How tight to pack a column?

[shadylane]

Often folks ask how tight to pack a column.
I don't have an answer, but I thought this might be a way to accurately test how restrictive the packing is and give a base line for comparisons.

[Dancing4dan]

Interesting idea.

[OtisT]

It’s been a while, but I recall using 1 pound of copper mesh to pack 36” of height in my 2” column. The rolls I got were all one pound but the width would vary: usually 5” or 6” wide. If it was a 5” wide roll I would measure the whole roll then cut it into seven equal length pieces. If it was a 6” wide roll, I would cut it into six equal length pieces. I’d roll those up fairly tight to fit them in.

When loading the column, I was careful not to compress the rolls by pushing one into the other hard. I used a stick with a mark every 5 or 6 inches, so I knew how far to push it in w/o having to cram things. The other end of the stick had a small cup hook for extraction. That let me pack/unpack w/o damaging the rolls. I’ll look for that post later to see if I can find the details.

[Copperhead road]

Interesting idea.

+1

[shadylane]

With the manometer connected this way, only the restriction caused by the packing would be measured.
The dephleg and product condenser would have no effect the measurement.

[Dancing4dan]

Found a gauge from an old sphygmomanometer that I should hook up for a reading.

[shadylane]

I had to google sphygmomanometer.
Seems to me it would be difficult to use a devise made for measuring blood pressure for what's needed.
The gauge only has one input and not meant for measuring differential pressure.

[Salt Must Flow]

shadylane, does a device have to read "differential pressure" to read backpressure within the boiler? Wouldn't a sphygmomanometer read similarly, but in a different convention? I think of a sphygmomanometer like a really sensitive pressure gauge. Wouldn't it read the boiler backpressure of a supposed 'properly operating' reflux column. The height of the fluid within a manometer could also be used to read the backpressure within the same supposed 'properly operating' reflux column. Wouldn't they both be essentially be doing a similar thing, but in a different way? I could be way off, but this is how I learn.

[shadylane]

For what's needed, the pressure measurement has to be differential and not based on a comparison to atmospheric pressure.
We need to measure only the packing not the entire still, otherwise restrictions to flow and pressure drop caused by the dephleg and PC would affect the accuracy.

[Yummyrum]

I have to agree with Shady .
Whole purpose of this topic is to measure pressure differential across the packing .

It would also be interesting to see the pressure differential between top of packing and atmosphere . …. Just for shits and giggles .

Perhaps two Spagnometers .One at the top , one at the bottom . The difference would be the pressure across the packing .

[Demy]

I'm following with interest......I guess the old procedure of blowing through the tube is out of place here...

[Saltbush Bill]

I'm following with interest......I guess the old procedure of blowing through the tube is out of place here...

Im following with interest to, but I think people are way over thinking this.
Regardless of outcome I'll just do it the way I always have... its hard to beat azeo.

[Dancing4dan]

I had to google sphygmomanometer.
Seems to me it would be difficult to use a devise made for measuring blood pressure for what's needed.
The gauge only has one input and not meant for measuring differential pressure.

Lol. It’s just a pressure gauge that actually reads air pressure from the rubber bladder of a blood pressure cuff. I’m out of province and will post a pic when I get back home

[Dancing4dan]

Don’t forget that a sphygmomanometer was a column of mercury that measured blood pressure acting on a air chamber pressurized by a hand bulb