The end section rotates and lowers a section of the upper canal to the level of the lower canal at the same time as rasing a section of the lower canal to the upper level; because it is balanced like this, the thing only runs on 20KW.
Ok, I think it’s cool, but I don’t really understand how it’s supposed to work even after looking at the picture, a little more explanation please.
Thanks in advance 
I’ll admit it’s cool, especially after watching the animation ( http://www.falkirk-wheel.com/members/modules.php?op=modload&name=Downloads&file=index&req=viewsdownload&sid=0 …a monster download) but I don’t get why one part of the canal is so elevated.
The picture at top left of the page shows the device partly rotated; the picture below that on the right (with annoying java ripples) shows it at rest.
When it is at rest, a boat travels along the upper channel (from the canal at the higher level) and enters the end(rotatable) section; another boat enters the lower section which is partially submerged in the lower body of water. Gates are closed and the device rotates, swapping a huge chunk of water with boat from the top canal to the bottom one and vice versa.
here is another site with some animations.
They are two separate canals Sue; unfortunately you can’t have a sloping canal (or you could go waterskiing without a boat); they were originally joined by a chain of locks. There was a time in Britain when a great deal of freight was moved by narrowboat on canals; these were constructed at whatever level was convenient at the time.
Ok, that makes sense now, thanks.
I’m thinking a bit more about this; there’s an elevated body of water and some work to be done, why didn’t they use some water from the top canal to drive the machinery? (OK, it would drain a bit of water, but not enough to drop the level noticeably).
It’s live now on the webcam! Moving and stuff. It’s so cool it hurts. “Engineering porn” says my civil engineer colleague, and I think he’s right.
I lived 5 miles away until last year, when I moved to London to sell my soul at below market rate. The canal winds through my home town, and my dad drove tour boats along what was then one of the larger sections between blockages as part of the Linlithgow Union Canal Society. I used to have to be crew - i.e. serve drinks, point out the safety exits (in a canal boat on a canal that’s max 1.5 metres deep - lives were not at threat). Dead waste of a sunday afternoon, I used to think. Now of course, I’m considering going coast to coast on the two canals during my precious holiday time. Bizarre.
As I recall, the natural water loss through usage is measured in millions of gallons, so I suspect that taking a little from the top to get it to turn each time could lead to shortages. Still it takes less energy than 20 toasters, which strikes me as a damning indictment on people’s willingess to waste energy rather than use the grill.
They’d probably have to run the water down a separate pipe from the upper level to avoid creating a flow in the upper channel; I’m n engineer, but I don’t reckon it would take a heck of a lot of water dropping from that height to drive the thing (bearing in mind that you wouldn’t have to convert the mechanical work to electricity and back again)
Hey, you could almost do it by just filling the top bucket to a higher level than the bottom one.
Having just watched it on the webcam, all I can say is: I want one!
OK, I don’t have an actual use for it… and it would take up a lot of room in my flat…
But it’s so cool! I want one!
Well, I’m not an engineer either. But that doesn’t mean I’m going leave well alone. (Actually, engineeers don’t leave wells alone either, they keep tinkering with them…no? Oh forget it.) I think perhaps one issue with putting more water in the top bucket would be that you want the wheel to come to a smooth halt at the top of the cycle, which suggests that you dump the water at some point. And working out where that point would be for different weights of boats might be tricky, as opposed the magic of the on/off switch. But this uninformed speculation - any with practical knowledge care to have a stab?
My WAG is that the volume of water involved to generate 20KW would be fairly high, and the amount of water available in the canal would only be that between the two nearest locks - not that huge an amount, and refillable only through the little sluice gates in the lock doors.
I reckon you could do it like this:
Design so that the water level in the top channel fills the buckets (say*) two feet higher than when they are at the bottom.
As an ascending bucket arrives at the top, you have to allow for it to be filled a little before the boat in it can leave (not unlike a conventional lock)
As a descending bucket arrives at the bottom, you have to drain it a little before the boat in it can leave.
I may be overlooking the obvious, but don’t boats displace their own weight of water? (so the bucket would weigh the same whether it’s just full of water to a certain level or contains water to the same level with half a dozen boats floating in it).
The extra weight of the top bucket provides most of the force to turn the thing, but this won’t get it started, as it begins at top centre, so you could divert a little of the water from the top level through a turbine to drive the thing, but once the heavier top bucket is off centre, most of the task of turning the wheel is actually going to consist of braking it (again, this could be done with hydraulics or something, I’m sure).
You might need to apply a little (hydrodynamic) power again just to get the buckets aligned at the end of the cycle.
Hmmm, I can’t believe this wasn’t considered for the Falkirk Wheel. Am I missing something?
I’m not sure how far the next lock is (or even if there is one; don’t forget this is a canal, not a river and the next lock up could be redesigned to let a bit pass by just for this purpose). Anyway, you’d never need to actually use the water to generate 20KW then use the 20KW to drive the hydraulic motors to turn the thing, losing something in the conversion both ways), you could keep the whole process mechanical.
Mangetout, that is exactly how the liftlock in Peterborough works. Completely weight-driven in its main operation.
Of course, it doesn’t rotate… that Wheel is exrtremely cool.
Well I actually am an engineer, and I’m going to use that fact as a licence to express unsubstantiated opinions. You can’t have that thing running on water out of the top canal, because every time that you did it, you would lose potential energy in the system (the weight of water at the top) to turn it into kinetic energy (moving boats and sections of canal). So to keep it running, you would have to top up the higher canal. And how do you do that? Well by pumping water back up of course. Which would take more than the 20 kW that are required to run it at the moment. The bottom line is that you can’t have a perpetual motion machine. It’s just good old conservation of energy in the system, nothing is lost and nothing is created. “Ah cannae change the laws of physics, Jim”, as an eminent compatriot of Amrussell will say in a couple of hundred years.
You could just top up the upper canal from a convenient river (I checked on a map and there is one up there)