Peat and its Uses as Fertilizer and Fuel

by Samuel W. Johnson

Weber's method.

At Staltach, in Southern Bavaria, Weber has established an extensive peat works, of which Vogel has given a circumstantial account.[24] The peat at Staltach is very light and fibrous, but remarkably free from mineral matters, containing less than 2 per cent. of ash in the perfectly dry substance. The moor is large, (475 acres), and the peat is from 12 to 20 feet in depth. The preparation consists in converting the fresh peat into pulp or paste, forming it into moulds and drying it; at first by exposure to the air at ordinary temperature, and finally, by artificial heat, in a drying house constructed for the purpose.

The peat is cut out by a gang of men, in large masses, cleared of coarse roots and sticks, and pushed on tram wagons to the works, which, are situated lower than the surface of the bog. Arrived at the works, the peat is carried upon an inclined endless apron, up to a platform 10 feet high, where a workman pushes it into the pulverizing mill, the construction of which is seen from the accompanying cut. The vertical shaft b is armed with sickle-shaped knives, d, which revolve between and cut contrary to similar knives c, fixed to the interior of the vessel. The latter is made of iron, is 3-½ feet high, 2 feet across at top and 1-½ feet wide at the bottom. From the base of the machine at g, the perfectly pulverized or minced peat issues as a stiff paste. If the peat is dry, a little water is added. Vogel found the fresh peat to contain 90 per cent., of water, the pulp 92 per cent. Weber's machine, operated by an engine of 10 horse power, working usually to half its capacity only, reduced 400 cubic feet of peat per hour, to the proper consistency for moulding.

Fig. 10.—WEBER'S PEAT MILL.

Three modes of forming the paste into blocks have been practiced. One was in imitation of that employed with mud-peat. The paste was carried by railway to sheds, where it was filled by hand into moulds 17 inches by 7-¼ by 5-¼ inches, and put upon frames to dry. These sheds occupied together 52,000 square feet, and contained at once 200,000 peats. The peats remained here 8 to 14 days or more, according to the weather, when they were either removed to the drying house, or piled in large stacks to dry slowly out-of-doors. The sheds could be filled and emptied at least 12 times each season, and since they protected from light frosts, the season began in April and lasted until November.

The second mode of forming the peat was to run off the pulp into large and deep pits, excavated in the ground, and provided with drains for carrying off water. The water soaked away into the soil, and in a few weeks of good weather, the peat was stiff enough to cut out into blocks by the spade, having lost 20 to 25 per cent. of its water, and 15 per cent. of its bulk. The blocks were removed to the drying sheds, and set upon edge in the spaces left by the shrinking of the peats made by the other method. The working of the peat for the pits could go on, except in the coldest weather, as a slight covering usually sufficed to protect them from frost.

Both of these methods have been given up as too expensive, and are replaced, at present, by the following:

In the third method the peat-mass falls from the mill into a hopper, which directs it between the rolls A B of fig. 11, (see next page). The roll A has a series of boxes on its periphery m m, with movable bottoms which serve as moulds. The peat is carried into these boxes by the rolls c c. The iron projections n n of the large roll B, which work cog-like into the boxes, compress the peat gently and, at last, the eccentric p acting upon the pin z, forces up the movable bottom of the box and throws out the peat-block upon an endless band of cloth, which carries it to the drying place.

The peats which are dried at first under cover and therefore slowly, shrink more evenly and to a greater extent than those which are allowed to dry rapidly. The latter become cracked upon the surface and have cavities internally, which the former do not. This fact is of great importance for the density of the peat, for its usefulness in producing intense heat, and its power to withstand carriage.