By Mildred Cookson
From 11–14 May 1881, London hosted the International Exhibition of Flour Mill Machinery, a remarkable showcase of innovation at a time when milling technology was changing rapidly. For millers and mill owners, exhibitions such as this provided a rare opportunity to examine the latest equipment, compare different systems and see new machinery in operation before committing to investment.
Exhibitors included firms whose names would become widely known in the industry: Dell, Throop, Nagel & Kamp, Simon, Childs and Daverio. Their exhibits illustrated the transition then underway in flour milling as traditional stone grinding began to be integrated with new mechanical processes for milling, cleaning, purification and product handling.
Two exhibits in particular attracted considerable attention: a large demonstration mill installed by WR Dell & Sons and an experimental electric middlings purifier developed by Smith & Osborne.
WR Dell & Sons and the New Process System
One of the most substantial displays at the exhibition was presented by Dell. They presented an elaborate demonstration mill designed to illustrate the New Process System associated with the American milling engineer George T Smith.
At the centre of the installation were two American bolting chests, each containing four reels and shown in Britain for the first time. Detailed transverse and longitudinal drawings accompanied the display, allowing visitors to study the complete arrangement of machinery within the mill, including the wheat separator and smutter.
The exhibit was arranged across several floors in the manner of a working mill. The basement level contained the main driving mechanism together with the lower sections of the elevators. These elevators carried wheat and intermediate products through the successive floors of the mill, illustrating the increasingly sophisticated handling systems being adopted in modern installations.
On the first floor stood three pairs of millstones, each measuring three feet in diameter and six inches thick, mounted within American-style hustings. The layout demonstrated how the New Process System combined traditional stone grinding with improved mechanical separation.
Although only three pairs of stones were installed for the demonstration, the layout allowed space for as many as five pairs, indicating how the system might be expanded in a commercial mill.
The second floor contained equipment for cleaning and treating the intermediate products. Installed here were several purifiers, a Victor smutter, a centrifugal bran separator designed to treat bran from the rolls, and grinding bins used for wheat storage and feed control.
On the third or top floor were additional preparation and reduction machines. These included a Barnard & Leas oat and weed separator, a Victor brush machine, and three sets of rolls: smooth chilled iron rolls, porcelain rolls and grooved chilled rolls used in treating bran.
This floor also housed the two four-reel bolting chests. driven by vertical shafts connected to a horizontal shaft running along the top of the mill. The pulleys for the elevators were mounted on this shaft, eliminating the need for separate belts to drive the bolting machinery.
Such an arrangement simplified power transmission and improved reliability. Since the elevators extended from the ground floor to the top of the structure, flour and other intermediate products could be directed by spouts to wherever they were required within the process.
Brush machines and the smutter were driven directly from the vertical shafts, illustrating the compact and integrated mechanical layout typical of advanced mills of the period.
An impressive feature of the exhibit was its sheer scale. Contemporary reports noted that the model mill weighed approximately 100 tonnes, making it one of the most substantial displays at the exhibition.
Smith & Osborne’s Electric Middlings Purifier
Another exhibit that attracted considerable interest was the Electric Middlings Purifier developed by Smith & Osborne. The machine represented an unusual attempt to use electrical attraction to improve the separation of bran from middlings. The principle relied on electrified rolls that attracted the lighter bran particles while allowing the heavier middlings to fall away.
The operation was straightforward. A mixture of middlings, bran and flour dust entered the machine at one end and passed slowly beneath the electrified rolls at a distance of about two inches. Agitation of the sieves caused the lighter bran particles to rise to the surface of the material stream. These particles were attracted to the rolls, where they adhered until removed by travelling brushes.
The brushes swept the bran into shallow gutters positioned in front of each roll, from which it was carried into a bran receiver fitted with a spiral conveyor. Meanwhile, the heavier middlings, unaffected by the electrical attraction. continued downward by gravity and passed through the bolts, where they were separated into grades according to fineness. By the time the material reached the final row of rolls, the bran had been largely removed and the middlings graded.
The purifier had already undergone practical testing. After trials in New Haven, the machine was installed at the Atlantic Mills in Brooklyn, New York, where it reportedly operated continuously for a year as part of the milling plant. According to contemporary reports, the purifier performed equally well with spring and winter wheats and worked across different grades of middlings with minimal dust.
Its claimed advantages were significant. Without increasing the power required, the introduction of the machine was said to allow a mill’s output to increase by around ten percent. In the case of the Atlantic Mills, which had a maximum capacity of 700 barrels per day and normally produced around 600 barrels, the new purifier reportedly freed 2000 square feet of floor space by replacing conventional air purifiers.
Innovation on display
The 1881 exhibition provided a revealing snapshot of an industry in transition. Traditional millstones were still widely used, yet new systems for purification, mechanical handling and process control were rapidly transforming flour milling.
Events such as this allowed millers to examine new ideas at first hand and assess their practical value before introducing them into their own mills. Some innovations would prove temporary curiosities, while others would help shape the future of the industry.
More than a century later, the exhibition stands as a reminder of the constant technological experimentation that has long characterised the milling profession.
