Hi there I'm wondering why the solution uses the gauge pressure at point 3 (P3) surely the bolt has to oppose the absolute pressure at point 3 and I don't see how Patm would cancel out.
Thanks for your time.
Sorry for the bad quality of picture.
https://www.dropbox.com/s/q2apipdk8pvxzs6/2015-01-16-346.jpg?dl=0
https://www.dropbox.com/s/35ebfzz6fgi4dnw/2015-01-16-345.jpg?dl=0