Tank valves
- Thread starter Frog
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Lost Yooper
Guest
On a first stage like the Zeagle T50D (Apex TX50), they have a swival which allows the hoses to rotate around. It's hard to explain in writing for me. Regs like the Zeagle Flat Head do not have the swival, and the first stage is one solid piece of brass. Die hard DIRer's don't like the swival as it could be another failure point, I guess. I have the T50D, but would probably get the non swival if I had to do it over again.
Mike
Mike
Frog, the vast majority of what you read doesn't apply in the UK.
ALL tanks in the UK have to meet BS5045, which is in the process of being replaced by EN144. DoT is the US equivalent of BS5045 / EN144. You can't use a US spec tank in the UK, and vice-versa.
The US standards allow you to overfill SOME tanks (marked with a + at the end of the DoT markings), but this is not allowed under UK law.
In the US tanks are sold by the ammount of air at atmospheric pressure that can be squeezed into them (eg 80 cuft) and their working pressure eg HP or LP. So, a US HP80 and LP 80 both (nominally) contain 80 cuft of air. But, the HP tank is physically smaller as the air is at a higher pressure.
Now, throughout europe tanks are sold by internal water volume (the ammount of water that would fill the tank). So, tanks are generally refered to as 7, 10, 12, or 15 Litre tanks. Then you have the HP and LP. LP in europe is 232bar (HIGHER pressure then the US LP tanks) and HP is 300 bar. So, in europe a 10L HP and 10L LP tank have significantly different ammounts of air, but are physically the same size.
When it comes to choosing a tank, you need to analyse what type of diving you do, how much air you need, and what type of setup you need.
Personally I have a 300Bar 12L tank for most of my diving - this is the escorting students type of diving, or just popping into the water for some fun. This will often last me two dives if they are 20m or less. If I am going deep (>35m) or going on a wreck I will supplement this with my 3L pony.
For more challenging (deco, or nitrox on a long shallower interesting dive) diving I take twin 10L 232Bar tanks with me as this gives me plenty of air.
The general (and I say again general) guideline is that a UK 232Bar 10L is approximately a US 80cuft (either LP or HP).
In the UK, aluminium cyliners are pretty non existant. This comes down to the fact they are positive at the end of a dive. If you have to wear a significant ammount of weight due to wearing a drysuit, then you don't want extra because of +ve cylinders. By far the most common cylinders are 10L, and 12L 232Bar (you probably learned with a 232bar 12L) with the 15L 232Bar being the choice for longer dives (note a 15L 232 bar, is pretty much the equivalent ammount of air to a 12L 300Bar, but quite a bit bigger - the reason that I use a 12L 300Bar!)
If your basic course didn't cover all of this then I think that you were sold short. The PADI propaganda (sorry - teaching materials) are very bad on local regulations - the instructor is supposed to teach you all that.
Jon T
Green_Manelishi
Contributor
Frog,
I might be called a heretic for saying this, however, you
do not NEED a cannister light. If you NEED a light then a
cannister is the best way to go (IMNSHO) however, if your
diving is such that a light is not needed then don't buy
a cannister light.
I own a cannister light but I do not always carry it on
a dive. What is the point if the water is 30 feet deep
and the sun is shining? A backup light is more than adequate
for peering underneath rocks. Heck, I do not carry a light at all unless it is deep, dark, or night; i do not like
carrying more gear than needed, nor do i enjoy cleaning
gear that was unnecessarily "dirtied".
G_M
Great, many thanks Jon T for that explanation. It has clarified a few things. Ok so idealy i would like to opt for a 300 Bar single 12L but alot people (including my instructors) told me that most places in the UK dont do 300 Bar fills! I read some articles as well that suggested regs and such, used on 300 Bar cylinders fail more frequently and wear out more quickly. Is this true? Cheers
Lost Yooper
Guest
Frog,
Remember, you're not going to pump the tank to those high pressures. Strict DIR doesn't advocate HP tanks as it puts too much stress on the gear. It's the toughness of the 300 BAR DIN valve the is important.
Mike
Remember, you're not going to pump the tank to those high pressures. Strict DIR doesn't advocate HP tanks as it puts too much stress on the gear. It's the toughness of the 300 BAR DIN valve the is important.
Mike
I've never had difficulty getting a 300bar fill. Look in the small ads in the back of diver. Lots of places advertise air to 300Bar.
For what its worth, I find that IF I can't get a 300bar fill, I just use my twinset - or if it is really mickey mouse diving, 232Bar in my 300bar tank!
Regs like the Apeks which are desined for this have no problem with the pressure - if in doubt get it serviced more often! - my 300Bar tank has had a hydro and two visuals, and has had no problems.
Jon T
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