Abstract: A safety valve for use in a hydrocarbon production tube comprises a valve member which is opened by a piston tube displaceable as a result of the intake of hydraulic fluid into an operating chamber therefor, and a tubular receptacle for receiving an auxiliary safety valve recoverable by means of a cable. The receptacle is longitudinally displaceable between inactive and active positions and is engaged telescopically with the piston tube in a sealed manner to define, with the piston tube, the operating chamber. The receptacle is normally retained in its inactive position by shearable elements, but after the elements have been sheared, descends to its active position simultaneously driving the piston tube to its lower position to open the valve member.

Abstract: The present invention concerns a process and equipment for drawing off a sample for a chromatographic analysis installation. In addition to the chromatographic analysis apparatus 22 per se and a set of rotary pneumatic valves to which it is normally associated, an additional rotary pneumatic valve is connected as follows:an inlet pipe of the gaseous stream to be analyzed;two pipes connecting this valve to the first valve of the above-mentioned set of and;an open-to-air pipe that is associated to means of injecting water vapor and/or drying gas, at counter-current to the flow direction of the open-to-air stream.