THE MANUFACTURE OF MONIER PIPES. 



By F. M. Gummow. 



[Read before the Engineering Section of the Royal Society of N. S. 

 Wales, June 21, 1899.] 



The development of the combination of concrete and iron for the 

 purpose of obtaining the maximum strength with a minimum of 

 material, and at the same time manufacturing an article light, 

 easily handled, and cheap, has led to the establishment of a 

 factory in Sydney for the purpose of making concrete-iron pipes. 



These are of varying dimensions and shapes, and are used for 

 sewerage work, storm water-drains, as sheathing for piles, cylinders 

 for bridges, etc. 



Tt is a well-known fact that pipes under pressure are subjected 

 to tensile strains on the inner and outer surfaces alternately. In 

 order to take up these strains, and at the same time produce 

 a pipe with the minimum of thickness and a maximum of 

 strength, it is necessary to augment the tensile strength of the 

 cement-mortar by the use of iron, which in this case takes the 

 shape of a spiral wire. The spiral wire is either concentric — 

 and, in case two of them being used, one is placed near the inner 

 and the other near the outer surface (Type A) — or eccentric, in 

 which case one spiral wire is sufficient, passing alternately from 

 the inner to the outer surface of the pipes, as shown on the 

 diagram (Type B). 



The pipes are made with a flat bottom, to ensure better pack- 

 ing when laid, and also to make sure that the pipe is placed in 

 the proper position as designed. 



A resume of the process of pipe manufacture may be briefly 

 stated thus : — 



The pipe machine consists of a framework of iron or timber, 

 with the necessary appliances for revolving the iron sockets, into 



