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vsaks

Violent bubbling in the parrot

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We are testing our new production pot stills/condensers with water and there is violent bubbling/turbulence when the condensate starts for the first 10-20 minutes. I am assuming this is dissolved air escaping, and trying to figure out how to eliminate it before the parrot. We have air vents (to vent air) on the steam jacket, but the still is closed except for a 0.8 psi press relief valve. This is puzzling as I have experienced nothing like this in the small 5 gallon still used as a proof of concept. This is so bad that it would have broken any hydrometers/thermometers in the parrot.

I suspect this would happen with CO2 and air dissolved in wash runs too. Do we need to put a vent before the parrot ? Or is this a technique issue, because we'd run it slowly initially to prevent the still puking (due to the foam) ?

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The output from the condenser comes straight into the parrot, with a bypass valve on the bottom. I'll post a picture later today when I am back on site.

5 minutes ago, Silk City Distillers said:

Does your parrot have a surge breaker/vent tube?  Post a pic.

 

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Yeah that’s your problem, noncondensable gasses are coming through the parrot without a way to vent.

Easy process adjustment is to run out the drain for a little bit before you close the valve and run through the parrot.

Does your parrot attach via fittings?  If so you can improvise a vent.

Caveat - assuming you are not blowing vapor through.

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When I have seen this in the past it has always been because the product line from the condenser down to the parrot (or flow meter) has been too small and the liquid flowing down entrains air sucked in via the condenser vent.  The solution is just to use a larger diameter drain pipe from the condenser.

But it seems this is not the reason in your case. If you genuinely do not have a vent after the condenser there is nowhere for the air that is in the system at startup to escape - except via the parrot.  As the water is turned to steam and displaces the air, the air will be forced out via the parrot.  Seeing that it stops after 10-20 minutes I suspect this is the cause rather than the small drain pipe I mentioned above.

Edited by meerkat
Clarity

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If I am understanding your setup correctly then leave the drain open at the bottom of the parrot, with a bucket to catch initial condensate, until condensate starts flowing fully.

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You need a surge breaker.  Email me a picture of your parrot and description of the connections and I will fix you up with something.

paul@distillery-equipment.com

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All, thanks for the input on this issue.

@Silk City Distillers,
  Here are some pictures and a video of the parrot/condenser and another one showing how violent the bubbling gets. It seems to be the air in the system which is escaping.

parrot bubbling.mp4

@PeteB, if I bypass the parrot initially, I am wondering if I might miss the initial cut-in for the heads. Also I won't know the temp for the condensate to adjust the cooling water.

@Southernhighlander, It is a bunch of tri-clamp connections. However I wonder if the air vent will have to be somewhere higher than the height of the jar so air can escape above the fluid level.

@GeekSpirits, lots of cooling water running.

@meerkat, 1 inch pipe coming down from the condenser. As the video shows, it seems that the air builds up and eventually breaks through.

parrot bubbling.png

parrot condenser.JPG

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Yes a surge breaker or a atmospheric breather............

just put a tee fitting with a tube going up about 4' at the first joint coming off your condenser.

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It looks like maybe its not cooling all the vapor back down to liquid and its forcing a bubble out the parrot.  As mentioned a breather would help but it might just start spilling out vapor into the air.   Id put a breather on first and see if all the vapor is condensing back down and if it is still pulsing then add a surge breaker. 

 

Good luck that looks scary

 

 

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@Dehner Distillery,
  Thanks for the suggestion. Will give that a try.

3 hours ago, Dehner Distillery said:

Yes a surge breaker or a atmospheric breather............

just put a tee fitting with a tube going up about 4' at the first joint coming off your condenser.

 

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@whiskeytango,
  we are just running water now for testing, and the condensed water is cool to touch. So I doubt any of the vapor is not condensing.

3 hours ago, whiskeytango said:

It looks like maybe its not cooling all the vapor back down to liquid and its forcing a bubble out the parrot.  As mentioned a breather would help but it might just start spilling out vapor into the air.   Id put a breather on first and see if all the vapor is condensing back down and if it is still pulsing then add a surge breaker. 

 

Good luck that looks scary

 

 

 

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4 minutes ago, vsaks said:

@whiskeytango,
  we are just running water now for testing, and the condensed water is cool to touch. So I doubt any of the vapor is not condensing.

 

The vapor can push strait through the the condenser without spending enough time in it to even heat the water.  Just because you have cold condensing water coming out doesn't mean its cooling all the vapor.     What is the condenser look like?  Call the still maker and ask them WTF.  

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It appears that the stainless vessel to the right of the parrot in the photo is the condenser.  If that is so, then you will have a problem installing a vent.  In order for the condensed liquid to develop sufficient head to flow over the top edge of the parrot the level of liquid in the condenser will have to build up to slightly higher than the top edge of the parrot.  This will create a liquid seal at the bottom of the condenser and gas will not be able to get to the outlet.

If you were only concerned with flushing trapped air at startup then the suggestion by PeteB to open the bypass would be adequate. But there will also be dissolved air and CO2 in the fermented beer and this could continue to come out during operation. There will also be light ends (aldehydes etc) that some operators allow to escape from the vent by setting the cooling water flow to get a fairly high temperature for the condensate. Colder isn't always better.

By creating a seal at the bottom of the condenser you will force the pressure in the still and condenser to gradually build up (due to incondensible gases) to the point where the seal is blown and you get the surging you are seeing now.

In my experience the outlet from the condenser either flows to a small vented pot and then drains from the bottom of the pot to the parrot, or else the vent is mounted on the body of the condenser itself.  This second option is common when the condenser is mounted at floor level. We cannot see the other side of the condenser in the photo - perhaps there is already a vent mounted there?

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Agree with meerkat, this can not be easily vented.  Very odd design.  Are you sure you didn’t overlook a valve on the backside  of the condenser.  Put it together properly?  Sorry, gotta ask.

I think you are going to need a good fabricator/welder to fix that. Easy fix, parrot needs to be entirely below the condenser output and vent.  Maybe you can do it with triclamp fittings but you’ll probably need custom lengths.

Who built the still?

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The top of the liquid level where the hydrometer sits in the parrot needs to be at least 4" below the liquid level at the very bottom of your condenser.  You need a vent tube coming off of the line that feeds the parrot, that is at least 8" above the top of the liquid level in the parrot if vented to atmosphere inside the distillery ( If you do it this way you need an ethanol detector right above the vent output with an alarm or automatic shutdown).  The best thing to do is vent to the outside of your distillery to a safe area. Before you do all of that, you need to make sure that your condenser is knocking down 100% of the vapor.   Who set your parrot up the way that it is now?  Also who built your still?  Let me know where you are located. I may have someone up your way soon, as my employees travel all over.

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@meerkat, @Silk City Distillers, the condenser is above the flange so it is 5" above the parrot liquid level (per the attached picture) for drainage. What you see below the flange is the stand, with a drain from the condenser tapering to the 1" tri-clamp tube at the bottom. The simplest solution would be to put a tri-clamp tee to vent up from the bottom tube as @Dehner Distillery had suggested. Ideally the vent to start above the parrot liquid level (in the 5" space between the bottom of the condenser), but trickier to fabricate now that everything is in place. Just drilling a hole in the 1/8" thick stainless steel wall of the stand to the drain without a drill press would be a nightmare.

@Southernhighlander will send you an email. We are in San Francisco bay area.

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To eliminate the liquid U-seal formed by the tapered section below the condenser and the parrot itself you can either lower the parrot or raise the entire condenser.  Once you have the levels changed so that the section of pipe coming out of the condenser stand no longer stays flooded with liquid you can install a vent as suggested by Dehner.  It probably sounds like a lot of hassle to do, but if you don't this setup will always be awkward to operate.

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