Comparisons of American and British Milling
Web Masters Note: The original article that appeared in "The Millers Review and Feed Forum," was not accompanied with illustrations.
Many of us may think we have the best mills, the most up-to-date equipment, and, therefore, that we are using the best methods of milling. We get a jolt when we find by comparison with other mills that there is much room for improvement. Consequently, in order to keep step with the times, we set out to make the comparison which we have spoken of, and by so doing, we set our feed towards greater progress, becoming less egotistical through prying into other systems, and other methods of milling. Only by Comparison Can Worthy Opinions be Formed With this in mind, it will be my endeavor to try to point out to you a few things with show up in making comparison of our American and Canadian methods of milling, against those of Europe and Great Britain. It was in the older countries, possibly above all others, I might mention Hungary, that the milling industry was first developed. About 1880 the stone mills were superseded by what we know as the roller process, this change being first noted in Hungary. This roller process spread first throughout Europe and Great Britain, and later was adopted by mills on the North American continent. My knowledge of the British milling industry has been gained from actual experience, and is not merely book knowledge. This applies to the Canadian milling business also, having had a varied experience in every type of small mill operated by water and electricity, and eventually, getting back to the big capacity mills, and enjoying the experience of installing and operating some of the largest mills in Canada. The "Gentle Treatment System" It was while connected with one of the largest port mills in Liverpool, England, that the most interesting development and experiments were carried out that I have ever witnessed; which experiments at that time were expected to revolutionize the milling trade. The new method was called the "Gently Treatment System." Briefly, it consisted of the idea of handling the mill stock as lightly as possible. The break rolls, were placed on the top floor, and the succeeding breaks on the floors below, so that there would be no re-elevation of the break stocks. There were tow sieves placed inside the hoppers of each break roll, and two distinct separations were thereby made. The siftings from the breaks passed on to very large purifiers, and the entire stock was treated before passing on to their respective purifiers and reels. The idea of passing the entire break stock to the break purifiers was in the expectation of extracting a certain amount of bran powder from the break flours. This experiment did away entirely with all spiral conveyors in the mill, and everything which was conveyed was on belt type conveyors. The result of this method of milling was very pure stocks to the sizings and middlings rolls. It was not a system which was generally adopted, perhaps due to the great amount of capital required for the extra machinery needed. However, it certainly was a great experiment, and for those of us who had the opportunity of working with it, as it meant a great many new ideas which have been helpful ever since. Since that time many other extensive experiments have been carried out by the British milling engineers, and I feel quite safe in saying that they have brought about far greater improvement in the British mills that we have seen here in the United States or in Canada. I am afraid we have been inclined to be too self-satisfied, too much taken up with the idea of capacity, and still more capacity; all at the expense of building up better systems. We have crowed our mills, and thought more of a machine which would increase the output than of installing a new machine which would improve our milling methods. We are now awakening to the fact that we must pay more attention to quality if we are going to hold our trade in competition with the British and Continental mills. As we have the privilege of milling some of the best wheats in the world, we have every chance of keeping in the lead by paying constant attention to the quality of flour produced on our mills. We will make this comparison as fair as possible, treating each department of the mill in turn. Wheat Cleaning More Thorough With Disc and Magnetic Separators Speaking generally, the machinery used in the smuts and wheat cleaning department of the American mills compares very favorably with that used in the British mills. If you studied the flow sheet and made a comparison, you would not find any great difference. In both countries the receiving and milling separators, wheat aspirators and scourers are used. If there is any difference I am inclined to believe it is in favor of the American methods of cleaning, due mostly to the more extensive use of the disc separator. If I were asked where the greatest improvement has been made in the machinery used in the modern flour mill, I would say that it was in the introduction of the disc separator, used for extracting seeds and oats, particularly in the latter. This disc separator had nothing short of revolutionized the cleaning of wheat before passing on to the tempering and condition system. Further, there have been great improvements made in the manufacture of separators, and it is these machines with the strong air currents which undoubtedly prepare the wheat before passing to the next stage in the milling process. Still another machine has come into the limelight recently, namely, the magnetic separator, which is being used more and more for the extraction of foreign matter, especially particles of metal from grain. The American mills are in the lead in the adoption of this machine. Conditioning Any and All Varieties In endeavoring to give you an idea of the British methods of conditioning, I would point out all wheat are washed, mostly for the purpose of first getting the wheat thoroughly clean, and secondly, to add moisture to the grain for conditioning, but in some cases the washing process is carried our to even reduce the moisture in certain of the world's wheats. It is necessary to picture the British mills having more of the world's varieties of wheat to condition prior to blending for their mill mix that anywhere else in the world. The wheats going into the mill mix would probably include Russian, Indian, Argentine, and Australian, together with American Red Winter, Manitoba, and their own native wheat. Often each of these varieties are washed and tempered separately, each having various degrees of water and different hours in the conditioning process; each variety being thus handled scientifically so as to put it in proper condition before being mixed together, and before going to the first break rolls. You will agree that this part of the milling process is a science in itself, and is worthy of the best brains in the milling business. So accurately does the British miller arrange his mill mix, both from the standpoint of conditioning and uniformity that it has been the writer's experience to see that where one country's wheat has been excluded from the mill mixture, it had been found necessary to add tow or three other varieties of wheat in order to obtain the correct balancing of the mill mix. It is, therefore, seen that the washing and conditioning process in the British mills is an art itself. Contrast this fact with our American method of conditioning, where practically no washing is attempted, and therefore, somewhat of a very ordinary method of conditioning done. It possibly may be said that in this country it is not necessary to go to all the trouble, due to the excellent wheat which we have the privilege of using in our mills. However, as time goes on, and our wheat get dirtier, due to the land become poorer, and more contaminated with weeds, it will behooves us to make a closer study of the art of conditioning and to my mind, we may well copy the established practice of the British mills in this respect. Thoroughly Washing All Wheats Produces Better Flour I feel confident that in the near future we will see adopted in our up-to-date mills the general policy of washing all the wheat which goes to make up our mill mix. It is only reasonable that if the wheat is thoroughly washed, we are bound to have a flour of better color, with less foreign matter, and consequently less bran powder and less ash. As we progress in this art of washing, so will we improve our methods of conditioning, which will open up another field for development, and that is the principal of heat in relation to more perfect tempering of the mill mix. I would like to give you a few points regarding the importance which the British mills attach to the conditioning of wheat. By conditioning I mean distributing the moisture content of the grain so that the best and cleanest separations are made during the subsequent milling process, and at the same time, the baking value of the flour is improved as far as possible. There is a great deal of difference between the grinding of wheat which has been properly conditioned, and wheat which has not passed through this process. In the former case the bran comes away cleaner from the endosperm in large flakes, with very little pressure on the rolls; the sizings are clean and of an even shape and size, so that the purification is very much simplified. The power consumed by the mill is substantially reduced, and the work done by the bolters and reels is more improved. Wheat which had not been properly conditioned makes poor sizings, small bran, and an excess of bran powder, most of which eventually finds its way into the flour. Conditioning has, therefore, become one of the most important processes in connection with scientific milling. British Modern Conditioning Method In British mills they have a machine for this work of conditioning, known as a "Conditioner," and vast strides have been made in perfecting same. This machine is after the style of the one which we use for drying purposes when handling tough wheat, but the British millers uses this "Conditioner" on all the wheats milled. To our mind, conditioning of wheat on this Continent means only applying water and putting it into bins, whereas, by the British method, the wheat is passed through a modern conditioner, where the application of heat is scientifically carried out, and far better results are obtained. We all know some wheat need the moisture driven into the grain, and in others, the moisture needs to be extracted. All this is done in the British mills by the aid of this "Conditioner." Moisture, heat evaporation, and humidity are all scientifically controlled by this type of machine in handling the wheat, preparing it for the first break. Web Masters Note: The author may forget that in American mills, the tempering and conditioning bins are located in the mill's attic or upper floors where the added moisture with heat, heat evaporation, and humidity are administered by nature without the aid of an additional machine. I would urge all millers interested in those latest types of conditioners to make a close study of their value to the mill. If we are going to keep pace with the British miller on the export market, and improve our own domestic flours, the day is not far distant when we will have to use similar equipment to that which is proving such a success in the British mills. Purifiers and Purification This very important department of the milling industry has never seemed to receive the same serious consideration as it has in the hands of the British system. As we now stress very much the importance of ASH, it is quite apparent that the purifier plays a very important part in the regulation of this, which some millers feel is the BIG thing in the milling business. It is will know that the progressive millers of the United States and Canada are becoming more and more aware that the ash content is the one great test as to whether the mills are performing properly or not. The operative miller soon realizes that his job depends upon his turning out a flour containing an ash content as set by his company, and if he is unable to deliver the goods he soon loses their confidence. I think it is good for the miller to have to live up to the requirement, although it might cause him sleepless nights, or even if he does sleep, he may dream of the ash bug-bear which confronts him at all times. But without doubt, the miller becomes more efficient, and keeps the mill under better control than he otherwise would without having to live up to certain requirements. Ash Comparisons You might as what has ash to do with the comparison of British and American methods of milling, and my answer is, it is one of the most important departments in the milling process. Taking for granted that the wheat is properly cleaned and conditioned, the purifier undoubtedly plays one of the most important parts in producing clean stock for the rolls, with a minimum amount of ash in the flour, and in my mind the British miller has it all over us in having improved purification and cleaner stocks. Not only that, but in training of the British operative miller is more thorough, as he is made to realize that the purifier is a most vital and important machine. That it requires constant attention as the grinder gives to his rolls. Whereas, we so often find that the purifier is the most neglected machine in the mill, due to the general run of purification not realizing that it is the proper method of milling. Good purification means good milling, and if were asked to check up a mill, I am sure that we would want to see the working of the purifiers as much as any other department. In fact, I would say let me see the working of the purifiers, and I will at once tell you if the mill is turning out a good quality of flour. Many Types of Purifiers There are many types of purifiers, briefly outlines as follows: 1. A standard tinless machine such as in common in our American and Canadian mills. It is will constructed from an engineering point of view, and in which all the liftings go directly through a high velocity channel to the dust collector, and the heavier impure particles over the tail. 2. A machine with a small high velocity air trunk stretched right across the sieve at the tail end of each compartment so as to carry away all the excess matter which is left on the silk by the ordinary tinless machine. 3. The standard British machine, fitted with tins stationed above the sieves, running the full length of the machine. In comparing the different types, I have always considered the British purifier fitted with tins to be the most effective, making the most perfect separations and cleanest stocks. I am hardly prepared to agree with an opinion expressed with says that the American type of purifier is definitely inferior, but I must say vast strides must be made to improve it, if it is going to perform the work we would like it to do. Grinding - Fast and Slow Overloading Capacity versus Quality The chief difference which the writer had found between the handling of stocks on the rolls in our American and Canadian mills as compared with the British methods is as follows: In the British mills the rolls are run very much slower, with much lighter loads, and consequently the result is more accurate grinding. They are extremely against the heating of the stock when grinding, and the writer has seen many a man discharged because the British superintendent on his rounds in checking over the grinding, found the rolls warm. Our idea over her had been, heavy grinding on our rolls, with the result that our stocks have not been as evenly and as finely reduced as in the case of the rolls carrying lighter loads. To illustrate this, the British milling engineers figure as high as 3 1/2 inches per barrel; roll surface, whereas, we boast of only requiring as low as one inch per barrel, and think we are performing wonders. The stocks going to the sizings and middlings rolls are indeed much better classified than in the general flow of our American mills, with the result that they are not up against the same difficulty of producing a uniform flour, particularly where the ash content plays such an important part. There are certain disadvantages of the British rolls - principally their exceedingly long length. For instance, their 60 - inch rolls, which are used on the breaks, and the 40-42 inch on their reductions. On this side we favor the shorter rolls, the same having greater accuracy. Of course, the large roll with us would be an absolute impossibility, on account of the heavy streams which we put on them. It is also interesting to not that the British rolls on the middlings often carry as high as 60 to 80 corrugations per inch. This can successfully be done done due to the wonderful double feed rolls feeding a think stream, and also because of the special attachment on the rolls themselves. The drawback of good grinding on our rolls in the United States and Canada, as before mentioned, often due to our desire for capacity. We overload our rolls, and instead of a thin feed going to the roll it is often otherwise on our systems, with the result that instead of the rolls themselves reducing all the stock, a percentage of the stock against stock is reduced. The consequent result is that the material is unevenly ground because of the lack of proper feed roll delivery. Compare the improvements on the British rolls (except for their length) with those manufactured here, and it is at once realized that we are not as well off in this respect as the British miller. We have seen very little improvement in our roller mills, and there is a distinct lack of better feeding arrangement of the stock to the rolls, in comparison with the double feed roll attachment on the British roller mills. Bolting With Silks 16 to 18 XX Some of the features in connection with the comparison of the bolting principles of the British mills against ours are as follows: Only a comparatively few years ago the entire bolting and sifting machines in the British mills consisted of round reels and centrifugal reels. Very few sifters were used up to 20 years ago. Since then, sifters have been favored for handling the break scalps, but these machines were never used for bolting flour. They still cling to the centrifugal reel for all their flour bolting. Undoubtedly, we have made far greater strides in this department, and some of the types of our sifters are no to be equaled anywhere in the world. Possibly there is an explanation for the British mills continuing to use the centrifugal reel, in the very fine flour which they produce. It has been my experience to use the centrifugal reels clothed with silks as fine as 16 to 18 XX. You can well imagine how almost impossible it would be for us to bolt flour as finely as this on the ordinary sifter, and it is perhaps for this reason that the British have stuck to the centrifugal reel for their flour bolting. The moisture content of their flour is, of course, much higher than ours, which has been another reason for keeping this type of machine. Those of you who have closely inspected British made flour, will have been impressed with its wonderful dress. It is practically free of any specks, due, of course, to the careful purification of their stocks, and fine bolting, coupled with the higher moisture content. All of which tend to produce a flour of a very high color, and very fine granulation. Dust Collectors In comparing the British against the American methods of machines used for collecting dust both in the smuts and in the mill, I feel that there has been far greater advancement in the British mills than in ours. Speaking of the dust collectors, in the mill proper, the problem in the British mills has been reduced in somewhat of a minimum due to the fact that all their machinery runs cools, and that they are not generating the same amount of heat, as is done on our mills. They have types of dust collectors, particularly, the suction filter type of machine, where they can take in the entire roll dust into the machine, and deposit the air back in the same room, practically free from dust. It has often been the writer's experience to see this done. It is such a contrast to even the best dust collectors which we have in our mills. The minimum of heat generated in the milling process, due to higher grinding, and from the fact that the dust collectors discharge cool air back into the room, gives better control of humidity in the mills than we experience in the States or in Canada. Therefore, it is important that we endeavor to make greater strides to improve the types of dust collectors used, and also to improve the humidity control in our mills. Briefly, I would like to describe the suction filter type of dust collector, which I consider the most efficient one on the market. It consist of a nest of sieves enclosed in a close compartment which is connected to the suction fan. The dust laden air passes first into the hopper and from the hopper upwards into a number of vertical textile sleeves which are generally about eight inches in distance. The air then passes through the sleeves into a closed air chamber, and from this away by the clean air outlet to the fan. By means of a mechanism the outlet to the fan is at intervals closed, and the compartment at the same time opened to the atmosphere. In this way a reverse air current is drawn from this opening through the sleeves into the hopper, and so through the other compartments to the fan. While this is happening, the same mechanism shakes the sleeves. This shaking combined with the reverse air current, cleans the sleeves with the reverse air current, cleans the sleeves very differently, rendering it possible to use a fine cloth without any risk of choking. The result of this machine is that the air is delivered so clean that it can be blown straight into the mill and the interior of the machine is always below atmosphere pressure, so that if there are any leaks, they are inwards, and not outwards, and no dust nuisance results. For Cleaner, Healthier, Safer Mills It is interesting to not that the British mills, the Cyclone and this type of dust collector are used. In the United States, and in Canada, the Cyclones and Pressure dust collectors are still the commonest type of machinery used. Practically every miller here, I think, is dissatisfied with the progress which has been made in the type of dust collectors used on this Continent. It has been said by a British writer that the majority of the millers in Great Britain take more pride in having a clean and well-kept mill than do the millers in the United States, or in Canada, and I am afraid that there is a great deal of truth in this statement. Therefore, it behooves us as operative millers to endeavor to make a greater study of the dust collecting system, and by so doing, have cleaner mills, healthier to work in, giving the mill operators a greater incentive to take pride in the general upkeep and appearance of the mill. Then, of course, there is the financial bearing of this matter, more of the dust would actually be collected, and a greater amount of dust recovery could be made. To Produce the Best Flour As operative millers, it is always our desire to have the best and most up-to-date machinery, in order to produce the highest class of flour possible, but to do this, it cost money, and in making a comparison between British and American methods of milling, we have to take into consideration the capital cost involved, and the relative cost per barrel. If you studied a British flow sheet, as compared with ours, the greater cost of machinery used in the British mills would be quite apparent. This with their longer system, means a greater cost per barrel. Without any doubt, our cost per barrel, both in the United States and in Canada, is the lowest of any country, when capital cost is taken into consideration. It is our desire not only to make the highest class of flour possible, but to produce it at a reasonable cost. To do this it is necessary for us to be on the alert studying the milling methods of other countries, ready to adopt improved machinery and methods, and to discard the unprofitable and out-of-date machines which we have been content with in the past. Final Comparisons In making the final comparison between British and American flours, we must remember that a flour which will suit the purchaser from the British miller, may not suit the purchaser of flour from a miller in the United States or in Canada. We are making distinct types of flour, both from the spring and fall wheats, and as our wheat are of such high quality, it naturally follows that our flour does not need to take second place to any produced. The criticism which I have offered is with one object in view, and that is in the hope that we, as operative millers, will not rest content, thinking that we are making the best flour, but to try for a higher standard, and to do this we must have the co-operation of all the operators in our mills, each man giving his best, which, together with the aid of our milling engineers, in producing milling machinery of a higher class than ever before, will insure a forward march in the milling industry. Web Masters Note: The demonstration miller knows or cares nothing for these things. They are directed or mandated to grind our more words than flour.
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