Observed repair objects, the temperature range of 170 ℃ ~ 230 ℃, sub-value of 0.1 ℃, with the middle of the bubble and safety bubble. There is a large internal bubble (equivalent to 4/5 intermediate bubble), the amount of mercury on the bubble less. After consideration, the temperature of the low-temperature tank was set to -16 ° C and the temperature of the high-temperature tank was set to 250 ° C. Put the glass thermometer into the low-temperature tank to cool down. When the temperature dropped to -9 ° C, take out the glass thermometer and try to knock a few times and find that the mercury on the bubble is broken into 4 pieces and hangs all over the wall. Think of the heat into the tank can be heated to repair the wall, so first with a low temperature dry cloth on a low-temperature dry cloth wipe the surface of the glass thermometer liquid, then the glass thermometer 1/3 into the high temperature tank to see the mercury Remove the glass thermometer from the exposed thermometer graduation line, all the 4 wall, the repair is over.