Spring-loaded pressure relief valve — the last line of defence when abnormal pressure threatens the silo structure. Sudden excess or suction pressure has to be dealt with instantaneously, and while a PRV should ideally never have to act, it has to work reliably when it does. Hundreds of thousands are in service worldwide. Options include a stainless steel weather protection cover, mechanical set-up for an inductive signalling sensor, inspection hatch, bird net and non-standard pressure settings.
