In complete contrast to my 21st century energy posting yesterday, here is one about a 19th century one.
Fakenham is home to a rather unusual museum, namely a preserved gas works. It closed in 1965 when the town was connected to a regional pipeline but up until then it had been faithfully serving 500 homes in this small town for over a hundred years. It wouldn’t have lasted much longer anyway as we stampeded towards north sea gas during the 60s and 70s. Whilst inevitably altered and tweaked over the years, it retained its very old fashioned hand stoked process as it probably wasn’t economically viable to introduce automation or more efficient equipment.
The manufacture of town gas is a relatively straight-forward process, although there are several stages involved producing some by-products along the way. Coal is baked in air tight ovens until it sublimes, giving off various gases and leaving coke. The gas is then processed to remove tar, sulfides and ammonia, leaving mainly methane and hydrogen (along with carbon monoxide).
Visiting such a small works puts it on a human scale, Fakenham used to employ eight people whereas the mighty Beckton gas works was a small city and employed 4,000 people at its peak.
This is a view of the retort house. It had two furnaces with eight and six retorts respectively. The gas rises up the vertical pipes into something called the hydraulic main. Here the ends of the pipes were submerged in a water trap forming an air lock so that the system was unaffected when a retort was opened. Each retort needed to be emptied and recharged once the coal had been sufficiently depleted. At Fakenham, this was done by pulling the coke out into oversized wheelbarrows using elongated tong tools then the space would be restoked using shovels.
A retort is an 11′ deep “D” shaped ceramic tube holding about 4cwt of coal. This must have been hot unpleasant backbreaking work as a stoker, especially as a third of the retorts are above head height and they need replenishing every ten hours or so. Apparently the worst job was in raking out the ash boxes underneath the furnaces.
The raw gas passes along from the hydraulic main to the foul main which runs around the roof of the retort house. Here a certain amount of tar condenses out and drops down into the tar pit. (The black square tube to the left a couple of pictures above is called the tar tower).
The tar pit can be emptied via this hand pump. Another pump (at a different height) could be used to pump off ammonia liquor floating on the surface of the tar.
The gas then flows through a condenser tower to complete the distillation process, condensing out residual tar and ammonia liquor. This one dates from 1953 replacing an older one. (Parts at Fakenham came from all over the place as other sites were consolidated).
A washer purges any residual ammonia.
The final stage is removal of hydrogen sulfide (rotten eggs smell) through purifiers, passing the gas over iron oxides on wooden boards. These would be used on a cyclic basis for replenishment, hence the valves.
The spent iron oxide was spread in this open shed, producing sulphur, another by-product.
This is the crusher, used for crushing the coke from the retorts for subsequent sale. (Some of it was used directly in the furnaces as required).
This is an engine house known as the exhauster house. This housed the exhauster pump for moving the gas through the works and could run on gas, petrol or electricity for redundancy.
In order to track efficiency of the gas works, a large meter was used on the output pipe so that gas produced could be compared to coal consumed and shift effectiveness tracked. This meter dates from 1929 and it is enormous.
Unlike electricity, gas can be stored so that demand and supply don’t have to be quite such a thin line to tread. Fakenham still has a gasholder, this one dating from 1888 and holding 400 cubic metres when full. The design is simple, being an inner sleeve (the lift) sealed at the edges of the base by a water bath. The pressure of the gas when it is being produced faster than demand raises the lift and the weight of the lift provides pressure to the mains feeding the town. The exhauster pump can now raise the lift, although as it apparently takes three weeks to raise it and it goes down again in three hours, they don’t do it now with petrol being expensive.
The gas pressure is sometimes inadequate at periods of very high demand, traditionally Sunday mornings when lunch was being cooked. To accommodate this, a booster pump would sometimes be used.
On closure Fakenham had a second gas holder more than three times the size of the 1888 one, now dismantled, actually the third on site. These valves controlled gas flow around the works.
The site also had workshops, the foreman’s cottage and a showroom. Every space is taken up with some item of history, either on the topic of gas, or local history. This shot of the valve house shows various forms of gas lighting.
The workshop has an extensive display of historic gas meters, powered by air from the original meter testing machine.
The showroom has a wide range of cookers & associated appliances.
Here David models a gas powered iron used for a billiard table.
There are even two gas powered fridges, although no gas radio. (They did exist, the gas heated thermocouples for the electricity).
What a delightfully quirky and arcane museum. I personally found it the most fascinating visit in Norfolk, aided by a volunteer who had never actually worked there but had been showing people round for twenty years ever since it opened as a museum. The other Greys were not quite as impressed as I was, of course, it became a running joke about how it only opened certain days and whether we would be going back or not. (Once is probably enough!)