A method for reducing emissions from a vessel includes isolating the vessel from a downstream fluid flow line, purging a fluid from the vessel by injecting purging media into the vessel to push the fluid through a check valve of a vent tubing and into the downstream fluid flow line, and draining the purging media from the vessel. A first end of the vent tubing is coupled to the housing of the vessel, and a second end of the vent tubing is coupled to the downstream fluid flow line. Further, the vent tubing includes a check valve disposed between the first end and the second end, and the check valve is configured to allow fluid to flow from the housing to the downstream fluid flow line.

An apparatus for loading a pig into a pipeline includes a support member for engaging the cylindrical pipeline outer surface to support the apparatus on the pipeline, a tubular reducer, a force-transmitting member with a pig-engaging surface, and a guide member that is attached to the support member and permits axial movement of the force-transmitting member relative to the reducer. The apparatus includes outer and inner pipeline-engaging members attached to the force-transmitting member and disposed to engage the pipeline outer surface and the pipeline outer and inner surfaces, respectively, to brace a portion of the attached force-transmitting member against the pipeline. The reducer may be removably attached to the support member so that it may be interchanged with another reducer having a different inner diameter, thus adapting the apparatus for pipelines having different wall thicknesses. A hydraulic cylinder may actuate movement of the force-transmitting member.

An apparatus for loading a pig into a pipeline includes a support member for engaging the cylindrical pipeline outer surface to support the apparatus on the pipeline, a tubular reducer, a force-transmitting member with a pig-engaging surface, and a guide member that is attached to the support member and permits axial movement of the force-transmitting member relative to the reducer. The apparatus includes outer and inner pipeline-engaging members attached to the force-transmitting member and disposed to engage the pipeline outer surface and the pipeline outer and inner surfaces, respectively, to brace a portion of the attached force-transmitting member against the pipeline. The reducer may be removably attached to the support member so that it may be interchanged with another reducer having a different inner diameter, thus adapting the apparatus for pipelines having different wall thicknesses. A hydraulic cylinder may actuate movement of the force-transmitting member.

A pig loader device can include a breech assembly having a chamber body, a ramrod compartment, a breech, and a neck. A ramrod having a push plate, a rod, and a breech plate may be disposed within the ramrod compartment and configured to slideably traverse the ramrod compartment and the breech. In use, the device can be connected to an ancillary pipe via the neck, and a pig may be placed within the breech and aligned be to be slid within the breech and neck upon engagement with the ramrod to facilitate pigging operations of a pipeline. The ramrod may then be forced forward to an extended position, thereby urging the pig through the neck to be seated within the pipe. The device may then be detached from the pipe to enable continued pigging operations.

A pig loader device can include a breech assembly having a chamber body, a ramrod compartment, a breech, and a neck. A ramrod having a push plate, a rod, and a breech plate may be disposed within the ramrod compartment and configured to slideably traverse the ramrod compartment and the breech. In use, the device can be connected to an ancillary pipe via the neck, and a pig may be placed within the breech and aligned be to be slid within the breech and neck upon engagement with the ramrod to facilitate pigging operations of a pipeline. The ramrod may then be forced forward to an extended position, thereby urging the pig through the neck to be seated within the pipe. The device may then be detached from the pipe to enable continued pigging operations.

A method is provided for the autonomous assessment of pipelines. The apparatus combines commercially available mechanisms for pipeline assessment in a unique untethered pipeline assessment device that is propelled through the pipeline by the flow of liquid in the pipeline, thus allowing for the assessment of pipelines much cheaper, faster, safer and less disruptive to the community than the current assessment methods.

A method is provided for the autonomous assessment of pipelines. The apparatus combines commercially available mechanisms for pipeline assessment in a unique untethered pipeline assessment device that is propelled through the pipeline by the flow of liquid in the pipeline, thus allowing for the assessment of pipelines much cheaper, faster, safer and less disruptive to the community than the current assessment methods.

A trap door cap for sealing around a trap door of a trap is disclosed. The canister includes a closed end and side walls extending from the closed end, wherein the side walls and the closed end together define a cup-shaped body having an open end opposite the closed end. The trap door cap further includes a seal configured to selectively apply a pressure-tight seal around an exterior surface of the trap at a longitudinal location of the trap inward of the trap door and a pressure-tight connection between the seal and the open end of the cup-shaped body, wherein the side walls, the closed end, the seal, and the pressure-tight connection together form a pressure-tight inner volume within the canister.

A trap door cap for sealing around a trap door of a trap is disclosed. The canister includes a closed end and side walls extending from the closed end, wherein the side walls and the closed end together define a cup-shaped body having an open end opposite the closed end. The trap door cap further includes a seal configured to selectively apply a pressure-tight seal around an exterior surface of the trap at a longitudinal location of the trap inward of the trap door and a pressure-tight connection between the seal and the open end of the cup-shaped body, wherein the side walls, the closed end, the seal, and the pressure-tight connection together form a pressure-tight inner volume within the canister.

A compact subsea pig launcher comprises a tubular magazine for holding a plurality of pipeline pigs in longitudinal succession ready for launching successively into a subsea pipeline. The magazine is shaped to define at least one turn such as a coil around an upright axis. Thus, a series of pigs are stored in longitudinal succession along a path that is curved in plan view around the upright axis. During launching, at least one of the series of pigs is advanced along the path with angular movement around the upright axis.