108 HALIFAX WATER WORKS. JOHNSTON. 



Incrustation of Pipes, and Cleaning. 



In 1875 the old 3-inch water pipes laid by the Halifax 

 Water Company having become 'almost choked up with rust 

 and sediment, they were cleaned out during the succeeding 

 year by a scraper attached to iron, rods and propelled by hand. 

 The scraper had four arms or knives, attached to a center 

 and sprung outwards by a thick rubber disc. This method 

 was not practically applicable to pipes of a larger diameter 

 than 12 inches. The cost of cleaning was 14 2-10 cents per lineal 

 foot. In 1880 about a mile of 12-inch pipe was cleaned by a self- 

 acting mechanical scraper, imported from Scotland, and known 

 as the Kennedy scraper. 1887 Mr. Keating, the city engineer, 

 at that time, constructed new scraping machines which differed 

 from the others in having additional springs for the cutters 

 and pistons. These scrapers consist of an iron rod to which are 

 attached two pistons and two sets of cutting tools, one in front 

 of the other. The cutters aire each made up of four strips of 

 steel 2^ inches broad, sloping -backwards from the rod, and at 

 their outAvard termination sharpened like the barbs of an arrow, 

 thus they can yield when necessary and the cutting diameter can 

 be altered by moving the steel strips. The pistons are of iron, 

 lead and leather to which are added rubber springs. All the 

 main supply pipes were cleaned in that year at an average cost 

 of 2 8-10 cents per lineal foot. The immediate results were 

 that the average pressure on twenty-five hydrants on the 

 wharves increased from 34.2 pounds in February, 1881, to 

 52.4 pounds in February, 1882. These were on the low service. 

 On the high service there was a pressure of 19 pounds on 

 hydrants where in the previous year there had been no water 

 at all. The pipes have been cleaned periodically since that 

 date and usually twice a year. 



In cleaning the mains the water is turned off at the gate- 

 house and the exit opened and pipes emptied. A section of 

 pipe, jointed with collars and bolted together, is removed and 



