Trends in Flour Milling Equipment
September 01, 1997
by Teresa Acklin
World Grain offers a quick look at the some of the newest flour milling equipment designed to help millers meet the increasingly complex demands of their customers.
Over the past 10 years, demand has greatly increased not only for ready mixes and concentrates for bread, cakes and cookies/biscuits, but also for unusual mixed products such as fruit and nut fillings, dry sourdoughs and cream powders. The new Speedmix unit from Buhler Ltd., Uzwil, Switzerland, is the answer to this wide variety of mixing tasks.
The raw ingredients for the production of ready mixes are delivered in bulk truck, large or standard-size bags and various types of containers and then are stored in bins or tanks. All ingredients are accurately weighed and fed to the mixer. Here, coloring and flavoring agents, liquids and fats are added. On completion of the mixing time, the material is transferred either directly or by a conveying system to the bagging point, depending on the fat content.
But to be successful, this process must ensure that all the ingredients are dispersed absolutely homogeneously throughout the entire blend. These highly demanding requirements can be achieved with the aid of the newly launched core machine, the Speedmix DFML with chopper.
Further enhancements to the standard Speedmix Rapid Mixer, introduced in the market two years ago, include:
several knife heads (choppers);
new mixing tools ;
special shaft seals for processing sugar.
The exceptional characteristics of the standard Speedmix Rapid Mixer not only have been incorporated into the new unit, but have been further optimized for the production of ready mixes. The mixing times and thereby the throughput depend on the quantity of fat added.
In an initial stage, the dry ingredients are homogeneously mixed within 90 seconds. Material residues after discharge are absolutely minimal, amounting to 0.1% of the useful volume if no fat is processed, or 0.25% of the useful volume if a large amount of fat is added.
Flour millers traditionally have produced a large number of flours to meet demand based on many varieties of bread. The recent increase in market demand for frozen foodstuffs, confectionery and special bakery products has also has increased the need for particularly consistent quality in these flours. For these reasons, the miller frequently is compelled to change the type of wheat mixture, leading to an increase in the need for specialized personnel to optimize milling plant operations.
To avoid this complication, Braibanti Golfetto S.p.A., Padova, Italy, has designed and manufactured the Automill, an automatic rollermill gap adjusting system that alters the distance between the rolls according to the type of wheat being milled and the degree of grinding required. Though proving to be very useful, the Automill is not, however, “intelligent,” consequently presenting a series of limitations, the most important of which is the inability to compensate for roll wear, climatic variation and variation in wheat conditioning.
Conscious of the miller's desire to maintain optimal settings, Golfetto has undertaken a study into methods of automating this process into a continuous self-regulating system. In effect, the aim is to replicate the actions of the miller and laboratory technician to be able to control all stages of grinding to optimize milling results.
The intelligent self-regulating grinding system for obtaining predetermined percentages of the intermediate and final products is called “The Miller.” The product is sampled from each single rollermill passage and is sifted, and the two fractions are weighed, determining the hourly flow rate for each passage, the relative load percentage and the actual status of the passage with reference to its particle size curve. These parameters allow the system to regulate the distance between the rolls to obtain the desired results.
“The Miller” is very easy to install and requires no sanitation. Moreover, the grinding process is adjusted gradually and consequently is well balanced. Indeed, “The Miller” automatically carries out the operations that the miller has always done manually.
Kice Industries Inc., Wichita, Kansas, U.S., manufacturer of the shortflow milling technology utilizing the patented flow designed at Kansas State University, is expanding the available milling capacity of the Modular Flour Milling Units to two larger sizes 200 tonnes and 250 tonnes of daily milling capacity in single, modular designs.
These new units will possess the same features of low capital cost, low installation costs and less building requirements as the smaller 60- and 120-tonne units, which have proven themselves in more than 20 installations worldwide. These new units also include the advanced automation package, with programmable logic controller control and graphic display that allows for more consistent operation with less operator supervision.
The modular design streamlines installation and helps bring the new capacity on line faster, producing flour in as little as seven days after installation begins. When combined with the matching modular cleaning and tempering systems also available from Kice, a new or expanded facility can begin producing in a very short time.
The larger capacities will allow utilization of the patented Kansas State University revolutionary technology as main production units, reaping the benefits of low power consumption, reduced manpower and consistent flour quality that have won the approval of flour millers worldwide.
Ocrim, S.p.A., Cremona, Italy, is proud to present an innovative system for the automatic adjustment of the milling section. The heart of this system is the remote automatic gap control of the grinding rolls that is equipped with sensors to gauge roll position and the absorbed power of the motor.
The brain is represented by the “Expert System” that makes the remote adjustment of each pair of grinding rolls based on the comparison ratio between the value of the desired and actual overtails. The adjustment is obtained by combining one or more automatic rollermills with the relevant feeding and overtails flow measurers from the plansifter. The system, in conjunction with the rollermills and with the flow measurers, transmits the relevant corrections of the roll gaps to each controlled rollermill, closely maintaining the actual overtail ratio to the one programmed by the miller.
This automatic control has important benefits when applied to first breaks. For subsequent grinding or regrinding passages, the electronic set-up by the gap position could be sufficient. The system's purpose is to maintain the best grinding conditions in case of manless operations overnight or during weekends.
The system's scope is not to eliminate the role of the miller or to limit his field of action, but, on the contrary, to apply his decisions continuously and repeatedly. Actually, the real economic benefit comes from the preservation of the optimum conditions defined by the miller during the short period when he is not monitoring the process, such as during lab analysis, when the plant is overseen by non-qualified personnel or when it is operating without personnel at all.
A feasible economic analysis and evaluation of the investment can be obtained by taking into consideration the following observations:
the grinding process is variable, and variability can cause performance losses;
laboratory analysis of product samples usually requires long periods, which can delay interventions and adjustments. The plant could operate out of specification until the results of the next analysis are obtained;
the plant often is operated by non-qualified personnel. The performance of the plant changes during these periods and is inferior to the performance obtained by the miller;
automatic control increases the profit of the plant and the fast recovery of the investment; and
the automatic configuration of gap position for production changes reduces flexibility costs.
Contrary to conventional wisdom that automation is convenient only in large plants, the advantages of performance recovery and automatic controlled production are inversely proportional to the capacity of the plant. And a basic automation effective in achieving targets can be limited to the first and second breaks, with the only additional cost consisting of two flow measures.
Satake Corp., Hiroshima, Japan, continues to develop and introduce a series of innovative machines and items of equipment for applications within PeriTec and also in conventional milling processes.
The requirement to clean the crease area of debranned wheat prior to milling resulted in the recently launched SKW Kernel Washer, which is used in combination with the new SHD Hydrator to enhance the performance of the PeriTec system. Because of significant interest from millers, it has now been further developed as a whole grain “washing” device that can be equally effective when used with a conventional milling system.
In these days of concern over food security, it is a device with much to offer. Dry cleaning methods, which took over from wheat washing in the 1960s because of concerns over effluent disposal, are themselves being questioned because of high power consumption and less than satisfactory efficiency. The Kernel Washer uses low volumes of water to achieve a significant reduction in bacteria count.
Typically, water consumption is less than 2% of the weight being treated 180 liters per hour on a 10-tonne per hour system. A traditional washer and whizzer of this capacity produces around 2,275 liters per hour of effluent.
The Hydrator is an efficient mixer of wheat and water, giving extremely good kernel to kernel distribution. The combination of vibration, slow stirring and long dwell time gives excellent dispersion and full absorption at high rates of addition in a single pass. In many cases, this can eliminate two-stage damping.
Satake also has introduced the SRMD two high eight rollermill to complement the acclaimed SRMA, and the new unit shares many of its primary modules to minimize costs of maintenance and of the costs of stocking and holding spare parts.