I think i need to pig my penstock

[marcus]

hello all,

I've been running my hydro for a while at powers up to around 350w, but  recently been experimenting with increasing output, but with limited success - it seems to top out around 400w ( according to powerspout calc I should be able to get ~700w; according to H-hydro ~900w).

Checking back to when I started using it:
https://www.navitron.org.uk/forum/index.php/topic,21307.15.html
 I realise it's been going for ~7 years!  . Where does the time go?

Anyway, that coupled with clay soil/silts, and running the penstock below max output makes me think it probably needs cleaning.

any tips on what to use as a pig (the pipe is 90mm mdpe (~78mm i.d.))?

any tips on not getting the pig stuck?

I've read Pauls blog on the subject of course:-
https://lifeattheendoftheroad.wordpress.com/2018/11/10/the-pig-in-a-pipe/

I guess I can ask  http://pipelinepigging.co.uk/ that Paul referenced if they make pigs for 78mm - although I'm hoping to find a cheap option TBH


I should really have thought of this when the weather was warm and the stream low -  but...

[camillitech]

Aye Marcus,

good luck and keep us posted. I would love to be able to point you in the direction of John Macbeth of Manitoba Hydro who did that one.



https://lifeattheendoftheroad.wordpress.com/2018/11/10/the-pig-in-a-pipe/

Tragically John died suddenly a few months later of a brain haemorrhage  He was 32, fit as a butcher's dog, lean as rake, walked everywhere and didn't smoke or drink. Methinks John had actually made up his own 'pigs' for smaller penstocks using a simple sponge. Please keep us posted as I have an 800m long one that needs doing.

Cheers, Paul

[gravyminer]

When commissioning long lengths of water main ( cement lined ductile iron ) we used a tight fitting sponge and pushed it through several kilometers of pipe using the water pressure to drive it. It would have been a cellular foam ie water unable to pass through the matrix. They were around 0.5m long for a 250-300mm pipe. It would be easy enough to make one from a block.

It was always a relief to see it exit the pipe and sometimes it looked pretty knackered, even on one occasion, doubled up as the rear tried to pass the leading edge.
Usually single use as the cement lining is horribly abrasive.

And amusing what would coime out ahead of the pig - lunch boxes, flasks, waterproofs, gloves ..... the kind of thing that gets put in the open end of the pipe cos its clean and dry, then forgotten 

[Iain]

Hi
Would foam "Pool Noodles" work?
They are a closed cell construction., can be cut to length, and think they come in slightly different diameters. Might be one the correct size???

Iain

[Philip R]

I have seen several power station condenser pipe cleaning systems using the Taprogge system employing thousands of abrasive coated foam balls. The kit has an injection and recovery/ cleaning system, so no balls floating down the local river.
So following from Pauls suggestion about using a sponge and GM and Iains comments about the size of the pig sponge. Don't go too big as it might well get stuck. Better to pass one through a few times and see what comes out in terms of muck and detritus.

I had to unblock an external soil stack on a house where the upstairs wc was backing up with "brown" water. Took the branch off to the external stack to find a slow stream of dirty water coming out the loo stub out the wall. Owner gave loo a prod with a length of hose pipe and yours truly was outside. Suddenly a bath sponge, tooth brush flies out, I get out the way, and the semi solids hit the ground. Only for a lump to ricochet into my face yuck.  

Best of luck, keep us posted on progress.

Philip R

[marcus]

I'd never heard of pool noodles - done a search and they do make some big enough - 3.5" (3 1/8" would be nearer) - but all the uk suppliers i've found so far are out of stock. But closed cell foam? I have got a big pile of insulation offcuts celotex and EPS waiting for a trip to the tip - hmmm; celotex probably too crumbly but eps?

Although, maybe i ought to send down a more squigy pig first, just in case there's a bad spot in the pipe - there's a place near the bottom where the pipe goes horizontal for a few feet - maybe just a big cheap car sponge? - although it won't do if the water can get through it too easily - no, scrap that idea.

But yes to the suggestion of start small then go bigger.

found this youtoob vid (if the link works - remove space), and he uses a pair of drainpipe brushes with a 'piston' in the middle to catch the water:
https://www. youtube.com/watch?v=ROk4azf6PcI

I will post results when I get there but it may be some time - once I've found/made a pig, I won't be in a rush to actually do it. Not as bad as a soil pipe, that's true - the worst that can happen is getting soaked/hit in the face by a flying pig 

cheers for the ideas folks  

[biff]

Errr,
     How about cutting circles of 50mm Celotex, stick 3 of them together. Get a pair of old cord trousers and use the legs to sew up a tight fitting cord cover over the celotex.
 Making sure that the  cord goes across the pig as opposed to long ways  this would ensure that the pig would not need to be a terrible tight fit because the cord would wrinkle and act like piston rings as well as cleaning the pipe. It would also ensure that the insulation would not escape. It's an idea
      Biff

[marcus]

Hi Biff,
Not sure where i'd find a pair of corduroy trousers TBH  , but wrapping the celotex? mmm... maybe
cheers.
M

[smegal]

I'd never heard of pool noodles - done a search and they do make some big enough - 3.5" (3 1/8" would be nearer) - but all the uk suppliers i've found so far are out of stock. But closed cell foam? I have got a big pile of insulation offcuts celotex and EPS waiting for a trip to the tip - hmmm; celotex probably too crumbly but eps?

Although, maybe i ought to send down a more squigy pig first, just in case there's a bad spot in the pipe - there's a place near the bottom where the pipe goes horizontal for a few feet - maybe just a big cheap car sponge? - although it won't do if the water can get through it too easily - no, scrap that idea.

But yes to the suggestion of start small then go bigger.

found this youtoob vid (if the link works - remove space), and he uses a pair of drainpipe brushes with a 'piston' in the middle to catch the water:
https://www. youtube.com/watch?v=ROk4azf6PcI

I will post results when I get there but it may be some time - once I've found/made a pig, I won't be in a rush to actually do it. Not as bad as a soil pipe, that's true - the worst that can happen is getting soaked/hit in the face by a flying pig 

cheers for the ideas folks  

What about some ice cylinders for a first attempt? They'll probably melt too quickly to get that far down the pipe, but may help to check the concept.

[JohnS]

Quote from your original post:

the pipe (from the top down) is 110mm drainpipe for 12m, then 90mm HDPE for 100m (78mm i.d.), then about 200mm of 32mm flexible hose (although there's a short bottleneck in the form of a 1"BSP to 30mm hose adaptor - 25mm i.d. for 60mm), then 300mm of 28mm copper (narrowest point is the ball valve (~24mm i.d), then the nozzle.

Presumably you have decoupled the bottom of the 90 mm HDPE pipe before it reduces to the 32 mm flexible hose etc.    Can you send some rope down the HDPE pipe, maybe with a mini drogue to pull it through.  It is only 100m.  Then you can pull a pig or a wad of cloth, through without worrying about it getting stuck. 

Ditto for the 12m of 110mm drainpipe, or use drainage rods.

The 32mm hose and 28mm copper can easily be cleaned using a bottle cleaner lashed to a flexible stick or similar.

Hope this helps.

John

[marcus]

yes i can decouple the small hoses at the bottom - they're 50mm hoses now and reasonably clean.

Yes I have considered sending some stout cord down and using it to drag a pig through too - although this doesn't seem to be popular strategy among penstock cleaners - maybe most folks have longer penstocks?
cheers

[gravyminer]

I would be cautious regarding the use of PU foam for pigging.

If you have ever seen the CCTV footage of pipework, its surprising how horrible some pipe joints look, even on a well laid pipe.

The leading edge of a pipe can hang over the stop ring on the jointing collar and create quite a feature

And it all happens at once, no gentle curving ........

The sponge has proven to be forgiving enough to wriggle through 'pulled' joints.

[camillitech]

I would be cautious regarding the use of PU foam for pigging.

If you have ever seen the CCTV footage of pipework, its surprising how horrible some pipe joints look, even on a well laid pipe.

The leading edge of a pipe can hang over the stop ring on the jointing collar and create quite a feature

And it all happens at once, no gentle curving ........

The sponge has proven to be forgiving enough to wriggle through 'pulled' joints.

Sponge is good, tis what John used on small penstocks and most people already have one 

[marcus]

Ferrets?  TBH i think I'd have a better chance fitting a puck of insulation foam with a corduroy jacket than a ferret.

Thanks for the warning about joints; there's actually only one joint in the 100m (at 50m not surprisingly) and it's a blue Pipestock compression fitting so worst comes to the worst I could open it up at that point.

I think I'm familiar with the recommended foam: firm but squidgy and closed cell - i just haven't found anything in a suitable sized single piece yet (online).

As I said, I'm not in a great rush to get soaked so I've plenty of time to find something.