in a chain vice and torque the valve to about 30-40 lb feet. The mfgr usually recommends 50-60 lb feet which is fairly tight. Many divers do the "hand" tight thing and seem to get away with it. The O ring is expendable and should be replaced anytime the valve is to be reinstalled. I don't think much of striking the valve with a mallet or hammer. Unless you have access to the right tools it would be difficult to follow the mfgr recommendations or to service a leaking neck. For example, if you were on a sea voyage it might not be possible to remove a valve torqued to 60 lb feet. Personally, I think that one of the common problems seen with aluminum tanks--corrosion in the O ring seat--is caused by a loose connection. I'm not sure exactly how this happens but it might be related. When the tank is pressurized, the valve seems to tighten but what it is really doing is pushing away from the tank by a small distance. The soft aluminum threads tend to stretch a bit and this is aggravated by the slack. I doubt that this would happen with a properly torqued valve. I don't use aluminum tanks so it is not a going concern.

 

[oscar_2424]

Is there any special procedure in regards to assembling valves onto the tank? Do we just screw it in?

Thanks a ton!!!

wait a sec, uare an instructor and dont know this??? something is wrong here

 

[TeddyDiver]

wait a sec, uare an instructor and dont know this??? something is wrong here

They have personel (DM's) to take care of the equipments So all instructor got to do is to pick up the best looking chicks...

 

[Thalassamania]

wait a sec, uare an instructor and dont know this??? something is wrong here

Did we remember ... rightie tighty, leftie loosie? Never know what else was missed.:shakehead

 

[royalediver]

remember to use Dow 111 on aluminum tanks to prevent seizing. Some use Chistolube for nitrox or oxygen cylinders but I do not know if it prevents seizing.

 

[Saint_Thomas]

If it is the Sherwood K-valve (SVB5000) valve like mine,

they have teflon coated threads which never require lube for the life of the valve