Abstract: The invention provides an apparatus comprising a storage tank, a liquid piston compressor and a gas-fed device. The storage tank is configured to store liquefied gas therein. The liquid piston compressor is disposed downstream of, and in fluid communication with, the storage tank and is configured to receive boil-off gas from the storage tank and to compress the gas. The gas-fed device is disposed downstream of, and in fluid communication with, the liquid piston compressor, and is configured to receive compressed gas from the liquid piston compressor.

Abstract: The invention provides an apparatus for compressing a first fluid. The apparatus comprises a compressor piston comprising a piston cylinder and a piston assembly slidably mounted therein. The piston assembly comprises first and second spaced apart piston members defining a space therebetween. The space is configured to contain a second fluid used to cause compression of the first fluid. The piston assembly further comprises means for feeding second fluid to the space between the first and second piston members.

Abstract: A system for supplying compressed gas to several gas-fed devices is based on a liquid piston gas multistage compressor (100). Gas pressure measurements performed at a gas intake (10), an intermediate gas outlet (20) and at an end gas outlet (30) of the system allow controlling respective gas capacities of the compressor stages. Easy and reliable control can thus be obtained for the system operation. Varying the number of the compressor stages allows matching any pressure requirements for the gas delivery to all the gas-fed devices, and varying the gas capacities of the compressor stages allows easy adaptation to variable gas consumptions of the gas-fed devices.

Abstract: Apparatus for supplying natural gas fuel to an ocean-going tanker for the transport of liquefied natural gas (LNG), includes a first line with a compressor (12) having an inlet communicating with an ullage space (4) of at least one LNG storage tank (2) and an outlet communicating with a conduit leading from the compressor to at least one engine (38), and a second line with a forcing vaporiser (24) having an inlet communicating with a liquid storage region (6) of the tank (2), the second line being connected to the first line downstream of the compressor (12) and upstream of the at least one engine (38).

Abstract: This method for dispensing cryogenic liquid includes the following steps: connecting, in a sealtight manner, a fuel tank (2) to be filled to a storage tank, dispensing cryogenic liquid to the fuel tank (2) and determining firstly the flow of liquid being dispensed and the amount of liquid dispensed, and secondly the pressure prevailing in the fuel tank (2), stopping the dispensing of the liquid when the pressure exceeds a first predetermined threshold or else when the flow of liquid drops below a second predetermined threshold, degassing the fuel tank (2) after stopping the dispensing, while determining the amount of gas removed from the fuel tank (2) during the degassing, and determining whether or not liquid should be dispensed again on the basis of the amount of gas removed during the degassing.

Abstract: The proposed system comprises a supply line for at least one engine, on which line is situated a first compression unit (3) for said gas and a bypass to a return line on which are successively situated cooling means (10) and reliquefaction means (30). The cooling means successively comprise a second compression unit (11, 12, 13) and a heat exchanger (17). Downstream of the second compression unit (11, 12, 13) a bypass to a loop (18, 20, 21) comprises first expansion means (14), the loop rejoining the return line upstream of the second compression unit (11, 12, 13) after having passed through the heat exchanger (17) in the opposite direction with respect to the gas fraction not bypassed via the loop.

Abstract: Natural gas boiling off from LNG storage tanks located on board a sea-going vessel, is compressed in a plural stage compressor. At least part of the flow of compressed natural gas is sent to a liquefier operating on a Brayton cycle in order to be reliquefied. The temperature of the compressed natural gas from the final stage is reduced to below 0° C. by passage through a heat exchanger. The first compression stage is operated as a cold compressor and the resulting cold compressed natural gas is employed in the heat exchanger to effect the necessary cooling of the flow from the compression stage. Downstream of its passage through the heat exchanger the cold compressed natural gas flows through the remaining stages of the compressor. If desired, a part of the compressed natural gas may be supplied to the engines of the sea-going vessel as a fuel.

Abstract: A reciprocating cryogenic pump 2 comprises a piston reciprocable within a pumping chamber 44. The pumping chamber 44 has an inlet suction valve 48 for cryogenic liquid to be pumped and an outlet 32 for high pressure cryogenic liquid. The inlet valve 48 for the cryogenic liquid communicates with a cryogenic liquid reception chamber 46 in the cold end or head 6 of the pump 2. The pump head 6 is at least partially surrounded by a first jacket 8 retaining primary vacuum insulation. The first jacket 8 is itself at least partly surrounded by a second jacket 10. The jacket 10 defines a chamber for the reception of a coolant fluid such as liquid nitrogen and the second jacket has an inlet 20 and an outlet 22 for the liquid nitrogen. The thermal insulation can be further enhanced by a trapped gas space 73 between the first jacket 8 and an inner sleeve 52, the latter defining with an outer sleeve 50 vacuum insulation for the pumping chamber 44.

Abstract: A cryogenic liquid expansion turbine has a turbine wheel mounted on a rotary shaft, at least one radial inlet for cryogenic liquid to be expanded in the expansion turbine for the rotary shaft, and a dry gas sealing means at a position along the rotary shaft between the turbine wheel and the bearings. There is a thermal barrier member between the turbine wheel and the dry gas sealing means, a gas chamber on the dry gas sealing means side of the thermal barrier member, and an internal passage for cryogenic gas to the said gas chamber. A method is also provided.

Abstract: A dry seal apparatus (30) for a machine (10) includes a seal having a stationary portion (40) and a rotating portion (38); a space (44) disposed between the stationary and rotating portions; a biasing member (42) disposed proximate the stationary portion (40) and in contact therewith for applying a force to the stationary portion; and a labyrinth (37) proximate the rotating portion (38) and constructed and arranged for receiving a liquid for being vaporized before entering the space between the stationary and rotating portions of the seal. A related method is also provided.

Abstract: A primary stream of boiled-off natural gas taken from the ullage space of a liquefied natural gas storage vessel is compressed by a compressor. A flow of liquefied natural gas taken from the storage vessel is partially and forcedly vaporised in a vaporiser 36 so as to form a secondary stream of natural gas containing unvaporised liquefied natural gas. Unvaporised liquefied natural gas is disengaged from the secondary stream in a phase separator. The secondary stream is mixed with the compressed primary stream to form a supply of natural gas fuel. The fuel supply may be formed and used on board an ocean-going LNG tanker.

Abstract: A machine for recovering power from a flow of compressed gas, for example, natural gas includes a turbo-expander having a turbo-expander wheel, and a generator having a rotor able to be driven by the turbo-expander wheel and a stator about the rotor. The turbo-expander and the generator are housed in a length of pipe. The turbo-expander wheel has an obverse side facing the generator. There is a flow passage for the flow of expanded gas that places the obverse side of the wheel in gas flow communication with an outer surface of the stator. This outer surface typically carries fins to facilitate cooling of the stator by expanded gas from the turbo-expander.

Abstract: Liquefied Natural Gas (LNG) is converted to a superheated fluid at a temperature greater than 5° C. by being passed under pressure through a train of first, second and third main heat exchange stages in series, in which the natural gas is heated by a circulating heat exchange fluid flowing in heat exchange circuits. The heat exchange fluid condenses in the first and second heat exchange stages and is partially vaporised in subsidiary heat exchangers which may be heated by sea water flowing in open cycle.

Abstract: Boiled off liquefied natural gas flows from a storage tank and is compressed in vapour compression stages. The resulting compressed vapour is condensed in a condenser and the condensate returned to the tank. The condenser is cooled by a working fluid, for example nitrogen, flowing in a Brayton cycle. The Brayton cycle includes a heat exchanger which removes heat of compression from the compressed natural gas vapour upstream of its passage through the condenser. In addition a part of the working fluid is withdrawn from a region of the Brayton cycle intermediate the working fluid outlet from the condenser and the working fluid inlet to the heat exchanger and the withdrawn working fluid flows through another heat exchanger in which it removes heat of compression from the natural gas vapour intermediate the compression stages. The withdrawn working fluid is returned to the Brayton cycle.