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Dare I mention Spiral Prismatic Packing?

PostPosted: Fri Jul 27, 2018 8:08 pm
by Mr Tinker
I came across SPP (Spiral Prismatic Packing) for the first time about a week or so ago and I have to say it sounds promising.
There is a reasonable amount of info out on the net about it and a number of fairly fanatical supporters of it too (mostly in foriegn countries by the looks of it)
It doesn't seem to have gotten a very warm welcome on here though, and it looks like it hasn't been mentioned for some time or indeeed very much at all.

It looks easy enough to make so I'm not interested in where to find it or how to get it...

But is any one here using it? What is your experience with it?

*I’m about to build a packed section for my 4” bubbler.

Cheers!

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Sat Jul 28, 2018 7:48 am
by Doubleuj
The few times it’s been brought up the OP has become so defensive about its ability that the thread turns nasty.
A normal discussion about it is ok.
My thoughts are that whilst it may have better properties than scrubbers or copper mesh, the cost of it is way beyond its benefits.

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Sat Jul 28, 2018 8:13 am
by RC Al
If you think you can make it easily enough, go hard
Reflux column's are all about the surface area of the packing, so the spp is at least great on paper.
A few things I have read list graded scoria as nearly as good
I believe A lot of it comes down to getting the size/density right for the column diameter (any packing)
The main benefit (if it works out) would be more hept by height - if you have the height available, more regular packing will do the job

After I get some stuff built, on my list to try is chainmail, should be able to buy the butchers stuff by the meter and I've made some out of spring steel before, doing a few meters of small ring stainless would be bloody hard on my hands, it would have an awesome surface area, maybe not as good as scrubbies, but way easier to clean and pack consistently.

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Sat Jul 28, 2018 3:11 pm
by Mr Tinker
Yeah RC, my thinking is all about the ease of cleaning and packing.
I used ss scrubbers in my old 2" reflux column and while it worked exceptionally well packing evenly everytime and keeping it in good condition when removing and cleaning was my only concern. Butcher's chain mail is a very cool idea.

I was certainly leaning towards scoria until I came across the SPP.
I have to agree with Mr UJ though that previous discussions about the stuff have not been exactly friendly, which makes me somewhat skeptical.

That's why I was hoping someone had actually had some real world experience with it.

I've had a bit of a play around with making some up already, it is quite a bit of work, but it should be a one off effort if it works like it's supposed to.



Cheers,

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Sat Jul 28, 2018 6:36 pm
by Peregian
Use SPP in a reflux still, packed section is 1200mm in length. When first used it had one roll of copper mesh at the top to hold the SPP in place with the bottom section packed with rolls of copper mesh, the SPP was trapped between the two lots of copper mesh, the SSP took up about 600mm mainly towards the top of the column. This worked very well but got tired of cleaning and replacing the lower copper mesh, it became black and skanky.
Replaced the lower mesh with SS scrubbers but the resulting neutral is not as good with out the lower copper.

It pays to remove all the packing from the column between runs as the SPP will react with the copper column and pit the surface. All Stainless steel column would be OK I think, but I like copper.

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Sat Jul 28, 2018 7:27 pm
by Mr Tinker
Thanks Peregian,

Do you find it to be as good as they say HETP wise? I suppose it is hard to tell with only being around half of the column.

Cheers

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Sat Jul 28, 2018 7:56 pm
by warramungas
SPP is better than scrubbers as it packs the column more evenly so long as its sufficiently fine.
You can get copper stuff but it costs a bomb. Copper scrubbers suffice for most due to availability and they work fine as well.
Cost is the biggest issue with SPP.

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Mon Jul 30, 2018 8:49 pm
by scythe
Yeah it sounds like a good thing.
Most of the venom comes from people getting defensive about how much they've spent, on what some people view as an unnecessary luxury.

If you can make it, go for gold i say.
I would if i had time and wanted to run a reflux column.

Copper SPP would be easier to make being softer and handy that it comes in strands to begin with all you need to do is strip the insulation off and you good to start winding.

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Wed Aug 01, 2018 6:36 pm
by Mr Tinker
So I have gone ahead and made a whole heap of these little suckers.

There is a rule of thumb I found getting around the interweb, probably pulled from someones ass years ago, that says;

- Diameter of SPP = 1/10th - 1/12th of column diameter
- Length of SPP = Diameter of SPP
- Wire diameter = 1/10th of SPP diameter

I also found;
- a couple of people who said they thought that the SPP length was probably better off being 1.5 x SPP diameter
- the biggest problem most people had with this stuff (aside from the prohibitive cost) is column flooding, normally this is using small sized SPP.

Bearing all of this in mind I've made mine 8mm in diameter using 0.8mm SS MIG wire and cut them to roughly 12mm long.



20180801_160211 copy.jpg

madrel from top.jpg


It took a little bit of stuffing about to get the shape and size of the tang right, but not too much, I only ended up making the one.
I went with the rectangular shape because it seems to give a more open spiral. The tang has to be a fair bit smaller than I first thought it would.
It is made from an old drill bit and as you can (kind of) see from the wear on it, you probably wouldn't have a lot of luck with anything much softer.


on lathe.jpg


I had the roll of wire mounted in a vise on a stand (just out of the shot) and kept the tension by hand (too little or too much and it would lose traction and spring off the tang), I also had my knee millimetres from the E-Stop at all times but found that it was quite stable while running and didn't really have any probs.


in container.jpg

in bag.jpg


I made 4l all up, enough to fill a 500mm x 4" packed section. Roughly 5500 of the little suckers.
It took a couple of hours to get set up, and another couple to wind it all out (could probably run faster, but safety first right).
I cut it with side cutters sitting on the lounge watching the telly over a couple of nights, about 5hrs all up.
It took 4.5 Kgs of wire, around $100ish if you were to buy it, so still not exactly cheap!

One last thing I found was a chart that supposedly seemed to show theoretical HETP of different sizes of SPP in different sized columns.

- 2.5mm SPP = 60-70 plates/meter in 50mm column
- 5mm SPP = 20-30 plates/meter in 50mm column
- 8mm SPP = 10-11 plates/meter in 82mm column

This like all the other info I have found may be complete BS, but trying to use the small stuff and get ridiculously low HETP in larger columns with high flows is definitely going to lead you up the flooding path.
According to the chart my 8mm stuff should put me in the ball park of scrubbers, which I will be happy with (considering it should be easier to pack and clean), and who knows it might end up better and shouldn't cause any flooding issues.

So is this stuff the miracle packing some would have you believe??? Is it going to be a better option for those of us using packed sections on bubblers???...
Probably not.

Tune in in a couple of months when I'm ready to run it to find out 8-}

Cheers

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Wed Aug 01, 2018 6:48 pm
by bluc
Def whatching with interest. Any chance of a vid showing how its wound? I dont get how the die works...Have been wondering about this stuff for a while..

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Wed Aug 01, 2018 6:51 pm
by warramungas
I think that if you had the same material as the scrubbers (scrubbers are usually ribbon like) that it would compare favourably under lab conditions.
Under real world conditions with similar properly packed columns probably not so much.
I like the idea of them that you can just pour them in and out of the column very much though.
Love your commitment of sitting for 5 hours cutting.
Saw a video of a guy that set up a drill (I think as cant remember where the video was) with a pair of snips or something that automatically cut the spp at a set period (length). It looked very jerry rigged.
Dunno if something could be setup up on your lathe for that purpose but it looks like you have all the gear for it. :handgestures-thumbupleft:
Good luck with your testing.

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Wed Aug 01, 2018 7:09 pm
by Mr Tinker
bluc wrote:Def whatching with interest. Any chance of a vid showing how its wound? I dont get how the die works...Have been wondering about this stuff for a while..


Sorry mate, didn’t get any footage, but there is plenty on YouTube. It looks very cool. I don’t really intend to make any more either.


warramungas wrote:Dunno if something could be setup up on your lathe for that purpose but it looks like you have all the gear for it. :handgestures-thumbupleft:


I figured it would take longer to devise an automatic cutter than to do it by hand. In hindsight I may have been wrong :think:

Cheers guys,

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Wed Aug 01, 2018 7:40 pm
by scythe
Good work Mr Tinker.

Nah cutting by hand would be the best option unless you were make for others.
If you were making for others sell it as one piece and someone else can cut it when it arrives.

I think i remember seeing a youtube video where a flat tapered screw driver blade was used as the winding mandrel and is had an automatic shear set up.
Was very theraputic to watch actually.

How many RPM were you running it at?
It all looks safe enough to me, coil is feeding away from the chuck, coild of wire can't over run and get stuck in the chuck either.

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Wed Aug 01, 2018 8:10 pm
by Mr Tinker
scythe wrote: How many RPM were you running it at?


Not sure mate, it’s a pretty old lathe, belt driven. I just left it at the same speed that I machined the mandrel at. I think it probably had 1 or 2 notches up from there, but I felt comfortable enough both safety and production speed wise to not bother adjusting it.

It is definitely therapeutic to watch, almost hypnotic. 2 hrs or so straight of it is more than enough though.

Cheers

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Fri Aug 10, 2018 8:50 pm
by Kenster
Mr Tinker, we all get a buzz out of producing something valuable which aids our hobby. Having said that, over the years of fiddling n researching this gig, i have found that in my case it is better to save time and money, coz all i did before was blow it on stuff that did not significantly impact on end result and where i would sit around for hours on end.
I commend you on your success and labour of love ,as i too, went thru this whole exercise some time ago... RESULT, as WJ suggested, the 'numbers' on scoria are pretty much up there, surface area/adsorbtion etc. For the 100 bucks wire cost, there is over one TONNE of 5mm scoria. Rinse the stuff, pack col, chuck it after a while and replace with clean stuff. Works a treat...Simples...
Best, simplest and cheapest packing i have used to date with out a doubt.

Re: Dare I mention Spiral Prismatic Packing?

PostPosted: Fri Aug 10, 2018 10:38 pm
by RC Al
Scoria is a bit harder to find up here in Queensland, one yard in brissy brings it up from vic and charges 400/cubic meter. This is roughly the same price as buying a bag from big green shed.

This gives you a bag of different grades to sort some how, have seen plenty of posts about smashing it to size to suit the column diameter, I'm sure many don't bother, depends how particular you want to get....

Mr tinker has spent a bit of coin and time, more than bashing rocks, but it is part of the pride in saying "I made this"

The members down south have an embarrassment of riches for distilling with the used winery gear, an abundance of Olive barrels and scoria by the trailer load, we in qld then have it better than many of the wa ppl, who have it better than the nt/tas ppl, Australia is a big place with different challenges all over

It's all a matter of perspective. :handgestures-thumbupleft: