Keywords: PORV closed piston.JPG PORV_closed_piston svg PORV_closed_piston svg en wikipedia 2012 August 8 author Slightlymighty image missing spring how is it reset No internals in control pilot not shown there would be a spring there en wikipedia Zerodamage CommonsHelper 2009-03-19 Slightlymighty wikipedia en en wikipedia Slightlymighty Original upload log en wikipedia PORV_closed_piston JPG 2009-03-19 18 59 Slightlymighty 1229×802× 77013 bytes <nowiki>author Slightlymighty</nowiki> __NOTOC__ Valves |