The Future of Milling Technology

by Teresa Acklin
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Manufacturers design the latest innovations in milling equipment to meet ever-increasing market requirements.

   Since man first discovered how to make flour by crushing wheat between two stones, manufacturers of milling equipment have continually searched for new ways to help their customers do their jobs faster, easier and more efficiently.

   “Research and development of wheat flour milling machinery and techniques are ongoing processes,” said Elieser S. Posner and Arthur N. Hibbs in their 1997 book, “Wheat Flour Milling.”

    “Although we seldom observe sudden breakthroughs, changes are continuously tested, criticized, improved and accepted,” the authors said.

   Equipment manufacturers often commit enormous resources to research and development. This commitment to R&D is “the most effective method of answering the needs of today's demanding market,” according to Satake U.S.A., Houston, Texas, U.S.

   But new products are not introduced overnight. For instance, the Newtronic rollermill introduced this year by Buhler Ltd., Uzwil, Switzerland, took years of intense research and development.

   Whether it's a new rollermill or a new sifting solution, a new conveyor or a new debranning process, manufacturers are developing products that are the “milling technology of the future.”


   The Newtronic roller mill introduced this year by Buhler Ltd., Uzwil, Switzerland, is “the powerful synthesis” of the company's experience in the field of roller mill technology, said Martin Schlauri, milling engineer and managing director of marketing.

   “The roller mill is a traditional Buhler machine. The Newtronic stands for efficiency, yield and product quality, and meets the highest requirements of the modern milling industry,” Mr. Schlauri said. These requirements include reliable feeding, perfect and consistent grinding, non-compromising sanitation, high isolation degree, noise control, simple operation and an integrated control system.

   What makes the Newtronic unique, he noted, is that stock is gravimetrically measured “in an entirely novel way” across the wide inlet. The feed rolls are automatically controlled and monitored by an electronic system, with infinite variation of the product feed rate.

   In roller stands that process the same product on both sides, a higher and lower ranking control system ensures the necessary load compensation. With break rolls, larger feed rolls ensure the uniform discharge of difficult products.

   The Newtronic's compact roll pack offers precision adjustment and consistent grinding action. “The new roller stand generation is Buhler's uncompromising response to the most stringent sanitation requirements in food production that grain millers are expected to satisfy,” according to Mr. Schlauri.

   The machine's innovative design and state-of-the-art construction materials will set future standards in reducing noise and condensation, he added. The inlet aspiration system ensures a controlled air flow, also preventing condensation and dust accumulation.

   To reduce maintenance requirements, Buhler designed a swing-out feed module that allows for complete cleaning of the feed section. The roll bearings have been centrally lubricated, eliminating the need for lubrication throughout the life of the machine. But the most unique aspect of Buhler's new roll stand, Mr. Schlauri said, is the ability to make extremely fast roll changes.

   Each roll stand also has its own independent local control system, which maximizes operational reliability and ensures a consistent production process.


   The centrifugal impact action of the Entoleter Scourer Aspirator (ESA) effectively cleans dry, tempered wheat and other grains, making it standard equipment in many flour mills, the company said.

   Entoleter, based in Hamden, Connecticut, U.S., recently expanded its ESA line to include the Series 14-1SD direct-drive machine, which can handle up to 250 bushels per hour (7 tonnes per hour, wheat equivalent) and the belt-driven Series 27-3, which can handle up to 800 bph (22 tph, wheat equivalent). Both feature centrifugal impact processing, selective grain cleaning, high aspirating efficiency, a slow speed to clean dry wheat and a high speed to clean tempered wheat.

   The machine works by hurling grain against impact pins to dislodge grease, dirt, rodent hair, wheat beards and beeswing. The Entoleter Scourer Aspirator also breaks infested hulls and destroys internal and external insects.

   “The impact action can be closely controlled for either deeply infested grain or grain that's relatively clean,” Entoleter said.

   After impact, grain is thoroughly scoured in a swirling action against the conical inner surface of the scourer casing and discharged into the aspirator section. Grain is then dispersed against the housing in a very thin film; the uniform air velocity throughout the aspirator zone separates the debris and carries it to the dust collector. The result is minimum breakage of good grain and minimum fragments, Entoleter said.

   The ESA is effective on wheat, maize, barley, soybeans, sorghum, milo, mustard seeds and other grains, the company said.


   For many years, the “arched” triangular sieve cleaner has been recognized around the world as the most efficient shape. Filip GmbH, based in Gutersloh, Germany, said it has modified this shape for a new generation of plansifters. The company's triangular cleaners come in a variety of configurations, including the molded cleat and the brush-tip style.

   Sieve cleaners for new “no-backwire” sieve frames are designed to clean the cloth and the pan simultaneously.


   A new, proprietary frame clamping system from Great Western Manufacturing Co., Leavenworth, Kansas, U.S., improves sifter maintenance and sieve access, the company said.

   The system uses pneumatic cylinders to ensure constant sieve compression during operation. Sieves and frames can be completely removed, maintained and re-assembled in minutes, without tools, but with the touch of a button, the company said.

   Great Western also developed in-line sifting technology for pneumatic conveying. In-line sifting allows direct insertion into a vacuum or pressure pneumatic conveying line in order to remove small amounts of oversized impurities from dry, free-flowing grain, powders or granular materials.

   The company's In-Line Tru-Balance models are gravity-flow sifters engineered to work under pressure instead of a pressure vessel adapted to enclose sifter screens.


   Years of experience manufacturing drag conveyors made for a “natural and easy transition” in supplying enclosed belt conveyors, said Ray Vrtiska, vice-president, sales, of InterSystems, Inc., Omaha, Nebraska, U.S.

   “As conveying capacities become larger and the regulations for containment of emissions become more stringent, the industry has had to look for better methods of handling grain to satisfy these needs,” Mr. Vrtiska said. “Drag conveyors have been one answer to this need, but as capacities, horsepower and chain requirements have become larger, the enclosed belt has become a viable option, especially with its lower horsepower requirements.” InterSystems' new RollerFlo is a “feature rich” enclosed belt conveyor, Mr. Vrtiska said, and complements the company's existing bulk material handling line.

   The RollerFlo is available in belt widths from 18 to 54 inches, in capacities ranging from 5,000 bushels per hour to 50,000 bph. Standard features include external pillow block bearings on the idler spools that allow for vertical and horizontal adjustments, spiral wing tail pulley, reloading tail, rubber skirts in loader sections with external adjustment capability, 3/16-inch thick idler spools, “no tool” access, weather resistant covers and painted, stainless steel or galvanized housing.

   Because each application is unique, with its own special requirements, including location specifications, materials to be handled and environmental needs, InterSystems uses detailed computer analysis to assure that the system performs at the highest level of expectation, Mr. Vrtiska said.


   Ittifak Makina Sanayi A.S., Konya, Turkey, is the first Turkish milling equipment manufacturer to use automated systems in its flour and semolina milling systems, the company said.

   “The technologies in our flour and semolina mills, Selva-1 and Selva-2, are of the highest quality, and our machines are competitive in the sector,” the company said.

   Since it began manufacturing flour and semolina milling machines 10 years ago, Ittifak's largest trade volume has been in Konya, Turkey, in Middle Anatolia. In recent years, the company has exported its equipment to Europe, the Middle East and Africa through the foreign trade company Seleks Ic ve Dis Ticaret A.S., which also is owned by Ittifak Holding, Konya Turkey.

   Ittifak Makina, based in Konya, specializes in manufacturing equipment for the food industry, flour and semolina production, milling machinery, and animal feed industry, and produces automated systems for the flour and semolina milling and other industries. The company also supplies spare parts and after-sales services.


   Kice Industries, Inc., Wichita, Kansas, U.S., now offers state-of-the-art automated process control systems that produce high efficiency and repeatable results, the company said.

   Kice can upgrade existing manually operated equipment into a completely automated process or integrate automated equipment into a plant-wide automated system. Kice systems can monitor a process at the device level on the plant floor as well as generate detailed reports for purchasing, production scheduling or sales inventory.

   As an authorized Rockwell software strategic provider, Kice said it is kept up-to-date on new equipment and receives training on all software and hardware.

   “Kice Automation facilitates significantly enhanced efficiency and repeatability that is not possible with manually operated systems,” the company said.

   Kice also offers single-source supply capability for equipment, systems design, automation and system integration.


   Maztech MicroVision Ltd., Ottawa, Canada, uses proprietary digital technology to objectively measure grade and non-grade factors in grains and seeds on a per kernel basis, 24 hours a day. The company's latest innovation, the SPY Grain Grader, was introduced earlier this year.

   “Our customers asked for equipment that can quantify grain uniformity in order to maximize their processing efficiency,” said Kate Harrigan, director of sales and business development. “Kernel quality and consistency are of utmost importance to both producer and processor because it dictates grain value.” The SPY addresses the spread of fusarium head blight, Ms. Harrigan said, providing rapid detection of fusarium-damaged kernels and quantifying sound or diseased kernels, such as tombstone or ergot. Other types of fungal diseases cause discolorations on the kernel surface, which lowers the quality and increases the price of milled goods. “The SPY determines the amount of damage on the kernel surface and reports the percent of damage on each kernel,” Ms. Harrigan said.

   Size uniformity directly affects milling and flour yield, and morphological features are important in breeding programs. The SPY measures area, length, width, perimeter, aspect ratio and diameter, Ms. Harrigan said.

   Maztech also has developed imaging technologies that either enhance or replace subjective manual methods of analysis. In 1997, the company introduced the SPX Speck Expert, an automated instrument for objective speck counting in grain-based products. This system has become the benchtop method of choice for flour millers and food processors, Ms. Harrigan said.

   Maztech will verify customers' samples on the determinations previously described or test samples for new applications.


   The new floor-mounted Smart Sifter from Norvell Co., Inc., Fort Scott, Kansas, U.S., can be designed to fit any space, is simple and economical to operate and requires very little annual maintenance, the company said. All parts are designed to be repaired or replaced in the field.

   Manufactured with a rock-hard maple frame with top-grade plywood walls on top and bottom, the Smart Sifter has a stationary 430 magnetic stainless steel inlet and up to eight outlets. The press top is held down by self-locking adjusting screws. The sifter interior is epoxy painted, and the door is equipped with an aluminum wedge to enable the sieves align properly. The sifter exterior is available with either white epoxy paint or a clear lacquer finish. The dual action drive on the Norvell Smart Sifter has two 1.5 horsepower motors with a Goodyear Eagle belt drive enclosed in a steel guard. The sifter is suspended with steel cables from either a sturdy, maintenance-free steel tube or from the existing ceiling support structure.

   Norvell said its Smart Sifter can accommodate from two to 20 sieves and can make up to eight separations. The sifter is available in several sieve sizes. Revolutions per minute and circle size are easily adjusted by maintenance personnel, the company said.

   Norvell said the advanced drive system also eliminates the need for a stabilizing bar below the sifter that can interfere with outlet locations.


   The new RMQ/CS double high roller mill from Ocrim S.p.A., Padova, Italy, was designed to improve the superimposed grinding operation by incorporating the grinding and sifting actions. The main milling principle throughout the design process by Ocrim's research and development engineers was to separate the coarse from the fines after grinding.

   The new Ocrim roller mill is equipped with an intermediate sieve beneath the upper pair of grinding rolls. An optional sieve beneath the lower pair also is available, Ocrim said.

   The specially designed drum sifter is equipped with brushes that convey product against the stainless steel screen while keeping it clean. The screen perforation is based on the specific passage and application of the machine in the flow sheet.

   This sifting action has several advantages, Ocrim said. When separating semolina, flour is sent directly to the purifiers after the grinding passage, which increases the extraction of flour with low ash content. The sifter surface is reduced, and capacity is improved by separating fines from the upper grinding rolls.

   Other improvements, which also have been integrated in Ocrim's LAM/CS conventional roller mill, include an electronically controlled feed rate; electronic engagement and disengagement of grinding rolls by means of a pneumatic cylinder synchronized with the actuation of the feed rolls; advanced diagnostic programs to monitor the status of the devices; automatically regulated feed rolls speed by stock level, detected by a continuous capacitance sensor located in the feed inlet; three different settings of the feeding system: automatic, continuous and disengaged; differential transmission of power between grinding rolls by special profile belts; and automatic brushes or scrapers.


   A new debranning process from Prokop Milling Machines, Pardu-bice, Czech Republic, is the “new milling technology of the future,” the company said.

   Prokop TKAC Milling Technology (PTMT) removes bran layers step-by-step from the wheat kernel. “It has the same primary goal as the conventional milling process but does it in a new and more effective way, as it recognizes and makes use of physical and chemical properties of different bran layers,” the company said.

   The new debranning process simplifies milling technology, Prokop said, and increases flour mill capacity, improves flour color, increases extraction, allows the processing of sprouted wheat and improves the quality of by-products.

   Prokop has received ISO 9001 certification of its quality control systems.


   Satake U.S.A., Houston, Texas, U.S., says it has earned a reputation for its commitment to research and development. The company's newly developed FMHR rollstand is the leading machine in Satake high-speed milling concept.

   The new machine incorporates all of the previously developed features of Satake rollstands, and operates at higher speeds than conventional roller mills. “This leads to efficiencies in equipment allocation within a flour mill,” Satake said.

   Some of the features available on the FMHR include drive roll speeds of 1,500 rpm, which double the load per roll length; modular construction that enables fast roll change; and new rolls manufactured with “Super Tuf” steel, which significantly extends the life of the rolls.

   Satake said the new FMHR rollstand, when combined with its models SRM and SRMD, form an “unrivalled range of rollermills.”


   A new rice whitening concept that involves vertical whitening from top to bottom was developed recently by F.H. Schule Mühlenbau GmbH, Reinbek, Germany, a member of the Kahl Group.

   The Schule Vertical Rice Whitener Type VPC 470 operates with abrasive conical whitening discs with air-feed openings in between. The small diameter of the conical whitening rotor is located at the top of the machine, underneath the feeding section, while the large diameter is located at the bottom, in front of the outlet section.

   Product is conveyed to the machine by a vertical feeding pipeline. A conical distributor within the round inlet bin transfers the product uniformly to the feeding worm, which feeds the product into the whitening chamber.

   The counter-pressure disc, which can be adjusted by three springs in the outlet section, produces a uniform filling ratio and uniform pressure within the entire working chamber to ensure gentle and even whitening of the product, the company said. Air cools the product during the whitening procedure and supports discharge of the bran, which is removed by a separate pneumatic bran aspiration system.

   The degree of whitening is influenced by gap adjustment with the moveable cone. Other parameters, such as throughput capacity and the positions of brakes, also can be easily adjusted during operation.

   The Schule Vertical Rice Whitener VPC 470 has a capacity from 5,000 to 10,000 kilograms per hour, and is equipped with a maximum 55-kilowatt drive and 2.6-kw ventilator.


   For more than 10 years, Vibronet Graf GmbH and Co., Lahnau, Germany, has been involved in research for easier and simpler production and control processes. The company said its patented vibration damping systems and precision water control units have successfully shortened temper times.

   Vibronet's most recent technology is the non-contact infrared temperature control for roller mills.

   “The setting of the rollers according to their temperature is very important for the whole milling process,” the company said. In this new machine, Vibronet has replaced the manual action with an automatic operation.

   New machine regulations require that roller mills must be completely locked when in operation. Vibronet said its easy-to-install, non-contact infrared temperature control measures the surface temperature of rolls on-line from outside the roll stand.

   “The most important application is the monitoring of the smooth rollers,” the company said. “However, it can be used in all mill passages to control the grinding gap and, if needed, to shut down the mill or move the rollers apart immediately.” Vibronet said the machine also can be used to control temperatures in bearings, machine components and transport equipment, as well as in machines and devices that are subject to explosion hazards.


   The new eight-roller mill from Wittenberg Machine and Mill Engineering Ltd., Wittenberg, Germany, is the heart of the company's new “Challenge 2000 Plus” milling system.

   MMW was founded in 1878 as an iron and machine factory, but by 1888 had developed into a mill construction company. The company produces complete milling plants, including flour mills and rice mills, as well as machines for processing oats, barley, buckwheat, peas and lentils. In the past 25 years, more than 250 flour and rice mills and other grain plants have been delivered to more than 56 countries, the company said.

   One of MMW's recent projects included the construction of five 500-tonne wheat mills in Syria. The turn-key plants, which were completed in June 1998, each include a 50,000-tonne silo, a 3,000-kVA generator station, laboratories, workshops, weighing equipment and telecommunications.

   MMW also provides consultation, planning, production and assembly of milling plants and qualified milling personnel.


   The new DGJ series packing scale from Wuxi General Corp. of Supply & Marketing, Wuxi, China, is equipped with a simple, patented dynamic weighing technique. Three sensors on the bag holder guarantee high accuracy within 0.2%, the company said.

   No stock hopper is required, which minimizes flour leakage during filling and improves sanitation, Wuxi said. Moreover, the reduced height of the machine offers more possibilties of installation in low height floor.

   The machine consists of a filler, weighing holder, ramming platform and control system. Operation and data display are programmed and controlled by micro-computer.

   The DGJ packing scale is suitable for filling, weighing and packing flour, bran and other granulated products, such as rice, wheat, maize and pellets.

   The company also provide scale products for bulk weighing, continuous weighing and proportioning.