More questions for Uncle Pug--RE: CF trimix filling

[Capt Jim Wyatt]

OK---I have read and mulled over your last posts regarding the CF system I am using. I have decided to try and improve upon this system rather than go the booster route...in large part due to a minimum investment of about $4,000.

I think perhaps I need to get better regulators....what regulators do you use and/or suggest?

I'd appreciate a call on my toll free number at 1-877-886-6621 so I can pick your brain more..I'll be diving this afternoon ...but will be around this evening and tomorrow ....

Thanks in Advance..again

 

[omar]

Jim

What you want are 2-stage regulators. The 2-stage regulator will maintain a steady output pressure no matter what the supply pressure does. Then a quality flow meter with needle valve to adjust the flow from the supply to the blender. You can get a flow meter that will work well at Dwyer Inst. The Rate Master 5 inch model with brass valve will work good ($40). see:
http://www.dwyer-inst.com/htdocs/flow/qsrm.cfm#CRA

Then a little patience and time to determine the right flow rates for each mix.

oamr

 

[Capt Jim Wyatt]

I have the Dwyer flowmeter -- it is only used to meter the volume of sampling gas to the O2 & He meters.

My regulators are not 2 - stage & I will get two stage regulators.

What brand? Have a website for me to look at? What type do you have....?? I saw some at This web site.

I appreciate your help....

 

[omar]

Jim,

You NEED to put the Dwyer flow meter on the outlet of the regulator and use it to meter the flow into the blender!! This makes a world of difference. If you are using only the regulator output it is no wonder you are having poor results. Believe me it makes your life easier and you will reduce the amount of gas you waste. The 5” meters are $40.

The 2-stage regulators on the web site you posted will work fine. McMaster-Carr also has them for about the same price.

I have BOC and Matheson regulators. The BOC are expensive and more than you would need (I bought these before I knew better). The Matheson can be found on e-bay on ocassion. for some general info on regulators:

http://www.matheson-trigas.com/mathportal/_pdfs/family/regulators_selection_performanc.pdf


omar

 

[Uncle Pug]

Sorry Jim... I got busy and forgot to call... I'll try to give you a ring tomorrow (Tuesday.)

Like Omar I am using two stage regulators at the supply cylinders feeding Dwyer ball flow gauges but I have a needle valve between them.

One setup I bought from Masterline in Kent Wa for big bucks (Arnold used these for the commercial blenders he was producing.)

The other I put together using an O2 reg from an anesthesia machine... it is a preset two stage with the proper 50psi output.

I still have two anesthesia regulators left over if you are interested.

 

[Capt Jim Wyatt]

I did not realize the flow meter was for the outlet side of the regulator into the blender...I have seen regulators with a flow meter like the Dwyers...would these work as well?

The Dwyer I have meters the flow at litres/minute -- I *think* mine maxes out at about 10 LPM -- what flow rate is appropriate? I have been metering the flow in psi only...

What flow rate approximately are you using to flow out of the He regulator/O2 regulator when blending 18/40?

 

[omar]

For a 5 cfm compressor I use the 10-100 SCFH meters set at:

37 CFH for 32% O2
55CFH He & 36 CFH O2 for 30/30
45CFH He & 40 CFH O2 for 21/35

Remember that the flow meters are for air, the helium flow will be 2 – 2.5 times more than what the gauge shows.

10 SCFH is about 4.7 L/min.


omar