Abstract: A rupture disk. The disk includes a body having an inside surface defining a hollow therein and a fluid port disposed to make fluid connection between the hollow and a fluid pressure source. A method for operating a wellbore includes applying pressure though the port of a disk, and rupturing the disk with the applied pressure.

Abstract: A rupture disc configured to fluidly seal a passageway. The rupture disc includes a base extending from a distal surface to a proximal end, and a central portion extending across the proximal end of the base. The central portion traverses a central axis defined by the base. At least one surface of the central portion, such as an outer surface or inner surface, includes a plurality of facets defined by a plurality of seams. The facets may include one or more flat surfaces and/or one or more conical surfaces. A rupture disc system for fluidly sealing a portion of a wellbore includes the rupture disc disposed within and extending across a housing central bore of a housing, with one or more sealing members engaging the rupture disc and an inner surface of the housing central bore to fluidly seal the housing central bore.

Abstract: A vessel includes a body having an interior surface that defines an interior space. The vessel further includes a flexible membrane located within the interior space of the vessel. The interior space includes a first chamber at least partially defined by the flexible membrane, and a second chamber at least partially defined by the flexible membrane and a portion of the interior surface of the body. The vessel includes a pressure relief device configured to vent contents of the second chamber to an exterior of the body when the second chamber reaches a first predefined pressure. The flexible membrane is configured to tear or puncture when the first chamber reaches a second predefined pressure that is less than or equal to the first predefined pressure to prevent dangerously high pressures within the first chamber.

Abstract: An embodiment of the present invention relates to a cylindrical lithium ion secondary battery. The technical problem to be solved is to provide a cylindrical lithium ion secondary battery which is designed such that a safety vent is formed and at the same time or afterwards excess metal can be guided to a curved portion adjacent to the safety vent, thereby enhancing the flatness of a can floor and reducing damage to the safety vent. To this end, the present invention provides a cylindrical lithium ion secondary battery comprising: a cylindrical can; an electrode assembly accommodated in the cylindrical can; and a cap assembly for sealing the cylindrical can, wherein the cylindrical can comprises a circular floor portion, a curved portion curved from the floor portion towards the electrode assembly, and a safety vent formed on the curved portion.

Abstract: An overpressure protection system (30) for a magazine (10) for storing explosive materials. The magazine (10) comprises a wall (12) which defines an internal chamber (14) for housing the explosive materials, with a first aperture (20) defined in the wall (12). The overpressure protection system (30) is configured to close the first aperture (20). The system (30) comprises a burst disc diaphragm (32) for covering the first aperture (20), and a protective cover (34) for locating outside of the chamber (14) and over the burst disc diaphragm (32). The protective cover (34) is spaced apart from the burst disc diaphragm (32) to form a cavity (38) with an opening (36) for venting fluid from the cavity (38).

Abstract: A rupture disk includes a body including an internal wall extending from a first end of the body to a second end of the body. The internal wall defines an opening extending through the body. In some embodiments, the body further includes an internal flange formed on the internal wall, and the internal flange has a stepped surface. A rupture membrane is positioned within the body, and secured, for example, by cold welding. The rupture membrane may be secured to the stepped surface. The rupture membrane is positioned within the body such that the rupture membrane does not extend beyond the first end of the body. A process system including the rupture disk is also provided. A method of maintaining a process system that includes the rupture disk is also provided.

Abstract: Methods and apparatus for forming a metallic dome are provided. More specifically, the present invention relates to a metallic dome that may be used to seal an aerosol container. The metallic dome includes a novel flattened relief panel and an inwardly oriented arch configured to deform in response to pressure within the aerosol container exceeding a predetermined amount. In one embodiment, the flattened relief panel is substantially planar. Optionally, the metallic dome includes at least a first inwardly oriented arch with a first radius of curvature and a second inwardly oriented arch with a second radius of curvature.

Abstract: A multi-pulse rocket propulsion motor for use with vehicles, such as space vehicles like satellites, rockets, and the like. The propulsion motor is a modular system that is capable of providing a plurality of discrete, controllable propulsion pulses. The propulsion motor can be used for primary propulsion of the vehicle and/or as a maneuvering thruster of the vehicle. The propulsion motor includes a plurality of propellant housings each containing a combustible propellant grain, a discharge plenum defining a plenum volume in communication with the discharge of each propellant housing, and a nozzle downstream from and in fluid communication with the plenum volume.

Abstract: A rupture disk for use in a fluid control system includes a membrane and a compressible flange, around a perimeter of the membrane. The flange defines at least one perimetrically extending void.

Abstract: A downhole apparatus comprises a casing string with a removable plug therein to block flow therethrough. A flow barrier is positioned in the casing below the removable plug and the removable plug and the flow barrier defining a buoyancy chamber therebetween. A debris barrier positioned above the removable plug includes a frangible disk. A stretchable connecting ring is connected to the frangible disk and to the casing.

Abstract: Methods and apparatus for forming a metallic dome are provided. More specifically, the present invention relates to a metallic dome that may be used to seal an aerosol container. The metallic dome includes a novel flattened relief panel and an inwardly oriented arch configured to deform in response to pressure within the aerosol container exceeding a predetermined amount. In one embodiment, the flattened relief panel is substantially planar. Optionally, the metallic dome includes at least a first inwardly oriented arch with a first radius of curvature and a second inwardly oriented arch with a second radius of curvature.

Abstract: According to certain embodiments, a device for conditioning a flow of air includes a casing with an inlet and an outlet. The device has a flow conditioner disposed within the casing and concentrically aligned with the casing. The flow conditioner has a cylindrical portion and a domed end portion capping the cylindrical portion. The flow conditioner forms an annulus region between the flow conditioner and the casing. The flow conditioner also forms a mixing chamber interior to the flow conditioner. The flow conditioner also has a plurality of holes throughout the flow conditioner that are configured to permit air to pass from the inlet of the casing and the annulus into the mixing chamber. The device also has a flow straightener located at the outlet of the casing configured to straighten the airflow as it flows from the mixing chamber out of the device.

Abstract: A pressure relief valve assembly includes a rupture disc that is shaped to only be inserted into a particular rupture disc cavity in the correct way. The rupture disc includes a cylindrical rupture disc stem and a radially protruding upper lip. A relief valve body in the pressure relief assembly includes an internal radial shoulder at the entrance of the rupture disc that is narrower than the protruding upper lip of the rupture disc but that is wider than the rupture disc stem. The shoulder allows only the rupture disc stem to be inserted into the rupture disc cavity, not the protruding upper lip. Optionally, the relief valve body is marked with some indicia to indicating the direction of inserting the rupture disc stem and/or a shrapnel catcher for trapping shrapnel of the rupture disc upon rupturing.

Abstract: A water table for cutting metallic materials comprises an upper water pool supported above a false vessel bottom. The surface of the upper pool water volume is regulated relative to workpiece support rails secured above the upper pool surface. An actual vessel bottom is positioned below the false bottom and supports a lower pool volume. Bearing directly upon the lower pool surface is an enclosed air pressure volume regulated by an air supply source. The upper and lower pool volumes are hydraulically linked by flow conduits. A frangible rupture disc in a pressure release vent assures an absolute pressure limit within the air volume to avoid over-pressurization or under-pressurization of the water table.

Abstract: An accessory for an unmanned aerial vehicle (UAV) comprising a baseplate that is attached to the UAV unmanned aerial vehicle, at least one dispersant canister that is removably attached to the baseplate, a radio frequency receiver, an auxiliary circuit board, at least one battery, first and second wire pairs that supply electrical current from the auxiliary circuit board, a protective housing, and a radio frequency transmitter that is in communication with the radio frequency receiver. In alternate embodiments, the invention further comprises an electric match, linear solenoid, or electric primer.

Abstract: A dispenser (10) for dispensing flowable materials has a container (12) having an outer wall (16) and a membrane (34) collectively defining a first chamber (18) configured to contain a flowable material. The membrane (34) extends from the outer wall (16) at an angle. The membrane (34) has a thickness and a weld seam (40), and the weld seam (40) has a thickness less than the thickness of the membrane (34).

Abstract: A solid propellant rocket motor has a tubular casing accommodating a mass of solid propellant material and at least one opening for the space in the casing to communicate with the outside closed by a closing head; the closing head being coupled to the casing by means of one or the other of two blocking portions with different strength both carried by a movement device which can be elastically deformed and operated from the outside.

Abstract: A self-venting self-resealing pre-cut elastomeric closure for vials, bottles and the like, comprising a dished elastomeric septum supported for closing an opening in a container, a cut across the dished elastomeric septum, and additional cuts defining with the cross cut one or more flap areas elastically displaceable from a closed condition to a venting condition in response to insertion of a liquid transfer implement through the central area of the septum dish.

Abstract: An inlet support structure for use with a rupture disc, the inlet support structure including an annular member having an inner diameter, an outer diameter, a plurality of spaced apart cut-outs extending from the inner diameter towards the outer diameter, a central non-circular opening extending through the annular member and including the cut-outs, the cut-outs providing additional space for the petals of a rupture disc to be received therein when the rupture disc ruptures so as to provide a greater flow area through the rupture disc.

Abstract: An inflator includes a rupturable plate in a circular shape for closing an opening of a pressurized gas-filled space. The rupturable plate has a fragile portion formed by grooves in a regular polygon on one surface, including first fragile portions formed by grooves forming a circumference of the regular polygon, and second fragile portions formed by grooves extending from all apexes of the regular polygon to a center thereof creating a plurality of triangles formed by the first fragile portions as a base and the second fragile portions as the remaining two sides. The depth (h1) of the first fragile portion is less than the depth (h2) of the second fragile portion whereby, when pressure is exerted on a rear surface opposite to the fragile portions, the second fragile portions will rupture as the first fragile portions bend.

Abstract: A capped spout of the present invention has a spout (1) and a cap (30) that engages with the spout. Spout (1) has a cylindrical body (3) and a welding part (4). Cylindrical body (2) has an interior that serves as a discharge passage (2) for discharging liquid content in a bag-shaped package, wherein the cap (30) is attached to the cylindrical body (2) in order to close an opening of an outlet end of the discharge passage. The welding part (4) is formed outside the cylindrical body (3) and is welded to an opening of the package. The capped spout of the present invention further has a thin film part (11) that is formed inside the cylindrical body (2) in order to close an opening of an inlet end of the discharge passage. Thin film part (11) has a first surface that faces an interior of the cylindrical body, the interior being closed by the cap (30) and the thin film part (11). A circular groove (12) that is concentric with the thin film part is formed on the first surface.

Abstract: In one form, a vent apparatus includes an inlet frame, a venting member, and a retainer member. The venting member includes a mounting portion, a weakened area or burst slit, and a domed portion. The mounting portion of the venting member is secured between the inlet frame and the retainer member. The retainer member includes vent retainer portions or tab portions that extend over the burst slit. The vent apparatus is configured to burst when an inlet pressure exceeds a predetermined level, where the tab portions will bend away and the venting member will bend past the tab portions to relieve the pressure. The inlet frame is configured to support against a vacuum pressure acting in the opposite direction, with the tab portions generally free from the load caused by the vacuum pressure.

Abstract: A pressure relief device and method of making the same are provided. The pressure relief device includes an over-pressure relief area with a plurality of co-linear spaced apart recesses located thereon. Gap segments are interspersed between the recesses to define a line of opening having desired performance characteristics during opening of the over-pressure relief area.

Abstract: A rupture disc (10) is provided comprising a line of opening (16) formed in at least one face thereof. The line of opening (16) is formed by laser machining of the disc's face and includes at least one disc opening control feature (20). The disc opening control feature (20) may be an opening-initiation feature configured to assist with initial rupture of the disc (10). Alternatively, the opening control feature (20) may be an anti-fragmentation feature configured to dissipate the energy acting upon the disc (10) so as to prevent separation of the petal formed upon opening of the disc.

Abstract: A pressure valve is made of gas-permeable flexible material, and an actuation portion and a supporter are formed integrally with each other. The actuation portion includes a thin portion and a thick portion provided in an outer region of the thin portion and having a thickness greater than that of the thin portion. When viewed from the direction of the thickness of the actuation portion, the thin portion has a cross-like shape, and the outer edge of the thin portion is shaped to include a plurality of first arcs each protruding toward the inside of the thin portion, and a plurality of second arcs each protruding toward the outside of the thin portion.

Abstract: An aircraft fuel tank vent (100, 200, 300) having a first interface (102, 202, 302) for fluid communication with an aircraft fuel tank interior, and a second interface (104, 204, 304) for fluid communication with an aircraft fuel tank exterior, the vent comprising: a first flow path (118, 218, 326) between the first interface and the second interface, the fuel tank vent having a baffle (126, 226, 317) positioned in the first flow path, and, a second flow path (124, 224, 326) between the first interface and the second interface, the fuel tank vent having a overpressure device (120, 220, 322) positioned in the second flow path, wherein the first and second flow paths are common along at least a part of their length such that they are coincident at the second interface.

Abstract: A pyrotechnic pressure accumulator includes an elongated body extending from a first end of a pyrotechnic section to a discharge end of a hydraulic section. A propellant charge located in a gas chamber of the pyrotechnic section, a piston movably disposed the hydraulic section, and a fluid disposed in a hydraulic chamber between the piston and the discharge end, wherein the fluid is exhausted under pressure through a discharge port in response to ignition of the propellant charge.

Abstract: A rupture disk for a gas insulated switchgear which includes a thin dome plate that includes a first flange portion and a first dome-shaped portion formed in a dome shape, at the center of the first flange portion; and a rupture guide plate which includes a second flange portion, laminated on the first flange portion, and a second dome-shaped portion has a plurality of slots formed therein to define a rupture shape so that a part of the first dome-shaped portion is ruptured, in a predetermined shape, when an internal pressure increases. End portions of slots, disposed at both edges among the plurality of slots, are provided with rupture restriction openings, respectively, to configure a hinge portion of the second dome-shaped portion.

Abstract: In one form, a vent apparatus includes an inlet frame, a venting member, and a retainer member. The venting member includes a mounting portion, a weakened area or burst slit, and a domed portion. The mounting portion of the venting member is secured between the inlet frame and the retainer member. The retainer member includes vent retainer portions or tab portions that extend over the burst slit. The vent apparatus is configured to burst when an inlet pressure exceeds a predetermined level, where the tab portions will bend away and the venting member will bend past the tab portions to relieve the pressure. The inlet frame is configured to support against a vacuum pressure acting in the opposite direction, with the tab portions generally free from the load caused by the vacuum pressure.

Abstract: A pressure relief device of domed construction for venting an internally pressurized container. The pressure release device includes a coined pressure vent and is characterized by a relatively high venting pressure in combination with a failure pressure in the absence of venting which is higher than the intended venting pressure. The pressure relief device includes a sloped sidewall having an outer annular segment and a sloped annular intermediate segment. The sloped annular intermediate segment has a width dimension greater than the width dimension of the outer annular segment. A circular central plateau defines a flat dome top. The circular central plateau has a center point with an arc shaped coin line extending about an arc with the apex of the arc positioned at the center point of the circular central plateau.

Abstract: A rupture disc (10) is provided comprising a line of opening (16) formed in at least one face thereof. The line of opening (16) is formed by laser machining of the disc's face and includes at least one disc opening control feature (20). The disc opening control feature (20) may be an opening-initiation feature configured to assist with initial rupture of the disc (10). Alternatively, the opening control feature (20) may be an anti-fragmentation feature configured to dissipate the energy acting upon the disc (10) so as to prevent separation of the petal formed upon opening of the disc.

Abstract: An overpressure indicating disk apparatus for indicating an overpressure condition in a pressurized system includes a body having end portions, a bore, and a reverse buckling disk having an annular peripheral portion and a concave convex dome portion. The annular portion surrounds the dome. The first end portion is attached and in pressure communication to the pressurized system. The pressure in the bore is the same pressure as the pressure of the pressurized system. The annular peripheral portion is mounted to the body. An indicating component/ring is affixed to the body and disk. A central tab is mounted inside the ring. The concave side faces the central tab. The convex side faces the pressure inside the bore. When the pressure in the bore exceeds a preselected maximum pressure value, the disk reverses to engage and displace the central tab thereby indicating visually that an overpressure condition exists within the bore.

Abstract: A non-metallic explosion vent is provided for protecting a confined space from a high overpressure condition. Reinforcing material having greater tensile strength than the resin, such as glass fiber roving, mesh or fabric, is embedded in the panel. An elongated, overall U-shaped groove extends inwardly from one of the surfaces of the panel through only a portion of the thickness of the panel. The groove interrupts the reinforcing material and defines a line of weakness that presents a relief area of the panel that opens under a predetermined overpressure condition. A plurality of spaced reinforcing components preferably overlie the groove, and optionally may extend across the relief area of the panel, transversely thereof and at an angle to one another. The reinforcing components contribute to control of the burst pressure of the vent and assist in preventing separation of the vent area from the body of the panel and/or fragmentation of the vent area during opening thereof.

Abstract: A rupture disc for use in a pressure relief system includes a dome having a concave and a convex side and a circumferential flange associated therewith. At least one control score is formed or otherwise produced in the dome at a radial position between an apex of the dome and an outer circumference of the dome. At least one of a depth, a width, a length and the radial portion of the at least one control score is selectively controlled so that the depth, width, length, and/or radial position of the at least one control score controls the pressure at which the dome will start to collapse.

Abstract: A reverse-acting rupture disc (10) having a laser-defined reversal initiation feature (16) is provided in the bulged section (12) of the disc. The reversal initiation feature comprises at least a first lased area (22) that has a reduced thickness relative to rest of the bulged section. A second lased area (24) may also be provided within the margins of the first lased area. The second lased area has a depth that is greater than the depth of the first lased area. A line of weakness (40) may be formed in the bulged section that functions to direct reversal of the bulged section toward a particular area of the disc, such as line-of-opening recess (56).

Abstract: A rupture panel of three layers employs a lower layer (e.g. foam) that is adhesive, a middle layer (e.g. metallic) and a hold down layer. The middle layer has a weakened portion (scoring, openings, for example) that defines the panel burst pressure. A part of the lower layer does not connect to the middle layer. That part that does not connect to the middle layer adheres to the hold down layer. The hold down layer can be in the form of a ring with an open center, the weakened portion of the middle layer occupying a position within the open center of the hold down layer.

Abstract: A pressure control system for controlling pressure in a tank is provided. The pressure control system includes a pressure relief valve and a rupture disc subassembly. The pressure relief valve is connected to the tank. The rupture disc subassembly is located between the pressure relief valve and the tank and is connected to the tank. The pressure relief valve is connected such that removal of the pressure relief valve does not affect the connection of the rupture disc subassembly to the tank.

Abstract: A fluid reservoir assembly includes a base assembly defining an interior cavity that is adapted to receive a fluid. A cover assembly is engaged to the base assembly. The cover assembly includes a first end and an oppositely disposed second end. A first plurality of fasteners engages the first end of the cover assembly to the base assembly. The first plurality of fasteners has a first strength. A second plurality of fasteners engages the second end of the cover assembly to the base assembly. The second plurality of fasteners has a second strength. The first strength is less than the second strength.

Abstract: A pressure control system for controlling pressure in a tank is provided. The pressure control system includes a base plate, a pressure relief valve, a rupture disc, a first connector and a second connector. The base plate includes a tank side and a valve side. The pressure relief valve includes a body and a connection portion for coupling the pressure relief valve to the base plate adjacent the valve side. The rupture disc is positioned between the pressure relief valve and the base plate. The first connector extends between the base plate and the pressure relief valve to secure the pressure relief valve to the base plate and secure the rupture disc. The second connector is positioned for securing the base plate to the tank.

Abstract: A safety valve for a battery which is mounted on a sealing plate for sealing an opening portion of a gastight battery case, and which can rapidly release a gas in the battery when a battery internal pressure is elevated is provided. In a safety valve for a gastight battery, a thin-wall valve element is formed on a sealing plate which seals an opening portion of a battery case, and the valve element is opened when a battery internal pressure becomes a predetermined value or more so as to release a gas in the battery to the outside of the battery. The safety valve includes: an outer annular groove formed of an annular thin wall which is formed on the periphery of the valve element and is provided for releasing the whole valve element; an inner annular groove formed of an annular thin wall which is arranged in an area inside the outer annular groove; and a connecting groove formed of a straight thin wall which connects the outer annular groove and the inner annular groove to each other.

Abstract: An aerosol can has a dispensing valve at one end and discharge device at another end that allows the pressurized can to be safely depressurized. The discharge device has two elements that collectively fit into a wall of the aerosol can. The second element has a through passage within itself and is threadingly connected to the first element. The first element can be rotated such that the second element can move toward the interior of the aerosol can, which in turn opens the through passage to allow pressurized air to exit the can safely.

Abstract: A rupture panel of three layers employs a lower layer (e.g. foam) that is adhesive, a middle layer (e.g. metallic) and a hold down layer. The middle layer has a weakened portion (scoring, openings, for example) that defines the panel burst pressure. A part of the lower layer does not connect to the middle layer. That part that does not connect to the middle layer adheres to the hold down layer. The hold down layer can be in the form of a ring with an open center, the weakened portion of the middle layer occupying a position within the open center of the hold down layer.

Abstract: A pressure relief device of domed construction for venting an internally pressurized container. The pressure release device includes a coined pressure vent and is characterized by a relatively high venting pressure in combination with a failure pressure in the absence of venting which is higher than the intended venting pressure. The pressure relief device includes a sloped sidewall having an outer annular segment and a sloped annular intermediate segment. The sloped annular intermediate segment has a width dimension greater than the width dimension of the outer annular segment. A circular central plateau defines a flat dome top. The circular central plateau has a center point with an arc shaped coin line extending about an arc with the apex of the arc positioned at the center point of the circular central plateau.

Abstract: A reverse acting rupture disc and methods of forming the same are provided. Generally, the rupture disc comprises a bulged portion and a circumscribing flange area surrounding the bulged portion. The bulged portion includes a mechanically formed line-of-opening recess comprising a singular channel. In certain embodiments, the mechanical process by which the recess is formed utilizes a high-speed mill which removes a portion of metal from the bulged portion of the disc without disrupting the substantially uniform metallic grain structure of the metal adjacent the channel.

Abstract: A rupture panel of three layers employs a lower layer (e.g. foam) that is adhesive, a middle layer (e.g. metallic) and a hold down layer. The middle layer has a weakened portion (scoring, openings, for example) that defines the panel burst pressure. A part of the lower layer does not connect to the middle layer. That part that does not connect to the middle layer adheres to the hold down layer. The hold down layer can be in the form of a ring with an open center, the weakened portion of the middle layer occupying a position within the open center of the hold down layer.

Abstract: A gas seal for containing a pressurized fluid in a container. The gas seal includes a rupturable portion having a stress riser formed therein, and an extension coupled to the rupturable portion proximate the stress riser such that a predetermined minimum force applied to the extension is transferred to the stress riser to produce a rupture of the rupturable portion.

Abstract: The bursting disc assembly has a primary bursting disc (10) and a secondary bursting disc (20) immediately behind and supporting the primary bursting disc. Each of the said discs (10,20) is made of metal and is gas impermeable, and the bursting strength of the assembly is derived from both of the bursting discs acting in combination. The primary and secondary bursting discs are in contact over the whole of the operating area of the disc, and are shaped together as a pair. The materials of the two discs can be chosen suitably for their functions. The primary disc is for example corrosion-resistant.

Abstract: A molded plastic container includes a side wall having a valve seat feature molded into the side wall, the valve seat feature comprising a central recess in the outer surface of the side wall, and an annular valve seat surrounding the central recess. The container has one or more holes extending through a portion of the side wall bounded by the annular valve seat into the interior of the container for venting gas from the container. A label is affixed against the outer surface of the side wall and is under tension, the tension of the label causing the label to firmly abut the annular valve seat. Excess pressure of gas inside the container is able to momentarily lift the label away from the annular valve seat to establish a flow path between the label and the annular valve seat such that gas under pressure is vented from the container.

Abstract: A low-profile burst disk assembly for safely venting excess pressure from a pressurized fluid system by way of a tortuous fluid flow path. A burst disk plug includes a male thread and is thereby adapted to thread into the body of a pressurizable chamber. The burst disk plug further includes a fluid receiving port placed in fluid communication between the burst disk and one or more bleed channels open to ambient pressure. The one or more bleed channels generally run axially through the burst disk plug, either intersecting or bypassing the male thread. Embodiments with a plurality of bleed channels generally include a distribution manifold positioned in fluid communication between the fluid receiving port and the one or more bleed channels to ensure an even distribution of venting pressure among the bleed channels.

Abstract: An aerosol container (10) dispenses a fluid product under pressure. A pressure relief mechanism (30) vents the container in a controlled manner when the container is subjected to excessive pressure so to prevent the container from bursting. The container has a container body (12) of a hollow, generally cylindrical shape. Pressurized contents of the container are expelled through a valve assembly (18) installed at one end of the container. An end piece (22) attached to the container body at the other end of the container has a first circular shaped section (26) surrounded by a ring shaped outer section (28). The pressure relief mechanism comprises U-shaped score lines (32) formed across the transition between the two sections of the end piece. These score lines create lines of weakness in the material from which the end piece is made for the end piece to fracture along the score lines when the pressure within the container exceeds a predetermined pressure level.