A vertical spring loaded valve is required for a compressed air receiver.The valve opens at a pressure of 1 N/mm2 gauge and fully opens at lift of 4 mm at a pressure of 1.2 N/mm2 gauge.The diameter of the port is 25 mm.Allowable shear stress in steel as 480 MPa shear modulus as 80kN/mm2.designspring
Dear Candidate,
You can search the same on various portals on internet for step by step method & better understanding. Kindly know, we are limited by our answering options, still I will try to help you.
1. Force on spring when pressure in reservoir is 1N/mm2
P1 = 491N
2. Force on spring when pressure in reservoir is 1.2N/mm2
P2 = 589N
Spring index, C=6, Wahl's factor
K = 1.2525
From tau find the nearest standard diameter, (Coil dia = 6*d = 29.262)
For number of turn, formula for deflection will be used
Delta = [(8*P*D^3)/(G*d^4)]*n , n= effective number of turns
Now,
P2-P1 = 98N
n = 9.2 (after calculating delta)
Actual number of turns with bent = 9.2+2 = 11.2
Now,
Initial deflection at P1 = (491/98)*4 = 20.04mm
Maximum deflection at P2 = (589/98)*4 = 24.04mm
Difference is of 4mm
Now,
Free length of spring
= n'*d + Delta(max) + (n'-1)*1.0
n'= actual number of turns
Therefore free Length of spring,
= 88.86mm(after calculating the whole equation)
Thanks. Hope it helped you a bit.
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