Looking for info on Oxygen Concentrator and national 8 torch

[Noelford]

I am working with a National 8 torch. My husband want to purchase an Oxygen Concentrator for my christmas gift. My question is, I would like to be able to use a SM-7 and SM-21 tips. I have seen the chart from National Torch and don't know how to convert the CFH. It looks like the PSI would be high enough. Does anyone have any recommendations? I appreciation any suggestions!

Thank You!
Darla

[Lorraine Chandler]

Sure! I have an excellent recommendation for your needs.

Call up Sundance Glass in Paradise California. They have a concentrator on sale, only $40.00 shipping and they have the national tips you want. You can get everything you need and they should be able to answer all of your questions.

[Dale M.]

Some years ago I had a National 8M with SM7 tip loaned to me ... I was running it with a 1/3 psi (pancake) regulator and a 5 LPM oxycon. This combination worked sufficiently to make many small to medium size hot glass objects... This combination only puts out a acceptably moderate flame.....

One oxycon will not run the 8M sufficiently to use the SM 21 tip... Actually it will not even power SM7 tip if you want a raging (aggressive) flame. You will need at least two 5 LPM oxycons linked together to use a SM21 tip....

You may want to contact manufacturer for oxygen requirements. At one time they had a "consumption" chart on site, but I am unable to find it...

http://www.nationaltorch.com/index.html

Dale

[ArtcoInc]

Here you go, Dale

http://www.artcoinc.com/tip_pressure_and_flow_chart.pdf

Malcolm

[Dale M.]

Originally Posted by ArtcoInc

Here you go, Dale

http://www.artcoinc.com/tip_pressure_and_flow_chart.pdf

Malcolm

OK ...good...

That is not the one I had seen on their site some time back, but it works....

Thanks

Dale

[Noelford]

I called them on Friday and my husband emailed. He got the chart, and I was told that SM-21 would need to be about 30 psi. That seemed a little high to me and I was just trying to find out if anyone uses a SM-21 tip and the psi they really use. I do appreciate the responses so far.

Thank You!
Darla

[glasshouse]

I ran the SM21 at at least 20 psi on tanked oxygen. Never less than that, and I loved the flame it produced. I also have had a Bobcat, a Minor, a Mega Minor, a Mid-Range Plus and the Barracuda I'm using now. The National 8M with SM21 tip beat them all out for most favorite. The only reason I don't currently use my 8M is because it costs so much for tanked oxygen and I never found a concentrator with that pressure output. I am seriously considering the Onsite Pro4 generator. That would power it!

[kbinkster]

Keep in mind that tank pressure does not translate directly to the static pressure output of a concentrator. It might be that 10 psi setting on an oxygen regulator is what is required to get enough flow out of the tank to feed the torch, but if you have a concentrator that provides enough flow, you may not need the high pressure output to get it to the torch.

The maximum flow rate of the 8M using the SM21 tip is 76 CFH. That is just shy of 36 LPM. Now, whether the is a pass-through rate or an actual measurement i the largest neutral flame before distortion, I do not know. Some manufacturers simply open the torch valves all the way and measure how much gas they can pass through the valves. This is impractical because the torch flame may fall apart long before the point where the valves would be open all the way.

Even if 76 CFH is a real measurement of an actual, usable flame, whether you need that much oxygen really depends on how you work and what you want to do. It could be that you would be quite happy with half of that amount. It could be that you need all of it for what you want to do.

[psinatra]

http://www.lampworketc.com/forums/sh...15&postcount=3
This was discussed elsewhere on this site. The link is above. It may not answer your specific question, but the information is relevant.

[Lisi]

Originally Posted by glasshouse

I am seriously considering the Onsite Pro4 generator. That would power it!

That's my dream machine! One of these days!

[kbinkster]

Originally Posted by psinatra

http://www.lampworketc.com/forums/sh...15&postcount=3
This was discussed elsewhere on this site. The link is above. It may not answer your specific question, but the information is relevant.

Actually, the information in the post you're linking is somewhat misleading.

First of all, when torch manufacturers give a recommended psi setting for running their torches, they are referring to tank regulator pressure settings. When you set an oxygen tank regulator to 10 psi, for example, you are setting the line pressure. The regulator reads the pressure in the line and opens and closes the gate from the oxygen tank to keep that line pressure steady at 10 psi. If you open the gate at the torch (the torch oxygen valve) the oxygen in the line goes through that gate and the line pressure drops. In response to that drop, the regulator opens the gate from the oxygen tank to let in oxygen until that line pressure gets back up to 10 psi. If the torch gate is close quickly, then it reaches that 10 psi line pressure rather quickly. If the torch gate is kept open, then the oxygen tank gate has to be kept open, and might have to be opened wider to catch up. The amount of oxygen going through the line during any given time period is the flow. Adjusting the tank regulator is really just a way to govern the flow.

When you have the torch gate shut, and you set the regulator to 10 psi, the oxygen fills up the line and goes nowhere. It is still, or static. The regulator reads that pressure, that static pressure, as 10 psi until you open the torch gate. At this point, with the torch gate shut and the 10 psi line pressure reached, the gate to the oxygen tank is closed and there is no flow. Once you open that torch gate and the oxygen has someplace to go, it's running or working, the regulator reads that running (or working) pressure. Because the oxygen in the line is now moving and the gate to the oxygen tank is open, there is flow.

All sorts of things affect the running pressure. The length of the line is a big factor. How many twists and turns and other restrictions also plays a role.

Now, concentrators are labeled most often by their static pressure. An analyzer is hooked up to the machine (blocking the flow) and a pressure reading is taken. If you were to take a running pressure reading, with the machine wide open, then it would be different it you took the reading right at the machine than if you took it several feet away. It would also be different if you hooked up a torch downline. It would again be different with one torch than with another, and on and on and on. This is probably why most concentrators are labeled with the static pressure.

GTT tested the running pressures of some machines when they were measuring oxygen consumption rates. They ran an M-10, which is supposed to put out 10 psi and I believe is the machine that the person whose post you linked sells, and found that the running pressure was about 1 psi going through their set-up. So, even if you have a 10 psi concentrator, it might not be putting out a 10 psi push at the torch with the torch wide open running the biggest neutral flame.

There has to be a certain volume of oxygen mixed with a certain volume of fuel in order to get a certain volume of fire. There has to be some push behind the volume in order to get it down the line and through the restrictions of the torch and to all the jets it needs to feed. As long as that oxygen can reach the torch head, then you have what you have. Some torches have more restrictions and/or more jets than others. You will need more push to get the volume to where it needs to go. Other torches, however, have less restrictions and/or less jets and don't require very much push from the oxygen feeding them.

On the torches that have more restrictions and need higher pressure from the oxygen to feed them, they still need adequate volume. You can't give it high pressure low volume and expect a bigger flame. You have to give it the volume it needs (from the LPM of the concentrator) AND it has to have enough push to get there (the running psi). Most of the time, the higher the static pressure, the higher the running pressure. So, the psi label of a machine is useful. But, no matter what, the flow (LPM) is crucial.

It just so happens that the torch and tips in question do not present very many restrictions. They're pretty free-flowing and do not need a concentrator with a high psi output. The do, however, need a high volume of oxygen and would do better with a concentrator with a high LPM output or two or three concentrators with low to moderate LPM outputs.

[actonglass]

Originally Posted by Noelford

I am working with a National 8 torch. My husband want to purchase an Oxygen Concentrator for my christmas gift. My question is, I would like to be able to use a SM-7 and SM-21 tips. I have seen the chart from National Torch and don't know how to convert the CFH. It looks like the PSI would be high enough. Does anyone have any recommendations? I appreciation any suggestions!

Thank You!
Darla

SM-5 and SM-7 and SM-21 tips are all designed to run on 10 psi for oxygen.........and 1 to 5 psi for the fuel................the SM-5 at full neutral burn is 14.15 lpm for oxygen.................the SM-7 is 28.3 lpm for oxygen.................the SM-21 tip is 35.846 lpm for oxygen...............................THERE ARE 28.3 liters in 1 cubic foot................so if you have SM-7 tip at 60 CFH for oxygen then divide by 60min/hour to get 1 cubic feet per minute then multiply by 28.3 liters/cubic foot to get 28.3 lpm ......................the SM-21 has 76 CFH so divide by 60 to get 1.27 cubic feet per minute .............then multiply 1.27 times 28.3 equals 35.846 lpm ................................HERE IS A LITTLE TRICK THAT WILL GET YOU CLOSE WITH NO MATH...........WORKS FOR ALOT OF OTHER CONVERSIONS TOO..............if you have 30 CFH just take that in half and you get 15 lpm which is real close to the exact answer of 14.15..................take 60 CFH and take that in have to get 30 lpm which is close to the exact answer of 28.3 lpm......................if its 76 CFH then take half which is 36 lpm which is close to the exact answer which is 35.846 lpm .................I HOPE THIS HELPS SOMEONE ..............anyone has a question about what I said then just ask me ................I am looking for glass working friends.................ALWAYS KEEP IN MIND IF YOU ARE LOOKING AT A CHART FROM ARTISTRY GLASS THEN YOU ARE LOOKING AT A CHART OF LIES

[actonglass]

an SM-21 tip requires 37 lpm of oxygen at full burn..................if you get a 40 lpm oxycon running at 91% that gives you 36.4 lpm ................the tip requires 10 psi for the oxygen so you need an oxycon that has 10 psi and 40 lpm to run an 8M torch with an SM-21 tip at full capacity...........an SM-7 tip requires 10 psi and 28.3 lpm so you need a 30 lpm oxycon with a 10 psi..................cause 94% of 30 is 28.3 lpm .....................................the reason I mulitiply by 91% and 94% is because an oxycon is only like 90 to 95% pure oxygen.............so I take that into consideration when I do the math.............

[actonglass]

one last thing................if a tip or torch is designed for a certain psi for oxygen .................lets say 10 psi ...................and you want to get a oxycon ...............I suggest getting a 20 psi oxycon that you can adjust the psi..............I am not going to get into it because kbinkster goes into it about in a post right before my several post so go read it if you want to know why I said ........what I said about getting a higher rated psi oxycon.......................but static psi and a psi with a working load is 2 different types of psi

[Noelford]

Thanks for all of the information. He purchased two 5 lpm machines for me. I never did buy the bigger tip. I haven't had any issues using the smaller tip with those machines. Maybe I'll upgrade both the Oxycons and tips this winter.

Darla