THE WATER WORKS OF BALE.
In 1875, the city of Bale, Switzerland, purchased its water works from the company by which they had been constructed and operated since 1866, and from that time to the present successive improvements and enlargements have been made.
The source of supply orginally consisted of a number of springs situated at Grcllingen, in a village of the Jura, about fifteen kilometres distant. The maximum supply thus obtained, limited only by the capacity of the mains, was about 11,000 cubic metres pet day, while the minimum has fallen as low as 2,500 cubic metres per day, this latter having been the case after a long drought in 1893.
In order to increase the supply, a steam pumpjng system was next constructed, taking the ground water from a gravelly water bearing stratum found at I.angen Ellen, about nine kilometres from Hale.
Experimental borings were made in 1878, and, the quality of the water being found satisfactory, an artificial spring was dug, from which a supply of 8.5 xi cubic metres was obtained in twentv four hours; and, as this was kept up continuously for two weeks, it was decided to go ahead. Exploration borings showed that this spring drew from a radius of only about 25′.) metres, which seemed satisfactory. The steam pumping station was started in tSSl, the plant consisting of a pair of coupled direct acting: condensing engines and pumps The steam cylinders of these engines are twenty-three and one half inches bore by forty-two inches’ stroke, the pump piungers having the same stroke by ten and three-quarter inches diameter. The steam cylinders are provided with admission valves of the poppet type, and “gridiron” exhaust valves, while the pump valves are of the so-called “ etagenventile ” variety, formed of annular rings arranged in a ccne of steps. These engines operate at twenty five to thirty revolutions per minute, and their united capacity is about 10,500 cubic metres per day.
The increased demand caused several new wells to be sunk between 1SSO and 1894. and in the latter year the new water works, or, rather, the extension was begun. Instead of repeat ing the installation of steam pumping engines, it was decided to try gas motors, using Dowson gas produced on the spot; and. as the new system has been placed in an extension of the old building, the two systems tnay be seen in operation fide by side. The gas producers stand in a room corresponding to the boiler room of tile older plant, while the engine and its pumps adjoin the original steam pumping machinery.
The gas engine is a double cylinder motor of the Deutz Gas Engine Company’s make, the two cylinders facing each other and the fly wheel shaft lying between them The cylinders are each twenty-one inches’ bore by thirty inches’ stroke,working at 140 revolutions per minute and developing 160 horse power. This engine drives a triple set of pumps the pump shaft being connected to the engine shaft by a cotton rope transmission consisting of ten separate ropes, each fifty millimetres in diameter. The pump consists of theee single acting plungers operated by cranks placed 120 degrees apart, the plungers being each ten inches’ diameter by twenty-seven and one-half inches’ stroke, and the shaft making sixty revolutions net’ minute. In tests made of the gas engine plant last April, by Prof. Meyer of Zurich, there was shown a con su.nption of 0.86 kilograms of coke in the gas producer for each actual horse power measured in water raised. This, of course, gives the efficiency of the entire plant, including the loss in the pumps. Separate tests of the pumps showed an efficiency of ninety six per cent., so that the net effective power of the gas engine was obtained at a consumption of 1.81 pounds of coke per horse power per hour.