Abstract: The invention relates to a leak detector comprising a primary pump unit, a secondary pump unit having at least one secondary pump, a gas analyzer, a test module, a calibration module, a delivery module of the secondary pump unit, valves, and link segments. In the invention the leak detector includes a one-piece main block provided with spaces making it possible to integrate at least some of the component elements of the leak detector.

Abstract: A leak detector including at least one analysis unit connected to the inlet of a first secondary pump, a pre-evacuation set connected to an inlet coupling, the inlet of said pre-evacuation set further being connected to the outlet of said first secondary pump via a pipe provided with a first valve, wherein said pre-evacuation set comprises a second secondary pump and a mechanical primary pump connected together in series, and wherein a pipe provided with a second valve connects an intermediate point of said first secondary pump to the inlet of said second secondary pump.

Abstract: A tracer gas leak detector that analyzes a test gas for presence of a tracer gas therein, including at least one gas analyzer, a secondary pump whose suction inlet is connected to the gas analyzer, a primary pump connected to the secondary pump outlet via a first pipe fitted with a first valve, and a second pipe connecting the first pipe from a point situated between the first valve and the primary pump to an inlet of the detector for connection to an enclosure via a pre-evacuated flow and said gas analyzer receiving said test gas from a part of said pre-evacuated flow, the second pipe being fitted with a second valve, the primary pump serving to pre-evacuate the enclosure, wherein a sampling member for sampling the flow travelling along the second pipe is situated directly on the wall of the second pipe in direct contact with the flow and is connected via a duct directly to the analyzer, the sampling member having flow conductance enabling the pressure in the duct to be compatible with operation of the gas a

Abstract: A helium leak detector includes a gas analyzer and a secondary pump having at least on its discharge side a Holweck type stage. The pump is of a type enabling the suction pressure to be reduced to a value at least equal to 10.sup.-4 mbar and a discharge pressure which is sufficiently high to be compatible with the suction pressure of a dry primary pump having at least two stages. The secondary pump is connected to the low-pressure output of a sampling unit on an intermediate point of the secondary pump where the flow conditions are molecular. A sniffer probe is connected to the high-pressure side of the sampling unit. This high-pressure side is further connected to the dry primary pump between its at least two stages.

Abstract: A tracer-gas leak detector includes an analysis unit and a primary pump whose inlet is connected to an inlet orifice of the detector via a first pipe equipped with a first valve. A secondary pumping set has an inlet connected to the analysis unit and an outlet connected to the inlet of the primary pump. The primary pump is a dry pump. The secondary pumping set includes two secondary pumps of the mechanical type separated from each other by a second valve. The secondary pump that is proximate to the dry primary pump is the second secondary pump and includes a dynamic seal stage at its outlet. A second pipe connects the inlet of the second secondary pump to the first pipe downstream from the second valve. A third valve is disposed on the first pipe between the outlet of the second secondary pump and the junction where the second pipe meets the first pipe. The third valve is controlled by a pressure sensor placed at the inlet of the second secondary pump.

Abstract: The invention provides a tracer-gas leak detector including a secondary pumping set, a sole primary pumping set, a mass spectrometer connected to the inlet of the secondary pumping set, the outlet of the secondary pumping set being connected to the inlet of the primary pumping set by means of a duct equipped with an electromagnetic valve, and at least one pipe connecting a coupling for connection to an enclosure to be tested to the secondary pumping set, said pipe being equipped with a pneumatic valve which is opened by suction, wherein a buffer volume is connected both to a suction inlet of the primary pumping set by a link duct equipped with a first electrically actuated valve, and also to said pneumatic valve by a control duct equipped with a second electrically actuated valve.

Abstract: A pumping apparatus for pumping a gas having application to helium leak detectors has a vane and oil-seal type vacuum pump immersed in a closed tank (9) partially filled with oil (10). The apparatus also includes an oil pump (20) for renewing the oil seal located inside the tank. The oil pump is equipped with a noise-reducing mixing device enabling the oil for constituting the oil seal to be mixed with a noise-reducing gas. The noise-reducing gas is fed from the outside of the tank to the mixing device by means of a pipe (24) passing through the wall of the tank and opening via a Venturi tube to the suction duct of the immersed oil pump.

Abstract: A mechanical pump assembly (20) for pumping a secondary vacuum, the assembly comprising two pumping stages, the first stage having a suction inlet (9) and the second stage having a suction orifice (10), said inlet and said orifice both opening out to the outside, both stages having a common delivery outlet (4), the pump assembly being characterized in that both of said pumping stages are of the Holweck drum type, said first stage having a compression ratio of about 50 for a gas such as helium and of about 30,000 for air, the pumping speed of the first stage being about 4 l/s for air and about 2.5 l/s for said gas, and in that said second stage has a pumping speed of about 3.5 l/s for air and of about 2 l/s for said gas, the nominal speed of rotation of said mechanical pump assembly being about 27,000 rpm.

Abstract: The present invention relates to a circuit for processing a signal received by an electron multiplier. The circuit comprises an electron multiplier followed by an electron collector, a power supply for the electron multiplier, a gain-compressing amplifier for processing the signal delivered by the electron collector, and a feedback path for continuously modulating the gain of the electron multiplier by means of a control circuit which acts on the HT power supply of the electron multiplier. This circuit is particularly suitable for use in mass spectrometry and in helium leak detection.

Abstract: A tracer gas leak detection system for: a first duct provided with a pre-evacuation valve, enabling a test chamber to be connected to the suction of a pre-evacuation pump. A gas analyzer is connected to the suction of a mechanical secondary pump whose delivery is connected by a second duct to a primary pump. At least one connection is provided with an inlet valve connecting of the text chamber to the mechanical secondary pump and the system further includes a second mechanical secondary pump situated on the first duct downstream from the pre-evacuation valve.