Convert mg/s to SCCM (Standard Cubic Centimeters per Minute)

[jagadeeshr]

Hello,

Can anyone explain the procedure to convert mg/s to SCCM?

I'm working with an Alicat Mass Flow Controller, which regulates Argon (Ar) mass flow from 1 to 6 mg/s at 27^o C or 300 K (room temperature).

For documentation purpose, I need mass flow in terms of mg/s, as well as, SCCM.

Thank you
Jagadeesh

 

[BvU]

Hi,

mg/s is a mass flow and SSCM is a volume flow.
They are linked via the equation of state. For argon you can use the ideal gas law $pV = nRT$

Key is to find the proper standard conditions (confusion lurks, so be sure to mention them)

 

[FluidDroog]

Hi,

BvU is correct. To derive the relationship of cubic centimeters to 'standard' cubic centimeters of gas, you use the gas law equation of state. Standard means P_s= 101325 Pa, T_s = 273.15 K and Z_s = 1.
The derivation from reference [1] below should be sufficient to explain. It is a matter of setting the number of moles equivalent.
n_x =n_s => P_x * V_x / (Z_x*T_x) = P_s * V_s / T_s
Then solve for V_s = standard volume of gas

To answer your question more directly, use these conversion factors.
Molar flow is converted to standard volumetric flow via the standard molar volume 22.414 x 10^-3 m³ mol^-1 [2].
1 sccm = 0.74358 µmol/s [3].

To convert from mass flow (mdot) to molar flow (ndot):
ndot = mdot / MolarMass
To convert between molar flow rate and
sccm = (Standard Molar Volume) * (unit conversion factor) * ndot = 22.414 * 60e3 * ndot
In this case, the unit conversion factor is for seconds to minutes and m³ to cm³

References:
[1] Converting mass flow to volumetric flow rate. https://www.first-sensor.com/cms/upload/appnotes/AN_Massflow_E_11153.pdf
[2] Codata standard molar volume. https://physics.nist.gov/cgi-bin/cuu/Value?mvolstd|search_for=molar+volume
[3] NIST published conversion value from sccm to mol/s. https://tsapps.nist.gov/publication...4154&msclkid=d34cae6cabff11ec8093320a4d23498a