L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des

L'air Liquide

Maurice Molozay

Gerard Loiseau

Catherine Bonge

Sylvain S d'Appollonia

Michel Rigo

Jean Arnoult

A primary flow (Q) of a carrier gas is divided into a series of flows of predetermined flow rate (q.sub.1 -q.sub.10). There is introduced into a first of these flows (q.sub.1) a predetermined quantity of gas (A) to be analyzed, so as to obtain a first mixture (M.sub.1). This first mixture (M.sub.1) is diluted with a carrier gas flow (q.sub.3) to constitute a second mixture (M.sub.2). A portion (d.sub.1) of this second mixture is diluted with a carrier gas flow (q.sub.5) to constitute a third mixture (M.sub.3), and so on. A calibrating gas (U.sub.5) that contains very little of the second gas is provided. These flows feed a series of outlets, usable in parallel, of controlled flow rates of different mixtures over different ranges from very low content to higher content of the gas to be analyzed. The invention is useful particularly for the calibration of high sensitivity hygrometers.

Process and apparatus for furnishing gas to a high sensitivity analyzer

The line of gas to be analyzed, the 'zero' gas line and calibration gas line are each provided with a restriction operating in sonic rate supplying a nominal constant flow and downstream, have a discharge duct provided with a flow regulator. The nominal flows in the first and second lines are higher than the given flow supplied to the analyzer so that during each of the calibration and analysis steps, the whole of the circuit portion of the device is permanently flushed with the nominal gas of the line and/or by a portion of the recirculated flow of gas originating from another line.

Process and apparatus for supplying gas to a very highly sensitive

In a gas flow regulating valve, the needle (37) axially shifted by a rod (40) includes a recess (70) which is of variable depth and cooperates with an expanding sealing element (43). The valve is provided with a safety closure means comprising a valve member (33) which has a spring (35) and whose displacements are controlled by a free connection tube (30).

Gas regulating valve

An installation for the delivery of a gas of high purity under a constant pressure from either of two vessels each of which is connected to a utilization outlet via a separate supply pipe and a switching system. A switching control system acts on two high-pressure valves, one for each vessel, downstream of which is situated a single pressure regulator which controls the outlet gas pressure. The valves are actuated by an auxiliary low-pressure gas via a pneumatic memory and two detectors measuring the pressure prevailing in the two gas vessels.

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Le Mesnil Saint Denis, France

Maurice Molozay