Critique my homebrew PP blending whip

[KD8NPB]

Any thoughts?





I have some Sherwood line valves, cleaned with boiling TSP, ready to rock with new Kel-F seats... however, I wasn't sure if I needed them. I was going to add one between the orifice flow restrictor and the QD male fitting on the O2 tank portion of the whip.

Flow chart is as follows:
CGA 540 -> Street Tee (gauge, el-cheapo) -> Orifice, flow restrictor -> QD male (have not installed yet) -> QD female -> check valve -> male-to-male SS bushing -> braided O2 hose -> O2 needle valve -> street tee (gauge, Dwyer DPG-011) -> DIN fill w/ bleeder

The QD fittings are the Parker ST series, so they are a pass-through with no restriction.

The Dwyer gauge has not been installed because I still want to clean it with some 3M Novec 7011 vapor degreaser.

 

[SCUBA_Phil]

Looks good! I would not bother with cleaning the gauge. The surface contact area is insignificant, it is tangent to the flow and it's factory fresh.

 

[dumpsterDiver]

I like to take a cooly cup and cut some of the foam and affix it to the perimeter of the guage as a shock absorber. They get smacked around on the boat and this helps the guage to last longer..

 

[rjack321]

Don't bother cleaning the gauge.
You don't need boiling TSP, simple green and hot tap water are fine.
Swap out the wrench CGA 540 with a QD and then get hand tightening CGA 540 and 580 fittings with QDs on them.

 

[KD8NPB]

Looks good! I would not bother with cleaning the gauge. The surface contact area is insignificant, it is tangent to the flow and it's factory fresh.

Thanks! However, the gauge is not quite factory fresh... I bought it from a local precision tooling & measurement place as surplus. They cleaned, rebuilt, and gave it an "official" certification sticker, but I would feel better if I gave it a good cleaning.

I like to take a cooly cup and cut some of the foam and affix it to the perimeter of the guage as a shock absorber. They get smacked around on the boat and this helps the guage to last longer..

Thanks for the tip, I will do that. Zipties save the day.

Don't bother cleaning the gauge.
You don't need boiling TSP, simple green and hot tap water are fine.
Swap out the wrench CGA 540 with a QD and then get hand tightening CGA 540 and 580 fittings with QDs on them.

It was a cheap, available, OSHA-approved method of oxygen cleaning for brass & stainless fittings, so I used it. Better overkill than underkill with oxygen, no?

Thanks for the tips with the QD, however, I don't anticipate helium blending for some time. I'll probably go through maybe 2 T-Cylinders this year...the wrench tights were on sale for less than $10, so I went with that.

 

[rjack321]

Its not really possible to clean gauges, they end up contaminated with whatever degreaser get up inside them since they are almost impossible to rinse thoroughly. Unfortunately its hard to know the history on used gauges, unless you buy one from a diver getting out of mixing.

TSP is a pretty harsh skin irritant and moderately toxic by inhalation. http://www.nationalchemicals.com/msds/documents/MSDSTSP7_10.pdf So yes it is possible to overclean something - at least to the point where its causing more harm to you and not making it any safer from an O2 fire perspective.

 

[KD8NPB]

Its not really possible to clean gauges, they end up contaminated with whatever degreaser get up inside them since they are almost impossible to rinse thoroughly. Unfortunately its hard to know the history on used gauges, unless you buy one from a diver getting out of mixing.

TSP is a pretty harsh skin irritant and moderately toxic by inhalation. http://www.nationalchemicals.com/msds/documents/MSDSTSP7_10.pdf So yes it is possible to overclean something - at least to the point where its causing more harm to you and not making it any safer from an O2 fire perspective.

I checked with Dwyer, they had O2 cleaning procedures in place. For this particular pressure gauge, it is a small straight shot less than 1/4" long in to a fluoroelastomer sensor pad. 3M Novec 7011 is approved for electronics use and is an environmentally safe, almost non-toxic substitute for Trichloroethylene & n-pB based vapor degreasers...no rinsing required, although I will blow it off / out with low pressure OCA.

For the valves, I rinsed with boiling water for 30 minutes. I was wearing nitrile gloves the whole time. Both a bubble test and pH test showed up negative for presence of detergents.

 

[USMC]

I have a "T" and a "K" tank I fill myself with a Homefill II compressor and OxyGen that produces 95% clean O2 for medical use. I have it for my glass working torch. I may try this and PP blend my own tanks that are already cleaned.
How do you calculate the amount of O2 to fill? Seems simple enough using a spreadsheet.

KC6YRS here...

 

[KD8NPB]

I have a "T" and a "K" tank I fill myself with a Homefill II compressor and OxyGen that produces 95% clean O2 for medical use. I have it for my glass working torch. I may try this and PP blend my own tanks that are already cleaned.
How do you calculate the amount of O2 to fill? Seems simple enough using a spreadsheet.

KC6YRS here...

The most IMPORTANT part of PP blending is whip cleanliness, followed shortly by valve & tank cleanliness. Most O2 fires occur during the addition of O2 to the tank, not during the "air" top-off.

 

[USMC]

That makes perfect sense. I have been filling my torch tanks for a while so that part (whip) I am not much concerned with. I just need to clean the adapter (post whip) for my "yoke end attachment".