738 



Popular Science Monthly 



Pipe Bending — A Growing 

 Industry 



THE growing use of bent pipes 

 in various branches of engi- 

 neering has called for a systema- 

 tized method of bending, a process 

 involving mathematical calcula- 

 tions of some difficulty. 



Pipe-bends have a variety of 

 applications, among which are the 

 following: to provide flexibility 

 and to compensate for contraction 



Pipe-bends are necessary to provide flexibility 

 and to compensate for contraction and expansion 

 of steam-lines; to reduce the number of joints, and 

 thereby losses, in pipe-lines; to avoid obstruc- 

 tions such as columns, and to reduce friction 

 in piping 



as columns, pipes, etc. ; to reduce 

 friction in piping. The commonest 

 use of pipe bends is in the construc- 

 tion of heaters and refrigerating 

 plants. In the accompanying 

 photographs, two large pipes in pro- 

 cess of bending are shown. Heavy 

 crane machinery is employed, and 

 great pains are required in apply- 

 ing the heat correctly. 



A Saw-Guard Which Has a 

 Clean Record 



and expansion of steam-lines; to reduce ALTHOUGH in use in various mills 

 the number of joints, and thereby losses, xA for the past three years, a saw- 

 in pipe-lines; to avoid obstructions such guard manufactured in Ohio has to its 



credit a record of no acci- 

 dents of any kind. The 

 guard is suspended from a 

 bracket over the table and 

 covers the saw completely. 

 When a board to be sawed 

 is pushed against its lower 

 front end, it automatically 

 rises until the board is 

 under it. When the board 

 has passed through, the 

 guard drops back in place. 

 A small pulley against which 

 the board is pushed, and an 

 arrangement of levers causes 

 the guard to be raised. 



The value of this guard as 

 a safety appliance cannot be 



--,, . J , over-estimated, since saws 



When a board to be sawed is pushed agamst its lower , pl^av^ hppn a source 



front end this guard rises, but when the board passes ^^^^ always Deen a source 



through, the guard drops of many accidents. 



