Mechanical removal of Deposit from Water Mains. 6 3 



to 5^ inches diameter and the smaller pistons used. The 

 scraper was inserted at the upper hatchbox and travelled down 

 with a low rumbling noise to a point where the main suddenly 

 drops into and passes under the river. At this point it stuck, 

 the bend being too sharp. The pipes were cut, the scraper 

 removed, and bends with larger radii inserted. The scraper 

 was again started at the reservoir and travelled down safely to 

 the hatchbox placed about midway between the reservoir and 

 Omagh, carrying before it an enormous quantity of peat and 

 iron rust, which was discharged at the latter point. The 

 larger pistons were now fixed on the scraper, the knives set to 

 5^ inches, and the apparatus started at the reservoir. It 

 pursued its course steadily for about 1,100 yards when it was 

 suddenly stopped by striking against something with a heavy 

 thud. On locating its position with a long stethescope (which 

 can be easily done when the pipes are at ordinary depths, owing 

 to the hissing noise of the water passing the pistons), I had the 

 pipes cut, and found on the inside a projection consisting of 

 indurated tar and sand, past which the pistons could not get. 

 This was cut out, a new pipe inserted, and the scraper started 

 again. It had not, however, gone 300 yards when it was again 

 stopped by a similar defective casting. On this being removed, 

 the scraper passed safely to the middle hatchbox ; and, although 

 I sent the scraper several times between these hatchboxes again 

 I had no further stoppage or delay. 



It would be mere repetition to enter into the details of the 

 operation of cleansing the main from the middle hatchbox to that 

 in the town. Suffice it to say I was stopped twice by the defective 

 castings before described, and once by a piece of lead weighing 

 over 15 lbs., which had through bad workmanship got into the 

 pipe while making a joint. Having removed all these 

 obstructions and passed the scraper without stoppage through 

 this length of the main, I had the middle hatchbox closed, and 

 inserted the scraper at the upper hatchbox, when on turning 

 on the water it made the run through to town without a single 

 stoppage, covering the distance in 47 minutes. In its course it 

 cleared off a little iron oxide, but not more than enough to 

 discolour the water, so I considered the process complete. 



