StillSmart

I had a few goes at welding when I was eighteen - I was not very good at it. Today I spent the day with my brother in-law, the plan was to familiarise my self with a plasma cutter (very cool) and a MIG welder.

My bother in-law cut the hole for the element fitting, and I did the small 1/2" pressure relief connection. And after a few test runs, I went ahead and had a go at doing the welds - I made a bit of a mess of it - had to clean up a load of splatter - but in the end I'm pleased with the result.

Here is the 2-1/4" stainless full socket for the element.


And this is the 1/2" socket that I'm going to use as pressure relief.

I am green with envy for a variety of reasons, perhaps the main one is the fact that you have useful inlaws. Having plasma cutters and MIG welders in the family is something that I can only dream of, you married vey wisely.

You keep telling me that you are not DIY orientated but I think you have been kidding me - well done.

I am looking forward to seeing what goes in the pressure releif fitting, it is something that I think about regularly but never come to a conclusion.

Great work! I am in a similar boat to YHB though, no useful inlaws or mates unfortunately. I have looked at college courses in welding etc (mainly to fix my own cars to be honest but would be handy here) but <rant mode on> they're either expensive or else they're in the day, which means if I was a dole scrounger I could go on the courses but seeing as I have a job I am excluded... where is the justice there eh?!?! <rant over!>

Yes, it is useful, however, it's all been done with a bit of smoke and mirrors - I wouldn't tell then the real purpose of the boiler - I have said it is for steam mashing grain for home brew beer - they are not drinkers, and straight as an arrow.
If they were in on it, that keg would have had an 8" ferule for cleaning access

Oh, just to add on the pressure relief. I have an hot water system relief valve, but I am not going to use it. Its rated at 3 bar - 45psi, there is no way I want vapor venting under that sort of pressure - it does have a nice gauge, and can be manually triggered, but I've decided to go down another route.

Basically I plan on having some 22mm pipe, one end out the 1/2" fitting and the other end submerged in the wash just above the level of the element.
If something blocks head the pressure will then push the wash out the pipe, but never to a level that exposed the element -
this should give me time to react before the vapour starts out the pipe. Also if I attach some air line to the pipe and have this running to a bucket i would get bubbling, then wash being pushed out, then if shutting down the still wasn't enough the vapour would be vented into the bucket, hopefully cooling it enough that it would be harmless.

I plan on testing this out, so watch this space.

If I read this right - the two options are;

1) Boiling mash being ejected from the vent

2) Equally as hot vapour being bubbled through the water trap

Both these seem to have inherent risks the severity of which, I would imagine, depends on the speed at which the liquid / vapour is travelling and where it is vented? I would think that squeezing the volume of vapour down to the size of an airline would result in relatively high speeds or am I reading your proposal incorrectly?

It has always been my intention to have a play with a pressure switch from a washing machine they seem economical and very sensitive and are used to control the water level in the washing machine quite accurately. Some of the switches have 2 or 3 pressure settings to choose from. Does it seem feasible that I could add one of these switches into take off line similar to yours to operate an alarm / or a contact to switch off the power?

Do you have any washing machine engineers in the family?

You do read it right - I recently had a mishap when boiling up some grain for a wash - no alcohol in the boiler - just water and grain. Had the column on to try and prevent aromatic compounds from being boiled off, column got blocked and still overpressurised. - this was a very stupid thing to do with grain in the boiler.

As I was not taking anything off - 100% reflux of the water vapour if you will, there was no noticeable signs before the lid started hissing.
I killed the power - and at arms length undid a clip and ran.
The result was a room full of vapour and a very wet garage, this happened in a fraction of a second.

I have no idea what pressure was in there, but I don't wasn't to experience a violent depressurisation like that with volatiles in the mix. That is why I'm thinking more along the lines of ejecting the mash first - it will start to happen at a really low pressure - Sweede over on AD has a set up where he pumps out his still to waste using a bike pump to pressurise the system
I will be looking at some sort of silicon hose that will stand up to the heat - 1/2" diameter.

of course this has its risks - but a "pop" style refief that lets the still get to a high pressure then violently depessurising is much less controlled.
All I'm looking for is a head start, to kill the power and get out of there.

I use a large bore (1") condenser - I cant see me having any issue when running the pot. I might want to stick a 3" column on the larger boiler sometime next year so thinking about it now.

I have thought about pressure switches - my concern is material it is made of, as I sometimes charge with 40% spirit - or the small diameter of the sensor could become blocked with grain - if stilling on the grain.
I have thought about this, which could be used to transform low pressure changes into readings that a less sensitive pressure transducer could be used, and is isolated from the vapour - some sort of inert\non-toxic hydraulic fluid could be used -

Capt'n

Sorry yor sketch is a bit small and I can't read the writing, any chance of a larger version?

If you are planning to convert the pressure into physical movement, a piston of sorts ( that I am sure your sketch shows but I cannot read )would not a simple micro switch and a relay do what you are trying to do without the need for the other half of the hydraulic circuit?

The washing machine pressure switches I was quoting work on air pressure. This link http://www.youtube.com/watch?v=HZZ2bDMspj8 explains it better than I can. If the guy can actuate the switch by blowing I think it should be sensitive enough to pick up the changes in pressure we are looking for. Could the switch not be placed in the wash overflow line away from corrosive vapours and sediment in the mash?

It's late and I have had a long day, maybe I am not thinking straight. I will have a doodle tomorrow and see if I can put my thoughts down on paper.

Brian, the sketch is a bad idea - works well converting high to low pressure, not so good the other way - a bit of a brain fart.
Will get back to you later today when i'm not so drunk

Capt'n

Hope you enjoyed the drink, some of yours?

Just a thought. Is dumping the mash going to achieve anything?

The pressure is coming from the vapour, I would have thought that the volume of liquid that will be draining from a boiler in comparison to the amount of steam still being produced until things cool down will be very small and therefore will do little to reduce the amount of pressure.

How about this as a method of identifying pressure build up without being concerned about the hot corrosive environment of a boiler?




I am sure that this set up would send a signal that would allow the washing machine pressure switch to actuate a relay that would close down the heater micro seconds before the pressure build up blows the plastic device to pieces and allows the steam to spew out everywhere.

OK perhaps the recycled washing machine was a bad idea, but it was only a start. If the configuration in the sketch works and it gives a clean indication of pressure build up then there must be lots of sensors that will stand the pressure (lets say 4 or 5 bar)?

You mentioned that there was a manual over-ride on your Pressure Relief Valve - what type of control, wheel or lever? - could you fit an actuator?

I am thinking - very low sensitivity pressure switch - open relay - 1) operate flashing lights ( bells and sirens would attract to much attention) - 2) cut power to boiler - 3) actuate PRV - if all fails and pressure continues to build - automatic opening of PRV at 3 bar and tell the neighbours that you have just bought a new steam cleaner for the car engine.

YHB wrote:Hope you enjoyed the drink, some of yours?

Of course - some nice gin, and then later on a blend of wheatgerm and cornflake\malt extract whiskies - its a bit to caramel for my tastes - but a nice drop.

this is the relief valve I have.

Boiled some water last night, after doing the electricals and getting the element sealed.

I'm running a 3Kw element here, as I'm on a 13amp plug - its drawing 12.5amps, I would prefer to have it on my 16amp socket in the garage for the safety margin- but its cold and dark, and more importantly the troosers is down at her mums, so i can have a keg in the kitchen.
had a bit of bother sealing it as it's an old element and I ripped the gasket removing it, so no gasket, and didn't want to use sealant as its days are numbered.

Going to fit a 20amp socket in the new-year to run a 4.5KW element - should speed the strip up considerably.





Once the output stops tasting like shit, I'll get her a jacket, condenser support arm, and think about what I'm going to do with pressure relief. - won't have any issue here as the smallest restiction is 1".

You learn a lot when you build a still.

Yesterday I thought an autoclave was a musical instrument.

Today I know that an Autoclave is a big shiny thing made from stainless steel that can hold 50 litres has a 3 kw heater a beautiful locking lid and pressure safety valves.

This link will take you to a picture of an Autoclave - Out of my league but something else to lookout for on the second hand sites and e-bay.

And capt'n this is the type of clamp I was thinking of making for my boiler.

http://www.palsurgical.com/?q=node/5

Why am I commenting here on this thread?

I stumbled on Autoclaves when I was looking for pressure safety valves.

This is an adjustable PSV that can be set below 0.5 bar, well below your current 3 bar model and should not take a lot of mating up to your half inch fitting

http://dixons-uk.com/autoclaves/support/safetyvalve.asp

If nothing else it would give you an earlier and less dramatic warning than your current valve letting go at over 3 bar.

Is this of any interest to you?

I am quite keen on this one. I will contact them when everyone gets back to work after the holidays and get a price.

Captain,

I contacted the Autoclave suppliers to ask about their Safety Valves.

For 30 / 50 litre models they recomended two valves per boiler and the price? a cool eighty five pounds each.

I tried not to stutter so I asked them for a price for a 30 litre boiler complete with 3kW heater, seals, thermometer, pressure guage and two safety valves - two thousand five hundred pounds.

Somebody posted a couple of weeks ago asking about boilers and said that cost was not an issue. Perhaps he would appreciate the lead?

hehe, you do get the odd thing popping up on ebay with tri-clamp fittings that are suitable for our use - if you inquire about new its just not ever going to be a possibility - you could get an engineering company to build something bespoke for a lot less.