An intresting thing with outlet flow rate

[gary.angie]

howdy

I was doing a stripping run today on a gerber and i had removed the packing from column etc and turn of head cooling coil
strip went great , the taste was great from the rolled oats ,
But at the start i thought the still was having a hisss, i had steam coming out in surges , and big drops and blops on low wines.
I only had 23 liters in a 50 l keg , and i was adjusting the heat up and down and even had the head cooling running al over the place trying to settle this beast .
I first thought blockage,then weather as it was a hot day , but i kept trying to tune it in , thinking this never happened on the last strip.
Any way i suddenly realized that the last runs i had this copper fine mesh about 7 inches long, texture like a scrubber,inserted in the out let end of the condenser.
so i found it and inserted it and presto no steam and now a nice constant solid stream of low wines for about 3 inches and then turns to droplets as it falls.

so to those masters out there , am i creating a slight back pressure ? which stops the steam or is it replicating the column scrubbers.

what ever it is its great i could ramp the heat shut the head cooling and it just flows out ,temp holds well , and av is good .
with out the copper gauze up the end of the condenser, its like, the condenser cant handle (cool fast enough )the pressure of open path of flow from the boil.

any one have ideas or experienced this .

Cheers
GAry & Angie

[Hawke]

Mesh/scrubber in a liebig condenser is almost always used to stop the surging.
If you have a way to add a bit of turbulance at the head end, that will also improve performance.
I use a twisted ribbon of copper, same width as the I.D. of the pipe by 4 inches long. Give it a 180* twist and slide it in.

[Ayay]

The vapors like to run down an incline and go too fast for the heat transfer. In my limited experience a twisted ribbon will cause turbulence in a leibig but does little to slow the vapors down. A scrubber will slow down the vapors and sort things out better. I guess slowing down = back pressure; if the vapors go too fast then they arrive at the output un-condensed.

[Hawke]

The vapors like to run down an incline and go too fast for the heat transfer. In my limited experience a twisted ribbon will cause turbulence in a leibig but does little to slow the vapors down.

When I added the ribbon to my liebigs, I cut my waterflow by about 25 to 30%, for the same heat input. The idea is to break laminar flow of the vapor, which causes more heat transfer.

[rad14701]

A coiled copper wire may also work if you don't have copper sheet to cut a strip from... You should be able to coil the copper wire around the same size tube as the OD of your inner liebig tube, or a bit smaller if available, with the coils about 1/2 tube diameter apart... It shouldn't take too much coaxing to get the coil slid up into the smaller ID of the liebig... Even if it doesn't go all the way to the top it should work fine... Getting at least 1/3 to 1/2 way up should suffice but full length would be optimal...

[gary.angie]

Thanks people appreciate the responses , its good to know whats happening , and, that it is also what people are doing.
I had not herd of seen mention of it before , maybe someone has written about it in detail in this forum somewhere .
i like the idea of a flow interrupt at the head end as well for the stripping runs.
I assume that it wont be so much of an issue when the column is packed.

Thanks again

Gary & Angie

[HookLine]

Strip the insulation off a piece of electrical cable (stuff they use for standard household wiring), twist it further, then wind it around a pencil or similar at about 30º, give the overall spiral a bit of a twist, cut to roughly the length of the cooling jacket, give it a vinegar bath for a couple of hours, rinse very well, slide in the Liebig.