Supporting Small SPP

I'm using 36 inches of 2.5mm SPP packing in a 2-inch CM still built using SD parts. I've been holding the SPP in place using about 4 inches of SPP scrubber sitting on top of a teflon gasket that's slightly undersized in the center, but I'm no longer happy with that approach (the gasket doesn't seal as well as I'd like).

I've considered other ideas, such as stringing a thin wire or two over the opening, under just a couple of inches of scrubber -- but I'm concerned about causing leaks in the gasket. I have an SD filter disc, but have heard it's not a good idea to use them to support packing.

If you're using a similar small sized SPP, I would be interested in hearing how you're supporting it.

Comments

  • I run something almost identical. I use 1 meter of 2 inch pipe filled with SPP. On top of that I use a 4" SD reflux condenser, 180 bend, then product condenser.

    I run it with huge power input (18-19 amps) and collect 4+ liters an hour at 96% according to my shiny new E-parrot.

    I support the SPP by just stuffing a handful of stainless mesh in the bottom of the column nice and tight, maybe 2-3 inches worth. Then I just pour my SPP in the top.

  • edited July 14

    I just sent out a 3" column packed with 50" of packing that is supported this way.

    I cut a circle of stainless steel woven wire mesh (5mm grid) so it was ever so slightly bigger than the internal dia of the lower column ferrule.

    Pushed in from the bottom it forms a slight cone that is nearly self holding but I soldered it for security. On top of that is a single teased open stainless scrubber and that holds up the rest of the packing. Another stainless scrubber acts as a plug above the packing.

    In my case the packing is lava rock gravel but the packed column is over 11kg and that cone of wire mesh supports the packing with no problem

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  • Those are SD brass ferrules with the slight internal ridge. The mesh cone sits resting on that internal lip and was fitted before the column tube. Works a treat.

  • edited July 25

    @mark85 said: I support the SPP by just stuffing a handful of stainless mesh in the bottom of the column nice and tight, maybe 2-3 inches worth. Then I just pour my SPP in the top.

    That's pretty close to what I've been doing, except I'm using a teflon gasket for a little added support. I'm using about 2.6 lbs of SPP, which is 0.8 psi pushing down on that mesh -- even more when I'm moving the column around.

    Your post gave me an idea. Instead of putting the mesh in a straight section of pipe, I pushed it down into a tee, first pulling some into the tee part, then pushing it through the opposite straight-through opening. That way, the mesh supports much more weight without moving than it does the old way.

    Photo below -- old way on the left, new way on the right.

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  • SD Filter plates work great for the bottom end and are very inexpensive, but the SS Scrubbie is best on top.

    DAD... not yours.. ah, hell... I don't know...

  • edited July 25

    @dad said: SD Filter plates work great for the bottom end and are very inexpensive, but the SS Scrubbie is best on top.

    Like one of these?

    2" Filter Disk @ StillDragon Europe

    I have some of these from a carbon filter setup but haven't even tried them with SPP because I feel almost certain they wouldn't allow reflux back to boiler and would act like a bubble plate with no downcomer

  • Yes there have been some people who find that the SD filter discs act to hold up the reflux and cause flooding at higher reflux rates. You could drill some larger holes to alleviate it.

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • DAD is right about the scrubber on top tho, the first time I ran it I didn't use one and found a few little springs had been thrown into the PC. Oops

  • I have a copper scrubber on the top of the column (packed similarly, except with a thermowell cap), SS on the bottom for support, acting as another theoretical plate. I'm sure the vapor flow isn't perfectly smooth around either one.

    I have an SD filter plate on-hand, but haven't used it to support the SPP, since I've heard from others who tried it that it increases the risk of flooding.

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