MILKING MACHINES — CREAM SEPARATORS — A MACHINE FOR DRYING MILK

MILKING MACHINES

The farm labourer, perched on a three-legged stool, his head leaning against the soft flank of a cow as he squirts the milk in snowy jets into the frothing pail, is, like the blacksmith's forge throwing out its fiery spark-shower, one of those sights which from childhood up exercise a mild fascination over the onlooker. Possibly he or she may be an interested person in more senses than one, if the contents of the pail are ultimately to provide a refreshing drink, for milk never looks so tempting as when it carries its natural froth.

Modern methods of dairying demand the most scrupulous cleanliness in all processes. Pails, pans, and "churns" should be scoured until their shining surfaces suggest that on them the tiniest microbe could not find a footing. Buildings must be well aired, scrubbed, and treated occasionally with disinfectants. Even then danger may lurk unseen, and the milk is therefore for certain purposes sterilised by heating it to a temperature approaching boiling-point and simultaneously agitating it mechanically to prevent the formation of a scum on the surface. It is then poured into sealed bottles which bid defiance to exterior noxious germs.

The human hand, even if washed frequently, is a difficult thing to keep scientifically clean. The milkman has to put his hand now on the cow's side, now on his stool; in short, he is constantly touching surfaces which cannot be guaranteed germless. He may, therefore, infect the teats, which in turn infect the milk. So that, for health's sake as well as to minimise the labour and expense of milking, various devices have been tried for mechanically extracting the fluid from the udder. Many of these have died quick deaths, on account of their practical imperfections. But one, at least, may be pronounced a success—the Lawrence-Kennedy cow-milker, which is worked by electricity, and supplies another proof of the adaptability of the "mysterious fluid" to the service of man.

On the Isle de la Loge in the Seine is a dairy farm which is most up-to-date in its employment of labour-saving appliances, including that just mentioned. Here a turbine generates power to work vacuum pumps of large capacity. The pumps are connected to tubes terminating in cone-shaped rubber caps that can be easily slipped on to the teat; four caps branching out from a single suction chamber. As soon as they have been adjusted, the milkman—now shorn of a great part of his rights to that title—turns on the vacuum cock, and the pulsator, a device to imitate the periodic action of hand milking, commences to work. The number of pulsations per minute can be regulated to a nicety by adjusting screws. On its way to the pail the milk passes through a glass tube, so that the operator may see when the milking is completed.

This method eliminates the danger of hand contamination. It also protects the milk entirely from the air, and it has been stated that, when thus extracted, milk keeps sweet for a much longer time than under the old system. The cows apparently do not object to machinery replacing man, not even the Jersey breed, which are the most fidgety of all the tribe. Under the heading of economy the user scores heavily, for a single attendant can adjust and watch a number of mechanical milkers, whereas "one man, one cow" must be the rule where the hand is used. From the point of romance, the world may lose; the vacuum pump cannot vie with the pretty milkmaid of the songs. Practical people will, however, rest content with pure milk minus the beauty, in preference to milk plus the microbe and the milkmaid, who—especially when she is a man—is not always so very beautiful after all.

CREAM SEPARATORS

In the matter of separating the fatty from the watery elements of milk machinery also plays a part. The custom of allowing the cream to "rise" in open pans suffices for small dairies where speed and thoroughness of separation are not of primary importance. But when cream is required in wholesale quantities for the markets of large towns, or for conversion into butter, much greater expedition is needed.

The mechanical cream separator takes advantage of the laws of centrifugal force. Milk is poured into a bowl rotating at high speed on a vertical axis. The heavier—watery—portions climb up the sides of the bowl in their endeavour to get as far away as possible from the centre of motion; while the lighter particles of cream, not having so much momentum, are compelled to remain at the bottom. By a simple mechanical arrangement, the—very—skim milk is forced out of one tube, and the cream out of another. An efficient separator removes up to 99 per cent. of the butter fat. Small sizes, worked by hand, treat from 10 to 100 gallons of milk per hour; while the large machines, extensively used in "creameries," and turned by horse, steam, electric, or other power, have a capacity of 450 gallons per hour. The saving effected by mechanical methods of separation is so great that dairy-farmers can now make a good profit on butter which formerly scarcely covered out-of-pocket expenses incurred in its manufacture.

A MACHINE FOR DRYING MILK

Milk contains 87 per cent. of water and about 12 per cent. of nutritive matter. Milk which has had the water evaporated from it becomes a highly concentrated food, very valuable for many purposes which could not be served by the natural fluid. Until lately the process of separating the solid and liquid constituents was too costly to render the manufacture of "dried milk" a profitable industry. But now there is on the market a drying apparatus, manufactured by Messrs. James Milnes and Son, of Edinburgh, which almost instantaneously drives off the water.

The machine used for this—the Just-Hatmaker—process is simple. It consists of two large metal drums, 28 inches in diameter and 5 feet long, mounted horizontally in a framework with a space of about one-eighth of an inch between them. High-pressure steam, admitted to the drums through axial pipes, raises their surfaces to a temperature of 220° Fahr. The milk is allowed to flow in thin streams over the revolving drums, the heat of which quickly evaporates the water. A coating of solid matter gradually forms, and this is scraped off by a knife and falls into a receptacle.

The milk is not boiled nor chemically altered in any way, though completely sterilised by the heat. This machine promises to revolutionise the milk trade, as farmers will now be able to convert the very perishable product of their dairies into an easily handled and imperishable powder of great use for cooking and the manufacture of sweetmeats. Explorers and soldiers can have their milk supply reduced to tabloid form, and a pound tin of the lozenges will temper their tea or coffee over many a camp fire far removed from the domestic cow.