Terminology

[Durg1]

What is a H valve and a Y valve, and when would you use either?

In relation to buoyancy what is trim? Is it something to do with adding weights?

What is an AL80?

What is the difference between a DIN and a A-clamp? which is better?

I dive cold water...Ireland, what is the best regulator to use? (pretend i'm rich!)

Thanks for your help,
Durg

 

[boney]

An AL80 is an aluminium 80 cf tank.

If you're in Ireland you may want to look at Apeks regs. I believe they are located in England and are good performers that are suitable for cold water...
I'm not 100% sure on the other stuff you asked about so instead of feeding you wrong information I'll let someone else answer that...
I'm sure you'll get plenty O responses...

 

[Tractor Tom]

Trim relates to your position in the water when diving (head up, head down, while swimming) and will have something to do with your bouyancy. If you are negatively bouyant (either too much weight or not enough air in your BC) you will tend to trim a bit head up, and fin a bit to swim along. Placement of weight has a lot to do with trim. Many of the folks I know wear ankle weights to adjust trim. I tend to be a little 'feet heavy' in my drysuit, and have put some trim weights on the top tankband of my backplate to allow me to trim out horizontal when in the water.

You can test your trim by getting to what you think is neutrally bouyant and just hang in the water, still. See if you hang horizontal in the water, or if your feet drift up or down. You can adjust the placement of your weight belt, or move your weights around to find good trim...

There are LOTs of good cold water regulators around. Poseidon are highly rated for cold water and ice diving, but the DIR folks don't care for them much. Aqua Lung makes a model they call a Glacia that has foils in it to keep it from freezing in very cold water. I use an Aqua Lung Titan LX here in Northern Michigan and have never had a problem in water down to around 31 degrees in the northern Great Lakes. A good idea is to find one that has good local support and parts available for when it comes time to have it serviced...

I'm NOT an instructor, just another diver, so this is what I believe to be true...

Good luck!

 

[theskull]

H valve or Y valve is a way to put 2 first stages on one tank for redundancy. One first stage would supply the second stage you breathe, and the other would supply the second stage of your safe second reg(ocotpus). Y valve looks like a Y-with two posts coming out of the top at a 45o angle; H valve has 1 post which branches out to the side and down to the second valve.

A DIN valve is one in which the regulator screws "into" the valve post, and is considered by many tech divers to be a more secure attachment; it does allow you to handle higher pressures of gas in your tank, above 3000 psi.

An A-clamp, or yoke, is one in which the regulator fits up against the valve and has a yoke that wraps around the post and is tightened against the post on the opposite side, and is the most common setup in the recreational and to-rent dive world.

theskull

 

[ScubaJorgen]

I think most of the questions have been answered.

About regulators for cold water :ice: just a remark.

Problem
Problems occur with regulators in cold water. The reason is that in a regulator air expands. Laws of physics imply the air (and hence the regulator) cools down. When diving in water of a few degrees Celcius it means the regulator can become at temperatures below 0 degrees Celcius. Water comming into contacts freezes.

Simple regulators have moving parts that come into contact with water (it is needed to apply the water pressure to these parts). Bad luck when these parts are below 0 : water freezes and the moving parts get stuck .

Solution
More advanced regulators apply seals or membranes covering the internals of the regulator from being exposed to water. Through the membranes the water pressure is applied to the piston. This prevents the piston from becoming stuck, since there is no direct contact with the water/ice. I think I once read about a regulator that has an oil reservoir behind the membrane as additional buffer/isolation.

Another improvement is to add ribs to the external of the regulator. This improves heat transfer from water to regulator to prevent the metal from cooling down to much.

Refer to my site for an more exhaustive description (Item Tech->regulators).

Apex TX40
I myself have a Apex TX40. I recently unintentionally tested it. Me and my buddy dove in 2 deg C water. The regulator of my buddy started blowing. So we both used my regulator and finished the dive (15 minutes or so). No problems at all

Advise
When diving cold, do not breathe above water using your regulator. Above water the regulator can not get rid of the cold, whereas in water heat transfer is much better.

Make sure you do not get water in your regulator (during rinsing). Having fancy membranes does not help when there is water IN your reg.

 

[Wreckie]

Most of whats been said so far is good, but is in american speak so i will translate :429:

What is an AL80?

It is an aluminium 80cuft cylinder. It contains 80cuft of air when filled to its 'normal' working pressure. It is roughly equivelant to a 10 liter cylinder (12L=100cuft, 15L-120cuft). It is worth remembering that any comparison is a little redundent however as the liters refers to its water capacity, in other words how big it is, the 80 refers to how much air it can hold, any variation from this set working pressure (high or low) means it no longer has 80cuft of gas in it.

What is the difference between a DIN and a A-clamp? which is better?

DIN is an acronim for something very long and very foreign! It is by far the safest option as the way in which it screws in holds the o ring captive, it cannot be knocked, twisted or pulled out once the air is on. An a clamp (yoke) if hit hard enough will bend, the o ring will be forced out of place by the air pressure and *bang* all your gas escapes. This is actualy easier to do than you may think.

Din comes in 2 varieties, 300 bar and 232 bar. A clamp is limited to 232. 232 din has 5 threads on the screw, 300 has 7.

So if you imagin a 300 bar cylinder (7 threads deep) the regulator with 7 threads can screw all the way in and seal, with only 5 threads the 232 regulator is too short, wont reach, wont seal and therefore wont explode! However a 232 cylinder (5 threads) both the 300 and 232 bar regulators can reach. In short your 300 bar din reg will fit any din cylinder, your 232 one wont. You can get converters to swits your reg from a clamp to din and back. depending on make its not difficult to do.

I dive cold water...Ireland, what is the best regulator to use? (pretend i'm rich!)

I dived in ireland for 3 years with apex tx50's, they never let me down and are still going strong. They come in 300bar din for the same price and if you want the kit to swap back and forth you can get it for £20. The new Atx range is also very good.

If you need any thing else let me know.

Mike

ps most charter boats in the uk have cylinders convertable din/a clamp so you dont need to mess with your reg at all.

 

[cyklon_300]

do a Google search on 'scuba dictionary'....

You'll get links to several different glossaries of terms.

 

[Durg1]

Thats great guys, thanks for your time. That helps alot.

Durg