Tag Archives: IHAI

Sluices and streams

The heading shows I’m trying hard to find a waterways link for this ….

If you’re anywhere near Belfast, visit Patterson’s Spade Mill near Templepatrick on the Antrim Road. The IHAI visited it after the April 2012 AGM and it was quite fascinating. Did you know that there were once 171 different types of spades in use in Ireland, catering for different uses and different types of soils?

Some of the many types of old spades on display

The mill is powered by water, using a turbine, and it’s the last water-driven spade mill in These Islands:

The channel taking water from the stream to the turbine. Part of the channel runs in a trough made by Portadown Foundry

The turbine

The turbine turns a shaft, which turns these wheels, and the belts power many of the machines in the mill

The water-powered trip-hammer towards the back

A spade after being hammered (just one of the many stages in its production)

The mill (which is original, not a reconstruction) is absolutely packed with machines and must have been a hellish place to work when in full production, with the heat from the furnace, the noise from the trip-hammer and several workers producing spades at the same time. The spade-maker above is one of the last six in Europe and really knows what he’s talking about: not just the process but the uses to which spades were put. The other guide, who took us around the other parts of the site, was also knowledgeable and helpful.

Some new spades

Highly recommended.

 

 

 

 

Skew arch bridges

The IHAI AGM at the weekend, in Newtownabbey Borough Council’s splendidly restored Mossley Mill,  included a tour of the premises and its museum. Then Professor Adrian Long of Queen’s University Belfast gave a short talk about the FlexiArch bridge, which his team have been developing since the 1990s.

Professor Adrian Long with a wooden model of the FlexiArch bridge

He said that their work started by asking why nobody built arched bridges any more; they developed a system that used pre-cast voussoirs (the wedge-shaped blocks) linked by a polymeric flexible membrane. The voussoirs for any bridge are cast to give the correct taper for the span and rise required for that bridge.

Arch rings arrive on site stowed flat on the back of a truck; when they are lifted off, they fall into the correct shape and are lowered into position on previously-installed footings. Each arch ring is 1m wide; several of them can be placed side by side to give whatever width is required. The end walls are added and the structure is filled and given the appropriate surface (eg tarmac).

FlexiArch is manufactured by Macrete of Toomebridge (beside Lough Neagh); their website shows several examples of installation including one at a name familiar on Irish waterways. There is a brochure [PDF] and there is a video showing the installation of a 15-metre bridge.

Wooden model as a skew arch

No, I haven’t any shares in it. I just thought it was interesting, for three reasons: first, the speed of construction is very impressive; second, there is a link to Lough Neagh; third, it might encourage the construction of more skew arch bridges over canals.