Why should I calibrate a digital refractometer
Before measuring, the instrument needs to be calibrated. Calibration can be carried out using distilled water or standard glass blocks (standard glass models are marked with refractive index)
1. Calibrate with distilled water
(1) Loosen the locking wrench of the prism and wipe it clean (note: use sewage alcohol or other volatile solvents, and wipe it dry with lens paper)
(2) Use a dropper to drop 2-3 drops of distilled water into the middle of the two prisms, close and lock them tightly
(3) Adjust the prism to rotate the handwheel so that the refractive index reading is exactly the desired data
(4) Check whether the black and white dividing line of the tube in the measuring lens tube coincides with the intersection point of the fork wire. If it does not coincide, adjust the scale adjustment screw to ensure that the intersection point of the fork wire accurately coincides with the dividing line; If the field of view is small fox fairy dispersion, adjust the Amici prism handwheel until the dispersion disappears
2. Calibration with standard glass blocks
(1) Loosen the prism locking wrench and pull the incoming prism apart
(2) Drop naphthalene bromide (high refractive index liquid) onto the polished bottom surface of the glass block and stick it to the surface of the shading prism. The polished measuring surface of the glass block should be facing upwards to receive light and make the field of view of the measuring lens tube bright
(3) Adjust the handwheel so that the refractive index reading is exactly the known refractive index value of the standard glass block
(4) If the dividing line does not coincide with the intersection point of the fork wire when observed from the measuring lens tube, adjust the screw to make them coincide. If there is dispersion, adjust the handwheel to eliminate dispersion.
Maintenance and upkeep of refractometer
Before and after use, and when replacing samples, the working surface of the refractive prism system must be cleaned first.
2. The instrument should be placed indoors in a dry and well ventilated environment to prevent mold from forming on optical components due to moisture
3. When testing corrosive liquids, timely cleaning work (including optical parts, metal parts, and their surfaces) should be done to prevent erosion damage. Cleaning work must be done after the instrument is used
4. The tested sample should not have hard impurities. When testing solid samples, the surface of the refractive prism should be roughened or indented
5. Always keep the instrument clean, and strictly touch the optical parts with your right hand or sweat. If there is dust on the surface of the optical parts, you can use high-grade deerskin or long fiber Cotton wool to gently wipe it and dry it with a hair dryer. If oil stains appear on the surface of optical components, they should be promptly wiped clean with a mixture of alcohol and ether
6. Instruments should avoid strong vibrations or impacts to prevent damage to optical components and measurement accuracy
7. If the bulb in the spotlight lighting system is damaged, the spotlight can be removed along the axis, replaced with a new bulb, and the left and right positions of the bulb can be adjusted (loosen the adjacent set screws) to make the light focus on the low beam surface of the refracting prism without causing significant deviation
8. When the condenser is different, the instrument should be covered with a plastic cover or placed inside the box
9. Users are not allowed to disassemble and assemble the Abbe refractometer condenser at will. If the condenser malfunctions or fails to meet the accuracy requirements, it should be promptly sent for repair.
