Apparently a massive proportion of water cleaned in the modern world and piped to our homes is lost on the journey in antiquated mains pipe networks riddled with leaks – obviously very wasteful, and in some countries dangerous given their water shortages.
According to many water companies fixing such leaks is not cost effective as it involves digging up roads in major urban areas and replacing miles of ancient pipes.
The idea here is to fix leaks in these mains pipes without having to dig them up, that is - fix them from the inside. What is required is some substance that can be produced in very small particles, is insoluble in water, neutrally buoyant and shrinks when wet.
How this would work is that such particles would be injected into the mains network as water leaves a plant, and extracted at various major junctions ‘downstream’, there being a known leakage problem on route between.
As I have specified that the particles are insoluble this extraction is possible with some kind of fine filter, and the water can continue to consumers without harm.
However, as the particles have also been specified to shrink when wet, then at any point along the route where the water forces itself out of the pipe work they will eventually dry, or at least become dryer than the saturated particles in the water flow, and thus expand. Outside the pipe, particles will begin to form a blockage as they expand, and eventually will be able to force themselves (and hence the water) a smaller and smaller distance from the leak, until that distance becomes zero, and therefore the leak is now blocked.-- raintonr, Oct 23 2003 Radiator Additives http://shop.store.y...di/radiatoradd.html [phoenix, Oct 04 2004, last modified Oct 06 2004] (?) Nuvo Radiator Stop Leak http://www.nuvo.cc/...r%20stop%20leak.doc"The critical particle size of the fiber sealant ensures that leaks will be quickly sealed and the proper operation of the passenger compartment heater will not be affected." [phoenix, Oct 04 2004, last modified Oct 06 2004] Bar's Leaks http://www.barsproducts.com/coolf1.html"installed, the Bar's Leaks particles shrink up to 15 percent. On an external leak, the tiny particles flow to the point of the leak." [phoenix, Oct 04 2004, last modified Oct 06 2004] (?) Pipe Lining Technology http://www.insitufo...ns/water_index.htmlInsituform has been retrofitting leaking and/or corroded existing water mains and sewage lines in major metropolitan areas for over 25 years . Their proprietary system utilizes a polyethylene liner that is able to be pumped into and reline existing pipes in increments up to 5000 feet without having to dig up the city streets, suspend services for extended periods, or seriously impede commuter traffic. Click on the "How We Do It" button on this website for an animated description of how their various processes can be applied in municipal, industrial, and oil and gas piping applications [jurist, Oct 04 2004, last modified Oct 06 2004] I wonder if this would work with small expanded polystyrene beads. They don't shrink when wet, but they do compress under pressure.-- st3f, Oct 23 2003 Some existing efforts in this area use "sleeves" that are inserted into the pipes from existing valve fittings. I've seen contractors in my area doing this kind of work.
Wouldn't the particles tend to clog up the extraction filter, that being their job and all?-- krelnik, Oct 23 2003 I like the concept. I have some doubts however. If the pipe has a leak, the area surrounding the pipe will be saturated (been there, dug that up). How will the particles ever get dry?
If they don't expand inside the pipe to block the leak, or adhere very aggressively to the outside of the pipe, I don't think the particles will be able to stop the leak.
It's tough to stop a leak from the outside of a pipe with the pressure working against the process.-- half, Oct 23 2003 Well, the idea is the particles are spec'd to only expand when they become 'dryer' so they wouldn't clog the filter as it would still be fully wet. Of course, when you're done you'd take the filter out (and all the stuff with it), rinse it out to reclaim the particles for another use.
Some good points about pressure - you'd also try and get them to expand when the pressure is releaved (ie. they are now outside the pipe).
Also - these links seem only to be for small, radiator sealing and the link. I'm talking larger scale than this.-- raintonr, Oct 23 2003 Tiny little plumbers in tiny little scuba gear with tiny little underwater welding equipment?-- half, Oct 23 2003 Heck, some apartment buildings in New York City are installing broadband by sending little swimming robots up the sewer pipes dragging the cables behind them. So why not?-- krelnik, Oct 23 2003 Adding leakstop on a constant basis seems impractical. Someone would drink some for sure, amd it would be much diluted by all the water. A better application of this idea is to stop the water and flush the entire pipe with leakstop. Once the pipe was full of the stuff, you could stop up the far end and increase the pressure, forcing the leakstop out of any cracks. Then flush the leakstop out with water - allowing you to reclaim a lot of it for use in other pipes.-- bungston, Oct 23 2003 There is an entire (heh) "underground" industry that already exists to tackle this problem that can be found by researching "Trenchless Pipe Rehabilitation".
Take a look at the Insituform links posted for a product that baked this idea over 3 decades ago. In fact, I was so impressed with the technology Insituform East was applying to restore aging infrastructure in major East Coast American cities, I bought five rounds (500shares) of their stock in 1980 and held them for nearly a decade. They have succesfully re-lined thousands of miles of corroded sewer lines and water mains. It's one of the most compelling product/service ideas I have ever found; Unfortunately, against the swelling tide of more flamboyant high-tech stocks in the late eighties and nineties, it was only a mediocre investment. Perhaps it's better now.-- jurist, Oct 24 2003 Great link, jurist. I've seen those Insituform trucks working on the mains in my area, its neat to see exactly how it works.-- krelnik, Oct 24 2003 If you drank water that had some of this in it, would you no longer be able to go to the bathroom?-- sophocles, Oct 24 2003 Hmm kinda like radiator leak-stop.-- tedhaubrich, Jun 09 2004 random, halfbakery