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.

Abstract: A cap assembly (40) for attachment to an external fixture (44) on a tank (52) of a tanker trailer (50), including: a collar (42) configured to secure the cap assembly to the tank external fixture and defining a collar opening (46) concentrically aligned with an opening (54) of the fixture; a lid (60) that is moveable between a closed position where the lid covers the collar opening and is in sealing engagement with the collar, and an open position where the lid is vertically raised from the collar and pivoted laterally away from the collar opening; and an actuator assembly (72) that is configured to move the lid from the closed position to the open position during a single stroke of the actuator assembly, and which is remotely operable from a location off of the tanker trailer.

Abstract: A cap assembly (40) for attachment to an external fixture (44) on a tank (52) of a tanker trailer (50), including: a collar (42) configured to secure the cap assembly to the tank external fixture and defining a collar opening (46) concentrically aligned with an opening (54) of the fixture; a lid (60) that is moveable between a closed position where the lid covers the collar opening and is in sealing engagement with the collar, and an open position where the lid is vertically raised from the collar and pivoted laterally away from the collar opening; and an actuator assembly (72) that is configured to move the lid from the closed position to the open position during a single stroke of the actuator assembly, and which is remotely operable from a location off of the tanker trailer.