boiler exhaust pipe

[FlippinMental]

d'ya think this will be ok to vent boiler steam? is anyone using something similar?

http://cgi.ebay.co.uk/32mm-x-500mm-FLEX ... 4cf385a719

fm

[Kev888]

I can't see why it wouldn't work, though it would get very hot so take care. Here's my latest effort:

Its important to slope it downwards so that condensation doesn't run back to the boiler - theres quite a bit of liquid condenses too so you don't want any u-bends to get full and stop the steam. Mine is just plastic waste pipe with no supports (yet) so it sagged a lot when it warmed up and the joints needed tightening when warm too but it seems to be standing up to it.

Boingy did something similar (giving me the idea) but he used a tank connector to terminate it, which is probably better. I used a sink waste as I had a used one but it causes some restriction.

EDIT: This later failed (see post on Page two) because on bubblier brews I couldn't stop the bubbles rising up, and they caused it to get blocked with hops.

Cheers
kev

[FlippinMental]

Cheers kev888, no concerns using non-food grade plastics? i remember in the good days a warning not to ferment in black plastic bins as this could be poisonous. With all the heat going up the the spout, so to speak, is there a chance of nasty chemicals leeching, albeit your arrangement greatly reduces any return.

fm

[Kev888]

Not enough to concern me personally, really. The sink waste I used is stainless so only the first couple of inches of waste pipe could drip anything back into the boiler, and I couldn't find anything about the white plastic waste pipe to scare me. I guess if I had then I could have used a short stainless section to start with, after that anything else goes away from the boiler anyway which means I won't have to worry about sanitising it.

Boingy took his out of the side of the boiler (at the top) - I guess if you have the headroom to do that there's even less chance of stuff dripping back in and it doesn't annoy you every time yoiu want to raise the lid. I'm not sure if the plastic tank connector he used was technically food grade, but if it concerned you there must be stainless pipe fittings that would serve, at a price.

You've got me thinking again now - it would be quite useful to have a more flexible section to help in taking my lid on and off or maybe a separate entry hole for the extraction pipe.

Cheers
Kev

[Dr. Dextrin]

Interesting thread as I need to cobble together something like this.

Is 32mm about the minimum pipe diameter that'll do the job?

[JontyR]

I'm not sure how PVC would fayre but you can but 3 or 5m lengths of 32mm or 40mm flexible conduit complete with gland and locking nut for very little from any cable management suppliers. If it was suitable for the task it would be really straightforward to drill a hole and fix in place using the gland.

[Anavrin]

Im in the process of building a new 100litre boiler, something I was considering was to make a condensing chimey so that the steam would condense and flow back into the boiler, this would reduce the losses during the boil, has anybody tried this or heard of anything similar in the past?

[GrowlingDogBeer]

I think the idea is you do not want the steam to condense and flow back into the boiler as it contains all the nasties that you are boiling off. I would think building a condensing chimney would be a bad idea.

[Kev888]

Interesting thread as I need to cobble together something like this.
Is 32mm about the minimum pipe diameter that'll do the job?

I asked a similar question when I was thinking of using 22mm copper to condense the steam on the way out - here (Boingy's second post has a link which points to a thread with a link to his setup too, if you see what I mean.

Nobody recoiled in horror at the 22mm, but I did some tests and decided that it was perhaps too small - it worked but there was a reasonable pressure build up and I didn't want to restrict the escape of stuff that should be boiled off. 40mm seems much better and I have a plug-hole waste thing causing quite a big restriction in mine, so a genuine 32mm would probably be better (I do have to clamp the lid quite a bit to stop 'any' steam leaking out so I think my plug hole could do with a revision).

Cheers
Kev

[Dr. Dextrin]

Interesting thread as I need to cobble together something like this.
Is 32mm about the minimum pipe diameter that'll do the job?

I asked a similar question when I was thinking of using 22mm copper to condense the steam on the way out - here (Boingy's second post has a link which points to a thread with a link to his setup too, if you see what I mean.

Nobody recoiled in horror at the 22mm, but I did some tests and decided that it was perhaps too small - it worked but there was a reasonable pressure build up and I didn't want to restrict the escape of stuff that should be boiled off. 40mm seems much better and I have a plug-hole waste thing causing quite a big restriction in mine, so a genuine 32mm would probably be better (I do have to clamp the lid quite a bit to stop 'any' steam leaking out so I think my plug hole could do with a revision).

Cheers
Kev

Thanks, probably best to avoid 22mm then.

I've just checked and found about a metre of copper pipe I had lurking around that seems to be about 35mm OD (it was a waste pipe at one time). It'll need some serious cleaning, but if I can find some fittings I think that'd make quite a nice duct to take the steam far enough away to avoid the non-food safe plastic problem. Should look impressive too!

I fear the fittings might be a bit pricey, though.

[boingy]

I'm not sure if the plastic tank connector he used was technically food grade...

Indeed it isn't. It's one of only two components in my kit that is not food grade, the other being the Hozelock mixer tap connector.
In the case of the tank connector I figured that it is not in direct contact with the wort and that the majority of nasties that leech out are likely to be carried away and down the steam pipe rather than into the wort. It's not ideal but I think it is only a small risk.

[Kev888]

Yes i feel exactly the same about my inverted U bend. I'm a fairly cautious sort but I feel its a calculated risk, unlikely to have any issues and only very small ones if it does.

BES do a range of stainless threaded nipples you could combine with nuts to make a connector instead (they may also do brass but I've not looked). I would have done something like that if I'd been more concerned, but the bigger sizes are a little costly and I wasn't.

Cheers
kev

[Dr. Dextrin]

Maybe you could minimise the risk further by insulating the U-bend up to where it starts to turn down. If it can't lose heat, then steam can't condense in it and you won't get any run-back from that section. In an ideal world, anyway.

[BarnsleyBrewer]

I use the plastic type, works great..


BB

[Graham]

I think the idea is you do not want the steam to condense and flow back into the boiler as it contains all the nasties that you are boiling off. I would think building a condensing chimney would be a bad idea.

I don't know where this idea came from; I have seen it many times repeated on the interweb, but I do not believe it is an issue. Surely if steam is escaping, then the volatiles are escaping with it. If steam isn't escaping, you have a bomb on your hands. The small amount of condensation that might fall back into the wort will be recycled as steam and will eventually escape. Apart from a few micro-breweries, no long-established commercial brewery has an completely open copper. They have a domed copper and a chimney to a design that has been around since the nineteenth century. The copper or stainless dome will cause some condensation to occur; it is unavoidable, but it is not deemed a problem. In an earlier life, when working with micro-breweries, some local authorities have "smelliness" bylaws if the proposed brewery is/was close to habitation. To deal with this we fitted condensing chimneys; basically a u-tube from the lid of the boiler with a fine cold-water spray in the downward (floorward) section. The steam, along with the smell, condensed into a nearby drain.

I would expect that the biggest issue with a lid on would be coping with the extra foam cased by the slight positive pressure and slightly higher temperature that the restriction causes, and a reduced atmospheric cooling effect on the surface, but which has a big effect on the foam produced. Similar to boiling vegetables in a saucepan with the lid on. Take the lid off and the foam subsides. A sufficiently oversized boiler is a necessity.