Flour Production

Flour Production. Production process. Modern industrial mills, in contrast to the obsolete artisanal mills (water and wind mills), represent factory enterprises of varying scale with wide application of mechanization and automation principles in the production process. The numerous operations that make up the process of transforming grain into flour are concentrated in two main departments of the mill - the grain cleaning (husking, scouring) and milling departments. The initial phases of grain cleaning aim to remove foreign impurities - mineral (earth, sand), plant (inferior grains, weed seeds such as darnel and others, broken stalks, etc.), animal (mouse droppings, etc.), and sometimes metallic (nails, etc.) impurities. For this purpose, grain is passed sequentially and for the most part repeatedly through a series of mechanisms: a) sieves of various systems - flat or cylindrical (burats); in both, grain¹ is sorted by size: smaller, unsuitable particles fall through the sieve, while better quality ones move on for further processing; b) separators, tarars and similar machines that use air suction, under whose influence the material is sorted by specific gravity: foreign particles, being lighter, are separated from the grain and removed; c) purifiers (triers), in which grain, sorted by shape, is cleaned from spherical seeds of darnel - one of the most harmful impurities; d) on many mills, magnetic devices are installed, through which grain is passed to remove iron particles. The second phase of cleaning, aimed at freeing the grain from its own natural parts that spoil the flour (outer shells, beard), is carried out in so-called husking machines, or huskers - rotating cylindrical or conical drums with an abrasive working surface. For final cleaning, grain is passed through brush machines, from which it emerges ready for milling - free from outer shells and smoothly polished. In the milling department, where the product is fed either directly from the huskers and brushes or from bins, grain again passes through a series of mechanisms, gradually being crushed and at the same time becoming increasingly free of particles that do not contain starchy substances (bran). The milling process, which has many variants, especially in the production of higher grades of flour ('fractional milling'), basically comes down to the following groups of operations: a) crushing grain into particles, larger ones ('grits') and smaller ones ('dusts', or 'middlings'); and b) the actual milling of these particles, which are pre-sorted by size and specific gravity. Crushing and milling are carried out partly with the help of one of the oldest milling devices still in use - millstones, but mainly on roller mills, on which grain is cut, crushed and ground between rotating cylindrical rollers moving in opposite directions. The sorting of the product is done on machines similar in principle of operation to the mechanisms of the cleaning department: on flat sifters, in cylindrical burats (sifting through sieves) and on various systems of aspirators (blowing with a stream of air). As a result of the zigzag passage of particles through these systems - from milling to sorting and back - flour of various grades is obtained; the flour is diverted to bins, from there to the packing area in sacks, which after weighing and sewing are sent to the warehouse, where they are stacked in piles. For the automatic movement of the product during its processing, and in the most advanced mills also for the transport of grain to the mill and flour to storage, various devices are used: screws (Archimedes' screw), belt conveyors - for horizontal movement of the product, bucket elevators - for moving the product up and down, pipes and chutes, transport screws, sack elevators, etc. Machines in both the cleaning and especially the milling departments are equipped with dust-extracting devices; the extracted dust through pipes goes to dust collectors of various systems, from which it either goes back for processing or is removed as waste from the mill. Hazards and dangers. Despite the advances in milling technology in the field of dust removal from the production process, the dustiness of the air, the main hazard of F. p., on most modern mills, at least in the USSR, still remains high. This is due on the one hand to technical backwardness - defects in the equipment itself, insufficiency of aspiration systems and their irrational operation, and on the other hand - insufficient care of the mechanisms. The table below shows the average dustiness of workplaces in Moscow mills according to 1923 survey data. Similar figures, generally somewhat smaller but still sufficiently high, were found in later studies (on Kyiv mills, Tashkent, Nizhny Novgorod and others). Mill workers are exposed to two types of dust: grain and flour. Grain dust, mixed in composition, contains along with organic substances large amounts of inorganic impurities, reaching depending on the degree of grain contamination 70-80% with a significant content of silica particles in them. Microscopic picture: hairs, threads, bristles, etc. organic formations and a large number of particles of round and irregular shape of mineral origin. Flour dust contains a negligible percentage of mineral impurities (1-2%) and gives a uniform microscopic picture - starch grains. Mill dust is often contaminated with microorganisms - smut spores, mold, etc. Seeding of dust from the milling department of one of the washing rooms of a mill gave in 1 m³ of air growth of 375,000 colonies with 12 types of bacteria, among them 6 pathogenic ones. Excessive physical strain, associated with lifting and carrying heavy loads - a hazard that in the past (and in artisanal and village mills still today) constantly accompanied the work of all mill personnel, is now particularly sharply expressed in the work of certain groups: loaders, grain fillers and flour packers. Other workers - machine attendants, sweepers, etc. - have to lift, turn and carry weights periodically: during repairs, accidental accidents, etc. Other hazards: a) work in unheated premises (mills, with rare exceptions, have never been heated for production and fire prevention reasons, which under the conditions of electric lighting and central heating cannot be considered sufficiently justified); this hazard is particularly strongly experienced by the staff of the cleaning department (in the milling department t° is higher due to the heat intensively produced by the operation of the mechanisms), then flour packers, who in most cases work with doors wide open (for convenience of flour transport); b) the influence of abnormal atmospheric conditions of the outside air, to which loaders are mainly exposed; c) noise and clatter of mechanisms and d) floor vibration (especially on upper floors). Along with the hazards, the work of mill workers is associated with multifaceted dangers of accidents. The causes of the latter are a) explosions of flour dust, which usually cause enormous destruction and are accompanied by numerous victims; b) bursting of millstones; c) dislodging of runners; d) putting belts on while moving without protective devices, which is very common on mills; e) workers falling when lifting and carrying heavy loads into open floor hatches, when walking on scaffolds, crossbeams and gangways, which are widely used on mills, especially during loading and unloading operations; f) operating mechanisms, engines, wires, transmissions, etc. Professional morbidity. Indicators of the overall morbidity of millers according to statistical data are relatively low, which is obviously explained by natural selection (millers are predominantly strong and healthy people, women to this day are not represented at all in the main professions of F. p.), in previous years - frequent interruptions in mill work (lack of grain, water and absence of wind), and in the later period - the gradual introduction into milling technology of the principles of mechanization of the production process. Against this background, the high level of morbidity of millers with certain types of diseases, etiologically directly related to their working conditions, stands out very prominently. Here, first place is occupied by diseases of the respiratory tract, mainly in the form of catarrhs of its upper parts - rhinitis, pharyngitis, laryngitis and bronchitis.

According to data from the Leipzig hospital fund, the rate of respiratory diseases for millers is 80.5 compared to an average of 56.3 for all insured persons (per 1,000 insured). The same rate according to data from the Bromberg fund (Germany) is 63. According to materials from Kharkiv insurance funds in 1922-23, the prevalence of respiratory diseases among millers was the highest among all other branches of the manufacturing industry. Among those examined in 1923-24, millers (329 people), respiratory diseases were found in 47.8%, including rhinitis in 33%, laryngopharyngitis in 21.5%, and bronchitis in 27.8% (Pik). Kulikov (1925) found among Leningrad millers (127): rhinitis in 68.5%, pharyngitis in 42.5%, laryngitis in 25.2%. Among 70 Odessa millers (Kagan; 1929), bronchitis was detected in 33 (47.1%). In regard to lung diseases, mill workers generally show more favorable indicators. Emphysema occurs relatively frequently, as well as acute pneumonias; tuberculosis of the lungs is expressed very moderately. Pneumoconiosis apparently occurs very rarely. Some authors have noted cases of bronchial asthma under the influence of inhaling flour dust. A number of cases of pneumomycoses have also been described, based on contamination of grain and flour dust with mold and other fungi. Other diseases etiologically related to mill dust: skin diseases - erythema, acne, prurigo, furunculosis, urticaria, etc.; eye diseases - mainly conjunctivitis; ear diseases - catarrhal and purulent otitis and very frequently occurring in millers, earwax plugs; dental diseases - mainly caries. Other types of diseases that occur relatively frequently among millers: joint rheumatism [according to Hirt 15.6% of the total number of miller patients, according to data from the Leipzig hospital fund 31.9 per 1,000 insured]; myocarditis [according to data from mass examinations as a percentage of the total number examined - 25% (Moscow; 1924), 22.8% (Nizhny Novgorod; 1921), 18.9% (Odessa; 1923)]. Many authors, especially older ones, point to the frequency of hernias among millers. In regard to injuries, flour production ranks among the most dangerous branches of industry. According to statistical data from different countries, a characteristic feature of injuries in flour production is the high level of coefficients of the most severe accidents, i.e., those that result in death or complete disability. Health improvement measures should go mainly in the following directions: a) maximum use of the achievements of ventilation technology for dust removal in all phases of the production process; b) systematic removal of dust masses, both aspirated and settling in work premises; c) maximum application of the principles of mechanization and automation of the process; d) careful implementation of measures for safety engineering and fire prevention; e) supplying workers with rational special clothing and protective glasses; f) implementing measures of individual hygiene: installation of washbasins, showers, baths, supply of drinking water, etc. Specific measures to combat hazards and dangers in flour production in the USSR are provided for in the 'Mandatory resolution of the NKT USSR on the procedure for the arrangement and maintenance of flour mills' of June 19, 1925. Workers in the dustiest professions, provided there is no proper ventilation, are granted an additional 2-week vacation by legislation. Adolescents under 18 years of age are not admitted to work in the cleaning department.