Directory_and_Chronicle_1903 — Page 710

19047.

THE BERKEFELD-FILTER

Continued.

TEST OF WATER FILTERS made by Surgeon-General Dr. Plagge, and published by the Medical Division of The Royal Prussian War Department (Vol. IX, 1895,) says:-

Page 60. The Kieseleguhrfilter (System Nordtmeyer-Berkefeld) shows the greatest progress made in the Filter Technik during the last ten years; they are absolutely germproof, and give a flow of filtered water 5-10 times as rapid as the Pasteur-Chamberland Filter. Since three and a half years the filter has been subjected to the most severe test and gave perfect satisfaction. Of all the filters now in existence the Berkefeld stands the highest and is the only filter that can be recom- mended for military purposes.

The filtering medium is a hollow cylinder of burnt infusorial-earth closed at one end. The water is forced to pass the walls of the cylinder from outside to inside. The excellent efficacy is caused by the innumerable microscopic pores of the filter, which possesses the following advantages; 1. It will filter large or small quantities according to pressure, and the filtered liquid will be absolutely free from any solid particles and from germs.

2. Each cylinder can be thoroughly sterilized by being placed in cold

water, and boiled for an hour.

3. The filter can easily be cleaned by washing the cylinder with a sponge, piece of Loofah or a small brush under a tap or in a vessel of water, as all impurities remain on the surface owing to the density of the material. If after a long time of use, the pores of the surface are thus glued up with organic material, that a slight washing does not open them, take a hard brush and the surface will be renewed. 4. The filter can be used in any case, viz:-a. Pressure-

filter, directly fastened at the supply-pipe, will give 1⁄2 gallon per minute at a pressure of 40 lbs. ¿. Drip- filter will give one pint per hour. Air-pressure-filter will filter pint per minute. c. It may be used with any pressure-pump to draw filtered water from wells and cisterns. d. It is a tourist's and traveller's com- panion. e. For use in Factories, Mineral Water Works, Brewers, Bleachers and all businesses requir- ing pure water, large supply filters are constructed by combining a great number of cylinders. Every cylinder bears the Mark, "System Nordtmeyer- Berkefeld."

The first gallon of filtered liquid may be a little cloudy, owing to the powder or meal which is caused in boring the cylinders: after this is out, however, the filtrate will be as clear as crystal.

SOLE AGENTS FOR CHINA:

VOELKEL & SCHROEDER (Pharmacie de l'Union).

SHANGHAI. zed by

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