TESTING STONEWARE PIPES USED IN RETICULATION SEWERS. LV. 



large toothed wheel, is a cast iron cylinder of 9 inch internal 

 diameter, the piston being 7 inch diameter. This piston exerts a 

 pressure on a block of wood 6 inch square, curved on its lower 

 face, to suit the outer circumference of the pipe. The pressure is 

 obtained by pumping oil into the top of the cylinder, causing the 

 piston to descend till the pipe breaks, when the pressure is read 

 off on a pressure gauge attached. The oil is pumped from a 

 reservoir on the machine, into the main cylinder, through a small 

 cylinder shown end on in the photographs. In this small cylinder 

 are five openings for oil to pass, three being on the side next the 

 reservoir, and two being on side next the main cylinder : of the 

 three the centre one is for the suction pipe, while the other two 

 exhaust oil from the top and bottom of the main cylinder alter- 

 nately. Of the two openings in the other side of the small 

 cylinder, one connects by a pipe with the top of the main cylinder 

 and the other with the bottom. The piston of the small cylinder 

 is moved by a hand lever. In one position, the oil is pumped 

 from the reservoir into the top of the main cylinder causing the 

 piston to descend, and at the same time to force any oil below 

 the piston head back into the reservoir. 



The pipe having been broken, the position of the small piston 

 is altered, so that oil is pumped into the bottom of the main 

 cylinder as the piston rises, the oil above the piston head is forced 

 back into the reservoir, so that the same oil can be used over and 

 over again. 



The principle of the machine was supplied by Mr. J. M. Smail, 

 M. Inst, c.e., and the details were worked out in the drawing office 

 of the Road and Bridges Branch of the Public Works Department, 

 under the supervision of Mr. J. A. Macdonald, m. Inst. c.e. The 

 machine was locally made and has been in use for about thirteen 

 years. The two photographs show a pipe just before and just 

 after breaking in the machine. 



Before a specification was drawn up, it was found necessary to 

 obtain some data as to the pressure the local pipes would stand. 

 By the direction of the late Mr. W. C. Bennett, m. Inst, c.e., Engineer- 



