Five matters needing attention in the operation of Cohen moisture tester
1. The problem of full sealing of the system: the technical level and overall strength of Karl Fischer trial manufacturing should be further improved. 6. The connection of the non side gap and rigid high-speed road must be fastened, from the reagent bottle to the metering pump and then to the reaction tank, otherwise the reagent leakage will directly affect the test results. Another problem with its airtightness is that the end point of titration will be delayed due to the absorption of air moisture by Karl Fischer reagent during the test
2. Accuracy of sampling: when calibrating Karl Fischer reagent, 10mg water needs to be taken, and 10ul sampler should be used as far as possible, which is not only accurate and fast, but also can prevent water droplets from adhering to the surface of parts with corrosion or obvious corrosion traces. Similarly, there are similar problems in taking methanol reagent and ethyl ester. After taking and placing, attention should be paid to shortening the opening time of the reaction tank as far as possible
3. Adjustment of magnetic stirring speed: in the reaction tank, because the titration reagent is added locally and not at the same place with the electrode, the stirring speed is best to be fast until no turbulence is formed, so that the end point can be reached as soon as possible
4. The titration speed should be set fast first and then slow: when titrating, it should be fast first to shorten the test time as far as possible, and when approaching the end point, the strain is slow, which can improve the measurement accuracy
at the same time, 5. Cohen moisture meter should be far away from strong magnetic field to avoid electronic display jumping and abnormal phenomena during operation. The manual moisture meter must use the glass automatic burette to measure Karl Fischer reagent and methanol solvent, and the glass burette itself must be connected to the outside world because of the balance pressure
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