Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
CALIBRATION METHOD FOR MASS SPECTROMETRIC GAS LEAK DETECTOR
Document Type and Number:
Japanese Patent JP2675954
Kind Code:
B2
Abstract:

PURPOSE: To correct the fixed voltage of detecting gas automatically at the time of measurement by performing mass spectrometric sweeping at the time of internal calibration of a detector and determining the mass spectrum of one compositional gas of the air and then employing a sweeping voltage corresponding to the peak value as a reference.
CONSTITUTION: When a detector is actuated, an applying voltage V1 for detecting nitrogen and an applying voltage V2 for detecting a detecting gas are read into a RAM from a ROM. At the time of internal calibration, a sweep starting voltage Vs and a sweep ending voltage Ve are read into the RAM from the ROM and the applying voltage sweeps between the voltages Vs and Ve. The voltages Vs, Ve are set to cover nitrogen. A secondary ion detecting section detects nitrogen spectrum and a voltage drift amount ΔV2=V1-V1' is determined from the peak position and the voltage V1' at the peak position. At the time of measurement, nitrogen concentration (b) is read in from a memory and after the voltage V2 is corrected by ΔV2, detecting gas concentration (a) is measured. Various characteristic fluctuations are eliminated by dividing the concentration (a) by the concentration (b) and the detecting gas concentration is determined by multiplying a/b by a constant k.


Inventors:
Fujiwara, Koichi
Kuwano, Hiroki
Application Number:
JP1993000011011
Publication Date:
July 18, 1997
Filing Date:
January 26, 1993
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
NIPPON TELEGR & TELEPH CORP <NTT>
International Classes:
G01F25/00; G01M3/00; G01M3/04; G01N27/62; G08B21/00; G08B21/16; H01J49/26; (IPC1-7): G01N27/62; G01M3/04; H01J49/26