Oil Flow Measurement - Small Diameter - Very Cold?

[Airfix]

Our company has run many oil component tests at room temperatures and above using impeller style flow meters. However these meters become inaccurate and difficult to calibrate at cold temperatures.

What is the best flow measurement method for measuring MIL-PRF-7808 oil in a swagelok type bench test with pipe diameters up to 0.5" at temperatures of -45F.

Are there any swagelok type bolt in flow meters that use orifice plate and the P1 P2 measurements?

Are we looking at a custom flow meter or can we get something off the shelf?

If the temperature is the issue I've thought about substituting the MIL-PRF-7808 oil for something with an equivalent room temperature viscosity to represent the 7808 at cold conditions.

Thanks.

 

[StoneCold]

When I worked on lab scale stuff, we used scales for mass moved over time that is the most accurate, We also had calibrated sight glasses that we could divert the flow to the sight glass and time how long it took to fill up. Now you now the flowrate of your pump or pressure transfer method and you just divert back to the normal path for the experiment.

Regards
StoneCold