Abstract: A pressure relief valve (100), having: an upper housing (104) defining a housing internal chamber (112) and comprising at least one window (108) between the upper housing chamber and the atmosphere; a lower housing (106) comprising a housing opening (134); a pallet (170) disposed within the housing internal chamber; and a pair of nested springs (116) disposed within the housing internal chamber and configured to bias the pallet toward the lower housing and thereby form a seal (180) between the housing opening and the housing internal chamber. When the pressure in the housing opening is at a full discharge pressure that is greater than and within fourteen percent of the start-to-discharge pressure, the pair of nested springs is configured to permit the pallet to travel a sufficient distance to expose a flow area of the at least one window that is at least greater than a flow area (138) of the housing opening.

Abstract: A pressure relief valve (100), having: an upper housing (104) defining a housing internal chamber (112) and comprising at least one window (108) between the upper housing chamber and the atmosphere; a lower housing (106) comprising a housing opening (134); a pallet (170) disposed within the housing internal chamber; and a pair of nested springs (116) disposed within the housing internal chamber and configured to bias the pallet toward the lower housing and thereby form a seal (180) between the housing opening and the housing internal chamber. When the pressure in the housing opening is at a full discharge pressure that is greater than and within fourteen percent of the start-to-discharge pressure, the pair of nested springs is configured to permit the pallet to travel a sufficient distance to expose a flow area of the at least one window that is at least greater than a flow area (138) of the housing opening.