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EOTDs and Pressure Relief Valves

John P Coates

Member
Joined
21 Feb 2014
Messages
164
Location
Bracknell
Hi Folks,

I read somewhere that the EOTD (end of tank dump) problem could possibly be averted by the use of a Pressure Relief Valve (PRV). As I understand it, the idea is to add one of these PRVs on the CO2 line connected to the injector/diffuser. In the event that the CO2 regulator stays open when cylinder pressure is low, the higher-than-normal pressure feeding the injector causes the PRV to open thus venting CO2 to the atmosphere. Apparently, some people use a length of water-filled hose as the PRV but my room isn't big enough!

So, I have been trying to find a suitable PRV but without success. There are plenty of PRVs out there but I have not found any specific to aquatic use. Can anyone help?

Thanks in advance.

JPC
 

John P Coates

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Thread starter
Joined
21 Feb 2014
Messages
164
Location
Bracknell
Dual stage regulators do that, don't they?
My understanding is that dual-stage regulators operate differently to single-stage regulators when cylinder pressure is low. But I have a JBL m001, which appears to be a single-stage regulator.
 

ian_m

Global Moderator
UKAPS Team
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25 Jan 2012
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5,247
Location
Eastleigh
Most "quality" single stage regulators don't end of tank dump. I have watched my single stage CO2Supermarket regulator, carry on working, but with lower output pressure (and lower bubble rate) right down to 10bar tank pressure, no sign of dumping. Obviously a better quality dual stage regulator would (hopefully) maintain output pressure better than single stage. EOTD from quality single stage regulators is something not to be concerned about.:)
 

John P Coates

Member
Thread starter
Joined
21 Feb 2014
Messages
164
Location
Bracknell
Most "quality" single stage regulators don't end of tank dump. I have watched my single stage CO2Supermarket regulator, carry on working, but with lower output pressure (and lower bubble rate) right down to 10bar tank pressure, no sign of dumping. Obviously a better quality dual stage regulator would (hopefully) maintain output pressure better than single stage. EOTD from quality single stage regulators is something not to be concerned about.:)
Your observation of a CO2Supermarket regulator is reassuring. But I wrote to JBL a few weeks ago explaining that I wanted to replace my old (defunct) JBL regulator with a two-stage regulator because I thought it would prevent an EOTD. If they were confident that use of their current single-stage (?) m001 regulator could prevent an EOTD, surely they would have said so. As things worked out, I purchased the JBL m001 thinking that I could always fit a PRV to my setup.
 

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