Temperature field device comprising a first drum, a second drum, and a filler inside the second drum and a space between the second drum and the first drum

A temperature field device, comprising:

• a bottom plate, a first cover plate, a second cover plate, an observation unit, a first drum, a second drum, and a filler, wherein:
• the bottom plate is mounted on a bottom of the temperature field device and covers an end of the first drum;
• the first cover plate is mounted on a top of the temperature field device and covers the other end of the first drum, wherein the first cover plate includes two first through holes configured to allow a gas to enter into and exit from the temperature field device respectively, rotation central axes of the two first through holes being perpendicular to a horizontal plane or forming angles of 3 degrees-20 degrees with a vertical line of the horizontal plane;
• the second cover plate is mounted inside the first drum and covers a top open end of the second drum, wherein the second cover plate includes two second through holes corresponding to the two first through holes respectively, the second through holes having the same rotation central axes as corresponding first through holes;
• the second drum is mounted inside the first drum;
• the filler is filled inside at least one of the second drum or a space between the second drum and the first drum;
• the observation unit is mounted above the first cover plate and connected with one of the two first through holes;
• and
• a concentricity among the first drum, the second drum, and the bottom plate is less than 1 mm.