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Having some real challenges with our StillDragon 100L milk can boiler with agitator.
We've been supplied what looks like a non-standard issue and it has no seals between the agitator and boiler. The result is ethanol and ethanol vapour spewing out of the unit during a distillation run. Sadly we've never had the unit work properly and now looking to get a seal made to help us use the boiler and agitator properly (and safely).
The issue is in dismantling the agitator and gear box from the still to help us remove the shaft and agitator completely. Once I find out how, I'll post some images and a video of the unit being used.
In the meantime, anyone else have similar issues and manage to resolve?
Thanks
Comments
Hi Shoogle, Can you post a few quick pics so that I can see what you have.
There are several types of mechanical seal set ups that we deal with depending on when the kettle was purchased. Does the assembly attach to the kettle with a DIN type spanner nut?
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Like this?
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If so, this is what you should have
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Images available here but a few linked as below. There are no seals apparent anywhere in the agitator and gearbox assembly. Looking to get some made but not sure it would solve the issue after browsing images above. Thoughts welcome.
Agitated Seals?
:))
Are you able to see inside of the kettle to inspect for a seal access inside the kettle?
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Yes, no seal present. Hard to see from image but shaft goes straight up and out of boiler.
Can you remove the shaft so I can see the pass through?
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I have a challenge in removing the shaft. There's a flange on it just inside the boiler preventing me from lifting the whole unit out. It appears that I have to detach the shaft from the gearbox and take it down through the boiler to remove it. This is where I get stuck. It's not clear how to do this and suggestions welcome.
Yes you will need to remove the gear box. Once the small spanner nut is removed from the top of the agitator shaft, the transmission will lift off. If it seems stuck, it is only because some surface rust has formed where the shaft extends through the gear box. If so, cut a wood wedge (or two) and hammer the wedges between the gear box foot and the kettle mount. Do not use a steel pry bar or screw driver.
Is the red circled space open / hollow?
If so, measure the diameter and the diameter of the shaft.
You should be able to match up a seal.
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Seal like this.
Grease/lube all surfaces with food safe silicone grease.
DO NOT use @punkin's recommend seal.
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Awesome thanks. Managed to get shaft out and gearbox seperated. It appears that the gearbox unit has seals enclosed. The hole into the boiler is entirely open with no seals. Should we be looking at additional seals to be added?
The seals on the gearbox are to retain the gear oil inside the gearbox. That is 320 gear oil btw.
If you can accurately measure the diameter of the opening in the top of your kettle and the shaft you should be able to size up a press fit seal. One seal is all that is needed. But buy two or three along with a jar or tube of food safe silicone grease.
I'm not sure how frequently you will use the agitator, but you should expect to service that seal at least once a year. Not greasing any mated surfaces will definitely reduce the service life of the seal.
The easiest way to source is the internet and readily available.
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Great resource for any future agitator seal questions! :-bd
Your Place to be >>> www.StillDragon.org <<< Home of the StillDragon® Community Forum
Fantastic. Appreciate the insight. I take it that the unit should have had seals installed from factory? It's been 'interesting' commissioning this one. Glad for the experience.
Sure I'll try and help as much as I can.
So sorry for any inconvenience , but this kettle is a one off and sometimes the info communicated to the factory isn't always interpreted as intended.
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In terms of reassembly, any recommendations for lubricating any of the moving parts? While it's apart, would be advantageous to do any routine maintenance.
Hi @Shoogle,
Yes wherever the shaft makes contact with the seal should be lubricated. Can swab any other carbon steel parts with the same silicone grease to keep surface rust at bay. After all the environment will usually be a wet environment.
As mentioned earlier the gear oil in the transmission is 320 gear oil.
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PTFE Seals on order for the agitator housing unit (shown as blue on sketch). Any thoughts on additional seals and or gaskets required? For clarity, the gearbox unit sits on top of the housing and bolted in using M10 bolts.
The kettle is not really under much pressure at all.
A single seal should be just fine. Could double them up I suppose.
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Had a gasket provided StillDragon Europe to remedy the issue. Must say I have real concerns on this making the boiler safe to use. Anyone have any thoughts on the suitability of this gasket?
I always keep a roll of silicone gasketing material around if I need to make my own gasket in a pinch. Trace it out, cut or drill as necessary.
Big flange gaskets can be tricky, and even if you can find the size, it’s often in an incompatible material like rubber.
Should always have some gasket sheet goods
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Good point. Sheet material on order.
We've had significant corrosion of the gear box unit supplied with our StillDragon unit and contamination of the batches being prepared. Is anyone else having similar issues? We've had a catalogue of issues since we received this still from StillDragon Europe. Now looking at an alternative. Welcome others thoughts and opinions.
Frankly, it surprises me when shaft seals don't leak. There is a probably somewhat unbalanced shaft revolving hours at a time. That has to be murder on the seals. Those type of seals probably should be replaced quite often, but as you know it's a real pain the ass to change them.
I think what you're distilling probably makes a difference too. I hesitate to use the agitator in my spirit still for this reason, ethanol is far more "corrosive" than the natural oil that's in the grain that's typically being distilled in a stripping still. The stripping still is sort of self lubricating.