I’m intrigued by early ‘automatic systems’ and this one seems particularly anachronistic. It is a water-level control system on the Crinan Canal (visited during our last holiday). In essence, a lever arm that raises and lowers a ‘plug’ from a hole in the floor of the canal – it’s been operating for more than 120 years. (See diagram below). The fact that the ‘sensing’ point is 30 metres downstream doesn’t seem to me to significantly influence the dynamics of water level. But I still can’t see why a weir wouldn’t be simpler, cheaper, more reliable and fail-safe. (There is in fact a weir discharging from the canal to the sea a short distance away). Maybe I’m missing something? On the other hand, despite a web search I can’t find evidence of another one of these devices so perhaps nobody else could see the point either.

Water waster poster 140809


BTW – a good video about the history of the canal can be found at www.islayblog.com/2014entries/20140106-interesting-crinan-canal-video.shtml



CruachanOn holiday last week, visited the world’s first high-head pumped-storage hydroelectric power plant at Cruachan in Scotland. Proposed by Edward MacColl in the late 1930s and built between 1959 and 1965, it’s a seriously impressive bit of kit. 440 MW used for peak-lopping and can go from standby to full power in 28 seconds (with turbines already spun up). What impresses me most though is their claim of a pumping efficiency of 90% of generating efficiency. That speaks to some interesting fluid and electrical machinery designs to meet such different requirements. 250 tonnes of rotating machinery in each of the four units. And very high levels of environmental impact management given their proximity to a fish farm. Deeply impressive

(Image from Argyll and the Isles Tourism – cameras not allowed on site.)