How to test the appearance of the bimetallic thermometer?

Bimetallic thermometer is a professional measurement - All kinds of medium temperature instrument between 50 to 500 c, wide application, household and industrial use can be. Bimetal bimetal thermometer is, accuracy is very important, appearance is just as important, also a thermometer, precision is the same case, beautiful must be preferred. So our bimetallic thermometer in front of the factory will do the following inspection: 1. Bimetallic thermometer outside surface should have good handling, colour and lustre is uniform, can not have burrs, Nick, crack, peeling defects such as peeling, corrosion and mildew spot; 2. Bimetallic thermometer on the surface of glass or other transparent material may have affect the reading of the defects such as porosity, corrugated; 3. Bimetallic thermometer pointer, table card and its scale, Numbers and symbols should be bright and clear, don't change color and do not fade, there should be no deficiency and influential readings contamination. 4. The pointer of the thermometer and table card should comply with JB/T9252 - And JB/T9253-1999 The provisions of the 1999; Pointer to the length ( The rotary center of the pointer to the length of the needle tip) Should comply with the provisions; Pointer indicating part and the distance between the table card surface is not more than 5 mm; Circular scale for 250 & deg; To 300 & deg; Part of the circle.