Testing & monitoring automatic containment of samples
Automatic Containment of Samples, its testing and its monitoring done for fluid research, material research, biological research, exploration. Can be used for containment of hazardous substances either safeguarding for chemical toxicity or biological toxicity. Main advantages: high reliability, high level of automation possibilities (to contain hazardous substances in remote or dangerous areas).
The leak rates and required number of containment levels commonly specified in space project depends on the toxicity of the substance to be contained. The more toxic, the lower the maximum acceptable leak rate is. When leakage of the substance is considered critical, a leak rate of max 1*10-4 mbar.l/s He is specified and a double containment is to be provided. When leakage of the substance is considered catastrophic then a leak rate of max 1*10-6 mbar.l/s He is specified and three containments are to be provided.
Leak rates commonly achieved in our projects are below 1*10-7 mbar.l/s He in case of a single seal configuration. Configurations with double seals (2 seals next to each other in the same leak path) easily reach levels below 1*10-8 mbar.l/s He (and are thus minimum 100 times better than specified).
Substantial experience has been gained in the leak testing itself and correct interpretation of results. Leak testing for instance is often hampered by the He-concentration in the surrounding air (the He-background concentration) which reduces the accuracy of the test results. Dedicated mitigation measures were developed to counteract this.
Extensive experience has also been built up with regards to the containment design. Designing the required levels of containment involves both FT (failure tolerance: fully independent levels of containment) as well as DFMR (design for minimum risk approaches: non independent levels of containment can be accepted given that a number of mitigations is in place) approaches.
For instance, in order to be accounted as an independent level of containment, no common failures should be present. A scratch which would damage the sealing surface of 2 consecutively placed elastomeric seals on the same leak path could result in a breach of these 2 containments. If no proper mitigations are taken, then these consecutive seals cannot be considered as independent levels of containment.
Innovations & Advantages
- Remote and hazardous areas
- Small sampling volumes (bacterial level) possible
- Very high leak rate levels (> 10-8, not measurable at QS)
- Up to Biological Level 4
Current and Potential Domains of Application
Containment, Packaging, Sampling, Nuclear ...