Page:Popular Science Monthly Volume 89.djvu/652

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038

��Popular Science Monthly

��A Simple Electrical Device for Purifying Water

ADEVICIC for purifying water by means of electricity can he made at \ery little cost by the use of a few ele- ments which are easily obtainable. It may be done by procuring an aluminum

tube A, 4K '"s^- 'o"K. "tl iK ins- in diameter. It is immaterial about the gage. Also purchase an aluminum rod B the same length, of %-in. material. A piece of hard rubber, or fiber, C, % in. thick, and i^ ins. each way. This is to be turned in a lathe so it will fit into one end of the aluminum tube.

Tile rul)ber lork thus provided has a central hole to receive the ^-s aluminum rod, as shown. One of the set-screws D, for holding the head C and tube A together, serves as a means for connecting with one of the terminals /'", while a screw / in the upper end of the rotl B acts as a binding-post for the other terminal G.

The tube B should have a few notches, as at //, at its lower end. An inch from the upper end are two or more holes /, the object be- ing to provide a means for circulating tlic water wluii the current is do- ing tlic work.

Tins manner of treat- ing water is known as the direct electrical method; whereas ozoni- /ation is the indirect means. F^oth sys- tums, however, depend on the generation and application of oxone, or na.scent o.\y- gen, which attacks the organic matter in water. The result is that such substances are coagulated and precipitated, thus leaving the water pure and wiiolesome. This system is in every respect superior In filtration, 'i'he latter method cl.irifies, i)Ut does not purify.

The arliiie thus ronslru(tc(l is .ul- Miirably adaplcil li> st.md in a glass of water, ;ls shown, fiir a minuli- or two.

���The water moves up along the space between the two electrodes and down outside the tube

��and then be taken out. Theaction of the current in passing through the water between the electrodes A, B, causes a milky appearance, which gradually changes. The solid matter first gathers at the surface of the water, and after giving off the gases contained in the globules, falls to the bottom, leaving a clear liquid.

A wonderful test of the efficiency of tliis method of purif\ing may be made b>' adding a few drops of ink to the water before putting in the device. It will be found that the precipi- tate will contain all the ink, and that the water will be as clear as before. The water moves up along the space between the two electrodes, pass- es out through the holes / and down outside of the tube B. By means of the circulation thus set up every part of the water is treated and the oxygen bubbles pass through the water, thus attacking the organic matter and eliminating it entirely.

The dui^lex wires E, G, should have an elec- tric jilug at the other end which may beapplieti to the ordinary socket. The dimensions given will be correct for a 220- \()ll circuit. In ca.se of a iio-volt circuit the tube A should be ij^ ins. in diameter, or the rod B should be larger, say, K '"• or y's '"• '" tii.uneterto give the most eflicient service. There is some dilTerence in the re- sist. mce of various waters, which is not sufficient to require a change in the s|)ecilications, but in such cases the ex- perimenter will .soon learn the correct time required to treat a certain quantity of water, and not allow the (ic%ice to remain in a<'tion too long.

Till' device will act e(|ually well by phmging it into a pitcher of water, if left there long enough to thoroughly ozoni/.e the whole.

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