RESTORING WATER MAINS TO THEIR NORMAL CONDITION.
Not long ago the idea of cleaning water mains by a very simple process was conceived, and patents were procured on appliances designed for carrying out the work. It was not, however, until the system was put into practical operation on pipes in existing waterworks systems and under varying conditions, that it became apparent it would prove so effectual. It may seem strange to say that the capacity of a water main has been increased 175 per cent, by the removal of incrustations on the inside; yet such was the case at Little Rock, Ark., the other day. It has become apparent that the practice of removing scales or obstructions from mains must be employed where the economic management of waterworks systems has to be taken into consideration. The reports from a number of places where hundreds of feet of mains of dimensions from 36 ins. to 4 ins. has been restored to normal conditions, leave no doubt as to the increase in their capacity *that may be obtained with so little disturbance of existing conditions and comparatively small expense. When streets have to be torn up to lay pipe, the cost of replacing pavements and the further cost of material and labor in laying new pipe must be taken into account, and it may be that more attention will in future be given to this important feature in waterworks practice. The illustrations herewith show the discharge of water from a hydrant before and after cleaning, and prove a very convincing argument in favor of removing existing obstructions from mains. This result was obtained at Wheeling, W. Va., where the pressure was increased more than too per cent., as the flow from the hydrant, after cleaning, clearly proves. The operation at Philadelphia will, perhaps, better illustrate the advantage of using this process. Mayor Gillette, till lately in charge of the waterworks system of that city, reported the effect of cleaning 447 ft. of cast iron pipe as follows:
Pipe laid in 1834.
Diameter before cleaning, 5 1/4″
Diameter after cleaning, 6″
Loss in head before cleaning, 12′
Loss in head after cleaning, 46″
Increase in efficiency, 95%
By this last it will be seen that the main was restored to its normal diameter of 6 ins. and capacity, without causing any disturbance of the system involved, so promptly was the work performed. Other tests have been made in several other places with equally favorable results; but that at Camden, N. J., may be briefly mentioned as corroborating the report of Mayor Gillette. In the month of May last, a 4-in. main was operated on under the direction of Robert Hollingsworth, chief engineer of the waterworks in that city, and he reported that, “before cleaning, the flow, as measured by a new Trident meter, was 100 gals, per minute, and, after cleaning, it was increased to 227 gals, per minute. A piece of this pipe was cut in the centre of the square, and examination showed that it was thoroughly cleaned and free from scale and deposit.” The sectional views of this pipe, given herewith, will serve to illustrate the effectiveness of the process. Such reports as these go to show that the method of removing obstructions in water mains, as practised by the National Water-Main Cleaning company, clearly demonstrates that it has long since passed the experimental stage and has established a new line of practice, which may be undertaken with considerable advantage in places requiring such work.