HAWING PIPES BY ELECTRICITY
Diagram of Connections for Thawing Water Pipes with Storage Batteries.
The severity of the winter months since January, 1904, has called forth methods of thawing pipes by electricity. This, of course, is not a novelty. In the twenty-fifth volume of FIRE AND WATER, pp. 173-74, will be found an illustrated description of the method by Supt. Heim, of the Madison, Wis., waterworks. So far as is known the thawing of pipes by electricity had never been practised before the winter of 1898, when it was first tried on the service pipes by two professors of the University of Wisconsin, and afterwards on water mains elsewhere, and in every case with complete success. These gentlemen did not patent their invention, and the various methods that have so conspicuously come into fashion this winter are simply adaptations of their discovery in more or less the same shape. Frozen water pipes can be electrically thawed out by an alternating current transformed down to voltage of 50. Such a current, however, cannot always be obtained, and, in such cases, storage batteries can be carted round, and will answer every purpose. In one instance, forty-eight 200-amperehour cells of battery were employed to thaw out a one and one-half-inch service pipe and a section of a two-inch main in Borough park, Brooklyn, New York. The accompanying diagram shows the connections that were made for thawing out the first, the main between the two services being thawed out afterwards by attaching the wire seen running to the house to it at 1. Before using storage batteries the amount of current and the voltage required to heat an iron pipe thoroughly were determined upon by experiments. Two ten-foot lengths of three-quarter-inch iron pipe, with a three-quarterinch tee, were connected. The outer ends of the pipe were plugged and filled with water, and a thermometer was inserted in the tee. The temperature of the water was found to be 39 degrees Fahr. The storage battery cells (4 volts) are connected with the ends of the pipes by heavy copper cables, while the voltage at the end of the pipe was 2½. Three additional cells were connected in series, giving an additional voltage on open circuit of 2 volts, and 260 amperes were sent through the pipes. The result was that in ten minutes (twenty minutes from the start) the temperature of the water was raised 59 degrees Fahr., and the pipe was uncomfortably hot to the touch. The battery was then taken to the house, where the joint of the service pipe and main were uncovered. A heavy wire cable and a special strap and clamp were used for making connections, while the other terminal of the battery was connected to the one and one-half-inch service pipe at the point where it came through the wall of the cellar. A voltage of 16 was obtained by the arrangement of the cells in series and multiple. The current, which was over 3300 amperes at the start, and gradually came down to that figure, was applied continuously for twenty minutes, and as at the end of that time, although the pipe became too hot for the hand to rest upon, no water flowed, it proved that the main, which terminated at that house, was frozen somewhere between it and the next house, where the water was flowing. The wire, which had been run to the house, was, therefore, clamped at I to the main, and the cells were arranged in sixteen sets of three each, connected in multiple, thus giving 6 volts, with each cell furnishing onesixteenth of the whole current. The amperage was probably about 2,000, and it was continued for three minutes, at the end of which time the water flowed. The experiment showed that, with storage batteries, there is no loss of energy in a rheostat or transformer, which gives them a decided advantage, it being possible to obtain the proper voltage for a pipe, and thus auxiliary resistance is rendered unnecessary.