Leak testing plays a vital part in quality control in a wide range of applications. Reliable integrity of primary packaging is of crucial importance in the pharmaceutical industry to guarantee sterility and protect drugs from any microbiological substances, oxygen or moisture that may ingress.
In the automotive industry, leak testing ensures that various components are operating perfectly, including parts guaranteeing the supply of gasoline. Pfeiffer Vacuum presented test technologies that satisfy numerous leak detection and measuring method requirements: leak detection using air, leak detection with a tracer gas and optical emission spectroscopy.
Leak testing with air
Pfeiffer Vacuum presented products made by its new subsidiary Advanced Test Concepts, Inc. (ATC) from Indianapolis, USA. The leak detectors that were exhibited work on the basis of leading leak testing technology using air, and so do not require any special tracer gases.
The devices operate according to patented Micro-Flow technology. This technology consists of an integrated micro sensor that works on accelerated flow. A sensitivity of up to 5 • 10^-4 mbar l/s is achieved with this method. This technology is used in the automotive industry, such as for testing power trains and gearbox housings.
A specific use of the Micro-Flow sensor is the Mass Extraction technique, which works on the principle of rarefied gas flow. Testing takes place in vacuum conditions to attain higher sensitivity. This type of testing is particularly suitable for packaging or enclosed objects, such as pharmaceutical packaging and electronic components, that require to be tested for watertightness. Sensitivity of up to 5 • 10^-6 mbar l/s can be achieved with this method.
Micro-Flow and Mass Extraction technology offer a number of advantages over other leak testing methods that work with air. The speed of testing and their low susceptibility to ambient changes are notable examples of this. They also stand out due to their higher sensitivity and accuracy, and do not require calibration on a daily basis.
Leak detection with tracer gas
The ASI 35 leak detector delivers excellent performance in integral and localizing testing methods, as well as combinations of the two, using helium or hydrogen as a tracer gas. The device combines high performance, reliability and repeatability with extremely short cycle times. This leak detector is designed for demanding testing situations with minimal background signals and enables short overall cycle times. The robust iridium filaments also ensure long durability. Particular applications for this device are the automotive industry but also the field of electronic and mechanical components, and refrigeration and air conditioning.
Optical emission spectroscopy
It is important that packaging preserves the stable condition of particularly moisture-sensitive medication such as dry powders for inhalation; at the same time, it must also prevent biological substances from the packaging from ingressing into parenteral drugs. This necessitates the use of high sensitivity integrity testing. The method used by the AMI measures leak tightness using a patented process that does not require a tracer gas. Instead, this method uses the existing gas mixture in the cavities inside the packaging to perform high-sensitivity testing over an extended measuring range. The procedure offers great flexibility: a variety of different packaging types such as blister packs, pouches, vials, plastic bottles, and sealed parts such as battery casings, can be tested in this way.
A big advantage of the AMI is its wide measuring range that also offers higher sensitivity than conventional tests. As a result, the AMI device can perform helium leak testing and rough leak testing with just one device. The procedure delivers deterministic test results with high repeatability, irrespective of the user, and with reliability and accuracy that comply with USP 1207.1.
Picture: Pfeiffer Vacuum ASI 35 modular leak detector (Source: Pfeiffer Vacuum GmbH)
Source: Pfeiffer Vacuum GmbH