Abstract: A helium leak detector characterized in that it comprises a first molecular pump (T) having a high pumping speed, having its low-pressure outlet connected to an inlet (E) of the detector, and having its high-pressure outlet connected either to a pre-vacuum assembly (10) comprising a first valve (V1) and a first primary pump (P1), or to a measurement assembly (20) for measuring helium pressure and comprising:a first selective filter (F1) constituted by a molecular pump having a low pumping speed and a low compression ratio; anda second selective filter (F2) constituted by a molecular pump having a low pumping speed and a high compression ratio;said first and second filters being connected to one end of a second valve (V2) having its other end connected between the turbomolecular pump and the first valve (V1), said detector further comprising a third selective filter (F3) in parallel with said second valve (V2), said third filter allowing helium to pass therethrough and preventing air or vapor from passing ther

Abstract: A leak tester comprises a vacuum chamber in which a device under test is placed and a helium leakage detector connected to the vacuum chamber. The device under test is adapted to be filled with helium or with air-helium mixture through an exterior pipe entering the vacuum chamber and incorporating a coupling for connecting it to the device under test. The coupling is surrounded by a collector chamber connected by a pipe to a vacuum pump outside the vacuum chamber.

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.

Abstract: A method of de-polluting a helium leak detector in which a pumping station and a gas analyzer (5) connected to the pumping station via an air inlet duct provided with an insertion valve (6). The pumping station comprises a sliding vane rotary vacuum pump (1) comprising a rotor (7) and a stator (8). The assembly is placed in a sump partially filled with oil (10). A suction duct (11) connects the interior of the stator to the exterior of the sump connects exhaust channel (12) connecting the interior of the stator to the interior of the sump which is in communication with the exterior via a point (14) of the sump which is situated above the oil level. The pumping station further includes a link duct (15) having a fastening (4) for connection to an apparatus to be tested at one end and having its other end connected to the suction duct via a pump isolating valve (2).

Abstract: A tracer gas leakage detector mainly comprises a primary vacuum pump which is selectably connectable to a unit to be tested for leakage, an inlet valve also connectable to the unit to be tested and communicating with a measurement cell capable of being evacuated by a primary pump and a secondary pump. The inlet valve includes a motor-controlled valve member to enable the aperture through the inlet valve to be servo-controlled to the inlet pressure of the measurement cell, and conversion means providing an electrical signal representative of the aperture.

Abstract: A cock for low-pressure bleeding of a gas from a gaseous mixture, said cock having a body (1) with an inlet (12) and a pumping outlet (13) for the mixture and a bleed outlet orifice (15), and a valve (2) which co-operates with the valve body and is situated between said orifice and the inlet, wherein the valve includes a semi-permeable membrane with a first surface (6A) which communicates with said inlet and a second surface (6) which communicates with said bleed orifice, the valve assuming a first position in which it allows the mixture to pass directly from the inlet towards the bleed orifice when the pressure of the mixture is lower than a given pressure, and a second position in which it closes the bleed orifice when the pressure of the mixture is higher than said given pressure, the gas to be bled off then passing through said permeable membrane.

Abstract: The invention relates to a helium leakage detector. It includes a measuring spectrometric cell (8) disposed in parallel with a molecular diffusion pump (6) whose outlet (7) is short-circuited at the inlet (5) by a pipe (10) upstream from a constriction (11) constituted by an adjustable valve.

Abstract: The invention relates to a helium leakage detector. It includes a measuring spectrometric cell (8) disposed in parallel with a molecular diffusion pump (6) whose outlet (7) is short-circuited at the inlet (5) by a pipe (10) upstream from a constriction (11) constituted by an adjustable valve.

Abstract: A leak detector comprises helium measuring means (6) for measuring helium sucked in by a sniffer (2) via a flexible hose (3) and a liquid nitrogen trap (5). A vacuum is maintained in the nitrogen trap (5) by a molecular diffusion pump (7) leading to a vacuum pump (18) which exhausts to the atmosphere. In order to speed the flow of gas, possibly including helium as a tracer element, along the flexible hose (3) most of the gas sucked in by the sniffer (2) is diverted from the inlet (4) to the nitrogen trap by a bleeder arrangement (12) connected to an auxiliary duct (11) which is itself connected to an intermediate point between two stages in the vacuum pump (18).