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DIR Kit questions Agonising over what to buy, ask other divers what they have done and what they have found. Bought something great or new - tell us.
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November 23rd, 2005, 05:54 PM
| #1 (permalink) |
| GUE Instructor  Join Date: Nov 2005 Location: London & Plymouth
Posts: 593
  | High Performance Regs - Loss of gas Was chatting with a few friends last night and this came up AFAIK theses are the maximum flow rates for the following regs: Mk25 - 10,000l/min Mk17 - 7,000l DS4/T - 5,000l Mk 2 - 3000l There's not much of a problem if a HP hose blows UW (happened to me once) as the aperture is so fine the air loss is quite small. However if an LP hose were to go, would the higher performing regs loose nearly double the amount of gas when compared to others eg Mk25 v DS4 in the same amount of time that it takes to shut down??? Although both DS4 & Mk25 are DIR compliant has anyone taken this into account and what are peoples thoughts on the above? Brian |
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November 23rd, 2005, 06:04 PM
| #2 (permalink) |
| GUE Instructor/DIRX Moderator  Join Date: Nov 2005 Location: Cambridge, UK
Posts: 1,098
 | Quote: (Originally Posted by Brian A) Was chatting with a few friends last night and this came up These values will only be achieved if you have a suitable system on the end of it to actually remove that much gas. A small hose with just a hole in it is not going to give you that system as there will not be a smooth flow out of the break. You can design a system to empty a cylinder using one of these 1st stages, but to get the decent flow you are going to end up with something looking a little like a race car exhaust system.AFAIK theses are the maximum flow rates for the following regs: Mk25 - 10,000l/min Mk17 - 7,000l DS4/T - 5,000l Mk 2 - 3000l There's not much of a problem if a HP hose blows UW (happened to me once) as the aperture is so fine the air loss is quite small. However if an LP hose were to go, would the higher performing regs loose nearly double the amount of gas when compared to others eg Mk25 v DS4 in the same amount of time that it takes to shut down??? Although both DS4 & Mk25 are DIR compliant has anyone taken this into account and what are peoples thoughts on the above? Brian HTH John |
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November 24th, 2005, 07:14 PM
| #3 (permalink) |
| "Two Sheds"  Join Date: Nov 2005 Location: Surrey
Posts: 400
| Quote: (Originally Posted by Brian A) Mk25 - 10,000l/min Also, the 'weakest link' is likely to be your pillar valve. With the valves fully open on my twinset it takes more than a minute to empty 100 bar, so I guess the flow rate through just the valve is going to be of the order 3000l/min.Mk17 - 7,000l DS4/T - 5,000l Mk 2 - 3000l So I would imagine that it doesn't really doesn't matter which 1st stage you have on - the pillar valve will restrict the flow the most. Janos
__________________ You can lead a horse to water but you can't climb a ladder with a large bell in both hands - Vic Reeves www.hellfins.com/shed  |
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