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reverse CM

These usually have the means for returning the spirits to the column and usually allow metering of the take off to help in the reflux.

reverse CM

Postby manu de hanoi » Fri Jun 04, 2010 5:52 am

basically a VM with a siphon.
The amount of cooling would control the amount of output (and not the amount of reflux as in regular CM).
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++ No uncondensed vapor escapes
++ the coolant use in the condenser is optimised all the time
++ There is a good chance that the VM valve be useless because of the suction strength created by the condenser. without valve this design would be cheaper than a VM

-- if too much coolant some air may be sucked in from the top reflux condenser, so a safety distance is required between the arm and the reflux condenser. A purge valve may be used during the run to remove air from the condenser (coolant is stopped so that vapor expels air from the condenser, same shall be done starting the device )




That would perhaps be a good contestant for the VM in the most convenient design. who wants to test ?
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Re: reverse CM

Postby Decoy » Fri Jun 04, 2010 8:18 am

that would work

but i think it would lack or be hard to control..
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Re: reverse CM

Postby manu de hanoi » Fri Jun 04, 2010 9:23 am

Decoy wrote:that would work

but i think it would lack or be hard to control..

Other advantages :
++Given that the flow of coolant is way higher than the flow of distillate, I believe the control would be higher than a LM/boka .
++If the water line of the product condenser is branched from the water line of the reflux condenser then the water distribution follow the respective needs of the 2 condensers. For instance, if you want to draw less product, then you reduce the water flow in the product condenser which will automatically increase the water flow in the reflux coil which is good because more reflux is needed then !!!
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Re: reverse CM

Postby mikejwoodnz » Fri Jun 04, 2010 4:35 pm

OK I am not a reflux column guy but from a pot still perspective I can't see how sufficient vapour will enter the liebig with the restriction to the flow caused by the sump at the bottom - looks to me that the vapour would just take the line of least resistance and go up the column to be refluxed and perhaps excess would escape through the top or maybe I just don't have the patience to collect drip by drip :cry:
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Re: reverse CM

Postby minime » Fri Jun 04, 2010 8:45 pm

Riku's original VM-E-Arc used a valve on the bottom of the liebig to switch to a numerically high reflux ratio when more reflux was needed. I don't think you'd get much product out Manu. Just my thought.
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Re: reverse CM

Postby Decoy » Sat Jun 05, 2010 12:05 am

the setup is based on the operation of a heat pipe..

in order to have 100% reflux the output condenser needs to be raised to 80c+
if you used the gate valve to restrict or stop takeoff the condenser would suck up air through the air lock out put then requiring some kind of priming or a method of re crating the vacuum to restart the take off.
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Re: reverse CM

Postby minime » Sat Jun 05, 2010 4:05 am

could put a vent pipe on the bottom of the liebig to make it open to atmospheric pressure. That would also make it more likely to work as described?
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Re: reverse CM

Postby manu de hanoi » Sat Jun 05, 2010 4:09 am

minime wrote:could put a vent pipe on the bottom of the liebig to make it open to atmospheric pressure. That would also make it more likely to work as described?

on the contrary, it's the vacuum created by condensation that sucks vapor in the condenser. Air would destroy that.
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Re: reverse CM

Postby minime » Sat Jun 05, 2010 4:27 am

manu de hanoi wrote:
minime wrote:could put a vent pipe on the bottom of the liebig to make it open to atmospheric pressure. That would also make it more likely to work as described?

on the contrary, it's the vacuum created by condensation that sucks vapor in the condenser. Air would destroy that.


There's no suction there Manu. I proved that to myself a long, long time ago.
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Re: reverse CM

Postby manu de hanoi » Sat Jun 05, 2010 4:33 am

minime wrote:
manu de hanoi wrote:
minime wrote:could put a vent pipe on the bottom of the liebig to make it open to atmospheric pressure. That would also make it more likely to work as described?

on the contrary, it's the vacuum created by condensation that sucks vapor in the condenser. Air would destroy that.


There's no suction there Manu. I proved that to myself a long, long time ago.

I dont see how minime, you didnt have a siphon or a closed gate on the bottom of the condenser.
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Re: reverse CM

Postby stillton » Sat Jun 05, 2010 5:29 am

i have tried to make a valve by trapping liquid to seal of the liebig. something like this:
Image

if i remember correct it more then halved the output rate when closed.
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Re: reverse CM

Postby minime » Sat Jun 05, 2010 5:57 am

manu de hanoi wrote:I dont see how minime, you didnt have a siphon or a closed gate on the bottom of the condenser.


I've experimented with different size and length liebigs, down pipes, water temperature etc, etc, etc. It made no difference whatsoever to output rate. What mainly drives our VM stills is the small pressure difference between column and atmosphere. Other variables play a very minor role. That's why Riku's VM-E-Arc works so well. The pressure difference is increased with the heads column above the takeoff port.

You've effectively blocked the output path with a siphon on the bottom so output rate will decrease.........I don't know by how much but I know it will
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Re: reverse CM

Postby manu de hanoi » Sat Jun 05, 2010 6:59 am

minime wrote:
manu de hanoi wrote:I dont see how minime, you didnt have a siphon or a closed gate on the bottom of the condenser.


I've experimented with different size and length liebigs, down pipes, water temperature etc, etc, etc. It made no difference whatsoever to output rate. What mainly drives our VM stills is the small pressure difference between column and atmosphere. Other variables play a very minor role. That's why Riku's VM-E-Arc works so well. The pressure difference is increased with the heads column above the takeoff port.

You've effectively blocked the output path with a siphon on the bottom so output rate will decrease.........I don't know by how much but I know it will

There is a ventilation on the bottom of the VM E ARC in Riku's book....
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Re: reverse CM

Postby stillton » Sat Jun 05, 2010 8:09 am

manu de hanoi wrote:There is a ventilation on the bottom of the VM E ARC in Riku's book....

that is only there to let the liquid out efficiently when the valve is opened if you use a small valve. that ventilation is blocked as soon as a few centiliters of liquid is pooled in the liebig.
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Re: reverse CM

Postby manu de hanoi » Sat Jun 05, 2010 8:40 am

stillton wrote:
manu de hanoi wrote:There is a ventilation on the bottom of the VM E ARC in Riku's book....

that is only there to let the liquid out efficiently when the valve is opened if you use a small valve. that ventilation is blocked as soon as a few centiliters of liquid is pooled in the liebig.

once air is in, it will disable partially the suction. It doesnt take much air to do so...
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