If it is a mercury thermometer, the watermark will not deteriorate and can be used.
Mercury thermometer edible note:
1, before use should be calibrated (can be used standard liquid temperature multi-branch comparison method for calibration or the use of precision more advanced thermometer calibration).
2, does not allow the use of temperature exceeding the maximum scale value of the thermometer's measured value.
3, the thermometer has thermal inertia, should be read after the thermometer reaches a steady state. Readings should be read in the temperature convex curved moon surface of the highest tangent direction, look straight ahead.
4, mercury thermometer should be perpendicular to the measured direction of flow or tilted.
5, mercury thermometer often occurs in the case of mercury column fracture, elimination methods are:
(1) cold repair method: the thermometer's temperature measurement package inserted into the mixture of dry ice and alcohol (the temperature shall not exceed -38 ° C) for the cold shrinkage, so that the capillary tube in the mercury shrinkage of all the temperature measurement package until.
(2) thermal repair method: the thermometer is slowly inserted into a thermostatic bath with a temperature slightly higher than the upper limit of the measurement, so that the broken part of the mercury is connected to the whole column of mercury, and then the thermometer is slowly taken out and gradually cooled to room temperature in the air.
Banning
Considering the mercury hazards of mercury thermometers, many countries have adopted bans on them. As early as 1992, Sweden banned the sale of all medical devices containing mercury. Britain, France, Denmark and the Netherlands have also banned the use and sale. In the United States, 13 states and cities, including San Francisco, Boston and Michigan, have banned the sale of mercury thermometers since 2000.
The European Commission has also banned the sale of mercury thermometers since 2005 and their export since 2011, and in December 2008, the Argentinean government announced it would ban the production and import of mercury thermometers. The World Health Organization has also established the Global Mercury Elimination Program, which aims to reduce demand for mercury-containing thermometers and sphygmomanometers by 70 percent globally by 2017.
But mercury thermometers have not been banned in China. Mercury thermometers are widely used in the medical field and in ordinary households, and are available in some pharmacies.
Data from the China Medical Devices Industry Association (CMDIA) shows that in 2008, the national production of mercury thermometers consumed 109.25 tons of mercury, which is equivalent to the amount of mercury used in 21.85 billion standard mercury-containing energy-saving lamps. According to statistics, the country produces about 120 million mercury-containing thermometers each year, and China has more than 10 tons of mercury disposed of as waste each year due to broken mercury thermometers.
As of August 16, 2017, the Minamata Convention on Mercury came into force for China, which specifies that "the production of mercury-containing thermometers and mercury-containing sphygmomanometers will be banned from January 1, 2026."
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