TECNICAL ASPECTS

This rich patrimony which lies between material culture and industrial archaeology, allows the reconstruction of the structural characteristics of the corn mills and their machinery.
These mills were built close to canals and torrents and provided with sluice-gates and flywheels, the water was carried along small channels of various sizes to turn the vertical wooden wheels mounted on transmission shafts; at first box wheels were used, then later cup or curved paddle wheels which were either ‘over-shot’ or ‘side-shot’ depending on the location of the factory and the fall of water.

The transmission shaft, called the ‘melo’, made from the trunk of a tree, was located inside the building and connected to a pair of millstones, the more ancient ones had smooth surfaces whereas the later ones were grooved after the French fashion, the lower one was fixed while the slightly raised upper one turned and the cereal was fed in through a hopper placed above it.

The flour produced was transported by a conveyor belt with cups housed into a wooden elevator in order to be coarsely sifted.

Usually one wheel turned just one pair of millstones but if the mill had two these turned alternatively.

At different times during this century, the mill plants have gradually been modified by installing Francis turbines, which caused the disappearance of the old water wheels, and by replacing the millstones with modern machinery such as the cylinder rolling mills which allowed for a better selection of flour and bran.
Charging basins connected to penstocks have been added along or uphill of the canals.

All this resulted in a more complex mechanised corn grinding cycle which moreover used a series of machines to clean the grain, riddle and separate the ground product which was continually made to go up and down and then pass through a plansifter, separators, and brushing machines positioned on the upper floors within a maze of elevators and conveyors for the subsequent breaking, re-grinding and sifting operations.

This new so-called ‘high grinding’ system replaced the ‘low grinding’ one, not only producing an ever greater quantity of flour required by the market but also preventing the product from becoming rancid, as cylinder rolling mills eliminate the oil present in the grain.

The corn mills which have introduced this new technology were operating up to a few decades ago, whereas the others have become disused and in some cases abandoned.

Cylinder rolling installations, dating from the early 1900s though now in disuse, can be found in the Zambon and Giovanni Cavedon Corn Mills in Marano Vicentino and in the Bonollo Corn Mill in Monte Magré.

Some aspects of the construction of the cylinder rolling mills are similar to those of industrial building: these multi-storey buildings with many windows, still found near water courses and rising above the surrounding dwellings, are no more than containers for machines and production cycles, having no particular aesthetic features. The maze of conveyors inside gives a fair idea of just how noisy they used to be.

The architecture of the most ancient corn mills is simple and essential; on the outside they look like rural houses, are of a similar size and cannot be distinguished from these, and are built with bricks, stones, stone slabs and materials found in the surrounding area where they fit in discretely and harmoniously. They are built parallel to water courses next to the miller’s house, and the main door is sometimes decorated with stonework; they are built low in the plains, but in the mountain valleys they can be built with several floors to exploit the limited space available, where the first floor is either lived in or used as a storehouse. They can be found deep in the vegetation on the pebbly shore of a torrent or rising up in steps, sometimes creating a spectacular effect.

Inside, the machines were located according to the usual installation criteria in rather small areas rationally exploiting the space. The use of wood, alongside sandstone used for millstones, gives the place a warm atmosphere and the impression that everything is ready to begin a new working day, timed by the sound of the water running outside.
Therefore, the corn mills can be considered an integral part of our historical environmental patrimony.

by Marina Campolmi Perfetti