How did you come up with the idea of developing a test stand for water permeability testing for GKD?

We constructed this test rig because there was and is no comparable product on the market yet. Although there is a standard for test methods to determine the water permeability of geotextiles, there is no such standard for filter fabrics. However, since we have a lot of applications where water, or a water-based liquid, flows through a fabric, such as sludge dewatering, ballast water filtration, wastewater treatment or fruit juice pressing, we have a great interest in knowing exactly how the fabric behaves in the flow. So, based on the standard for geotextiles, we built our own test rig.

How does the test rig work?

At the test stand, the filter fabric to be analyzed is clamped in an aluminum fixture. The three-meter-high cylinder mounted above it is then filled with distilled water. At the push of a button, the water begins to flow through the mesh. A radar probe at the top of the cylinder measures the water level every 100 milliseconds. Using hydrostatics, we can determine the pressure, and the water permeability is calculated from the temporal resolution of the water levels. These two values allow us to clearly describe the properties of the fabric as it flows through. Using mathematical methods, we can also model other pressure levels outside the measurement range.

How do GKD customers benefit from the new development?

This unique test rig allows us to determine permeabilities over a wide range of pressure values, which can be used for engineering design. This allows us to get as close as possible to the customer’s application and thus find a solution that fits optimally into their process.