Foreword
The core of the BeFree filter consists of a large number of hollow fibres whose pores are so small that particles and organisms smaller than 0.1 micrometres cannot pass through. This includes all bacteria and protozoa (excluding viruses) and makes it possible to obtain clean water for drinking from unfiltered water.
A defect occurs when one of these hollow fibres is damaged. This is the case if a fibre is severed or has a microfibre tear.
But how do I recognise whether my filter still has integrity?
The following integrity test can help.
Integrity test
Preparation:
For the test to work, the filter must first have absorbed enough water to fill the hollow fibres. To do this, we recommend pressing at least 2 litres of clear water through the filter. If the test shows a negative result, we recommend a second test, before which another 2 litres are pressed through. This can prevent a false-negative test result.
Integrity test:
- The membrane (filter) must be properly wetted, as the test only works when the fibres are filled with water.
- The bottle is now held vertically with the mouthpiece facing upwards and squeezed until little water emerges from the mouthpiece.
- To ensure that the test works properly, air is now blown into the bottle via the mouthpiece and held directly ‘overhead’ without interruption. Continue blowing for at least 5 seconds.
Evaluation:
If a fibre is torn or damaged, fine, small bubbles emerge from the filter in the form of a constant stream and usually at high speed. As the filter also has a few hollow fibres for air exchange, individual bubbles, usually the size of peas, can escape even with integral filters.
If the filter repeatedly shows a negative result or you are unsure about the interpretation, please get in touch with our support team using the contact form at katadyngroup.com > About us > Contact us with a video recording, we will be happy to help.