Abstract: The invention concerns a gas leak detector (1) having an inlet (3) enabling connection to a test piece or test chamber, a detector unit disposed within the detector (4), a high-vacuum pump (5) which is connected at one end to the detector unit and through which a test gas, such as helium, passes in the opposite direction, a back-up pump (6), a line (9, 13) joining an outlet of the high-vacuum pump (5) with an inlet of the back-up pump (6), and a line (7, 9) joining the test-piece connector (3) to the high vacuum pump outlet. In order to reduce the complexity and expense necessary to produce the back-up vacuum, the invention proposes that line (13) is fitted with a throttle (14) and including a further line (15) which is fitted with a valve (16), said line directly joining the test piece (3) to the inlet of the back-up pump (6).

Abstract: The invention relates to a high-molecular-weight reactor blend comprising a high-molecular weight polypropylene and a high-molecular weight ethylene-propylene copolymer and having an ethylene content in the range from 0.1 to 2% by weight based on the total amount of blend, a melt flow index MFR (230/5) of .ltoreq.5 dg/min and a molecular weight distribution M.sub.w /M.sub.n in the range from 6 to 20.

Abstract: The invention relates to a countercurrent sniffing leak detector (1) with a mass spectrometer (3) as the detector, with a high-vacuum pump (4) or high-vacuum pump stage (14) through which flows a test gas in countercurrent, with a sniffing hose (7) connected to the outlet side of the high-vacuum pump, respectively high-vacuum pump stage, and with a choke maintaining the pressure difference between the atmospheric pressure in the inlet region (8) of the sniffing hose (7) and the pressure in its outlet region (9); to improve the sensitivity and response time it is suggested that at least one segment of the sniffing hose (7), preferably the entire sniffing hose (7), is dimensioned such that the desired choking is achieved.

Abstract: A test gas leakage detection assembly (1) includes an inlet (2), a detector (3) in the form of a mass spectrometer, a first friction pump stage (5) which is driven in counter-flow, a second friction pump stage (7). The assembly further includes an intermediate connection (6) between the first and second friction pump stages, a pre-vacuum pump (8), a first connection line (13) which can be shut off between the leakage detector inlet (2) and the inlet side (9) of the pre-vacuum pump (8), and a second connection line (15) which can be shut off between the leakage detector inlet (2) and the intermediate connection (6). In order to detect leaks without using oil, the pre-vacuum pump (8) is a diaphragm pump. In order to shorten the response time, it is advantageous if the conductance of the second connection line (15) between the inlet (2) of the leakage detection assembly (1) and the intermediate inlet (6) is adjustable.

Abstract: A leak detection device includes a high vacuum pump implemented as a friction vacuum pump with two further vacuum pumps operating against atmospheric pressure. The further vacuum pumps are dry-sealing pumps in order to avoid hydrocarbon contaminations in a region of a test sample or a test chamber.

Abstract: The invention relates to a process for operating a test gas leak indicator (1) with a gas inlet (2) and a test gas-sensitive detector (4), in which all or part of a stream of gas containing the test gas reaching the inlet (2) is taken to the detector (4) in the event of a leak; in order to improve the sensitivity of the leakage detection, it is proposed that the stream of gas be preferably periodically modulated and the signal from the test gas detector (4) be processed in synchronism with the modulation of the gas flow.

Abstract: A leak detector (1) suitable for detecting leakage with a test gas connection (2), a test gas detector (3), a gas pump (4) and a test gas line (5) extending between the test gas connection (2) and the gas pump (4) and connected to the inlet (6) of the test gas detector (3) via a blockable branch; in order to shorten the response time, it is proposed that the line (7, 8) connecting the test gas line (5) to the inlet region (6) of the test gas detector be such that, during measurement, all of the gas flowing in the test gas line (5) essentially enters the inlet region (6) of the test gas detector (3).

Abstract: The invention relates to a test gas detector, preferably for leak detection instruments, with a selective, preferably test-gas-permeable inlet system (6) and with a device (5) recording the presence of test gas; to reduce the complexity in the production of the vacuum it is proposed that the test gas recorder (5) comprise a gas consuming vacuum gauge (8).

Abstract: A counterflow leak-detector unit (1) with an inlet (2) connected to a test specimen, or a chamber housing a test specimen. A high-vacuum pump (4) produces pressure in a test-gas detector. The inlet (2) to the leak-detector unit is connected to an intermediate line (16) in the high-vacuum pump (4). To increase detection sensitivity without any danger of the pressure in the detector rising to inadmissible levels, a constriction (17) is located between two high-vacuum pump states (5, 6) of the high vacuum pump (4). Pump stages (5, 6) are separated by the intermediate line (16). The inlet (2) to the leak-detector unit (1) is connected to the outlet side of the high-vacuum pump state (5) at a point upstream of the constriction (17).