Whaley Bridge pumps...

[nightjar]

Over the other side of the watershed would be a good place.

[Harry Bloomfield, Esq.]

Sorry, I ommited a smiley on the end of my post.

[Harry Bloomfield, Esq.]

Chris Hogg expressed precisely :

Correct and my car makes use of it. My suggestion of Dyson was intended as a joke.

[Harry Bloomfield, Esq.]

Tim+ expressed precisely :

As have I, it works fine on small pipes, but have you tried it on larger pipes - I have. Air rushes up above the water from the discharge pipe and soon breaks the syphon effect. If the discharge is kept below water, then air cannot be sucked in.

[Harry Bloomfield, Esq.]

The syphon only has to work for a few seconds and in a relatively short and narrow bore pipe. Try it for a longer time, with a longer and larger diameter pipe.

[mechanic]

See, for instance, the syphons on the Thirlmere - Manchester route. Not much pumping there!

[Tim+]

Only if your inlet is obstructed and the flow is very low. Otherwise the water velocity is too fast to allow air back up.

Well that?s true, but not necessary in my experience.

Tim

[jrwalliker]

Yes, the dam had been leaking for at least a year before they fixed it. Here it is: 51.344159, -0.384329 They installed interlinked steel pilings on the upstream face once the lake (called Middle Pond) was drained. The outlet ends of the siphon pipes were not submerged - the flow of water was enough to prevent air from bubbling back up. The pipe diameter was something like 10 to 15cm.

John

[Terry Casey]

Like a Chinook, possibly?

Sorry - only about 34 feet. Beyond that, you would just create a vacuum in the pipe as the weight of the water exceeeds the atmospheric pressure needed to push the water up the pipe.

[Steve Walker]

I was assuming that the depth behind the dam was less than it actually is. Today's report was that they'd got down to 8m below the top of the dam, with another 8m to go. I didn't expect it to be quite as deep.

SteveW

[Steve Walker]

They are commonly used in chemical and nuclear plants where you don't want to have to deal with leaky pump seals, moving parts, etc. and can have the power source outside the danger area.

SteveW

[Steve Walker]

Yes :)

Not only didn't he come up with the idea, but industial cyclones had been in use for decades. I am amazed that he was granted a patent - there was no novel technology there.

SteveW

[Vir Campestris]

You open the sluice gates top and bottom of each lock. The ones that let you fill and empty the locks with the gates shut.

That takes several minutes per lock full - but every little helps.

Andy

[Steve Walker]

Paddles not sluice gates (remembering back to a canal holiday almost 40 years ago!)

SteveW

[Mike Humphrey]

The sluice gates aren't normally interlocked. If you raise both sets of sluices at a lock it will let a lot of water escape - which is why one of the first things canal boaters are told about locks is to never do that.

Mike

[The Natural Philosopher]

Then technically it is an aqueduct...

[The Natural Philosopher]

No lessons will be learnt. Virtue signalling is more important than actually achieving reliable infratsructure.

[NY]

Hopefully the company that did the annual safety inspection and pronounced the dam "absolutely fine" is well insured - because all the work over the past week will have cost a lot.

[Steve Walker]

It was actually built as separate sections, eventually linked via a different route than originally proposed and was intended as a canal. It did supply water, but only for other parts of the canal system - and you can argue that any canal does that, at least for it's lower sections. After it closed and before it reopened, it was retained first for this purpose, but also due to a later agreement to supply Mid & South East Cheshire Water Board.

SteveW

[Swer]

But doesn't have as large a pipe as you would use to drain that dam quickly.