Monday, April 07, 2014

Four nights at the museum, a day up the Caldon (with a little detour).

We didn’t leave Etruria till this morning, the weather was a bit iffy, I had a few bits and pieces to do around the boat, and I wanted to have a look around Etruria Industrial Museum and the Bone and Flint Mill while the engine was in steam.

The  museum is quite interesting, although you’d be hard pressed (or a very slow reader) to spend more than an hour looking around the exhibits. But if you’re a fan of industrial archaeology, then the mill is definitely worth a visit.

The mill was built in 1857 by Jesse Shirley, after he and his brother Joseph inherited their step-father’s Bourne and Hudson Bone Works. Joseph seems to disappear from the picture, it was Jesse who had the new mill built, and it carries his name to this day.
The mill was built to provide raw materials for the burgeoning small potteries in the Five Towns, the larger Spode and Wedgwood factories had their own mills.

Fine Bone China is made from a mixture of ¼ China Clay (usually Cornish), ¼ flint and ½ bone. The flint and bone had to be calcined and then ground before use, and this was what the mill was built to do. Calcining involves heating the flint and bone for 12 hours or so at temperatures of around 1000°C. This changes the chemical composition of the material to make it suitable for china. The blend and process was perfected by Josiah Spode around 1790, and has remained the industry standard for Fine Bone China since.

At the mill, the raw material was first introduced to the kilns, alternate layers of fuel (wood for bone, coal for flint) and the bone or flint built up in chambers in the floor.

Calcining Kilns
2014-04-06 14.24.44

The firers were responsible for maintaining an even burn throughout the process, then the kilns were left to cool and the material drawn off through vents in the bottom of the kilns.

Kiln flue
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Large lumps were crushed into more manageable sizes before being hoisted up to the Pan Room where paddles pushed boulders of Chert around in large circular drums to grind the flint  or bone in water.

The pan room.2014-04-06 14.20.35

Slop in one of the pans.
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The resulting slurry or “slop” was then allowed to settle out, and sold in this semi-liquid form or dried.

All this, especially driving the pans, required power. This was provided by a Boulton and Watt design of double-acting beam engine.
These were expensive bits of kit, Shirley’s obviously couldn’t afford a new one, as this was already around 30 years old when it was installed at the mill. The piston rocks the beam which drives a 20 foot diameter 10 ton flywheel to even out the fluctuations in the power cycle.
All these old engines seem to have names, this is the "Princess".

It was difficult to get good pictures of the engine, the area is quite confined.

Looking towards the cylinder with the engine running at around 20rpm.2014-04-06 14.14.21
The blur to the right is the push rod for the flywheel’s crank arm, in the centre is the centrifugal regulator which controls the speed by regulating the flow of steam.

The cylinder, piston rod and end of the balance beam.
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Power from the flywheel shaft is taken through the wall into the gear room, where the shafts for the pans a level above go up through the ceiling. Each can be disengaged by moving the bevel gears out of mesh.

 The Gear Room.2014-04-06 14.40.00
Only the right hand side is operational.

Steam for the engine comes from a Cornish-style boiler, running at around 30psi. This is lower pressure than when it was fully operational, but the load is considerably less. The original boiler was a Lancashire pattern of about twice the capacity, but this had deteriorated beyond repair. The current one came from a swimming pool in Tunstall when it was replaced by gas heating. Recycling at it’s best!

Boiler House2014-04-06 14.18.30

Unfortunately, being of smaller capacity, it can’t provide a consistent head of steam to run Princess for more than 30 minutes. The stokers have to shovel franticly to keep up, but even so the pressure steadily drops until the engine has to shut down till it comes back up again.

About 2 tonnes of coal are used on a “Steaming Day”, that’s to run the old girl maybe 2½ hours… Before the plant closed it was run pretty well 24 hours a day.

We’re left with this amazing relic because when a new plant opened alongside in 1972 the old equipment was just abandoned.
It’s been restored to working order by volunteer labour since 1978, and is operated and maintained by volunteers today.

Looking through the pictures I noticed that I’ve none of the outside. I’ll correct that on the way back…

Right, back to cruising, and after a wet night today didn’t start too badly. We were off quite early, 09:30 in fact, because, due to a quartermaster’s oversight, we were running low on solid fuel.
This meant we had to go back out onto the Trent and Mersey, down to Festival Basin to turn, and collect some bags of smokeless from GT Thermal alongside Bridge 117.

Out past the museum and maintenance yard…SAM_8841
…and Mr Brindley

Turning at Festival Basin…

…and back onto the Caldon, 100kgs heavier, £46 poorer.SAM_8845

Not far past our mooring for the last couple of days are the first locks on the Caldon, a staircase pair alongside Bedford Road.

Mags looks a long way down as she enters the bottom lockSAM_8846

The pair of chambers lift the canal over 19 feet in not much more than two boat lengthsSAM_8847

Coming up the top chamber

The bridge I’m on when I took the above is odd, in that the parapets are of cast iron plates rather than brick.

Bridge 2, iron sides locally cast. “T. Shore and Sons, Engineers, Hanley”SAM_8850

The canal winds it’s way through what is initially a residential area, back-to-back terraces for the pottery workers now being replaces by modern apartment blocks.

Planet Lock (I wonder where that name came from?) is a shallow 3’10”, with anti-vandal locks on the top paddles.

Planet Lock

The large NHS building alongside was under construction when we last came this way.

Whoops, watch out for Bridge 9, it’s very low!SAM_8862

Had to back off and remove the coolie hat. The chimney went under with an inch to spare. If we hadn’t bought those 4 bags of coal…

The next obstacle to progress is Ivy House Lift Bridge, now semi-mechanised.

Ivy House Lift Bridge, No 11SAM_8865
No sign of “Ivy House”, just new apartments one side and a foundry on the other.

That’s pretty much it for the built-up area. The canal runs along the western flank of the Trent valley, and you start to get long views to the east.SAM_8857

We were just approaching the village of Milton when we had to give way to a boat coming under Bridge 13. It looked familiar…

Dave and Jan, NB Yesdear

First met on the Ribble Link, then more recently in Newark, it’s a while since we saw them. We had a 15 minute catch-up while drifting in the middle of the canal (as you do…). They’re heading south for Bristol, so we’ll probably not see them again for another 18 months…

We finally pulled up north of Milton, not far below Engine Lock. There’s a good stretch of piling here and open fields to both sides.

North of MiltonSAM_8869

And not a moment too soon! We’d just got tied up and were contemplating a cup of tea and a late lunch when the heavens opened!
We’d been lucky up till now, with only a bit of light drizzle at times. I’m so glad we stopped when we did.

To augment our solid fuel, we picked up a few bits of wood on the way, some that I’d spotted on my early Sunday morning run. Although the second stash of larger logs was a bit depleted by the time we got here. Never mind, soon be summer.

Locks 3, miles 4¾

1 comment:

Graham and Jill Findlay said...

Looks like we'll miss you again, we'll be passing Etruria tomorrow!