How to solve the inaccurate measurement of refractive index in digital refractometer
The phenomenon of Abbe refractometer indicates that the sector gear plate with a glass dial rotates around its main axis. This must be checked by removing the gear plate. Repairs are quite troublesome and also have some difficulty. The specific methods and steps to solve the problem are:
① Remove the prism rotating handwheel, gear shaft seat assembly, and disk cover in sequence.
② Loosen or unscrew the fixing screws of the gear plate.
③ Unscrew the stop screw in the gear plate element hole and screw on the "tool screw", which is another screw that is the same as the stop screw (M2.5).
④ Frequently rotate the Abbe refractometer prism group, i.e. the prism seat, to impact the tool screw head on the gear plate hole surface, causing the gear plate to loosen slightly from the spindle with the tapered end, or remove the gear plate and reinstall it, and tighten the fixing screws appropriately, so that the gear plate can rotate around its spindle.
⑤ Scrub the surface and square window of the prism group II, and add distilled water. Rotate and adjust the objective screw of the telescope with a square birch, so that the distance between the light and dark boundaries is symmetrical with the cross hairs as the reference center. Then rotate the prism base to adjust the dividing line to the center.
⑥ Hold the prism holder of the Abbe refractometer with one hand and hold it still, while rotating the loose gear plate with the other hand (while observing the field of view of the reading mirror) to the position where the reading on the right is before 1.333 and the concentration scale on the left is before 0-5. Tighten the gear plate screws. In this way, it is possible to align the reading of the water's refractive index with the alignment of the light dark boundary in the telescope's field of view and correct it at once.
