Abstract: The device for metering the volume of gas flowing in a pipe, downstream from an expander-regulator, comprises in succession a flow straightener, a velocity-measuring flowmeter, and a silent flowrate limiter. The straightener comprises a support ring in which there are mounted a first perforated plate having holes distributed over its surface, together with a first porous plate and a spacer in the form of an annulus co-operating with the first perforated plate. The limiter comprises an upstream web defining a second perforated plate perforated by a defined number of calibrated holes, the total flow section thereof being much less than the total flow section of the first perforated plate, a second perforated plate, and a downstream web defining a third perforated plate having holes of total flow section that is much greater than the total flow section of the second perforated plate of the upstream web.

Abstract: The flow conditioner for a gas transport pipe comprises at least one perforated plate disposed essentially perpendicularly to the axis XX' of the pipe and comprising a central hole and sets of additional holes that are regularly distributed over at least three concentric rings centered on the axis of the pipe so as to define a perforated plate that is axially symmetrical. Within any one ring all of the circular holes are of the same diameter d.sub.1, d.sub.2, d.sub.3. On going away from the central hole and on passing from any one ring to an adjacent concentric ring, the diameter of the holes changes alternately in a reduction direction and in an increase direction. Each ring has a number of holes that is equal to or greater than six. The perforated plate is advantageously associated with a porous plate situated upstream from the perforated plate and parallel thereto.