Closed Column issues

I have a 3” 180 gram closed column with dewaxing sleeve. I run dry ice isopropyl slurry, I let the column sit empty with the slurry for 30-45mins, I have my material -10f or so and I pack the tube, pull vacuum and let the material come down in temp 30-45 mins. Then I used the last 2 runs BVV triblend cans cooled to -20f or so, when I insert the tip into the inlet it makes a seal and then when I open the ball valve solvent goes everywhere, solvent goes in the chamber too, but why is it not all going into the chamber? Does it have to do with the temperature of the propellant?
Also my column is leaking this is the next day after being left over night.
Is that due to the fitting loosening as the metal cooled? I am meticulous about topping up my dry ice and iso every 30 mins

You're open blasting, but the column isn't taking the butane? Is it working for a bit and then clogging up or just not taking it from the get go?


Leak wise, the gasket might be too tight or too loose. Also some gaskets aren't designed for subzero temps.

All the gaskets are rated down to -70f, im thinking the leak is just the metal contracting. Idk it’s not supposed to be an open blast, it’s supposed to be a pressurized closed column. The issue is the fuel is partially going in and partially spraying out.

FlowerPower88 said:

All the gaskets are rated down to -70f, im thinking the leak is just the metal contracting. Idk it’s not supposed to be an open blast, it’s supposed to be a pressurized closed column. The issue is the fuel is partially going in and partially spraying out.

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Did you vacuum the columns beforehand? Also the lipids might be clogging up the filter if it isn't cold enough.

@Fadedawg is very knowledgable on this sort of thing

Yes I vacuum right after adding the material then add solvent after a short wait. It seems like the issue is before the solvent even makes it into the column

Do you have a gauge on your column, so that you can check it for seal integrity and vacuum decay before adding the LPG?

What material are you using for your seals?

Does it go everywhere immediately or does it first flow into the column?

I've never tried to vacuum a closed blast column, but let the LPG fill the tube before valving off the outlet and letting it soak. It floats or pushes out the atmosphere.

For what its worth, I also ran my closed horizontal column with elbows on both ends, and vibrated it. column

Fadedawg said:

Do you have a gauge on your column, so that you can check it for seal integrity and vacuum decay before adding the LPG?

What material are you using for your seals?

Does it go everywhere immediately or does it first flow into the column?

I've never tried to vacuum a closed blast column, but let the LPG fill the tube before valving off the outlet and letting it soak. It floats or pushes out the atmosphere.

For what its worth, I also ran my closed horizontal column with elbows on both ends, and vibrated it. View attachment 5269723column

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I do have a gauge on the column, and I’m stupid, there was vacuum decay, in my head I told myself, super cooling the column may have done this, but that doesn’t make sense. I think supercooling may be what led to the vacuum decay. My seals are BUNA-N. And I depress the can to the opening and then I open my valve, when I open the valve fuel sprays out, and some also goes in, there’s no obstructions in the valve or anything, im a bit baffled, I tried multiple fill tips as well.

Fadedawg said:

Do you have a gauge on your column, so that you can check it for seal integrity and vacuum decay before adding the LPG?

What material are you using for your seals?

Does it go everywhere immediately or does it first flow into the column?

I've never tried to vacuum a closed blast column, but let the LPG fill the tube before valving off the outlet and letting it soak. It floats or pushes out the atmosphere.

For what its worth, I also ran my closed horizontal column with elbows on both ends, and vibrated it. View attachment 5269723column

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How does this work exactly? The bottom is the material column right? How do you separate the goop from the material?

FlowerPower88 said:

I do have a gauge on the column, and I’m stupid, there was vacuum decay, in my head I told myself, super cooling the column may have done this, but that doesn’t make sense. I think supercooling may be what led to the vacuum decay. My seals are BUNA-N. And I depress the can to the opening and then I open my valve, when I open the valve fuel sprays out, and some also goes in, there’s no obstructions in the valve or anything, im a bit baffled, I tried multiple fill tips as well.

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Are you sure you aren't tightening the gasket too tightly? That would explain the leakage, but not the lack of taking the butane to begin with. What kind of filter are you using? How moist was the material going in?

Okay so the top is the inlet obviously with pressure gauge and ball valve. Then below that is the shower head diffuser I call it that diffuses the liquid solvent for even dispersion into the 3” material column, which is jacketed with a sleeve that a dry ice slurry can be poured into. Then there is a hemispherical reducer that has a 150 micron mesh buna n gasket at the bottom, followed by a 5 micron gasket below that, followed by a ball valve and outlet, vertically integrated.

lusidghost said:

Are you sure you aren't tightening the gasket too tightly? That would explain the leakage, but not the lack of taking the butane to begin with. What kind of filter are you using? How moist was the material going in?

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Yes I believe the leakage and the fuel back spray are unrelated. Could be over tightening, I doubt it though, I only hand tightened, that is probably more the issue. The filters are as stated above, bvv 150 and 5 micron screen attatched to buna n gaskets. And the material was dried with a light cure, definitely dry material, not over dry, but perfect smoking bud.

FlowerPower88 said:

I do have a gauge on the column, and I’m stupid, there was vacuum decay, in my head I told myself, super cooling the column may have done this, but that doesn’t make sense. I think supercooling may be what led to the vacuum decay. My seals are BUNA-N. And I depress the can to the opening and then I open my valve, when I open the valve fuel sprays out, and some also goes in, there’s no obstructions in the valve or anything, im a bit baffled, I tried multiple fill tips as well.

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You have an obvious visual leak. The operating temperature for Buna-n is -40F-150F so I suggest checking your clamp bolt torque and verifying that you have fixed your vacuum decay issues.

As far as blowback, your vacuum won't last long after LPG injection starts, sooo how will new LPG liquid get into a closed container with no vent for the vapor?

Can you skip the vacuum and inject from the bottom until it runs out the top, and then valve it off?

Fadedawg said:

You have an obvious visual leak. The operating temperature for Buna-n is -40F-150F so I suggest checking your clamp bolt torque and verifying that you have fixed your vacuum decay issues.

As far as blowback, your vacuum won't last long after LPG injection starts, sooo how will new LPG liquid get into a closed container with no vent for the vapor?

Can you skip the vacuum and inject from the bottom until it runs out the top, and then valve it off?

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i understand, if there is no vent for air then you can only push so much into a closed container, but if the vacuum is pulled and the can is inserted efficiently then the top valve opened wouldn’t it ‘pull’ the contents of the cab into the column until 0 atmospheric pressure, then propellant should push until the pressure in the column equals the pressure in the can? (Btw thank you for taking the time to help me understand this)

When you inject liquid LPG into the vacuum, it will vaporize and fill the space, so the vacuum doesn't last long.