Developments in Flour Milling

by Teresa Acklin
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A review of the latest in equipment and technology for flour millers

   Laboratory mills. For many decades, Brabender OHG, Duisburg, Germany, has offered a wide program of instruments for milling and baking laboratories. The program's focal points are the well-known dough rheological instruments such as the Farinograph, Extensograph and Amylo-graph — all trademark protected — for testing the quality of grain, flour and dough.

   These instruments are complemented by instruments for sample preparation, including moisture determination and milling. Brabender offers various laboratory mills to prepare grain for subsequent quality tests.

   The Break Mill SM3 is a small, sturdy mill with adjustable milling fineness, which is able to grind grain quickly (even large kernels up to the size of maize) for moisture testing and other analysis.

   The Quadrumat Junior is a precision laboratory roller mill with separation of flour and bran. The instrument is very easy to operate, and even small grain samples can be milled. Ash, yield and baking properties of the flour ground in the four-roll milling system correspond to industrially milled flours.

   The Quadrumat Senior is a fully automatic laboratory mill. Compared with the Quadrumat Junior, it has higher capacity and yield, and flours obtained correspond to an even greater degree with industrial production flours.

   The Quadrumat Senior is equipped with two milling heads, each consisting of the Quadrumat four-roll system. By using a plansifter system, the flour fractions can be separated in different ways, depending on the sifter arrangement.

   Moisture determination of grain and flour is very important for quality assessment and as a basis for further analysis. For this purpose, Brabender offers the Rapid Moisture Tester HAV, which can test 10 samples simultaneously.

   This instrument uses the principle of a drying oven, and the advantage is that hot samples are weighed in the oven after drying without the need to cool them in a desiccator.

   Results are given directly as water content with an accuracy of 0.1%. An updated version of the instrument, the Rapid Moisture Tester H-A-G E, uses the same principle but operates automatically with computer control and uses an electronic balance.

   For determining the quality of wheat and rye flours, dough rheological test methods play an important role. Physical dough properties, depending on grain quality and flour treatment, decisively influence baking characteristics.

   Such rheological tests cannot be substituted by a simple determination of the flour's chemical composition, including ash and protein. Brabender's Farin-ograph, Extensograph and Amylograph are used worldwide for dough rheological measurements. These instruments permit the production and control of flours of a defined quality and with consistent processing characteristics.

   The Farinograph measures the mixing behavior of doughs by recording the torque during mixing as a function of the mixing time. The Extensograph determines the dough stretching properties resulting from gluten structure and shows the influence of flour additives. The Amylograph measures the gelatinization properties of wheat and rye flours to determine enzyme activity (alpha amylase). All three dough rheological tests can be supported by a computer.

      Cleaning, sifting and moisture control.

   In developing its milling equipment, Buhler Ltd., Uzwil, Switzerland, targets a number of areas: reduced maintenance, ease of adjustment and supervision, high operational and energy efficiency, advanced automation and impeccable sanitation and product safety. Buhler's latest and comprehensive range of equipment has reached those targets.

   The Grain separator MTRB satisfies the highest requirements in grain storage and cleaning facilities. All offals are efficiently separated by size on the two screen decks with a curtain-type feed across the entire screen, and the grain can be classified. The rugged screens can easily be exchanged, and the stroke and angle of throw can be adjusted according to harvest requirements.

   The Combi-cleaner MTKB incorporates the latest research in sieve incline and air movement, resulting in top efficiency of the separation section with full use of sand sieves. The concentrator section separates healthy kernels from shriveled and infested kernels, which are treated separately on the stoner section of the aspirator. This machine guarantees efficient cleaning with the absolute minimum of adjustment, supervision and maintenance, and above all, it saves costs because of its smaller space requirements.

   The Scourer MHXS is sturdy and allows adjustment depending on the specific requirements of the wheat variety.

   The working principle and physical solution of the Automatic moisture control unit MYFB allows control of wheat moisture measured before or after dampening without the use of hazardous rays. The unit's moisture addition by precise feeders ensures accurate water dosing from small to large quantities. Combined with the Tri-rotor dampener MOZK, small to large quantities of water (up to 7%) can be added, and the intensive treatment in this dampener distributes the water so thoroughly that condensation problems in subsequent equipment and bins are minimized.

   Buhler's Square plansifters MPAH/MPAG NOVA incorporate a revolutionary design that gives even more sifting surface and higher sifting efficiency. The sieve backwires are eliminated, and the wooden sieve frames are replaced by metal frames. The combined sieve bottom-cleaners do the job effectively regardless of the time between cleanings (six to seven months).

      In-line sifters.

   The In-Line Tru-Balance sifters, model 611 and 631, are offered by Great Western Manufacturing Co., Inc., Leavenworth, Kansas, U.S. In-Line sifter are intended for quality assurance applications before packing or load out, or on receiving systems. Designed for direct insertion in a pressure or vacuum conveying line, sifting is accomplished at the conveying line pressure, not at atmospheric pressure.

   The advantage of using such a sifter is system simplification. The pneumatic system equipment requirements are greatly reduced, and because there is less equipment, installations costs, as well as maintenance, sanitation and power costs, are also lower compared with conventional gravity flow sifting systems.

   Great Western is known for its highly reliable gravity flow Tru-Balance sifters, and for years, its customers had asked the company to develop an in-line type sifter. Other manufacturers chose to simply mount a pressure tank on a drive mechanism and stick in some sieve frames. None of the features you would expect in a gravity flow sifter — accessibility, maintainability or dependability — could be found in these machines.

   Great Western's strategy in the development of its In-Line Tru-Balance sifters was to engineer a sifter to work under pressure conditions, rather than adapting a pressure vessel to act like a sifter. Because Great Western put the highest priority in sifting, its sifters have the features that engineers, sanitation and maintenance personnel and operators expect in any reliable gravity flow sifter.

   Great Western's In-Line sifters feature non-impact sifting technology that complies with BISSC standards. No beaters or impellers are used that can fracture the oversize impurities and drive them through the screen.

   The sifters also allow easy access for inspection and maintenance. The sieves can be completely removed, inspected and replaced in minutes, not hours. Great Western In-Line sifters use the mechanically reliable design that is inherent with all of the company's Tru-Balance sifters.

   On flour with a 30 or 40 mesh screen, the capacity range for Model 611 is typically in the 100 to 250 kilogram per minute range, while Model 631 can handle rates of about 450 kg per minute.

      Sifter cleaning balls.

   Sifter cleaning balls are of vital importance in the processing, grading and cleaning of products. Most sifter cleaning balls are made of rubber, but their effectiveness is limited, their wear-resistance is low, they are eroded by fats or they develop unhealthy build-up because of product adhesion.

   Karolee sifter balls, offered by Muller Beltex, Pijnacker, the Netherlands, solve these problems. Karolee sifter balls are made of highly elastic white polyurethane material, approved by the U.S. Food and Drug Administration, that does not absorb moisture and is non-porous. They are not subject to build-up and are bacteriologically safe.

   Because of their very high elasticity, Karolee sifter balls are very active in the sifting process, rolling and bouncing more than other balls. They also are long-lasting, reducing the downtime needed to change balls and screens and maintaining sifter capacity for longer periods.

   Karolee sifter balls are lightweight, and they do not damage sifter screens. They come in a range of diameters, from 12 to 50 millimeters, and are available in hardnesses from 60° A to 95° A shore.

      Compact flour mills.

   Using its extensive experience in the milling industry over the past 40 years, Orkimsen Ltd., Ankara, Turkey, has introduced an innovative product particularly targeted to users in rural areas — a compact type flour mill with a daily capacity of 30 tonnes. The mill is trouble free and even can be operated under poor conditions, such as in areas with inadequate industrial facilities, infrastructure and technical support.

   The state-of-the-art compact mill requires an area as small as 100 square meters. Its electricity consumption is 55 kilowatts per tonne, and it needs only 0.5 tonnes of water a day.

   The mill's main components are a ripple sifter, air channel, peeling apparatus, trio separator, intensive dampener, two airtronic-type roller mills, sifter, jet filter, 8-tonne capacity tempering bins, cyclones, aspirators, elevators, conveyors, pneumatic system and electrical central control panel. Two persons can easily handle the complete system through the main control panel.

   Orkimsen's new mill is so popular that the company received 10 flour mill contracts in Albania last year, all of which were successfully completed. This year, Orkimsen is installing three compact flour mills in Kazakhistan, and two mills are being commissioned in Ukraine.

      Flour and feed mills and equipment.

   The Prokop Company, Pardubice, the Czech Republic, was founded in 1870 when Josef Prokop started a small business making agricultural machinery. Over the years, the factory began producing roller mills and other flour-milling equipment.

   In 1992, the revitalized company began to trade under the name Prokop Milling Machines to affirm a century of tradition in the milling industry. Today, 126 years after the company was established, our constant attention to achieving the highest quality entitles us to claim a place among the world-class producers of milling technology.

   Our company assures you complete turnkey delivery of flour and feed milling equipment. We can supply intake, precleaning, storage and treatment machinery for grain and seeds; flour milling equipment for cleaning and milling plants including sifting and classification of processed stock; flour handling for bakeries; equipment for bran processing as well as complete feed mills; horizontal and vertical mechanical transport; positive and negative pressure pneumatic conveying systems; equipment for pollution control, air exhaust and cleaning for production and conveying systems; steel structures, complete buildings, storage bins and storage buildings; equipment for the manufacture of glue-stock sausage and salami casing; power and lighting electrical installations for production plants, including measuring and control means; computerized control and monitoring systems; and tools and fixures for machinery engineering.

      Tempering system.

   For the first time, there is a real solution to cereal tempering; the innovative Vibronet system enables grain products to absorb water with more speed, more hygiene and more economy.

   The new vibration method reduces your present tempering time by at least half, depending on grain variety — wheat, barley, oats, maize, rice and pulses — compared with all conventional tempering systems. Vibronet means gentle conditioning without breakage or abrasion and considerable energy saving; Vibronet requires less that 0.2 kilowatts per tonne per hour and gives a slight yield increase.

   Water addition of up to 8% in one pass is possible, and the shortened tempering time produces a microbiologically clean product. Vibronet gives flexibility throughout the production process and shortens production time.

   The new tempering system is highly cost effective in terms of lower construction costs because smaller-volume tempering bins are required. And increased capacity is no longer a problem.

   Installation is quick and easy even in existing milling environments. Vibronet is delivered completely cabled and connected with a control panel so that the machine is ready for use. Trouble free maintenance with extremely low wear is guaranteed.

   The worldwide patented Vibronet system has proved its value and is successfully operating in numerous industrial applications.