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is the name given to the machine invented by Dr. Martin Ekenberg for the purpose of removing the water content of milk and other liquids. It is not necessary to go into the minor details of the construction of this machine, and it would be difficult to do so, as some of its parts are exceedingly complicated. Briefly, however, it consists of a large vacuum chamber in which is hung a milk cylinder which nearly fills the vacuum chamber. This cylinder is supported at its axes by trunnions, one of which extends outside of the chamber, providing a means to revolve the cylinder. Connected with the vacuum chamber and in front of it is another chamber, also under vacuum. This chamber is known as the products chamber, and is separated from the vacuum chamber by a series of gates, the use of which permits the maintenance of a constant vacuum in the vacuum chamber and the opening from time to time of the products chamber.
There is also attached to the vacuum chamber a milk chamber which is constantly under vacuum, and into which the milk is drawn from the outside. Another important part of the apparatus is a specially constructed condenser to which is attached the suction pipe of a large vacuum pump, and this is also provided with a large stream of water, which, passing constantly through the condenser, cools the vapors, reducing them to water, which is carried away.
To the milk chamber is attached a pump which forces the milk through a spray pipe on to the revolving cylinder. The cylinder is heated slightly by exhaust steam, and on account of the high vacuum the thin layer which is deposited by the spray pipe upon the cylinder is quickly dried upon the surface of the cylinder, and a series of silver knives removes this film of dried milk. It passes directly into the products chamber, and by manipulating the gates it may be removed from the products chamber without the loss of the vacuum in the remainder of the apparatus.
The temperature of the milk at no time has thus far gone above 120° F., and in fact it rarely exceeds 110° F.
When the dried film of milk reaches the outside air it is slightly moist and flexible, and in order to crystallize the lactose or milk sugar which comprises from one-third to one-half the total weight of the dried milk it is necessary to place the product in a heated chamber at 90° F. from 20 minutes to an hour.
When removed from the drying chamber the product is in the form of dry, crisp chips and ribbons as thin as paper and as brittle as a wax wafer. It is then reduced to a very fine powder by specially constructed mills, which grind without heating or in any way injuring the delicate elements of which the milk is composed. As the milk powder comes from the mill it is packed ready for the consumer.
ATOMIZING AND HOT AIR SYSTEM.
Robert Stauf, of Posen, Germany, devised a process for producing dry powders from blood, milk, etc., by atomizing these liquids into supplementary regulated currents of heated air. The amount of air and heat supplied was sufficient to completely absorb and vaporize the moisture of the liquid and the resulting dry powder was separated from the moisture-laden air by means of a screen. The screen retained the powder and the air passed off through the screen. The Stauf process was the first spray drying process to be commercially used in the United States.
THE JUST SYSTEM.
The drying machine is comparatively simple, being composed of two polished metal cylinders placed side by side and slightly separated from each other. They are mounted in a heavy, solid iron framework, and revolve inversely at the rate of about six revolutions per minute. They are heated in the interior by superheated steam, at a pressure of about 45 pounds to the square inch, which makes the outer temperature of the rollers considerably above 212° F. The milk is introduced into the machine by a pipe which runs between the rollers, about 6 inches above their convergence, and as soon as the milk strikes the rollers evaporation commences. The milk passes gradually between the cylinders and is carried in a thin, uniform layer upon each, the layer being thinner than the thinnest tissue paper. Whatever water is not evaporated at the point of convergence is dried out of the layer in its passage on the revolving hot cylinder, until the film reaches a knife held in contact with the cylinder, which removes the milk in long, continuous sheets, which fall into a receptacle below, where they are broken into innumerable small pieces by the fall and rapidly cool. To collect and carry off the steam arising from evaporation the machine is provided with a large hood leading into a pipe. On an upper floor an exhaust fan is located connected with all these different pipes, thus carrying the steam rapidly out of the hoods and keeping the building absolutely free of it. As soon as the boxes into which the sheets or rather broken pieces of dry milk fall from the rollers are filled, they are wheeled to a brushing machine, where the product is reduced to a uniform powder, and after having been spread on large hardwood tables to cool thoroughly, is ready for packing and storing or shipping.
THE CAMPBELL SYSTEM.
The milk is pumped into a large round copper vessel, where it is agitated and heated by sterilized air blasts preparatory to its being pumped into rectangular concentrating vessels. These concentrat
ing tanks are provided with a circulating medium of hot water surrounding them and coils in their interior. They are also provided with pipes and fan-shaped nozzles for the introduction of sterilized air below the surface of the milk. This air is under pressure and is allowed to escape when the tanks are charged with milk, and causes the water vapor to be driven off. The milk here has a violent rolling motion. As the product becomes concentrated the temperature is lowered. The opening of a valve permits the mass to fall into the large roller drums with tapered ends, which are located on a lower floor. These roller drums are tin plated and are perfectly smooth on the inside, with cone-shaped ends. An air blast is then introduced into the head of the drum. The latter revolving about two turns per minute carries the pasty product up on its side, and as it approaches the top it falls back through the dried atmosphere, the air thus carrying away the moisture. This paste soon becomes too heavy to be carried up by the revolving of the drum and rolls into a large mass, the cone-shaped ends causing it to move unequally, and twisting and grinding it into small particles. These are then conveyed to the drier drums, where the desiccation is completed. These drier drums have a novel construction. Sterilized air is forced through a central shaft having lateral arms extending down into the mass, where the constant rolling of the drum exposes all parts to the desiccated air. When the product is bone dry, it is conveyed to a grinder, which brings it to about the consistency of corn meal, and it is then packed.
THE PASSBURG SYSTEM.
The Passburg dryer is a large steam-heated iron drum revolving in a vacuum chamber. The milk is fed to it cold, and is scraped off by a steel knife, in thin sheets, and is perfectly dry when taken from the receiver.
HOW THE PRODUCE DEALER MAY IMPROVE THE
QUALITY OF POULTRY AND EGGS.
By H. C. PIERCE,
Food Research Laboratory, Bureau of Chemistry.
In marketing poultry and eggs there is an enormous preventable loss in quality and value between the producer and the consumer. It has been conservatively estimated that this loss amounts annually to $75,000,000 in poultry and $45,000,000 in eggs. While this loss falls upon all who handle poultry and eggs it is borne chiefly by the producers and the consumers. The producers' loss, caused by a decrease in price, under present conditions represents that due to spoilage or poor quality. The consumers' loss is due to a curtailed supply because of the pounds of poultry and dozens of eggs that are either of poor quality or a total loss; hence the consumer has to pay a higher price for that portion which finally reaches him.
While these losses are increased at all stages of handling by the producer, the country storekeeper, the produce dealer, the railroad, the commission man and jobber, and the retailer, the greatest preventable loss occurs before the produce dealer obtains the goods, that is, while the poultry and eggs are still on the farm or in the hands of the small country storekeeper, whose responsibility is moral rather than financial. The produce dealer, in paying a flat rate for poor and good poultry and bad and good eggs, offers no incentive for any improvement in quality by the producer nor conservation of quality by the storekeepers who take poultry and eggs in trade for groceries or supplies. As the produce dealer controls the price paid for poultry and eggs in the country districts, he is the one best fitted to aid in the improvement of quality and increase in quantity of these products.
It is the purpose of this article to point out a few of the many ways in which the produce dealer may work for better quality in poultry and eggs in his district.
BUYING ON A QUALITY BASIS.
The quickest way to arouse a desire in the producer to raise better chickens and supply better eggs is to show him that good quality poultry and eggs are worth more than those of poor quality; the
produce dealer must pay more for large, clean, fresh eggs than he does for those which are small, dirty, and stale. Otherwise there is no financial incentive for the farmer to improve his output, or the storekeeper or other intermediate handler to market his eggs frequently. It costs the farmer more to produce large, clean, fresh eggs than it does to produce small, dirty, and rotten eggs, for the hens' nests must be kept clean, and the eggs must be gathered frequently and marketed often. Unless he receives an increase in price for his good eggs it is not good business for him to perform the extra labor necessary to conserve the quality of his goods.
DIFFERENCES IN PRICE.
The difference in prices paid for the different grades of eggs varies with the season and the market prices for the different grades in the consuming markets. In the spring, when egg production is at its flood, and eggs are cheapest, the difference in price may be as low as 2 cents a dozen. In the fall, when the hens are not laying freely and the prices for strictly fresh eggs are soaring, the price may differ as much as 14 cents a dozen between the highest and lowest grades of marketable eggs. As an example of the variations that may be paid, one southern poultry shipper in November, 1912, paid 35 cents a dozen for large, clean, absolutely fresh eggs; 28 cents for a second grade which were slightly smaller, but clean and a little less fresh; and 21 cents for a third grade, consisting of small, dirty, and stale eggs; rotten eggs were not purchased at any price. The average market price for eggs in his vicinity at the time was 27 cents. Thus the producer of the highest grade eggs received an increase of 28 per cent over the market price and 663 per cent over the price paid for the lowest grade. Such variations gave the produce dealer a profit on all grades and made it worth. while for the farmer to produce better eggs. Where eggs are bought at an average price the dealer must sell his lower grades for less than he paid for them and make up this loss and procure his profits from the sale of the higher grades.
KNOWLEDGE THE DEALER SHOULD HAVE.
Some produce dealers say that it is impossible for them to buy eggs on a graded quality basis because their competitors pay a flat rate. That this is not true is proved by the several firms throughout the country that are buying on a quality basis and making a profit thereby. The produce dealer must know, however, how to candle and grade eggs so that he may buy intelligently, and must