#openhouse: meet the Edwardian future, where your water comes from

So, Open House weekend again. Part of the fun is always the opportunity for gratuitous travel around London.

It sounded good on paper – just take a 121 bus from Turnpike Lane – but as soon as we got much past Haringey Civic Centre, it descended into farce. Every junction was dug up, every street lousy with cars, cars, cars. The trip became slow, and then late, and then ridiculous. It took so long that I felt it was far, rather than slow; distance dilation, by analogy with time dilation.

We passed grim and trafficky parades of dead shops, car-ridden and prosperous Thatcherite suburbs, the Barclays Bank branch where the world’s first cash machine was tested, rather elegant in honey-coloured stone and set in a massive traffic jam, the spectacular international modernist tube stations at Southgate and Oakwood, surrounded by cars, a glorious matzo-meal chip shop, a palatial Conservative Association unconservatively offering salsa and tango classes three nights a week, a giant 1960s working men’s club down the road in opposition to it, a vicious pub, in the same sense as a vicious dog, with a sign: REGULARS ONLY. But how did you get to be one in the first place?

Not long after that a vision drove onto the bus with an electric wheelchair, a tweed suit and cap, red hair bursting out from under it, dark red nail extensions, steel-framed glasses, puffing on an iFag, sucking oxygen from a bottle chocked under a basket of shopping marked in assertive block caps, THIS IS MY THINGY!, twice underlined. At the same moment we passed, very slowly, a corner house whose entire garden had been paved to house a Humvee-limo operation.

And eventually we found it. We were going to see where the water comes from. It comes from here, the King George V Pumping Station.

Note the taps.

Here’s the custodian of ultimate power, the Lady with the Tap. She’s from Reading and has a Scottish accent.

I asked her who has the keys. “Operations staff”, she said. That was the bloke with a grey ponytail and a hi-viz vest we met a few minutes earlier, expounding his political views to another visitor. He believed in a radical dialectical vision. Everything that had been done for the working classes had been rolled back, and would be rolled back all the way to slavery, before the revolution would break out.

Actually the taps control the inlets into pumps that aren’t used any more, so the worst you could do would be to flood a historic monument.

Inside the great building, the real source of ultimate hydraulic despotism over North London is here.

Inside the Edwardian industrial cathedral, these are the electric pumps that lift water from the Lee and the New River into the KGV Reservoir, from where it passes through filter beds just to the south, then parallel to the New River as far as Stoke Newington Castle pumping station, into the Amherst Main, and then into pipes. I know this because I listened carefully to another member of the operations staff, who inclined to a more mainstream social-democratic view. I had the impression, between the three of them, that the water was in good hands.

The water workers spend all their time around these huge Victorian or Edwardian infrastructures, usually invisible to the general public. Their builders tended to make everything spectacularly grand, and didn’t shy from pure facadism in getting there. Victorians would have made this one Gothic, but its Edwardian builders made it look like a great German public swimming baths inside, and a weird Neoclassical temple to technology outside.

Did I say weird Neoclassical temple to technology? Yes.

The hulking black shapes are the outlets from these.

That’s a Humphrey pump, a piece of Edwardian bleeding edge technology that’s still pretty bleeding edge now. It’s essentially a fluidyne, a form of prime mover related to the Stirling engine, that uses the fluid it pumps as the piston to pump it and has no moving parts beyond the valves you can see. As a result, and like a Stirling engine, it achieves incredibly high energy efficiency, approaching the theoretical maximum of the Carnot limit.

It’s basically a big U-shaped tube, with one end much higher than the other. This end, the lower end, contains the intake and exhaust valves and the combustion chamber. Below the combustion chamber is a volume of air, and below that, water. When the fuel and air ignite, the expanding hot gases thrust the air down on the water and the water around the U and up to the top where much of it pours into the receiving tank. Then, as the gases reach maximum expansion and cool, the water keeps going through its momentum, reducing the pressure below atmospheric pressure and sucking in fresh air. The remaining water flows back around the U, progressively scavenging the waste gas through the exhaust valve, and then compressing the new charge, in a two-stroke cycle.

That’s the theory. In practice they usually ran in four-stroke mode, i.e. half the output, because it was difficult to get the scavenging good enough, which may explain why the Humphrey pump didn’t take off. Only eleven ever existed, and five of them are right here. Out of the rest, two were exported to Canada, two to Australia, one to Egypt, and one to Texas. There was a plan to install fourteen of them in a massive drainage and irrigation project in Egypt, back in 1914, but then 1914 happened. It’s hard to say, though, that providing half London’s water is anything like failure.

The ones here ran until 1968, until their fuel caught up with them. The fuel was interesting in itself. Next door, anthracite was heated in the producer-gas process, generating a stream of carbon monoxide and nitrogen that the pumps burned. By 1968, anthracite got too expensive to source in the quantities required (perhaps because the railways weren’t buying any more?), and they tried running on London city gas, but it didn’t work well. I don’t know how North Sea gas would have done. And so they moved to electric pumps – you can see why, as the electric pumps take up about 30 per cent of the building and don’t require the messy, laborious fuel handling, make the noise, or puff out the pollution all that coal did.

The Aussie Humphreys ended up installed in Cobdogla, population 232, burning wood to lift water from the Murray River into the irrigation network. And wonderfully, one of them still works, in their museum.

So here it is, the water. 12.5 million litres of it.

Here’s some more water, around the corner in the awful tudor tesco estate built on the island where the Royal Small Arms Factory once stood.

They have a little museum under the clock tower, run by some of the last apprentices who went through the RSAF training course before privatisation closed it in 1988, learning to file a cube by hand so precisely that it would fit a flat plate tightly enough that only blue light could get between them. Blue light? Yes; longer wavelengths would be diffracted. They all, without exception, reminded me of my grandfather. We went up and wound the clock.