Twentieth century hand-book for steam engineers and electricians with questions and answers; a practical non-technical treatise .. (1913)
Swingle, Calvin Franklin, 1846- [from old catalog] · Chicago, F. J. Drake & company · leaf 151
thevalve its name, and it is sustained by the impact and re-action of the issuing steam, until the pressure has subsidedsufficiently to allow the spring to overcome these actions. A short space will be devoted to the consideration of thelover safety valve also, as it may be of interest to… … Fig. 56square feet of grate surface in the boiler^ and the seats ofall such safety valves shall have an angle of inclination of45^ to the center line of their axis/^ Boiler Setting and Equipment 139
