Page:Popular Science Monthly Volume 88.djvu/766

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��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.

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