Duncan's New Add System

Dave Sutton

YES!!

I was just going to reply to your PM, and found this. That's the correct part number. I just ordered a few bags of them today.

The filters I use are Part Number 98355K831

These are 40 micron in-line, which is larger than what Gordon used on the original KISS but which are plenty fine for our use. LOTS smaller than the orifice size. LOTS smaller than the other filter suggested, and lots less expensive. Works great.

Sorry for late reply to your PM's, I've just been away from my catalog.

Dave

__________________
"Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com

teomannaskali

Where do you mount the filter? After the ball valve or between just before the snubber?

I suppose if there is going to be any junk it will probably come from the ball vallve getting slightly worn out or some crud enterin through the o2 feed side.

Or it could alternatively travel from the o2 injection valve side. So maybe right before the snubber is best. But what if one where to install a one way valve. That way if you have to shut your o2 for some reason moisture will not travel from the loop to the valve and snubber. What part would that be now...

Teoman

teomannaskali

I have found this check valve It is male to female and is the vitton version.
7768K61


To install the filter you either need to modify the upper right T piece in the picture to accomodate the filter (get a t piece with all the holes are femail ie instead of this 50785K321 you have to get 50785K75)

or

you need to add sex changer (50785K91) to change the mail end of the filter to a femail one.

first solution will be more compact and have less parts hence it will be better.

To make the system more compact does anybody see any disadvantage chopping of some of the excess thread?

Teoman
Teoman

Dave Sutton

As close to the snubber as possible. It can be in the hose, or anyplace.

You can use a Male/Male nipple (as you say a "sex changer" to add the filter to the system.

You do not need check valves any place in the system. The part you found is a good one, I use them for other reasons, but not on this system.

Do not remove threads to make it smaller... the threads are tapered and need to be as they are.

In my PM I offered to accept your parts and to assemble, test, and then send the system to you. Let me know if that is good for you, it will make it easy, for sure, and since I get a great FEDEX discount it will probably be cheaper too.

I am making up another system for a local guy, parts will be here next week, so I will photo it with the filter installed and you can see how I do it.


Dave

__________________
"Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com

Duncan Price

After giving up on waiting for Swagelok to deliver the parts I wanted, I butchered a spare needle vavle delivery system for parts, plus another manual add system I was putting together.

Have tested Dave's rig in the lab with a depth compensated Posiedon Cyclon 300. At an I.P of 6 bar the flow is 0.45 l/min, rising by 0.1 l/min for every bar rise in IP.

Photos to follow when I get around to it.

Tom Rose

Dave, you might want to include a check valve just after the Orifice or at least between the assembly and the entry point in the loop. This can prevent a clog later on. A check valve is real insurance.

Tom

__________________
The 50-50-90 rule: Anytime I have a 50-50 chance of getting something right, there's a 90% probability I'll get it wrong the first time.

www.atlimp.com

Dave Sutton

Hmmm.... ??

I use a BC QD at the end, don't you think that'll keep crap from going upstream in the hose and into the orifice? With that said, there are some small and nice checkvalves in the catalog, I have a few on the bench and I'll photo one next week when I get home. No objection to adding one to the system though.

Al Pyatak, Captain of the Sea Lion and my oldest dive partner, is planning to dive the Andrea Doria in July with me using a Dolphin and a cheap-kiss assembly, so that ought to provide one good data point! I'll add a checkvalve to his system just in case.

Dave

__________________
"Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com

Duncan Price

I finally got it in the water today. Dived from Wookey Hole resurgence as far as Chamber 20 and back in the company of Dr Mike. The O2 add worked a dream as did my new heads up display. Many thanks to Dave's Sutton and Mager for putting these together.


This is the feed system from Dave Sutton - I added a filter and quick disconnects. The additional manual add valve is for diluent. Below it is the electronics module for the HUD and associated cabling.


Here's the electronics - an op. amp. on the right (with blue trim pots for calibration), a pic chip etc.



Here's the heads up display. Two banks of three LED's - one for each cell. Light sequence is:
0-0.2 - fast yellow flash
0.2-0.8 - slow yellow flash + steady green
0.8-1.2 - steady green
1.2-1.4 - steady green + slow red flash
>1.4 fast red flash

There is no digital display of ppO2 - calibration is done in air by adjusting the potentiometers until the green light comes on.

The only time I had to add O2 was to flush the loop and on ascent in a 1 hour dive.

The entire rig:

jmhardingjr

So, what's the verdict, mate? Does the orifice feed work like we said or what? I'm happy you made it through your dive well. Let's put this thread to bed with your thoughts?

__________________


". . . the sea's in my veins, my tradition remains, I'm just glad I don't live in a trailer . . ."

Duncan Price

An honest opinion after a 1 hour saw-tooth dive would be cavalier...but I am well impressed. I've used my needle valve system under similar circumstances and I would say that the orifice is ahead. A check valve would be useful.

[Hijack] Dave Mager's HUD is awesome. Dave advised me to use a regular ppO2 guage in addition but I was stupid enough (and knew the dive profile) to ignore him.[/Hijack]

I could hear the orifice doing its business and was totally confident in it. I was feeding it from a non-depth compensated first stage and it coped well.

Dr Mike did well on his first ever open circuit cave dive. He even is a convert to wearing a helmet.