Glass rod mercury thermometer glass and size requirement have?

About mercury thermometer glass rod, you must first think of is that we often use a thermometer. In fact is not only a thermometer, because the boiling point of mercury is higher, can measure the temperature of high material, mercury thermometer in industry because there are a lot of use. In addition to the industry, we referred to is glass mercury thermometer. We just met a mercury thermometer, but for the production of mercury thermometer is not very understanding! Especially about mercury thermometer glass rod's basic demands and the size of each part, today small make up you briefly explain for everybody. First is the mercury thermometer glass tube, glass tube surface should be bright and transparent, within the scope of the scale and thermal bubble can not have influence on the reading and the intensity of defect; If glass tube straight, cannot have crooked phenomenon; There is a cross section of a capillary glass should be round, capillary to straight, aperture must be uniform, tube must not contain any impurities, and should be filled with enough pressure in the dry gas. Capillary and thermal bubble, bubble, security bubble joint should be smooth arc, can not have necking phenomenon. Ceiling temperature not higher than 400 ℃, and security bubble at the top of the circle. Then that is the size of the glass rod mercury thermometer, to look at in detail: 1, the zero hour at the top of the line and thermal bubble distance shall not be less than 40 mm; Scribe lines 2, minimum temperature and middle distance shall not be less than 50 mm at the top of the bubble; 3, ceiling temperature scribed line and safety distance of the bottom of bubble should not be less than 30 mm; 4, the lower temperature is lower than 0 ℃ thermometer, the lower limit of temperature and thermal groove distance at the top of the bubble is not less than 90 mm; 5, the length of the thermometer should not exceed 540 mm; 6, glass rod thermometer thermal bubble diameter shall not be greater than the outside diameter of glass rod, internal standard of the thermometer is not big 78 thermal bubble diameter in nakedness casing diameter.