SEPARATOR HINTS

New Zealand Times, Volume XXXVII, Issue 8356, 17 February 1913, Page 2

SEPARATOR HINTS

FACTORS AFFECTING PROFITS. RESULTS’ OF EXPERIMENTS. Now that the home separation of cream is becoming so widely practised, any information that will tend to guide the operators of separating machines so that they will show the best results is of special value. The following experiments that were instituted by Professor Hunziker, of the Indiana station, and Professors C. H. Eokles and H. S. Wayman, of Missouri, in order to arrive at a better knowledge of the factors affecting the percentage of fat in cream will be found very instructive, and may help to dispose of many present causes of friction between the supplier and factory. VARIATIONS IN SPEED. Jn testing the effect of speed with five different makes of hand separators on richness of cream, the Missouri station found that with one exception the greater the speed of the machine the greater the percentage of fat in the cream, and this effect was much more marked when, the cream screw was set for thick cream. Within ordinary limits the greater the speed the less the amount of fat remaining in the skim milk. This did not vary to any marked extent whether the separator was set for thin or thick cream. The rate of inflow was uniformly increased by the speed. The explanation given for this is not that the greater the speed of the separator the more milk will run through it in a given time, but that it is due to suction caused by the flow of air through the machine. The capacity of the separators did not vary to any extent whether set for thick or thin cream. By varying the speed of the separator the Indiana station found the cream to vary in fat content from 10 to 65.5 per cent. Tile work of both stations proved that, contrary to the general assumption, the higher the temperature of the milk separated the thinner the cream. This was found to be more marked when the separator was set for thick cream than for thin cream. The colder the milk separated the greater the loss of fat in the skim milk. That the percentage of fat in the cream varies practically in direct proportion with the percentage of fat in the milk separated, or, in other words, that the ratio of cream to skimmilk. is not changed by the variation in the richness of the, milk separated, was demonstrated by both stations. Professor - Hunziker found that by varying the rate of inflow the percentage of fat in cream varied from 23 to 70. the greater the rate of inflow the thinner the cream. Tins was substantiated bv Professors Eckles and Wayman. who found that even the height of milk in the cream can effect the fat content of the cream to some extent. Acidity h-d but little effect, according to the Missouri station, except that with sour milk there is a tendency for the percentage of fat in the cream to be increased, especially when the cream screw is set for thick cream. A small obstruction in the skim-milk tube, due to dirt or some other foreign substance, does not. as a rule, make any marked change in the operation of the machine. If the cream opening is partly closed however, the cream becomes smaller in quantity and richer. The accumulation nf separator slime sometimes results in a larger quantity and thinner cream due to a partial obstruction of the .stim-milk tube. To show definite-

ly the effect the amount of water used to Hush the bowl on the richness of cream. Professor Hunziker conducted experiments, with the following results : When no water was used the average percentage of fat in the cream was 37.8; with water equal in amount to the capacity of the howl, 37.3; with sufficient water to cause the cream discharged to appear watery, 35; and when twice the amount of water needed was used the percentage of fat in the cream was 33.5. VARIATIONS IN RICHNESS. These experiments prove conclusively that, even though there is a wide variation from day to day in the cream tests, it does not necessarily follow that the creamery is dealing dishonestly with its patrons. They also show the necessity for uniformity in the care of milk on the farm, especially as regards separations, and in the sampling and testing of cream at the creameries. If cream is tested correctly, and if tlje tests of different lots of cream from the same patron vary; then these variations must be due to variations in tho richness of the cream. It is impossible to procure cream of exactly tho same richness from different skimmings from tho gravity can. The richness of cream from a farm separator is primarily determined and regulated by the cream screw. Tho richer the milk the richer the cream, if all conditions remain the same, for the ratio of skim milk to cream remains constant. During early summer months tho milk is usually comparatively low in fat. Advance in lactation period and change from succulent to dry feed cause milk to become richer in fat. The first drawn milk is much poorer in fat than the strippings. The greater the amount of milk running into a separator of a definite capacity per hour the thinner will be the cream. Tho greater the speed of the separator tho richer the cream. If the speed is too low a large amount of the fat is lost in the skim milk. Warm milk produces more and thinner cream than cold milk. The proper temperature to separate milk on the farm is from 90 to 95 degrees F. and immediately after it is drawn. The more water or skim milk is used to Hush the bowl, of the separator the thinner will be the cream. Tho most satisfactory cream for the creamery is that which tests about 35 to 40 per cent, fat. TO SECURE UNIFORMITY. . If the tests are to be uniform and ao (.urate, tho cream must he in such condition, when sampled, that a fair ana representative sample can bo taken. If, at the time of sampling, the cream is too thick, is tough, dry and leathery on the surface, is partly churned or curdy, it is very difficult to secure a fair sample, and tests of such cream are likely to ,bo irregular as well as inaccurate. In order that tl|o cream may be in proper condition for sampling and testing upon delivery to creamery, the farm separator should be thoroughly cleaned and scalded after each separation ; after separation, tho cream should he immediately cooled and kept cool by setting in cold water; the cream should bo stirred occasionally; the cream fehould bo delivered in cream cans not less than twice' per week in winter and three times per week in summer; in transit the cans should bo covered with a dry blanket or jacket in winter, and with a wet blanket or jacket in summer; cans should bo reasonably full of cream in transit to prevent churning.