Since a mechanical fault to the boiler feed pump ceased operations at our August Steaming weekend, our volunteers have been investigating the problem.

The boiler water feed valve next to the boiler acts as a non-return valve. When the pumps are working water is fed through this valve into the boiler. When the pumps aren’t working this valve stops the water flowing out of the boiler, therefore keeping the boiler full. We originally thought that this valve was stuck, meaning water couldn’t enter the boiler. Therefore the boiler wasn’t filling up and so as steam was being used by the engines the water level was falling, eventually to a level too low to allow us to continue.

The valve was taken apart, examined and rebuilt, however our volunteers couldn’t find anything dramatically wrong with it. There was a worry about a blockage in the pipe system between the boiler and the Header Pond. If there isn’t a need for water in the boiler while the pumps are working, this water is sent to the header pond instead. At the header pond there is a valve which lifts to allow the surplus water through. If this valve is lifting off at a lower pressure than the boiler it will always go to the header pond and never to the boiler. Our engineers connected a mains water pipe to the pipe that feeds water to the header pond which reached 30 pounds of pressure. This is higher than the 20 PSI working boiler pressure. This means that the weight on the valve in the header pond shouldn’t lift up until it’s got to a higher pressure than the boiler allowing water to enter. Also Proves nothing is stuck in the pipeline,

There was also a thought that there may be a leak in the pipeline somewhere, though no leaks were found.

So, although by dismantling the regulating valve and pressurising the pipe to clear a possible blockage we could have achieved a positive result, we could not identify a clear ’smoking gun’. So we decided to carry out a test run on both engines. This was successful with both engines delivering water to the boiler. We did notice though that whilst the valve in the header pond had lifted at a pressure higher than the boiler pressure in our static pressure test, it did not perform as well under operating conditions where it needs to lift and close around 10 times a minute with every stroke of the engine- some water was passing when in the ‘closed’ position, limiting flow to the boiler.

Before the last public steaming of the year on Saturday 23rd and Sunday 24th September we will strip down that valve and check its operation.

Volunteers at work investigating the broken valveGauge in place next to the Lancashire BoilerVolunteers at work

With the Tesco grant, we have purchased six iPads with rugged cases.  This means that visiting school and community groups can also take advantage of this system.  We also intend to use the iPads as an easy way of collecting feedback from visitors.

The new iPads are therefore helping us tell the story of Crofton’s 19th century technology to present day visitors using 21st century technology.  This adds to Crofton’s appeal as a place for school groups to develop their STEM skills, and helps us engage more effectively with our visitors.

There was an unusually high level of excitement for four and a half days at Crofton Beam Engines last week.  On Wednesday a request for help was received from Canal and River Trust, the water level in the Summit Pound of the Kennet and Avon Canal was found to have reached an unacceptably low level in the middle of the week.  Boaters were stranded and the fish had very little water in which to survive.  Following some swift communication with Crofton Beam Engine Volunteers, by 9.00 a.m. on Thursday morning ‘warm through’, the process for warming the boiler was getting underway. On Friday, Saturday and Sunday a dedicated team of Volunteers and a member of staff leapt into action for three days of steaming to replenish the water level in the canal.

Over the four days, one day for ‘warm through’ and three days of steaming, with the help of 23 Volunteers giving a total of 364 hours of commitment the task was completed.   As a result of the effort put in over the three days of pumping, around 19.5 million litres of water (18,000 tons) were pumped over 27.9 hours, enabling the Summit Pound to be reopened earlier than expected.

“Hard work, but a lot of fun for all.  Back to do it again tomorrow” Duty Engineer after Saturday steaming

“All in all it was a hard 3 days of work. Flexible working was required each day which was carefully managed and I think all the Volunteers enjoyed the challenge.” Duty Engineer after three days steaming

“My sister and I visited Crofton last Sunday when, as good luck would have it, steam was up on both engines.  We met with volunteers who explained everything with enthusiasm.  We had a very enjoyable, and unexpected, time at Crofton Beam Engines” Richard Jackson, visitor

Crofton Pumping station on the Kennet and Avon Canal in Wiltshire houses the oldest working beam engine in the world and is still able to do its original job, pumping water to the summit of the canal. Our 1812, Boulton & Watt engine and our 1846 Harvey engine are regularly in steam.

With the help of graduates from the Atomic Weapons Establishment (AWE) at Aldermaston and students from Bath University we have installed a sophisticated Mechatronics’ system, as used in F1 racing cars, to measure and record key parameters such as pressures and valve timings. We do not think this has been done before for such historic engines.

Figure 1 shows a typical Indicator Diagram produced after the engine has warmed up and is running smoothly. It shows both above and below piston pressures and shows that for the major part of the cycle pressures are below atmospheric. The approximate position of the valve timings is also shown.

Figure 2 shows the plot of a single cycle of the engine against time. The precise timing of the opening and closing of the valves can be observed. Variations in the pressures over the cycle can be seen, with fluctuations, most likely resulting from leaking valves or the piston.

The results enable us to monitor the performance of the engines, to prevent any damage, to monitor any changes and to show the visiting public their detailed workings. We are happy to make this data available to suitable accredited academic establishments.

By analysing unusual occurrences and comparing results over time we are in a unique position to identify any problems, ensuring early intervention if required. Analysis of the data can also significantly increase our knowledge of how these amazing machines work.

On Saturday 24th and Sunday 25th June we will hold a special Mechatronics Event when there will be experts available to explain the systems and presentations throughout the day.

Kennet & Avon Canal Fish Rescue

The Canal & River Trust’s project to replace the pumping system at Crofton, which ensures the charity can keep the summit of the Kennet & Avon Canal topped-up with water for boats, will be completed this winter. 

The works, started in September and will continue through to March 2023.  Costing £1.8 million, the project will see the canal’s 40-year-old pumps, pipes and electrics at Crofton replaced with a modern, more efficient and reliable system.

Draining a stretch of canal is a rare event, and hundreds of pounds of fish, were collected including some very large and ecologically important specimens.  The species rescued included roach, pike, bream, gudgeon and perch.

The fish rescue was carried out by specialist contractors who use electrofishing. This involves passing an electric current through the water to temporarily disengage the ability of the fish to swim.

They can then be easily netted, placed in large containers of water where they can recover for a few minutes, before being rehomed in a nearby section of canal that isn’t being drained.