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The upper end of the upper screen is also supported by two oscillating wooden springs. By this arrangement the two screens move always in opposite directions and shocks are reciprocally neutralized.

291 - Trial of the Hand Power Separator "Lacta 2," of the Machine and Bridge-building Company, Helsingfors, Finland.

REZEK, I. and WINKLER, W. Prüfung der Handmilchzentrifuge "Lacta 2 der Maschinenund Brückenbau- A.-G. Helsingfors, Finnland. K. k. Hochschule für Bodenkultur. Prüfungsstation für landwirtschaftliche Maschinen und Geräte. · Oesterreichische MolkereiZeitung, Year 20, No. 2, pp. 22-24. Vienna, January 15, 1913. On the construction of the seperator under examination the following is to be noticed: The drum consists of two parts, united by a ring and rendered watertight by a rubber ring. The bottom of the drum, which is raised in the centre, ends in a hollow cylinder which receives the end of the spindle, and on which the drum rests in such a way that its centre of gravity is lower than its point of support; it can thus balance freely, while rotating, on the end of the shaft. For this object the spindle head is provided with a metal cap AC (see figs. 1 and 2) fixed to it by a pin, which causes it to revolve with the spindle, but allows it sufficient play room, while the outer surface of the cap fits tightly in the hollow space at the bottom of the drum. The central tube through which the milk is fed is placed immediately above the cylindrical part of the bottom of the drum, against which the tube ends in a foot plate with three channels by means of which the inflowing milk is led to the neutral zone. Next follow 22 metal cones placed one above the other which at the top completely enclose the central tube. The whole set of cones is pierced vertically in three points which allows the milk to ascend and to spread between the conical plates; besides which they have three smaller openings on their flattened upper edge in order to allow the cream to rise. The set of cones are at a distance of 4 millimeters from the side of the drum and are covered by a top cone which embraces the central tube by means of a strong cylindrical support, and bears on its flat edge inclined inwards two outlets for the cream, the openings of which can be regulated by means of screws. The skimmed milk issues by the three grooves in the cynlindrical support of the upper cone, which convey it over the edge of the drum cover above the upper cone, whence it flows by centrifugal force.

The bearing consists of a strong brass socket which surrounds the shaft and which in its turn is held by a strong spiral spring.

The gearing shown in fig. 3 presents two novelties for separators. 1. The usual simple spur wheels are replaced by skew wheels, which offer the advantage of diminishing friction and of working noiselessly.

2. The intermediate shaft of the drum shaft is connected with the worm gear on it by means of a spring friction coupling, and the play room of the spring against the intermediate shaft is so small that by the motion of this shaft in one or the other direction it is immediately and automatically thrown into or out of gear.

The power required to work this separator was calculated by means of an electric method and also by Leuner's spring dynamometer.

Altogether 10 tests were made with the separator, the results being tabulated in the paper. They show that working under normal conditions the amount of butter-fat remaining in the skimmed milk is only 0.09 per cent., which is a very good separation.

When the number of revolutions was diminished by about 20 per cent. the intensity of separation changed but slightly and was satisfactory also at the low milk temperatures of 20° to 23° C. (68 to 73. 4o F.), the fat content of the skimmed milk not exceeding 0.14 per cent.

The noise produced by the machine when at work is very slight. The design of the separator is simple and suitable and it is carefully constructed. It does not require any particular skill to dismount, to remount and to clean it, all of which can be done in a few minutes. In view of these results the separator was pronounced to be an excellent machine.

292- A New Machine for the Extraction of Rubber from Bark.

Le

JUMELLE, H. Une nouvelle machine pour l'extraction du caoutchouc des écorces. Caoutchouc et la Guttapercha, Year 9, No. 106, pp. 6780-6783. Paris, December 15, 1912. The extraction of rubber from bark by trituration is not to be recommended in the case of all rubber-producing trees, although it is an excellent method to apply to lianes in general and also to such trees as usually afford only small quantities of latex when tapped.

The writer describes a new machine, "la Valour," which allows of the operation being carried out more rapidly, regularly and completely than when the material is crushed by hand in mortars. The entire apparatus consists of an iron cylinder driven by some kind of motor. The necessary force is about 3 H. P. The cylinder, which is placed horizontally, is pierced with numerous holes. Inside are about fifteen strong rollers, each weighing 371⁄2 lbs., and with a length almost equal to the cavity of the drum. These rollers are free, and when the drum moves at the approximate rate of 45 revolutions per minute, these bars of iron fall onto each other and also against the sides of the machine, acting in fact like the pestle in a mortar. If a certain quantity of bark is introduced into the cylinder it gets finely crushed. A stream of water, which passes through the perforations in the wall, removes the débris of the pulverised bark, while the pure rubber remains in the drum; it is then removed, carefully washed in hot water and formed into blocks by strong pressure. This machine can also work without water; in this case, the pulverised bark issues from the holes made in the drum for the purpose. The apparatus can be taken to pieces and thus transported on the backs of men or animals.

The cylinder is capable of containing 70 lbs. of bark. The block of rubber obtained in the course of an experiment made with the above weight of bark of Landolphia Thollonii represents 10 per cent. of the bark. It was of a maximum degree of purity, and only contained 1.15 per cent. of ash, which is much less than in the case of rubber obtained by tri

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