Navitron Renewable Energy and Sustainability Forum

HYDRO TURBINES => Hydro Turbines => Topic started by: camillitech on November 10, 2018, 07:51:01 AM



Title: Pigging a penstock
Post by: camillitech on November 10, 2018, 07:51:01 AM
Always wondered how it was done so yesterday went to help a mate do one on Skye https://lifeattheendoftheroad.wordpress.com/2018/11/10/the-pig-in-a-pipe/ It was jolly good fun, for me at least. My two compatriots got soaked.


Title: Re: Pigging a penstock
Post by: knighty on November 10, 2018, 09:46:04 AM
I think I would have been terrified it would get stuck right in the middle!

Nice job :-)


Title: Re: Pigging a penstock
Post by: camillitech on November 10, 2018, 10:28:56 AM
I think I would have been terrified it would get stuck right in the middle!

Nice job :-)

Aye, me too Knighty,

both mine will need doing at some point and I've been terrified of doing them, one penstock is 250m and one 900!!!! Helping John do this one has given me the confidence to 'give it a go'. The owner too was worried, especially when it DID get stuck but that was clearly an error on our behalf due to not having comms. An air release valve had been left open and so the penstock drained without creating a vacuum to suck the pig down the pipe. Lesson learned there, always take 'walkie talkies' cos hydro schemes seldom have a phone signal  ;D


Title: Re: Pigging a penstock
Post by: Philip R on November 10, 2018, 03:03:03 PM
Paul,

Your "Pigging" procedure for cleaning the penstock was interesting to read about.

Some of the thermal power plants use an online version of this for cleaning steam turbine and other cooler tube nests. The one I have seen is the German
Taprogge system using sponge balls of a diameter slightly larger than the tube id. the balls can be coated in abrasive Pan scourer * Scotchbrite*  or just plain sponge. These would be injected into the cooler inlet water flow and recoverred at the far end via a stainer and extraction port. If the strainers were damaged, the balls were lost to the sea, river and or cooling towers.

Your friends system could have done with a valved Tee off ahead of the turbine spear valve, with it exiting above ground so as to not flood the undergroung turbine  generator  enclosure.

Good result flow increase. However was one pass of the sponge enough to clean the pipe? Especially as the pig broke up.

I would not fancy potholing down penstock to extract a stuck pig without double isolation. The health and safety implications and safe system of work would be horrendous.

Philip R



Title: Re: Pigging a penstock
Post by: billi on November 10, 2018, 03:47:50 PM
well done Paul , must be fun to do such things nowadays  with all your backround collected from a long learnincurve  exhappy:


Title: Re: Pigging a penstock
Post by: camillitech on November 10, 2018, 04:08:40 PM


Your friends system could have done with a valved Tee off ahead of the turbine spear valve, with it exiting above ground so as to not flood the undergroung turbine  generator  enclosure.





Aye Philip,

John of Manitoba Energy from Raasay (man holding pig bits) usually does exactly that when he installs a system. He did actually quote for this job but ended up loosing it to another company. I suspect they were cheaper cos they didn't include extra valves and a pig extraction method ahead of the turbine shed. I think another pass would have been beneficial too but the pig was dead so to speak  :cross

I see that company http://pipelinepigging.co.uk/pigs/ does all manner of pigs, even some hollow ones to take a transmitter.

Apparently the name comes from the early ones used on steel pipes that were often bales of hay wrapped with barbed wire. As they went down the penstock, they squealed like a pig  ;D


Title: Re: Pigging a penstock
Post by: camillitech on November 10, 2018, 04:10:20 PM
well done Paul , must be fun to do such things nowadays  with all your backround collected from a long learnincurve  exhappy:

Aye Billi, a long and interesting curve indeed, been a while since I did something so new and exciting in the RE field  ;D


Title: Re: Pigging a penstock
Post by: desperate on November 10, 2018, 05:15:58 PM
Nice one Paul, good to know the output is back up where it should be, Pigging out a concrete pump is quite exciting too, the neighbour where we are working now has a rendered overlap fence panel sh*tfan: it is quite unique I think, luckily part of our contract is to renew all fences :crossed

Desp


Title: Re: Pigging a penstock
Post by: camillitech on November 10, 2018, 06:21:46 PM
Nice one Paul, good to know the output is back up where it should be, Pigging out a concrete pump is quite exciting too, the neighbour where we are working now has a rendered overlap fence panel sh*tfan: it is quite unique I think, luckily part of our contract is to renew all fences :crossed

Desp
Hmmmm Desp,

I've a concrete road wheel on me dumper from a similar episode post batching  ;D