Abstract: A tank filling and pressure relief assembly. A cover member has a seat for sealingly closing the tank opening. A stem is attached at one end to a piston in a cylinder (which is attached to the cover member and extends downwardly therefrom into the tank) and at the other end to a strongback. The strongback is pivotly mounted to swing the assembly away from the opening for filling thereof and to swing the assembly back into position to seat the cover member and is lockable in a position to lockingly urge the cover member to the closed position. The stem is flexibly coupled to the strongback to evenly distribute the seating force so that binding does not occur and is threadedly attached thereto so that the set pressure for pressure relief may be adjusted by access to the stem for turning thereof through an opening or cut-out in the strongback.

Abstract: A device relieves a positive pressure difference between the inside of a vessel and the outside of the vessel through an opening in the vessel. The device has a base portion, a cap portion and a biasing means. The base portion has a means for mounting the device in the opening; a cap seat providing an orifice through which the pressure difference may be relieved; and a generally hollow body portion attached to the cap seat and extending concentrically with the cap seat into the vessel. The cap portion has a cap having an external surface with a diameter larger than the diameter of the cap seat to retain the cap external to the cap seat in sealing relationship; a rod mounted concentrically and normal to the internal surface at one end, the other end extending into the body portion and terminating in a piston with a shoulder, the piston being in concentric sliding engagement within the body portion.