The Difference Between LP and HP

[NAM001]

Its confusing. Yolks were at one tie solely lp devices. now they re not. s din goes there are 200b and 300b din's lp and hp use. In the states we use a 4:1 safety factor whre other countries may use 2:1 or 3:1. In the us a 300b tank is ungodly heavy it has a 18000psi minimum burst pressure. Other countries with a 3:1 would have the tank min burst pressure at 13500. and then a 2:1 is 9000. a 9000 tank in the us has a working pressure of 2200psi.

As far as how do shops for an over fill ..... they fill a 2400 lp tank to 3000 psi. and in places a 2400 tank is filled to 4000. Burst disks in the us are devices made to rupture somewhere between 90% and 100% testing pressure. so a 3000 psi tank has a test pressure of 5000. the burst disk is 4500. There is a lot of room to over fill without blowing a disk.

Why do you complicate things so much?! Different sizes, different pressures and then use a LP/HP terminology that means... ...well, something...

And on this side of the pond, high pressure is 4350 psi!

How do shops cope with so varied service pressures?

How do you overfill? I thought you were required to have burst disks over there? And even if you don't, it doesn't seem like a good practice, it will increase the fatigue of the metal much faster, especially if aluminium. But on the other hand, I don't hear many cases of tanks blowing up...

---------- Post added March 31st, 2015 at 01:31 AM ----------

I have never seen markings like these you show. ekhr no idea next line is manufacturer and what loks like steel 100 cuft, no idea about spun japan. next is department of transportation DOT for the us (TC if for transportation Canada) the tank was made under a SP special permit # 12079, working pressure is 3442, test pressure is 5250.

Man...it is a lot more complicated then I thought. The tank that I have been diving with is a 100 steel. I'm new to the sport and I turned it up somewhat for the past two summers. I go to the wrecks BUT DONT ENTER. The deepest I do is 110 feet.
Being I did not see my name of my tanks any where on those lists can only lead me to believe the tank I have I not very good. If its not its OK...level with me.
When I looked on the tank this is what I read.
EKHR
GENESIS ST 100
SPUN JAPAN
DOT SP 12079
3442
TP 5250
Plus obvious hydro stamp

 

[Storker]

s din goes there are 200b and 300b din's

Tank valves, yes. They make it physically impossible - at least without some conciensious effort - to use a 300 bar whip on a 200 or 232 bar tank and overfill it. Regs, not so much. A 300 bar DIN 1st stage (the only type sold) goes just fine on a 200 bar tank valve.

lp and hp use.

One man's HP is another man's LP. 232 bar (LP DIN) is around 3350 psi.


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[tbone1004]

Your 100's are Asahi Spun tanks imported by Genesis. Nothing wrong with them but instead of taking a pancake slug of steel and pushing it down into a tube, they take a seamless pipe and spin the ends shut which makes them rather heavy on the bottom since it has to be reinforced. Some like it, many don't which is why you don't see them often. Nothing wrong with them though and they will certainly last.

Storker, not sure how the fill whips are over there but with the exception of a select few argon inflation regs made at 200bar to keep them as small as possible, everything over here is 300bar din fill whips included. I don't understand how you guys have to make a conscious effort to put a 300bar whip on a 200/232bar tank if your regulators are compatible. Our fill whip ends look just like the regulators and screw right on in.

 

[Storker]

Storker, not sure how the fill whips are over there but with the exception of a select few argon inflation regs made at 200bar to keep them as small as possible, everything over here is 300bar din fill whips included. I don't understand how you guys have to make a conscious effort to put a 300bar whip on a 200/232bar tank if your regulators are compatible. Our fill whip ends look just like the regulators and screw right on in.

Current DIN regs are all 300 bar. Screw a 300 bar DIN reg into a 200/232 bar tank valve, and the difference to screwing into 300 bar tank valve is just a couple of threads on the regs exposed. No problem there. A 300 bar fill whip valve around here is designed so that it won't deliver gas if it's screwed into a 200/232 bar tank valve, to prevent overfilling. You need an adapter which has a safety valve installed.

An example: Our club's compressor delivers 300 bar and has two fill whips, both 300 bar. If I want to fill my 200 bar tank, or if one of my clubmates wants to fill their 232 bar tank, we have to use the 300/200 bar adapter between the whip and the tank. We also have a DIN/yoke adapter to fill any yoke tanks that people may have, and then we need two adapters in series: whip - 300/232bar adapter - DIN/yoke adapter - yoke tank. And the last time I checked, we even had a couple of those DIN-to-yoke tank valve inserts They come in useful if a DIN-challenged diver needs to borrow a (DIN) tank from another clubmate. Those inserts are too short for a 300 bar tank valve and will only work with a 200 or 232 bar tank.

So, in short, the hardware is designed to prevent overfilling of LP (i.e. 200 or 232 bar) tanks. I believe (but I'm not 100% sure) that a 200 bar or 232 bar whip can fill a 300 bar tank, up to whatever pressure the compressor can deliver.

 

[tbone1004]

that is very strange. I doubt a 200/232 bar could fill a 300bar tank because it wouldn't have enough threads, but I wonder what the mechanism to cause them to not fill the 200/232 tanks is.

Here you have a 300bar whip, usually a yoke adapter screwed onto it *same ones used on the regulators*, and that's that. No 200bar whips, only the 300bar or yoke. Din divers will carry around a fill adapter that screws into the DIN valve either 200/300 bar and then has a yoke fitting on it for compressors with yoke only fill whips, and if they have 200 bar valves, they will sometimes screw the valve plug in to allow faster filling using the yoke fill adapter and then spin it out when it is done being filled.

 

[Storker]

Here you have a 300bar whip, usually a yoke adapter screwed onto it *same ones used on the regulators*, and that's that. No 200bar whips, only the 300bar or yoke. Din divers will carry around a fill adapter that screws into the DIN valve either 200/300 bar and then has a yoke fitting on it for compressors with yoke only fill whips, and if they have 200 bar valves, they will sometimes screw the valve plug in to allow faster filling using the yoke fill adapter and then spin it out when it is done being filled.

So your 300 bar whips can be used directly for filling a tank rated for 200 bar? :buggy: That's very strange for me. Unless I tamper with the whip valve, I physically can't fill my 200 bar tank without a 300 to 200/232 bar adapter (which is equipped with a 235 bar safety valve). I guess it's an attempt at idiot-proofing the hardware; I wouldn't like being close to a 200 bar tank which some idiot had filled to 300+ and then left in the trunk of a car standing in the sun...

 

[agilis]

My HP 80 is smaller and heavier than my LP65. HP tanks are made of steel, and modern LP tanks are usually aluminum. I think these days most standard aluminum tanks can be filled to 3000psi.

 

[Redshift]

So your 300 bar whips can be used directly for filling a tank rated for 200 bar? :buggy: That's very strange for me. Unless I tamper with the whip valve, I physically can't fill my 200 bar tank without a 300 to 200/232 bar adapter (which is equipped with a 235 bar safety valve). I guess it's an attempt at idiot-proofing the hardware; I wouldn't like being close to a 200 bar tank which some idiot had filled to 300+ and then left in the trunk of a car standing in the sun...

Same here and in other countries I have been. I'd like to see those whips. Because it's easy to understand how a 200 bar whip or reg cannot seal on a 300 bar valve (and that makes me also not understand how you say a 200 bar whip can fill a 300 bar cylinder), but having a 300 bar whip not sealing on a 200 bar valve I don't know how it's done... I can imagine a way, but not a safe one.

 

[Eric Sedletzky]

I love it when I get an "Oops" fill to over 4000 in my 3442 E-7 120.

 

[TSandM]

agilis, there are a lot of LP steel tanks. I owned LP 95s and currently dive LP 85 doubles, as well as LP72s (I'll admit that the 72s are antiques).