Tuesday, 10 September 2013
The big job
Closing a Ray - an Experience..
Hi there,
I thought I'd start this off to tell the tale of my conversion of a Drager Ray (ebay £300) to a kiss style CCR..
Having the bought the Ray and done the TDI SCR course I dived it as a semi for just under 2 years - that was enough to realise the rather severe limitations of SCR in general.
Determined to improve it I read long and hard on this forum and elsewhere to see what others had done.
I thought I'd start this off to tell the tale of my conversion of a Drager Ray (ebay £300) to a kiss style CCR..
Having the bought the Ray and done the TDI SCR course I dived it as a semi for just under 2 years - that was enough to realise the rather severe limitations of SCR in general.
Determined to improve it I read long and hard on this forum and elsewhere to see what others had done.
Quite a lot of posts suggest that
making a CCR Ray is in fact a pretty easy job ... You get posts saying all one has to
do is buy a couple of valves and plumb them in - alas this is not quite
the truth....
The basic ideas IO read consisted of the following.
1. Add an O2 cylinder
2. Add an orifice or needle valve to get a small - sub vital - oxygen bleed
3. Add ppo2 monitoring
4. Disable the Drager ADV continuous flow function
5. Add a manual diluent add - useful for flush drills and makes descents less diaphragm challenging (heaving on the drager adv is quite hard work)
6. Get a non -depth compensating 1st stage to drive the orifice without varying the flow with depth
simple huh ? So I thought.... 1st problem - cylinders....Since I dive in the uk I was already putting two tanks on the Ray - the original 5L and a 3L pony clamped to it via an ND pony clamp to provide drysuit inflation and bailout. Alas I generally found that this weighted me very bum heavy and resulted in lower back pain after a few days of diving. The thick plastic layer in the Ray wing just wasn't enough of a weight spreader with this extra load. so new cylinder mounting arrangement required.
2nd problem - Orifice. Ok you can buy these in handy valved packages all ready to connect in - but where do you put it ? Several people have put the Drager ADV on the bottom of the scrubber with extra ports drilled and fitted out for oxygen inject and diluent. This sounded bad - I didn't want to dramatically upset the ADV at this stage so I needed a way to connect the p-port at the base of the scrubber to the gas injection and flow.
Sources of these valves included...
Gorilla Valves
Tecme Constant mass flow
That's not the whole story though - you need an in line shut-off to go with these to deal with a failure of the valve that results in continuous oxygen addition to the loop.
Further trouble comes when you go looking for oxygen compatible hoses - Miflex are the only option it seems (well there is swagelock but those things are EXPENSIVE)
3rd problem Monitoring : Ah - bit of luck there - I'm a professor of Electronics - how hard can this be ? In fact this took me about 6 months of lunch hours to get working, admittedly I did do quite a lot of redesigns and upgrades along the way.
4. Disabling the Drager ADV : in fact this is easy - just buy the dolphin sealing insert and replace the Ray one (which has a little extra groove and hole, with the Dolphin one that doesn't).
Bypass sealing insert from W+S water safety Dolphin Bypass Dichtkratereinsatz | Online Shop | W+S Water Safety Europe GmbH | Seit 1999 (35 euro)
Really seriously don't muck about with trying to epoxy a Ray insert shut or welding it or soldering it - at this price its not worth the risk of the blockage failing during a dive.
5. Manual diluent add - can be bought lots of places but stupid me - I made one instead.
6. Non-compensating reg. So these should be easy right - they are basically the kind of reg people dived with in the 60s.... surely any rubbish basic reg like a Dacor should do this ? no alas. Had to get a DS4 and close its compensating port using a bit of plastic from Tecme.
The starting point was my 'old' Ray
This shows where I'd already put in a swivel T screwed into a spare p-port plug - not too happy with the 3/8x24 unf thread cut into POM but it seemed to work. Definitely need to sort this out as its a weak point for sure.
The two cylinders here are held on the standard Ray camband and as mentioned earlier were responsible for a lot of backache.
The gorilla oxygen control valve is on the right of the unit (black square with a green button) and contains the orifice. the manual DIL is on the left.
This was totally unsatisfactory and was never dived - the hoses were too long, the weight was wrong - yuck.
For the cylinders the plan was this:
It's based on the Travel light frame from Narked at 90 - they make it for the inspiration but what they produce won't work for the Ray due the annoying back mounted ADV and exhaust valves sticking out of the wing. My version has the two horizontal ribs of the 'skeleton frame' curved back away from the wing holding the cylinders about 50mm above the fabric. Mostly this works and the cylinders don't keep pushing the dump valve.
The horizontals are 440x100x3mm with two 25 degree bends each side, two 52mmx5mm slots for cam bands and an 8mm clearance hole where they screw into the backplate. the vertical is there to provide a stand and to stiffened the horizontals against rotation (they are bent around it). It is 520x100x3mm but has a 100mm length bent at 90 degrees (in two gently 45 degree stages) to make the stand. don;t bend the aluminium too much - it cracks.
I was originally hoping to get this made by N90 and they were willing to do it but time pressure meant I wanted it NOW so I went ahead with a garage job plus a lunchtime on the mill at work. It works but its rough I may wel;l go back to the experts to get a properly made version once I've worked the kinks out of this one.
here's the skeleton attached to the backplate
Next the scary bit. the two convenient places for holes in the AP backplate are the two recessed discs 30mm in diameter and 175mm apart. Measuring these up against the Ray I found that If I put one through the slots where the original cam band threaded (just making a hole in the neoprene cover over these one the user side of the wing) then I only needed to drill one hole through the wing for the upper frame. Problem - the buoyancy bladder and counterlungs lurk about in this region.
I ended up very carefully reaching up inside the wing (there's a zip along the bottom providing easy access) and pushing the lungs (the green bit) aside, smoothing the bladder and then clamping the whole thing with two bits of wood each with a predrilled 8mm hole aligned with where I wanted to make the bolt hole. I then shoved a hot soldering iron through the hole with baited breath.... it smelled bad but it worked and after a bit of tidying up using twist drills by hand I got a hole good enough to get the bolt through. I wanted to reinforce this hole using a brass eyelet but didn't have any handy - need to get some so this is ongoing. The fabric is pretty tough though and seems to be ok for a quick test...
Now I could try bolting my frame and backplate into place. Although they are most likely not required I've kept the original Ray straps - just tidied them away into the weight pockets and threaded the backplate harness through the straps that retain them.
Here's the results. left is my Ray with a hole for the top bolt, right the wing plus frame.
Ok so here is a problem - the top frame lays on top of the scrubber wrap and strap which wont do. My evil plan had two nasty long slits in store tor sort this out - I marked the wrap with a line where I wanted the top horizontal part of the skeleton to thread through it, then punched holes at each end with a small draper leather punch before cutting the slits using nail scissors. This is more very tough fabric as you are cutting through velcro but it worked. Now I have finished torturing my poor rebreather time to rebuild him, we have the technology etc.
The top horizontal rib threaded trough the 'wrap' sits just below the retaining strap. Sorry the pictures upside down...
Great - next to thread on the cam bands and mount cylinders. APValves make some nice short cam bands for clamping argon cylinders to inspirations so I bought 4 of these and threaded them on. They do next day delivery as well - AP valves rock!
Cam bands on - seems to work so far. Cylinders next.
And now to find out if the scrubber has enough room to fit in...... nice that is stands up now though - maybe will invest in some pony boots.
So finally to put in the modified ADV - couple of spanners to remove the old sealing insert and add the new, route the hoses and see if it all fits!
Alas my master plan fails - I wanted the hoses to reach the bottom of the scrubber behind the cylinders but the top of the lower rib is too close to the bottom of the scrubber for this. I could muck about but for now I've routed the hoses over the top of the cylinders - later I'll drill the hole in the Rib higher to leave a nice big gap between the scrubber and the rib and get the hoses in there.
How do things look from the front ?
Ok - the hose routing has lead to the manual DIL hose being too short so the valve is right up at the edge of the wing. not great but otherwise looks about to plan.
Finally bung on the electronics - that'll be a post for another day...
Does my bum look big in this ?
So - quite a lot of work. Does it actually work though ? Well that's a story for another day - more specifically after tomorrows trip to Stoney cove....
Total cost so far including the original Ray (£300) is £1007 - beware homebuilding isn't always cheap! - Its fun though :)
Parts list:
1. Dolphin sealing insert €34 == £28
2. Gorilla Oxyge control valve $210==£130
3. Miflex hoses £25x2=£50 (Dive show price)
4. DS4 closing plate €15 ==£12.35
5. DS4 oxygen clean service £60
6. Manual dil valve (made my own but it would have been $165==£102)
7. AP plastic backplate ebay =£15 (but got mine from our local dive club at the same price)
8. Pre cut 3mm aluminium 5082 alloy plates 2 of 440x100x3mm and 1 of 520x100x3mm from Aluminium warehouse for the princley sum of £14+12 postage=£26. cut slots in these with a mill but could have done it just as well but slower by drilling lots of 5mm holes in a row and dremelling for a morning.
9. Stainless bolts 60mm long M8 thread £0.04 each + washers and nuts from local hardware store - bargain.
10.Sensor housing - this was a small 'bottle trap' from a plumbing centre which modified as detailed later.
11 Sensors -3 of PSR-11-39-TME from tecme €75 each ==£185
12. MPX5700 pressure sensor (for sexy deco algorithm running readout unit) £25
13.OLED display £22 but i got mine free from a nice chap called simon in reading - thanks!
14. Battery and electronic canister - bought 1m or 50mm OD perspex tube on ebay £6, cut it to length. bought a pvc end cap and got an o-ring grooved plug machined at work.
15. Handset housing - basically a clear polycarbonate project box from hammond (1591ATCL) which I used to pot the oled and leds into using clear acrylic resin and epoxy. £4.50
16. HUD - 3 rgb leds and a 10mm dia plastic test tube along with more clear acryllic and an 8 bit shift register to minimise wiring. £2.50 for 10 tubes, 30p for the register, leds 13p each
17. Swivel T for gas addition to bottom of scrubber. £33
18 apvalves offboard gas cam bands £8.60 each x4=£34.4
The basic ideas IO read consisted of the following.
1. Add an O2 cylinder
2. Add an orifice or needle valve to get a small - sub vital - oxygen bleed
3. Add ppo2 monitoring
4. Disable the Drager ADV continuous flow function
5. Add a manual diluent add - useful for flush drills and makes descents less diaphragm challenging (heaving on the drager adv is quite hard work)
6. Get a non -depth compensating 1st stage to drive the orifice without varying the flow with depth
simple huh ? So I thought.... 1st problem - cylinders....Since I dive in the uk I was already putting two tanks on the Ray - the original 5L and a 3L pony clamped to it via an ND pony clamp to provide drysuit inflation and bailout. Alas I generally found that this weighted me very bum heavy and resulted in lower back pain after a few days of diving. The thick plastic layer in the Ray wing just wasn't enough of a weight spreader with this extra load. so new cylinder mounting arrangement required.
2nd problem - Orifice. Ok you can buy these in handy valved packages all ready to connect in - but where do you put it ? Several people have put the Drager ADV on the bottom of the scrubber with extra ports drilled and fitted out for oxygen inject and diluent. This sounded bad - I didn't want to dramatically upset the ADV at this stage so I needed a way to connect the p-port at the base of the scrubber to the gas injection and flow.
Sources of these valves included...
Gorilla Valves
Tecme Constant mass flow
That's not the whole story though - you need an in line shut-off to go with these to deal with a failure of the valve that results in continuous oxygen addition to the loop.
Further trouble comes when you go looking for oxygen compatible hoses - Miflex are the only option it seems (well there is swagelock but those things are EXPENSIVE)
3rd problem Monitoring : Ah - bit of luck there - I'm a professor of Electronics - how hard can this be ? In fact this took me about 6 months of lunch hours to get working, admittedly I did do quite a lot of redesigns and upgrades along the way.
4. Disabling the Drager ADV : in fact this is easy - just buy the dolphin sealing insert and replace the Ray one (which has a little extra groove and hole, with the Dolphin one that doesn't).
Bypass sealing insert from W+S water safety Dolphin Bypass Dichtkratereinsatz | Online Shop | W+S Water Safety Europe GmbH | Seit 1999 (35 euro)
Really seriously don't muck about with trying to epoxy a Ray insert shut or welding it or soldering it - at this price its not worth the risk of the blockage failing during a dive.
5. Manual diluent add - can be bought lots of places but stupid me - I made one instead.
6. Non-compensating reg. So these should be easy right - they are basically the kind of reg people dived with in the 60s.... surely any rubbish basic reg like a Dacor should do this ? no alas. Had to get a DS4 and close its compensating port using a bit of plastic from Tecme.
The starting point was my 'old' Ray
This shows where I'd already put in a swivel T screwed into a spare p-port plug - not too happy with the 3/8x24 unf thread cut into POM but it seemed to work. Definitely need to sort this out as its a weak point for sure.
The two cylinders here are held on the standard Ray camband and as mentioned earlier were responsible for a lot of backache.
The gorilla oxygen control valve is on the right of the unit (black square with a green button) and contains the orifice. the manual DIL is on the left.
This was totally unsatisfactory and was never dived - the hoses were too long, the weight was wrong - yuck.
For the cylinders the plan was this:
It's based on the Travel light frame from Narked at 90 - they make it for the inspiration but what they produce won't work for the Ray due the annoying back mounted ADV and exhaust valves sticking out of the wing. My version has the two horizontal ribs of the 'skeleton frame' curved back away from the wing holding the cylinders about 50mm above the fabric. Mostly this works and the cylinders don't keep pushing the dump valve.
The horizontals are 440x100x3mm with two 25 degree bends each side, two 52mmx5mm slots for cam bands and an 8mm clearance hole where they screw into the backplate. the vertical is there to provide a stand and to stiffened the horizontals against rotation (they are bent around it). It is 520x100x3mm but has a 100mm length bent at 90 degrees (in two gently 45 degree stages) to make the stand. don;t bend the aluminium too much - it cracks.
I was originally hoping to get this made by N90 and they were willing to do it but time pressure meant I wanted it NOW so I went ahead with a garage job plus a lunchtime on the mill at work. It works but its rough I may wel;l go back to the experts to get a properly made version once I've worked the kinks out of this one.
here's the skeleton attached to the backplate
Next the scary bit. the two convenient places for holes in the AP backplate are the two recessed discs 30mm in diameter and 175mm apart. Measuring these up against the Ray I found that If I put one through the slots where the original cam band threaded (just making a hole in the neoprene cover over these one the user side of the wing) then I only needed to drill one hole through the wing for the upper frame. Problem - the buoyancy bladder and counterlungs lurk about in this region.
I ended up very carefully reaching up inside the wing (there's a zip along the bottom providing easy access) and pushing the lungs (the green bit) aside, smoothing the bladder and then clamping the whole thing with two bits of wood each with a predrilled 8mm hole aligned with where I wanted to make the bolt hole. I then shoved a hot soldering iron through the hole with baited breath.... it smelled bad but it worked and after a bit of tidying up using twist drills by hand I got a hole good enough to get the bolt through. I wanted to reinforce this hole using a brass eyelet but didn't have any handy - need to get some so this is ongoing. The fabric is pretty tough though and seems to be ok for a quick test...
Now I could try bolting my frame and backplate into place. Although they are most likely not required I've kept the original Ray straps - just tidied them away into the weight pockets and threaded the backplate harness through the straps that retain them.
Here's the results. left is my Ray with a hole for the top bolt, right the wing plus frame.
Ok so here is a problem - the top frame lays on top of the scrubber wrap and strap which wont do. My evil plan had two nasty long slits in store tor sort this out - I marked the wrap with a line where I wanted the top horizontal part of the skeleton to thread through it, then punched holes at each end with a small draper leather punch before cutting the slits using nail scissors. This is more very tough fabric as you are cutting through velcro but it worked. Now I have finished torturing my poor rebreather time to rebuild him, we have the technology etc.
The top horizontal rib threaded trough the 'wrap' sits just below the retaining strap. Sorry the pictures upside down...
Great - next to thread on the cam bands and mount cylinders. APValves make some nice short cam bands for clamping argon cylinders to inspirations so I bought 4 of these and threaded them on. They do next day delivery as well - AP valves rock!
Cam bands on - seems to work so far. Cylinders next.
And now to find out if the scrubber has enough room to fit in...... nice that is stands up now though - maybe will invest in some pony boots.
So finally to put in the modified ADV - couple of spanners to remove the old sealing insert and add the new, route the hoses and see if it all fits!
Alas my master plan fails - I wanted the hoses to reach the bottom of the scrubber behind the cylinders but the top of the lower rib is too close to the bottom of the scrubber for this. I could muck about but for now I've routed the hoses over the top of the cylinders - later I'll drill the hole in the Rib higher to leave a nice big gap between the scrubber and the rib and get the hoses in there.
How do things look from the front ?
Ok - the hose routing has lead to the manual DIL hose being too short so the valve is right up at the edge of the wing. not great but otherwise looks about to plan.
Finally bung on the electronics - that'll be a post for another day...
Does my bum look big in this ?
So - quite a lot of work. Does it actually work though ? Well that's a story for another day - more specifically after tomorrows trip to Stoney cove....
Total cost so far including the original Ray (£300) is £1007 - beware homebuilding isn't always cheap! - Its fun though :)
Parts list:
1. Dolphin sealing insert €34 == £28
2. Gorilla Oxyge control valve $210==£130
3. Miflex hoses £25x2=£50 (Dive show price)
4. DS4 closing plate €15 ==£12.35
5. DS4 oxygen clean service £60
6. Manual dil valve (made my own but it would have been $165==£102)
7. AP plastic backplate ebay =£15 (but got mine from our local dive club at the same price)
8. Pre cut 3mm aluminium 5082 alloy plates 2 of 440x100x3mm and 1 of 520x100x3mm from Aluminium warehouse for the princley sum of £14+12 postage=£26. cut slots in these with a mill but could have done it just as well but slower by drilling lots of 5mm holes in a row and dremelling for a morning.
9. Stainless bolts 60mm long M8 thread £0.04 each + washers and nuts from local hardware store - bargain.
10.Sensor housing - this was a small 'bottle trap' from a plumbing centre which modified as detailed later.
11 Sensors -3 of PSR-11-39-TME from tecme €75 each ==£185
12. MPX5700 pressure sensor (for sexy deco algorithm running readout unit) £25
13.OLED display £22 but i got mine free from a nice chap called simon in reading - thanks!
14. Battery and electronic canister - bought 1m or 50mm OD perspex tube on ebay £6, cut it to length. bought a pvc end cap and got an o-ring grooved plug machined at work.
15. Handset housing - basically a clear polycarbonate project box from hammond (1591ATCL) which I used to pot the oled and leds into using clear acrylic resin and epoxy. £4.50
16. HUD - 3 rgb leds and a 10mm dia plastic test tube along with more clear acryllic and an 8 bit shift register to minimise wiring. £2.50 for 10 tubes, 30p for the register, leds 13p each
17. Swivel T for gas addition to bottom of scrubber. £33
18 apvalves offboard gas cam bands £8.60 each x4=£34.4
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