In winter, especially in north China, with lower temperatures, solidification, crystal precipitation and other phenomena will happen for too low ambient temperature when measured medium are transferred to the transmitter through the measuring pipe and the very low ambient temperature is beyond the normal operating temperature range, which will directly affect the accuracy of measuring instruments. However, the measuring medium of pressure, flow, level, temperature and other various instruments is liquid, which is more likely to cause measurement errors when affected by low temperature, even may cause poisoning, fires, explosions and other accidents.
That is why the cold frost work of instrument is particularly important in winter. And some large instruments and meters users have early preparations, for example, power,petroleum, chemical, and water plants have formulated systems suitable for their own business instrument of antifreeze, waste processing and so on.