Abstract: A closure [10] for a cylindrical vessel includes at least one holding means [30] configured to move the closure into a fully closed state, the holding means having a predetermined actuation force or torque to properly close the closure, the closure including one or both of the following failsafe failure detection features: a mechanical fuse [20] having a predetermined load failure force below that of a load failure force of at least one component of the holding means and above that of a predetermined actuation force or torque to properly close the closure; or a block[40] sized to at least partially overlap a pressure warning lock hole [19] of the closure door when the closure is not in the fully closed state and to fully expose the pressure warning lock hole when the closure is in the fully closed state, thereby permitting insertion of a pressure warning lock [17].

Abstract: A closure [10] for a cylindrical vessel includes at least one holding means [30] configured to move the closure into a fully closed state, the holding means having a predetermined actuation force or torque to properly close the closure, the closure including one or both of the following failsafe failure detection features: a mechanical fuse [20] having a predetermined load failure force below that of a load failure force of at least one component of the holding means and above that of a predetermined actuation force or torque to properly close the closure; or a block[40] sized to at least partially overlap a pressure warning lock hole [19] of the closure door when the closure is not in the fully closed state and to fully expose the pressure warning lock hole when the closure is in the fully closed state, thereby permitting insertion of a pressure warning lock [17].

Abstract: A pig launcher/receiver includes a fluid distribution grid arranged above a floor of the pig launcher/receiver's barrel to define a fluid chamber between the floor and the fluid distribution grid. The distribution grid has a plurality of ports arranged to form jets that discharge at least a portion of the fluid which enters the fluid chamber. A predetermined number of the ports are inclined relative to vertical and in a direction opposite a closure door of the barrel. The fluid distribution grid, which is preferably semi-circular shaped, can be a permanent weldment, bolted on, or removable. When used in launching a pig, the ports provide a differential pressure that lifts the pig and overcomes friction as the pig moves forward. Because a number of the ports are blocked by the sealing elements (cup or disc) of the pipeline pig, the number of pigs residing in the launcher/receiver can be determined.

Abstract: A pig launcher/receiver includes a fluid distribution grid arranged above a floor of the pig launcher/receiver's barrel to define a fluid chamber between the floor and the fluid distribution grid. The distribution grid has a plurality of ports arranged to form jets that discharge at least a portion of the fluid which enters the fluid chamber. A predetermined number of the ports are inclined relative to vertical and in a direction opposite a closure door of the barrel. The fluid distribution grid, which is preferably semi-circular shaped, can be a permanent weldment, bolted on, or removable. When used in launching a pig, the ports provide a differential pressure that lifts the pig and overcomes friction as the pig moves forward. Because a number of the ports are blocked by the sealing elements (cup or disc) of the pipeline pig, the number of pigs residing in the launcher/receiver can be determined.