New ShotGun Condenser Design

[Tim]

This idea is a future modification of my 5 plate bubbler that EG has made ... maybe ... I think I had a bit of a brain fart last night, I was thinking about the traditional "Shot Gun Condenser" and I believe that a lot of the vapour would pass through the middle of each tube untouched to be condensed on the elbow above ... where I came up with this idea, it may have been done before, I don't know, but by rotating the top plate approx 45 Deg or more "Twist the top" the tubes would be set at an angle and thus all of the vapour would flow up against the edge of the tubes to be cooled by the water flowing around them. As shown Below

Shot gun.jpg

Sorry guys was playing with "Maya" and was unsure how to cut the tubes at the top and bottom plate levels lol, but I think it gives the general concept of what I mean! :-D
I would think that this would greatly improve the cooling of the vapours at this point and better refluxing ... maybe requiring less water flow?
Using this idea you could have 2 rings of tubes ... inner and outer using thinner tubes etc ... What does everyone think?

[googe]

I had this idea with a deflag, soldered it up and made a right royal mess of it so scrapped it, I'm still keen to do another now ive learnt to solder a bit better. I reckon your right, it would work well. viewtopic.php?f=36&t=2769&start=20

[Brendan]

Hey Konrad,

I don't mean to shit on your idea, but a lot of people do this already for their product condensers.

Either way it is a good idea in general to knocking down more vapour...not sure if it would hold you back as a reflux condenser...might make it too hard for vapour to pass? But I don't know, I could be wrong :think:

[MacStill]

For a PC it will be very efficient, however for an RC it would suck ;-)

Better off going for reduced coolant volume and higher coolant flow than restricting the vapour path IMHO.

[Tim]

For a PC it will be very efficient, however for an RC it would suck ;-)

Better off going for reduced coolant volume and higher coolant flow than restricting the vapour path IMHO.

I don't understand why it would "suck" for an RC, which was what I was thinking of, If the pipe dimensions were the same as the original shot gun designs only at @45 Deg, there would be no restriction of vapour path through the RC, so it would be same, the only difference would be the amount of vapour conversion, in theory considerably more, than the original method ... if this has been done before, I would be really interested in how it performed :D Any links would be great.

[Brendan]

By 'restriction', Mac was referring to the vapour's ability to move through the RC...not a physical dimension restriction, but restricting it from remaining a vapour by knocking it down...

The argument against it would be that you don't want to knock all vapour down always like you do with a product condenser...when you are collecting, you are allowing a certain amount of the vapour to pass upwards through the RC. The benefit of using a straight through RC with reduced coolant flow, is that you have fine control and a quick response when you adjust the coolant. Having the twisted tubes in this configuration will induce more 'passive reflux' against the surface of the vapour tubes, and will probably give you less control in terms of how quickly it responds to your adjustments...it will knock down more vapour for sure...but is that good?? :think:

I can't say i've seen anyone use that design for an RC, but that doesn't mean you can't give it a go if you're keen. Be sure to let us know how it runs for the benefit of everyone here :handgestures-thumbupleft:

[MacStill]

That design would require such minimal coolant flow it would be ridiculous to control when you want to get the take off speed just right, I don't need to build one and test it to know it's going to be problematic.

You can attain full reflux with a single 2" pipe running through a 4" shell about 125 mm long, but I thought that was a prick of a design and only use straight through shotguns for the last few years.

Reduced coolant volume with increased coolant flow gives you better drivability, there's no need to go silly over engineering a simple design that already works "perfectly"

But hey, each to their own I guess 8-}

[Brendan]

there's no need to go silly over engineering a simple design that already works "perfectly"

This springs to mind... :))

overengineered-header-333x250.jpg

[Tim]

That design would require such minimal coolant flow it would be ridiculous to control when you want to get the take off speed just right, I don't need to build one and test it to know it's going to be problematic.

You can attain full reflux with a single 2" pipe running through a 4" shell about 125 mm long, but I thought that was a prick of a design and only use straight through shotguns for the last few years.

Reduced coolant volume with increased coolant flow gives you better drivability, there's no need to go silly over engineering a simple design that already works "perfectly"

But hey, each to their own I guess 8-}

Thanks Brendon & Mac ... very interesting, I am trying to get my head around how the shotgun achieves full reflux ... is it because left over vapour condenses from the elbow at the top of the still, or does the vapour act like a liquid when passing through the tubes and the cooling cools all of the vapour?

[emptyglass]

By 'restriction', Mac was referring to the vapour's ability to move through the RC...not a physical dimension restriction, but restricting it from remaining a vapour by knocking it down...

The argument against it would be that you don't want to knock all vapour down always like you do with a product condenser...when you are collecting, you are allowing a certain amount of the vapour to pass upwards through the RC. The benefit of using a straight through RC with reduced coolant flow, is that you have fine control and a quick response when you adjust the coolant. Having the twisted tubes in this configuration will induce more 'passive reflux' against the surface of the vapour tubes, and will probably give you less control in terms of how quickly it responds to your adjustments...it will knock down more vapour for sure...but is that good?? :think:

I can't say i've seen anyone use that design for an RC, but that doesn't mean you can't give it a go if you're keen. Be sure to let us know how it runs for the benefit of everyone here :handgestures-thumbupleft:

And Brendan wins a free drink at the bar for "best explanation of the day"

Konrad, there is no turning back now, the addiction has set in. If you wake in the night and rush to a sketch pad, its ok, you are amongst freinds.
I've made product condensers like this before, but the difficulty in production is not worth the benifit. Easier and cheaper to just add or subtract a bit of length to get what you want. As Mac said, there is more to a reflux condenser than just efficiency. There is a bit of effort to make one, and it sort of crosses to the point of diminishing returns.

It works the same way condensate forms on a cold glass. its looking for a place to condense, once it works its way through the tubes its attracted to the walls. Another way to think of it is the steam from a kettle condensing on a cold window.

[emptyglass]

there's no need to go silly over engineering a simple design that already works "perfectly"

This springs to mind... :))

overengineered-header-333x250.jpg

:laughing-rolling: :laughing-rolling: :laughing-rolling:

[Tim]

By 'restriction', Mac was referring to the vapour's ability to move through the RC...not a physical dimension restriction, but restricting it from remaining a vapour by knocking it down...

The argument against it would be that you don't want to knock all vapour down always like you do with a product condenser...when you are collecting, you are allowing a certain amount of the vapour to pass upwards through the RC. The benefit of using a straight through RC with reduced coolant flow, is that you have fine control and a quick response when you adjust the coolant. Having the twisted tubes in this configuration will induce more 'passive reflux' against the surface of the vapour tubes, and will probably give you less control in terms of how quickly it responds to your adjustments...it will knock down more vapour for sure...but is that good?? :think:

I can't say i've seen anyone use that design for an RC, but that doesn't mean you can't give it a go if you're keen. Be sure to let us know how it runs for the benefit of everyone here :handgestures-thumbupleft:

And Brendan wins a free drink at the bar for "best explanation of the day"

Konrad, there is no turning back now, the addiction has set in. If you wake in the night and rush to a sketch pad, its ok, you are amongst freinds.
I've made product condensers like this before, but the difficulty in production is not worth the benifit. Easier and cheaper to just add or subtract a bit of length to get what you want. As Mac said, there is more to a reflux condenser than just efficiency. There is a bit of effort to make one, and it sort of crosses to the point of diminishing returns.

It works the same way condensate forms on a cold glass. its looking for a place to condense, once it works its way through the tubes its attracted to the walls. Another way to think of it is the steam from a kettle condensing on a cold window.

Thanks EG, lol yes sometimes I do wake up at night, and think "Why wasn't that done this way" ... lol lots of thoughts. Have you guys tried increasing the amount of tubes to reduce the volume in the RC for quicker control as Mac said? And how did that go, was it too touchy?
I believe nothing is ever perfect, or we would all use pot stills ... but some very smart dude designed a plated bubbler and OMG how much better is this beast!! :D

[bt1]

Howdy,

I love tinkering about with designs. This is current RC on near on 4" glass column. It's the same idea as mac mentioned...reduced coolant volume for faster response times. It's a 7 x 19.7 3/4" inner tube type.
Works well.

IMAG0021.jpg

cheers
bt1

[Tim]

Looks great, you did a great job on that, what did you have to increase your flow rate to? To compensate?

[Brendan]

Howdy,

I love tinkering about with designs. This is current RC on near on 4" glass column. It's the same idea as mac mentioned...reduced coolant volume for faster response times. It's a 7 x 19.7 3/4" inner tube type.
Works well.

IMAG0021.jpg

cheers
bt1

Nice innovation there bt1...

You could've just used a tuna tin by the look of it! :laughing-rolling:

[bt1]

Howdy,

cheeky but freaky.. I call it TC 'tuna can" condenser...

It got another run on the glass still yesterday am for a neutral and pm for a Irish. Due to lower volumes to hold a 4" in near full reflux it needs to flow hard, but during the run it's self like it's larger two brothers 1 x 120mm and 1x 160mm it uses remarkably the same very small flows.

Once your RC sets up "cool zone" and especially the bottom surface of condenser drops a degree or two...it don't take much to maintain it during a run it seems regardless of the coolant volumes.

bt1

[snapperhead]

fluid dynamics hurt my brain

[snapperhead]

Its common in drag bike racing to run slightly smaller bore carbs because the increased flow vs volume makes for better metering and faster response, I have to agree with Mac & BT on this one, even though my brain hurts from thinking about fluid flow. Fluids should be for drinking, not thinking.