First, the extinguisher valve is removed and the threads and interior of the cylinder are checked for corrosion, pitting, and any other abnormalities. [29 CFR 1910.157(f)(3)] If the cylinder passes the visual inspection, it is placed into a steel chamber, which is then filled with water at normal pressure.
Updated April 17, 2017. The earliest dated printed book known is the Diamond Sutra, printed in China in 868 CE. However, it is suspected that book printing may have occurred long before this date. In 1041, movable clay type was first invented in China.
Such money began to be printed for the first time in world history in China during the tenth century. It was continued during the next two hundred fifty years, and taken over by the Mongols during their rule over China (1280-1367).ll of this was possible because we know how to make paper and to print with movable type  inventions which occurred in China. The world's first printed book, which is pictured below, was made in China, 1,074 years ago.