Switching blocks

Gobfish1 · 14th February 2008, 00:23

keep unit on you're back maybe

kwinter · 14th February 2008, 03:54

Quote: (Originally Posted by Dave Sutton)

YES, Switch blocks are generally not needed. No argument. I've been able to rig my system to work without them. I play with them and I gently caress them at the dive shows (cannot resist nicely made chrome plated brass hardware), but... I don't own one. Come to think of it, I don't know anyone else who does either.
.

I'm confused, Dave. In the thread you started http://www.rebreatherworld.com/revo-...nice-pair.html
there is a picture you posted.

Isn't that a switching block?

silent running · 14th February 2008, 07:13

Quote: (Originally Posted by Drmike)

I like to keep the 2 systems seperate OC and Rebreather. Blow a hose or o-ring with a linked system on a deep dive and you could lose much of your O2 supplies.

Hi Mike, I think I understand the above principle, but I wonder if it applies to the sytem I'm using-onboard 1st stage as a manifold. Because I haven't dived in months and am generally forgetful, I forgot to mention that the on-board dil whip has a ball valve shut off and that both the on and off-board reg valves are left open, obviously, to keep the ambient pressure from collapsing the lp hoses on descent. So if I had an HP seat failure on either the on or off-board reg, there would be no catastrophic gas loss of both supplies as long as the ball valve was closed, right?

And obviously if you have off-board O2 plugged into your on-board O2 reg with the same QC whip system, the same would be true if you have a ball valve btw the 2 lp hoses closed, right?

**Dave Sutton** · 14th February 2008, 11:56

Quote: (Originally Posted by kwinter)

I'm confused, Dave. In the thread you started http://www.rebreatherworld.com/revo-...nice-pair.html
there is a picture you posted. Isn't that a switching block?

Hmmm......: It's my rEvo's version to gain the functionally of the internal onboard/offboard diluent valve that's on my Mark-15. It's a simple on/off valve, not a 2 port Gas "A" or gas "B" valve, so it's not 'really' a switch block. Or maybe it is.... dunno. I guess it's how we use the term.

Tomorrow I'll be posting photos of a combination Solenoid or ADV isolation valve with integral offboard gas connection as well, on another thread. I suppose you could call this a "switch block" too, although (again) it's a simple on/off valve, not a 3 port ball valve.

Let's define terms: "Switch Block" to me means a block with a valve that has 3 ports, and the possibilities of having either "A" or "B" (and sometimes "off") positions. I differentiate it from a simple on/off valve for my own nomenclatural use. Is the hard mounted 3 way ball valve on the side of a Mark-15 for onboard/offboard diluent selection a switchblock? Maybe it is, and that same function can be done externally on other rigs, so.... I guess you're right.

I think I was addressing the posters questions assuming that he was asking about open circuit gas access controls, in which case all that DrMike and myself wrote in response apply. For intentional diluent switching from onboard to offboard, my answer is that the blocks have value. I just had not toggled to that side of the question. So, Good point!

Studying the "Mother of all Switch Blocks" now for the CIS Mk-5P. Let's see: Active Diluent: ONBOARD/OFF/OFFBOARD. Active 02: ONBOARD/OFF/OFFBOARD. O2 Control: SOLENOID AND MANUAL/SOLENOID ISOLATED/O2 to BOV WITH SOLENOID OFF. Includes manual add valves for 02 and diluent as well, an also has the offboard gas plug-in points.... the funny thing is that it's intuitive, flexable, and compact. Hmmm........... I need to make one of these!

Dave

.

divetheworld · 14th February 2008, 17:52

Quote: (Originally Posted by Drmike)

personally I carry/stage adequate bailout (especially shallow tanks which are the easiest to stage). I just dont rely/consider the variable small volume in my on boards for bail - i see that akin to carry a band-aid into a mine field

i think if people are considering the usefulness of that little 300L of O2 for bail gas then they simply arent carrying enough real bail gas! Just my opinion

Absolutely correct, cant agree more. Inboards (IMHO) should never be factored in as a gas you rely on for bail. There are many reasons you might be in a full bail and an O2 first stage failure has to be one of them which would make that gas inaccessable. But... If you can find a way of getting access to that gas, then when your against the wire it might be just what you wanted.
Whats important is that you balance your method of accessing that gas against any potential problems it may cause you. Having a strict mantra like Mike has endorsed has value. Its a choice each individual must make.
I for one have become comfortable over the years with a system, but will always keep an open mind that someone may suggest something that makes more sense to me and you can be sure I'll give it a go.
One of the main reasons I come to Rebreather World.

divelermentov · 20th February 2008, 05:06

Quote: (Originally Posted by kwinter)

I'm confused, Dave. In the thread you started http://www.rebreatherworld.com/revo-...nice-pair.html
there is a picture you posted.

Isn't that a switching block?

I think this is more a off-board on/off scenario and not a switch block as such.

I do agree with Mike, wouldn't put a switch block on my unit, as a am easily getting confused anyway. Off board supply should be qjd, as this is easier for me to see which gas is plumbed in. And if i want to turn one supply off - well i like that valve on/off thing.

for bailout - well just will have to carry sh$^$ loads of tanks, not real way around this anyway.

but these are only my .02

14th February 2008, 03:54	#22 (permalink)
kwinter New Member Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: NJ Posts: 11	Re: Switching blocks Quote: (Originally Posted by Dave Sutton) YES, Switch blocks are generally not needed. No argument. I've been able to rig my system to work without them. I play with them and I gently caress them at the dive shows (cannot resist nicely made chrome plated brass hardware), but... I don't own one. Come to think of it, I don't know anyone else who does either. . I'm confused, Dave. In the thread you started http://www.rebreatherworld.com/revo-...nice-pair.html there is a picture you posted. Isn't that a switching block?
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14th February 2008, 07:13	#23 (permalink)
silent running Mature mouth breather Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Jun 2005 Location: U.S.A. Brooklyn, New York Posts: 1,740	Re: Switching blocks Quote: (Originally Posted by Drmike) I like to keep the 2 systems seperate OC and Rebreather. Blow a hose or o-ring with a linked system on a deep dive and you could lose much of your O2 supplies. Hi Mike, I think I understand the above principle, but I wonder if it applies to the sytem I'm using-onboard 1st stage as a manifold. Because I haven't dived in months and am generally forgetful, I forgot to mention that the on-board dil whip has a ball valve shut off and that both the on and off-board reg valves are left open, obviously, to keep the ambient pressure from collapsing the lp hoses on descent. So if I had an HP seat failure on either the on or off-board reg, there would be no catastrophic gas loss of both supplies as long as the ball valve was closed, right? And obviously if you have off-board O2 plugged into your on-board O2 reg with the same QC whip system, the same would be true if you have a ball valve btw the 2 lp hoses closed, right? Last edited by silent running : 14th February 2008 at 18:00.
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14th February 2008, 11:56	#24 (permalink)
Dave Sutton Living on Animal Farm Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Classic Kiss rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,445	Re: Switching blocks Quote: (Originally Posted by kwinter) I'm confused, Dave. In the thread you started http://www.rebreatherworld.com/revo-...nice-pair.html there is a picture you posted. Isn't that a switching block? Hmmm......: It's my rEvo's version to gain the functionally of the internal onboard/offboard diluent valve that's on my Mark-15. It's a simple on/off valve, not a 2 port Gas "A" or gas "B" valve, so it's not 'really' a switch block. Or maybe it is.... dunno. I guess it's how we use the term. Tomorrow I'll be posting photos of a combination Solenoid or ADV isolation valve with integral offboard gas connection as well, on another thread. I suppose you could call this a "switch block" too, although (again) it's a simple on/off valve, not a 3 port ball valve. Let's define terms: "Switch Block" to me means a block with a valve that has 3 ports, and the possibilities of having either "A" or "B" (and sometimes "off") positions. I differentiate it from a simple on/off valve for my own nomenclatural use. Is the hard mounted 3 way ball valve on the side of a Mark-15 for onboard/offboard diluent selection a switchblock? Maybe it is, and that same function can be done externally on other rigs, so.... I guess you're right. I think I was addressing the posters questions assuming that he was asking about open circuit gas access controls, in which case all that DrMike and myself wrote in response apply. For intentional diluent switching from onboard to offboard, my answer is that the blocks have value. I just had not toggled to that side of the question. So, Good point! Studying the "Mother of all Switch Blocks" now for the CIS Mk-5P. Let's see: Active Diluent: ONBOARD/OFF/OFFBOARD. Active 02: ONBOARD/OFF/OFFBOARD. O2 Control: SOLENOID AND MANUAL/SOLENOID ISOLATED/O2 to BOV WITH SOLENOID OFF. Includes manual add valves for 02 and diluent as well, an also has the offboard gas plug-in points.... the funny thing is that it's intuitive, flexable, and compact. Hmmm........... I need to make one of these! Dave . __________________ . "All animals are equal, but some animals are more equal than others" Professional Small Boy: Never Successfully Cubicled. Last edited by Dave Sutton : 14th February 2008 at 12:05.
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14th February 2008, 17:52	#25 (permalink)
divetheworld Dive porn pimp Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Inspiration Vision Classic Kiss Other CCR Join Date: Mar 2005 Location: Leeds, England Posts: 1,505	Re: Switching blocks Quote: (Originally Posted by Drmike) personally I carry/stage adequate bailout (especially shallow tanks which are the easiest to stage). I just dont rely/consider the variable small volume in my on boards for bail - i see that akin to carry a band-aid into a mine field i think if people are considering the usefulness of that little 300L of O2 for bail gas then they simply arent carrying enough real bail gas! Just my opinion Absolutely correct, cant agree more. Inboards (IMHO) should never be factored in as a gas you rely on for bail. There are many reasons you might be in a full bail and an O2 first stage failure has to be one of them which would make that gas inaccessable. But... If you can find a way of getting access to that gas, then when your against the wire it might be just what you wanted. Whats important is that you balance your method of accessing that gas against any potential problems it may cause you. Having a strict mantra like Mike has endorsed has value. Its a choice each individual must make. I for one have become comfortable over the years with a system, but will always keep an open mind that someone may suggest something that makes more sense to me and you can be sure I'll give it a go. One of the main reasons I come to Rebreather World. __________________ Self praise is no reccomendation. Dont try to be a great man, just be a man and let history be the judge of you. CHECK OUT OUR INTERWEBS FOR CUSTOM REBREATHER UPGRADES *WWW.NARKEDAT90.CO.UK* *http://www.grpservices.com/pursuit/* Supporting Shearwater Research Products in Europe
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20th February 2008, 05:06	#26 (permalink)
divelermentov Nutty dentist - uwdriller Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: Auckland Posts: 586	Re: Switching blocks Quote: (Originally Posted by kwinter) I'm confused, Dave. In the thread you started http://www.rebreatherworld.com/revo-...nice-pair.html there is a picture you posted. Isn't that a switching block? I think this is more a off-board on/off scenario and not a switch block as such. I do agree with Mike, wouldn't put a switch block on my unit, as a am easily getting confused anyway. Off board supply should be qjd, as this is easier for me to see which gas is plumbed in. And if i want to turn one supply off - well i like that valve on/off thing. for bailout - well just will have to carry sh$^$ loads of tanks, not real way around this anyway. but these are only my .02 __________________ May The Sorb Be With You
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