Bolts in circulator pump

Strength calculation

Used bolts: 4 socket head screws M4x16 8.8

Strength class bolts: 8.8

Minimum tensile strength: 800 N/mm²Rack limit: 640 N/mm²

Maximum pressure (p) in the circulator pump: 6 bar = 6 x 105 PaSurface (A) = r2 x π = 0,04502 x π = 0,002025 m2

Fb = p x A = 6 x 105 x 0,04502 x π = 3817 N

FVmax = 3 x Fb

= 3 x 3817 = 11451 N

Divided over 4 bolts

11451 / 4= 2863N =2,863 kN

The tension of a M4 bolt will be around 3-5 kN (see tension table next slide)

According to the calculations the right bolts were chosen

(I had no information about the friction coefficient)

r = 0,0450 m

M4

Tension table

(I could not find a tension table with bolts smaller than a M5, so I had to estimate the tension for a M4)