Pb-1A spring loaded safety valve for a boiler is required to blow off at a pressure of 1.6 N/mm2. The diameter of the valve is 70 mm. Design a suitable compression spring for this safety valve. Assuming spring index to be 8 and 25mm initial compression. Maximum lift of the valve is 15 mm. Shear stress is 450MPa. Take G=0.84X105MPa. [5M]
Pb-2A bronze spur pinion rotating at 700 rpm drives a cast iron spur gear at a transmission ratio of 4 : 1. The allowable static stress for both pinion and gear is 50 N/mm2. The pinion has 36 standard 20degree full depth involute teeth of module 15 mm. The face width of the gears is 100 mm. Find the power that can be transmitted from the point of strength. (Assume Cv=3/(3+v) ) [5M]