oxygen flow measurement

[jdaher]

In hospitals there are oxygen tanks where trucks regularly discharge liquid oxygen. The oxygen is then consumed as required. The oxygen flows out of the tank in gaseous phase. The administration of the hospital needs to control the amount of oxygen purchased. In the discharge there is no measurement and the oxygen company charges the hospital an estimate. The idea is to install a flow measuring device at the output of the tank to have the information remotely in a PC. I need to find a manufacturer of this equipment. The hospital is inclined to use Siemens products but I contacted the local representative and they say there is no product for this application.
Any help will be apreciated.
Thank you.

Jorge Fernández Daher. Jorge Fernández Daher
jfernandez@conatel.com.uy

 

[IRstuff]

There are two options you can employ:

1> mass-flow meters for the gas phase, which should be similar to those used in the semiconductor industry. Omega makes a variety:

http://www.omega.com/toc_asp/subsectionSC.asp?subsection=D05&book=Green

2> level measurement of liquid phase in the tank itself, which should be readily available, since most semiconductor fabs use LN2 tanks with level meters. A link to a supplier:

http://www.trgn.com/LP7/LP7.html

TTFN

 

[DaleE]

I would contact Micromotion and ask if their mass flow meter meets your requirements. I've used them on Nitrogen
gas flow.

 

[Sierra]

Dear Jorge,

Measuring the usage of gas like yours has some special requirements:
1) You need to measure Mass (not temp and pressure dependend like volume)
2) You need a big rangeability (Be able to measure big and small flows)
3) Long term stability (Prefereable no moving parts)
4) Ability to check the meter in-line (Validation)

Thermal Immersable flow meters are perfect for this job. (If the gas pressure is below 10 Barg (150 Psig)) You can get them O2 cleaned, even as Ultra High Purity units!! They are relative low cost compared to other mass flow systems. If your pressure is over 10 Bar you have to look at corioles or the newer generation Multi parameter Vortex Mass flow meters or if you are rich: corioles meters. The old fashion Delta P with P+T compensation have a high "Cost of ownership" and a low rangebility.

Corioles work over about 5 Bar, but check the pressure drop and the noise + errors created in the transition zone (Reynolds No 2000 to 6000)

Let me know if you need more info!


Paul de Waal
the Netherlands

Well since everbody is calling names anyway: Try

http://www.sierrainstruments.com

Model 780S

 

[RayRogers]

This might seem dumb, but in a previous job we just measured the weight of the tank + gas. Couldn't you just continously weigh the tank in the hospital? This avoids the specialized equipment you need when measuring and regulating pure oxygen.

Ray