To measure a pressure of a wide range from an atmospheric pressure to a low pressure region by a single measurement sphere and improve a durability and a reliability, by constituting a grid to operate as a filament of a Pirani gage.
A grid 4 is connected to a Pirani gage operation circuit 12 with the use of an operation change-over switch 14 in a high pressure region from an atmospheric pressure to approximately 1 Pa. Gas molecules introduced from an upper gas introduction opening 2a and remaining in a vacuum container 1 collide with the grid 4 heated by the operation circuit 12 of the Pirani gage, thereby robbing the grid 4 of heat. An amount of the robbed heat is proportional to a pressure in a measurement sphere container 2. A pressure can be measured from a supplied power by controlling a temperature of the grid 4 to a constant temperature. Then, when a displayed pressure of a pressure display part 13 of the Pirani gage reaches a pressure where the ionization gage can operate, the switch 14 is changed over to connect the grid 4 to an operation circuit 10 of the ionization gage, whereby the grid 4 functions as a grid of the ionization gage.
| JP4036751 | Cleaning and etching methods and their equipment |
| JP3086011 | IONIZATION VACUUM METER |
TAMURA YOSHIICHI
OSAKO SHINJI
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