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Engineering challenge
ChrisW - 26/4/19 at 11:43 AM

Afternoon all

Got a bit of an engineering challenge and I thought where better to get some great minds thinking about it than on here.

We have a disused water pipe approx 1100m long and approx 600mm diameter. According to the map it is straight, but how accurate the map is and/or what tolerance they define as straight I don't know. The land rises by about 20m along the pipe length so it is fair to assume the pipe will do too. The pipe may have water in it and whilst we can drain that water out (which itself is a challenge, not least the getting rid of 300-ish cubic meters of water) it is safe to assume some sections where the pipe is entirely full will remain.

I want to get a fibre optic duct (essentially a plastic tube) through this. Or more likely a rope all the way through such that a duct can be pulled through with a winch.

We have no access to the pipe along the route, just at each end.

Can anyone think of any bright ideas for getting the rope through from one end to the other?

We've been discussing pushing something like a very long drain rod through although how you would go about applying the pushing force required for such a long distance isn't clear. Whatever the material being pushed would need a lot of lateral (is that the right word?) strength such that it doesn't just curl up in the pipe the first time it comes up against an obstacle.

Or perhaps building some kind of vehicle with sprung legs that grips inside the pipe and drives through. However there is a high chance that it will have to be completely submerged at points along the journey and there is also the issue of powering it over such a long distance.

All thoughts, ideas, suggestions, etc gratefully received!

Chris


jonkoxe11 - 26/4/19 at 11:53 AM

Radio controlled car should do it. Strap a torch and gopro to it and off you go.


nick205 - 26/4/19 at 12:00 PM

Do you not have any access to the land on the surface?

1.1km is quite a distance to travel underground, I'd favour trenching myself of some form to sink the cable from above (away from the pipe).


ChrisW - 26/4/19 at 12:13 PM

We're well versed with trenching. The issue is that the land owner above will not allow access to dig.... well, he wants a massive ransom to do it, which is as good as not allowing it.

The pipe runs right under his land, hence we can only get access at the two ends where it emerges onto other farms.

Chris


coyoteboy - 26/4/19 at 12:29 PM

radio controlled car won't do it if it's fully submerged at points. It also would struggle for traction with the weight of the rope unless you went with something like a dyneema kite line.

You want to make a pneumatically driven pipe pig.

Roller wheels, soft flexible seals at one face, seal off the end of the pipe with your full rope spool in it and hook up a compressor, then leave it to work its way out. That will evacuate the water and pull the rope through with ease. Caveat being the pipe needs a smooth inner diameter and to be able to hold enough pressure to counteract pushing the full weight of the water up the full rise height.

http://girardindustries.com/

Careful at when they come out the end https://www.youtube.com/watch?v=6sBO0lO7AFk


[Edited on 26/4/19 by coyoteboy]


Sam_68 - 26/4/19 at 12:33 PM

You might look at the crawler robots they use to undertake CCTV sewer surveys - possibly one of those could draw a fine line (look at braided - not monofilament - fishing line) through, which could then be used to pull progressively heavier lines through.


David Jenkins - 26/4/19 at 12:39 PM

BT sends cords through ducts using compressed air - the blast of air drags the cord along the duct. The cord is then used to pull cables.

No idea whether you could do something similar.

[Edited on 26/4/19 by David Jenkins]


ChrisW - 26/4/19 at 01:05 PM

We do exactly that with the fibre optic duct once it is installed. They are 12mm internal diameter for trunk cables and 5mm for customer drops and it works pretty well. You need a lot of air for the 12mm duct to get the cable floating nicely... think medium sized petrol compressor. It's not about the pressure, it's the flow rate (if that wasn't obvious!)

However this is a 600mm cast iron pipe with a rope going through. It will take a LOT of air to make even a very light rope float in that kind of space!

Chris


SteveWalker - 26/4/19 at 01:44 PM

A crawler sounds the best bet. Alternatively, if you want to blow it through, see if you can find someone with a jet dragster to lend you


JimSpencer - 26/4/19 at 01:47 PM

quote:
Originally posted by jonkoxe11
Radio controlled car should do it. Strap a torch and gopro to it and off you go.


If you simplify this it might?
I'd suggest a chunky 1/10 scale off road electric buggy, you don't want any of the radio gear in it, just motor, battery and it'll need a mechanical speed controller - lock the steering straight with a little bit of toe in, so it self centres.
Set the speed controller to jogging pace.
Attach the end of a fishing line (on a reel so it's very free) to the rear
Let it go, it'll have the range to do it.

As it's got no RC kit in it, it'd cope with being submerged for a short time.

Use a strong line, if it stops reeling out, then you can drag it back on it..

Worth a go before it gets expensive?


gremlin1234 - 26/4/19 at 01:49 PM

does the water ever flow in the pipe?
if so drop a tennis ball in, with a thin line attached


dmac - 26/4/19 at 01:52 PM

600mm is quite big, do you know anyone who likes spelunking?


Ivan - 26/4/19 at 02:58 PM

I would use an oil rig or ex navy diver- they are used to working in dangerous and confined spaces - one I employed would go down a 50' Franki Pile tube just wider than his shoulders dangling by his ankles to reattach the pile hammer rope.


Partofthechaos - 26/4/19 at 03:17 PM

Can you get the rope / line through before taking the water out? The water would reduce friction on a 1.1km rope and reduce the weight of what has to be dragged too. Attach the rope to a radio controled submarine...

Or, can the emptying of the water and the dragging a rope through be the same thing? Attach the rope to a big ball (like a fishing float) in the top end of the pipe. Make the ball about 1/2 the diameter of the pipe, add some water so it is the same density as the water, then remove the water from the pipe.


coyoteboy - 26/4/19 at 03:38 PM

quote:
Originally posted by ChrisW
We do exactly that with the fibre optic duct once it is installed. They are 12mm internal diameter for trunk cables and 5mm for customer drops and it works pretty well. You need a lot of air for the 12mm duct to get the cable floating nicely... think medium sized petrol compressor. It's not about the pressure, it's the flow rate (if that wasn't obvious!)

However this is a 600mm cast iron pipe with a rope going through. It will take a LOT of air to make even a very light rope float in that kind of space!

Chris


floating a bare rope, that's a clear no go. Pigs are designed for exactly what you're trying to do, and they don't need flowrate, they need pressure. They usually are used for either cleaning the pipe walls or flushing fluid out, plus carrying sensors and cables through.

[Edited on 26/4/19 by coyoteboy]

[Edited on 26/4/19 by coyoteboy]


Angel Acevedo - 26/4/19 at 05:20 PM

A horizontal drilling machine?
Maybe get 1200 mt of second hand 1 or 2" Steel pipe, put smoething on the working end to act as a bullet point..
Start shoving lengths when it gets hard, attach big drill to spin while pushing the pipe string...
Once you have reached the end, start pulling and disassembling as you go...
Disassemble other side..


mark chandler - 26/4/19 at 06:11 PM

Pretty safe to assume it's silted up as well in places so something that needs to grip the walls may not work. I would speculate £30 on a second hand nitro car from eBay and a reel of 20lb fishing wire and set it off from the high side, if it gets through result, if not pull it back and sell on.


02GF74 - 26/4/19 at 06:28 PM

I'd say let nature or physics do the work.

If there is a slope, then water will flow down it due to gravity.

Use a fishing line, light but very strong, tied to a very low density object eg play pen ball, that will be pushed along by the water.

You can tie thicker strings and pull them through.

Another possibility is to make a small submarine powered by battery or compressed air, assuming there is water in the pipe.

To check pipe is free flowing, stick hose pipe the add a couple litres of ribena or other dark coloured liquid an wait for it to appear at the other end.

Another idea is to push something light by compressed air, by putting in some petrol vapour and igniting it, obviously needs some testing first.

[Edited on 26/4/19 by 02GF74]


steve m - 26/4/19 at 06:53 PM

1) As the grumpy owner of the ground you wish to traverse is being an ARSE, are you actually allowed by law to go under his property ? or would you be doing so with out his knowledge ?

2) do we actually know that the pipe is one continuous pipe, and not split into other pipes, or even intact all of its 1100 meters ?

3) My cunning plan, that does not include me going anywhere near the pipe, as at 5'3" tall, I would of been some peoples choice

Purchase one air boat, (ebay 401755334981) attach said boat to a small skate board or add wheels, add powefull batteries and an on off switch, add at the rear fishing line to recover the boat, no need for rc, wouldn't work anyway

make a metal box of about 150mm square place on top of the air boat at the front, with guides to stop it falling off backwards or sidewards, and attach a second fishing wire going under the boat to a fishing reel

from the highest point of the pipe place contraption in pipe switch on and hold on tight to the fishing wire spool !!
This may not go the full distance, due to what ever,

Once the air boat has got as far as it will, tug the boat back, metal box will fall off, retrieve airboat,

now go to the lower end, and do exactly the same thing with the air boat, but with magnets on the front, send it up the pipe, until it meets the metal box, and pull gently until you have boat, box, , and a line between,

My next idea involves a ferret, with a line attached, and a fox, might be quicker, but the end result is not pretty

steve


HowardB - 26/4/19 at 07:36 PM

how about going back to the airflow technique and working with low pressure and a large surface are,.. stick a 500mm diameter beach ball in and then pump up the pipe behind it,. a large centrifugal blower,big blower.... attach a kite line - they are available in very long lengths - kite line this floats and is 1.2mm dia for 325kg break.

It may be that a smaller ball will get less stuck, but worse case it bursts, the line can be retrieved to have another go with a smaller ball...

man walks into a shop and asks for a beach ball and a 45kva 3 phase fan,... there has to be joke in there somewhere

hth


Sam_68 - 26/4/19 at 07:43 PM

quote:
Originally posted by steve m
2) do we actually know that the pipe is one continuous pipe, and not split into other pipes, or even intact all of its 1100 meters?

Obviously, if you were to use a CCTV drain surveying crawler robot, you'd find this out anyway... kill two birds with one stone?


bi22le - 27/4/19 at 06:55 AM

I would get someone in there as far as they can go to survey the pipe. Track distance, gradient, bends, wall condition from both ends.

Then see what you are up against.

Potentially an adapted toy amphibious vehicle towing a line of your choice, driven by the a person inside the pipe may work.

A person crawled as far in as possible may cut this distance down by a long way. Without knowing more we might as well suggest a modified firework or toy rocket!


theconrodkid - 27/4/19 at 07:26 AM

any local cavers, pot holers ?, may be up for a challenge.


Schrodinger - 27/4/19 at 07:41 AM

As you are trying to get the wire along this pipe you presumably have a legal right ? If that is so do you not also have a legal right of access to repair the water pipe? then dig down to it and re-bury with the wire?


Benzine - 27/4/19 at 08:27 AM

Any Thailand junior football teams nearby? Or Andy Dufresne?


Sam_68 - 27/4/19 at 08:32 AM

quote:
Originally posted by bi22le
I would get someone in there as far as they can go to survey the pipe.


Absolutely do NOT send anyone in there without breathing equipment. There are a lot of deaths in such circumstances due to pockets of carbon dioxide.


ALLAN 14 - 27/4/19 at 03:28 PM

Get a quote from the people who survey sewer pipes the little tug they use is waterproof and can go a very long way.
get them to work from one end and when the tug appears at the end tie a blue nylon rope onto it and let them pull it back.
If the camera tug is too expensive they also use a water-powered device which is like a pointed steel pipe with rear facing holes,
water is fed in and the water being forced out drives the pipe forwards.
Try an agricultural land drain contractor they use the same type of gear.


MikeR - 27/4/19 at 10:19 PM

bearing in mind the length, are the options for air powered / water things powered from a generator / pump at one end practical? I can't imagine any of them wanting to deal with more than 100 or 200m. The weight of the hose would be huge.

You don't say what is at either end except a farm.

I'd be tempted to push / flush a lot of water through the tunnel to try and clear anything already in there out - however thats a huge amount of water.

I was going to suggest someone from the local caving club, on a 'great escape' trolley with air working through the tunnel. However the friction on the line against the floor when pulled through would be huge and the only way i could imagine it wouldn't break would if it was quite thick, which means impossibly heavy to pull. putting the line on the trolley doesn't help as you still need to pull it to get the cable you want to lay through the tunnel.

So my conclusion is flood the tunnel and fire a torpedo through - with wheels (or something) to ensure it stays central. Hopefully the friction of the water is less than that of the tunnel walls/ weight of the rope.


ReMan - 28/4/19 at 12:13 AM

A km a s a long way for an unmanned device even / especially one tethered by cable/pipe, and adding in the water hurdle. I think you going* to be lucky to do it yourself, but hope you can


02GF74 - 28/4/19 at 07:40 AM

The distance is the real problem. Pipe crawlers, a buggy with 4 large wheels are available for typically £35,000 but tend to be tethered so have a range to around 300m.

As mentioned pulling a rope is likely not to work due to weight and friction.

Was the water flowing in the pipe pumped or under gravity. If latter, then blocking one end, filling it with water and putting a float to a fishing may be the best hope.

My calculations show pipe is 1/4 million litre so a fair amount of water. You may need to make reservoirs, tarp over a line of bricks to collect rain water.


coyoteboy - 28/4/19 at 02:24 PM

I'm now sitting back and expecting at least regular videos of the attempts to do this, I feel like it could be either very quick or a YouTube channel.


Simon - 28/4/19 at 04:19 PM

https://en.wikipedia.org/wiki/Project_Babylon


gremlin1234 - 28/4/19 at 06:04 PM

quote:
Originally posted by coyoteboy
I'm now sitting back and expecting at least regular videos of the attempts to do this, I feel like it could be either very quick or a YouTube channel.

perhaps a new ch4 show
'so you think your an engineer'
similar to / a cross between
great egg race, and scrapheap challenge

(I claim © on the idea unless prior art is out there)


ReMan - 28/4/19 at 08:55 PM

Would it be fair to say this link to drawing below (cant upload pics here're anymore) represents the situation?
PIPE HILL!

I'm proper intrigued and interested on it!
I've also looked online the closest I seen=m to get in uk is
https://ritelite.co.uk/cable-duct-rodding-systems/
But even then, max (standard length 600 meters

Chris original idea of a motorised sprung loaded wheeled waterproof sled driving battery powered robot is probably the most realistic, but I wonder also what the inside of the pipe is like?
Is it plastic or iron? Likely to be debris in it or just water?
As mentioend how much water as that could be a project in itself if it needs to be emptied (secretly?!)


Mr Whippy - 29/4/19 at 12:02 PM

Simply launch a large hobby rocket with fishing line attached on a reel up the pipe...it should cover that distance in a few second plus they go like a bat out of hell underwater too. You'd want long robust plastic rocket tube, maybe 1m long and a metal nose cone.

Just make sure you catch it in a net at the other end....

[Edited on 29/4/19 by Mr Whippy]


Angel Acevedo - 29/4/19 at 02:41 PM

Hiring a diver is not that far fetched.
I think 1 km is very doable with a couple of tanks that will provide ample reserve.
and 600 mm diameter is ok provided there are no serious kinks or obstructions.


nick205 - 29/4/19 at 03:48 PM

ChrisW

I'm sure you've probably considered all these, but...

Is there no route around the land to avoid the pipe and having no access to the land?

I'm guessing the connection speeds would be slower, but is there not a wireless method?

Can you "splice" the unwilling land owner into the connection somehow to make it worth their while allowing access?


Angel Acevedo - 29/4/19 at 05:54 PM

quote:
Originally posted by nick205
ChrisW

I'm sure you've probably considered all these, but...

Is there no route around the land to avoid the pipe and having no access to the land?

I'm guessing the connection speeds would be slower, but is there not a wireless method?

Can you "splice" the unwilling land owner into the connection somehow to make it worth their while allowing access?




I like that kind of lateral thinking..


Sam_68 - 29/4/19 at 06:20 PM

You could always give Elon Musk a call?


gremlin1234 - 29/4/19 at 06:45 PM

to check the path of the pipe, it maybe worth looking at google earth aerial images, since a pipe in the ground /can/ affect how crops grow.
note also google earth has 'historic' images so should be possible to see in different seasons,


Mr Whippy - 29/4/19 at 08:56 PM

Why do you need a fibre optic cable anyway can you not just transmit the signal


nick205 - 1/5/19 at 02:00 PM

Another thought...

What's the landowner got against giving you access...crops, livestock, grumpy?

[Edited on 2/5/19 by nick205]