Investigation: visual inspection: during the investigation, visible deposits in the inlet spout was determined.With the measurement of the plane parallelism could be determined with a value of -0.044 mm [outside the tolerance of 0 ± 0.02 mm] a deformation.Permeability test: a permeability test has shown that the valve is permeable.Computer control test: to investigate the flow in valve the opening pressure is measured using a miethke computer control test bench which simulates a cerebrospinal fluid flow.The valve is tested in the horizontal position.The results show that the valve is not operating within the acceptable tolerance in the horizontal position.A reduced outflow could be determined.Adjustment test: the progav was tested and is not adjustable.Braking force and brake function test: the brake functionality test has shown that the brake function is operational.However, the braking force cannot be measured due to the non-adjustability of the valve.Internal inspection: after dismantling of the valve, deposits were found in progav.Result : based on our investigation results, we can determine a reduction of outflow and adjustment difficulties.The determined deposits can be named as the cause for the functional deviations.Organic deposits in the cerebrospinal fluid can influence the function temporarily and are known side effects in hydrocephalus therapy.We can exclude a defect at the time of release.The valve met all specifications of the final inspection when released from christoph miethke gmbh & co.Kg.No further regulatory actions are required from our point of view.
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