Ketene Flow measurement Help

[mcnabda]

I am trying to find a flowmeter that could accurately measure gaseous ketene flow at <0 oC and <200 mmHg vaccuum. Our current flowmeter is a venturi meter with a DP Xmitter. But because of ketene's reactive nature, the residue formed from it's self-polymerization plugs the taps leading to inaccurate readings. Does anyone know of a reliable flowmeter that could measure gaseous ketene within 1-5% accuracy and that could handle the reactive enviroment?

Thanks

 

[hacksaw]

you can use purges, although these tend to result in deposition at the process/purge interface.

You can also mount you leads on top of the line to allow self draining. None of these will effect a permanent fix, however.

Does the polymer have a &quot;pour point&quot; that heat tracing can help with? Does it polymerize in the pipe? There are alternative meters, but they measure a velocity of some kind and therefore tend to produce meter indications that drift with the degree of polmerization taking place.

It is a tough service

 

[25362]

All of Hacksaw's suggestions are in line. Could you exploit the fact that ketene dissolves in acetone to keep it from plugging by self-polymerization ?