PURPOSE: To make it possible to measure a vacuum degree accurately by attaching a hot-cathode ionization vacuum gage to a standed cylindrical tube and preventing heat generation of the cylindrical pipe during the measurement of a vacuum degree.
CONSTITUTION: To a cylindrical pipe 5, a cooling fin 7, which is constituted of an inner peripheral surface 7a closely adhered to the outer peripheral surface of the cylindrical tube 5, plate shaped fins 7b for enlarging a surface area and enhancing heat dissipating effect and an attaching plate 7c, is attached. This cooling fin 7 is formed into a half-split shape and constituted in sets of two and attached to the cylindrical pipe 5 through the utilization of the attaching plate 7c by a bolt 8. As a result, heat is dissipated by the cooling fin 7 even if the cylindrical pipe 5 is heated by the heater of a vacuum gage and, therefore, the rising in the temp. of the cylindrical pipe 5 can be prevented.
ISHIKAWA YUUICHI
OTAKA KENJI
FURUSE MUNEO
Next Patent: JPS6093936