Patent ID: 8821132
Filing Date: 2014-09-02
Classification: B63J,F04B,Y02T

Abstract:
1. Apparatus for providing a supply of natural gas fuel comprising: a compressor having an inlet for a stream of natural gas, wherein the inlet is configured for being placed in fluid communication with a liquid natural gas storage tank in order to provide a supply of boil-off gas from out of the liquid natural gas storage tank, an outlet which is configured for being placed in fluid communication with a natural gas supply pipe, wherein the compressor comprises a first and subsequently a second compression stage, wherein the first and the second compression stage comprise labyrinth-sealed piston-compressors or piston-ring-sealed piston-compressors, and wherein the first compression stage has a larger piston diameter than the second compression stage, and wherein the compressor comprises at least a third subsequent compression stage, which comprises a piston-ring-sealed piston-compressor or a labyrinth-sealed piston-compressor, wherein at least one compression stage includes a bypass with a controllable valve, which feeds an output of the at least one compression stage back to an input of the at least one compression stage, for controlling the delivery volume and/or the delivery pressure of the at least one compression stage, wherein there is a non-return valve and no other fluid communication between the second compression stage and the third compression stage, and wherein all compression stages upstream of the non-return valve are oil free.